I’ve been meaning to get to this for a while, and finally tackled it this past week. Herewith, a tutorial on using the ‘Curves’ function in many image editing programs to adjust brightness and contrast within an image, selectively as needed.
As noted therein, this won’t work very well if your monitor is poorly calibrated for brightness, contrast, and gamma, so it’s recommended to tackle this first if needed before making any adjustments to your images. You can find a guide with useful images at https://w4zt.com/screen/.
One of the benefits of Curves is that it maintains a gradual change, with neighboring or flanking values within the image receiving some effect too, so no single area becomes drastically (and noticeably) different from another, a sure sign of manipulation and, too often, creating an unrealistic and bizarre appearance. It can still occur though, so keep an eye on all areas within the photo when doing editing, to spot those little patches that can sneak in and look out of place.
I said it several times in the video and now I’ll put it in writing: be subtle. When editing, it’s very easy to keep pushing things a little farther, since we seem to become insensitive to how far is ‘too far,’ so I recommend setting aside the edited version for a little while, looking at something else, and coming back to it fresh to see if it still looks acceptable. These suddenly renewed ‘first impressions’ can count for a lot, because anyone else may have that same first impression.
Also, you can use the various selection tools within your editing program to pick portions of the image to tweak in Curves while leaving the rest alone, which could have been done with the trees at sunset example – just be sure to Feather the edges of the selection to fuzz out and make the border of the selected area indistinct, otherwise if will often show very clearly.
Part 2 is coming next week (I think,) and involves using Curves for color corrections, as well as some creative editing. Meanwhile, this post documents one of the most specific adjustments that I’ve performed, as an extreme example. Yet to me at least, it still looks more realistic, and less doctored, than some of the fartistic approaches I’ve tried. Which is still fine, but those latter examples cross the personally-drawn line between a photo and a digital creation – you may have your own line, or none at all, but I still feel that accomplishing it “in-camera” is where the real skill lies.
Later weekly posts in the Tip Jar topic will expand on some of the things covered here, so I wanted to establish a baseline of knowledge first, for those who haven’t used such functions before.
The other day (well, eight days ago) when The Girlfriend and I were out doing various property tasks, she came across three nearly identical finds that remain a small mystery, one I may be attempting to solve as I find the means to do so. To wit:
Right in one of the paths through the less-traveled sections of the property, she came up with this, the carapace of, most likely, a common musk turtle (Sternotherus odoratus.) While it was a warmer day, it had recently been quite cold, and so unlikely for the turtle to be out and about on its own for any reason, nor was it likely that this had been in the path since the time when it would have been out.
And another, smaller, but same species; we can tell by the faint ridge along the spine, and the small plastron:
Any of the other species in the area that might have a carapace similar to what we’ve seen would also have a plastron (belly shell) larger than this. Noticeable upon close inspection, however, was that these were fairly fresh, and by that I mean, had been in possession of their living owner until relatively recently, since remnants of flesh were still within, not fully dried out nor scavenged by ants.
In fact, a third that she’d found still had ants working on it, and so did not get photographed in my palm like these. Even I have my limits.
What’s curious to me is, what was digging up turtles hibernating for the winter, most likely in the mud at the edge of the pond, to eat them so recently? I was vaguely suspicious of the white ibis, since a few days earlier it had spent the entire day on the property, but this isn’t the kind of meal they tackle, nor is their beak made for this; they swallow prey whole for the most part, and certainly couldn’t section out a turtle. So I’m leaning towards raccoon, because we’ve seen them here and this might be something they’re adept at finding. Certainly not the nutrias or the beavers, which are both vegetarian. Also odd that the turtles seem to have been eaten in roughly the same time frame, all left out in the open in plain sight.
Most such activity, of course, would take place at night, and while I’ve been out quite often at night and caught glimpses of various critters, the opportunity to actively observe them hasn’t been there, given that a) they’re usually aware of me before I’m aware of them (though not always,) and b) I don’t have that night vision thing going on. There are options and I’m working on a couple, but the property is also quite large and so covering any decent portion of it is tricky. We actually did have a camera trained on the backyard and pond edge, which may be back in operation within a week or two, but it was so distant from the pond (wide-angle lens, of course,) that its motion sensor probably wouldn’t be triggered by anything smaller than a deer. Still working on it all.
The same day as the turtle shell finds, the late afternoon light was great and the wood ducks were congregating at the pond edge, so I slipped upstairs and managed to open the window without spooking them, and thus got a few nice portraits while their feathers were shining in the bright sunlight. Usually they avoid such conditions but, you know, corn…
These were at 600mm focal length but quite far removed from the ducks, so this is tightly cropped but not bad for that. The color palette is what I was after, and this shows the iridescence of the head feathers, the muted blue iridescence of the wings folded across the back, and a faint hint of the very fine stippling that adorns their sides (seen in better detail here.)
And then a couple of direct portraits.
I like this one for the reflection, which is almost ideal, a chance timing thing when the rippling of the water was just right. I could do without the intervening branches (I say that a lot, don’t I?) and it would be nice if the water reflected greenery instead of the winter browns, but hey, I’ll still take it. and the next is better, I think.
Better light and head angle, even if we don’t have as much of the colors. It’s funny: we’ve unintentionally conditioned the nutrias, and to a smaller extent the beavers, simply by putting down corn for food, but the wood ducks haven’t even begun to habituate since they always flee at the first sign of us in the backyard – they don’t even realize it’s us that distributes the corn since they’re well out of sight before this happens. So my attempts to get closer portraits (and a wider variety) is not progressing much at all. The ducks, in fact, inhibit a lot of work I might do in the backyard since I hate to spook them. Then again, I remember what I was considering a little over a year ago, and it didn’t realistically include the ducks being right freaking here, so I can cope, even while I keep trying.
Just two this time, even though the last sorting session was pretty hefty – I just featured most of what I liked at the time that I took them (well, in a reasonable time frame thereafter, anyway.) So we only have these:
One of several images taken of a roseate spoonbill (Platalea ajaja) while at Sylvan Heights Bird Park, I liked this perspective just for how it highlights the beak, and the fact that the bird could easily open paint cans if it so desired.
And this one, same place:
With this, I discover that I’ve never featured a scarlet ibis (Eudocimus ruber) before, even though I have images of them dating way back, like mid-nineties or thereabouts. I could have done without the background, but while three of them were preening identically while all perched in the top branches of a tree, I had to snap the image – the one at top is in juvenile coloration. Part of the reason I have not featured these before is that they’re not native to the US; though they might make the occasional appearance in south Florida, they’re native to the Caribbean and South America, so all of my pics have been captives in one place or another.
And I realized a short time back that, while I announced a potential solution to autofocus woes during video in two separate blog posts, I think, I never followed through. I’d switched to using the camcorder for the night work with the nutrias and beavers, refining that option until it was working quite well, but I also improved the use of the long lens for the daytime work with the ducks et al, and that was by obtaining a Canon 70D body instead, one that does allow autofocus while shooting video. That’s what these, and all of the video from the bird park, were shot with, and it works quite well.
Credit where it’s due, since this was a christmas present from The Girlfriend, even though I was the one that not only picked it out (at her insistence,) but sealed the winning bid – she gets too anxious with sniping on eBay. It arrived a couple weeks before christmas, and I got a short while to test it out and ensure that it was in working order, then it got packed away until the 25th because early presents are verboten. But in that time, I bought myself the battery grip, batteries, and large memory card.
A note about Canon’s naming/numbering conventions: Normally they’re a little backwards, in that the high-end bodies are single digits (like the 7D) while the more basic, lighter-option models are often in the hundreds. I was shooting with a 7D (still am, really) and then received this 70D which is clearly an upgraded, high-end model, and after getting used to this naming convention I keep getting mildly confused when unloading either body. It does not help that the memory cards themselves are named identically (“EOS DIGITAL,”) so I have to remind myself of what I’m doing constantly.
But yes, actually having autofocus while shooting video is a major boon, though why this wasn’t included in the earlier bodies I don’t know, since the HFS-100 camcorder that I’m using is way older and manages it just fine. Probably something to do with being a DSLR. Regardless, I’m able to shoot video without constantly keeping my hand on the focus ring, which likely contributed at least a little to the large number of video clips that I also had to sort through this time. The real culprit, however, was having so many subjects easily at hand. Gonna need to upgrade harddrives in the workhorse computer soon…
Fairly basic one this week, since I have several that I’d like to tackle that will take more preparation than I have time available for right now. So we’ll talk about one of the staples, and that’s ISO, formerly (unofficially) known as film speed.
Short explanation: ISO refers to how sensitive the digital sensor (or indeed, the film) is to light; the higher the number, the more sensitive it is and the less light is needed to achieve a “proper” exposure, and that’s in scare-quotes because there is no such thing. There is an average, though, and that’s what camera exposure meters and light meters are calibrated to produce, but since not every scene or subject is average, they can’t always produce the ideal exposure, and it’s up to the photographer to accommodate these shortcomings.
Long and technical explanation: ISO actually stands for International Organization for Standardization – yes, that’s correct, I initially thought it was that way for the French version, but that’s not abbreviated ‘ISO’ either. It’s a system of rules to have all the different countries and cultures using the same measurements for everything, and you might already have experience with ISO 9001 with corporate culture, or other numbers if you’re into engineering. For photography, technically it’s ISO 6, or even 6:1993, and is a direct translation from ASA; ASA 100 films and ISO 100 settings on digital cameras have the same light sensitivity. You will likely never have a need for this info in your life, but at least this answered that idle question.
ISO progresses much the same way as shutter speed, so ISO 200 is twice as sensitive (requiring half as much light) as ISO 100. From there, 400, 800, 1600, 3200, and so on; these are typically called, “stops” or “EVs: for “Exposure Values.” Most cameras can be set for values in between these, such as 320, and these are subtle differences, partial stops or partial EVS, but even so, the math holds up: ISO 640 is twice as sensitive to light as ISO 320. We just deal with the whole hundreds because it’s easier overall, and ISO 100 is considered the base setting.
Generally, the way it works is, if your meter indicates that the correct exposure is f5.6, 1/50 second shutter speed at ISO 100, but you want a faster shutter speed to prevent blur, you could change the ISO to 200 instead and now use a shutter speed that was twice as fast at 1/100 second. Or keep going – ISO 400 and 1/200 second, ISO 800 and 1/400 second, and so on. Simple!
Only, like everything in photography, there’s a tradeoff, and the tradeoff in increased ISO is decreased quality and resolution. The simple guideline is, use the lowest ISO you can to get the shot – but get the shot.
2x resolution example of high ISO image degradation in a night sky exposure, the blotchiness in the dark areas, as well as the noise of bright red and blue pixels – the brighter grey and white pixels are stars and actually belong there.The funny thing is, for both film and digital, the effect of increasing ISO is almost the same, even though they use entirely different ways of capturing light. Mostly, it’s increasing blotchiness and ‘snow’ in the shadowy areas where there’s little light, but digital sensors also suffer from ‘noise,’ which is singular pixels of bright colors, very often in the exact same place in every photo.
Brief, and probably none too accurate, explanation: digital sensors work by converting light energy into electrical. When you boost the ISO higher, you’re attempting to read tiny voltages from the sensor and amplify them. But the sensor doesn’t just pick up voltage from light, but also from other sources of electricity (including the other parts of the camera itself, and static charges from the air,) as well as minor manufacturing defects that cause the sensor to be less than uniform. In scattered cases, individual pixels in the sensor produce a “full brightness” response to no input at all, producing red, blue, or green dots in an otherwise dark field. While in film, the chemicals that crystallized under light also had variability, causing small splotches of brighter regions usually referred to as “grain.” Just not the bright specks of “noise” that digital sensors produce.
This is mostly visible in shadowed or dark areas of the exposure, but could also show up visibly across the gentle gradient areas if the ISO is really high. And this blotchiness can also reduce the sharpness of the image, faintly blurring the edges that should be sharp.
Also, longer exposures give the sensor more time to register stray electrical charges, and so the noise will often be worse.
In short, avoid using higher ISOs as much as you’re able. But there are certainly times when you need that edge.
Note: complicated, detailed subjects will often hide the effects of high ISO, and you can get away with it more while shooting such subject matter. Conversely, large areas of the same tone or very subtle gradient changes will show the effects much worse. This is especially true when doing night sky exposures.
So, how high is too high? There’s no easy answer to that. Part of it depends on the camera itself, since manufacturers are constantly trying to improve the ISO response in their camera bodies (mostly in the image processing portion, since the sensors themselves undergo few changes.) And part of it depends on your subject matter, as indicated above. Part of it depends on how large you will be displaying the resulting image, or how far you will enlarge portions of it – if you’re reducing the entire frame down to web resolution, you may notice nothing at all. And part of it depends, quite simply, on how picky you might be.
ISO 800 with the old Canon 30D, alongside a 2x resolution sample of the sky at upper right. Acceptable at web resolution perhaps, but probably not as an enlarged printIn cases like the one above, the high ISO effects showed in the sky more than a little, but blended into the sand and driftwood. If you desired to make a larger print of an image like this, some editing might be in order, otherwise that ‘grain’ in the sky could be too noticeable.
There are some things you can do to cope. First off, you can occasionally avoid using a higher ISO altogether by using a tripod instead, or even just going with a wider aperture to let in more light that way. But if it’s a choice between blurring the image from camera shake during a handheld shot, or dealing with ISO grain, go for the gran every time – you can even use it to artistic advantage in a few cases. Some cameras have a Long Exposure Noise Reduction option that may be worth a try; I’ve only used this a couple of times with night shots, but the processing time took as long as the exposure did and thus prevented me from getting shots in the interim, not ideal when you’re hoping to catch meteors, but perhaps still worth a few experiments.
In the shot above where the grain shows most noticeably in the sky, you can often smooth out this blotchiness in an editing program: select by color range and pick the worst areas of the sky, and feather the edges of this selection by several pixels (perhaps as high as 20 pixels if doing this at full resolution,) then Blur your selection by 1.5 to 10 pixels or so – season to taste. You might have to do this for a couple of sections, just be careful about overlapping into the detail areas such as (in this case) the driftwood or the horizon line.
Sensor noise, especially during night exposures, can be eradicated almost entirely with editing – I have a page on this already. Just be sure to obtain a recent baseline noise register, because sensors will degrade slightly over time and more noise will creep in, so re-using an old noise baseline might miss the new noise pixels.
I recommend doing a few experiments with your camera with different scenes, but most especially something with distinct dark or shadowed areas, and keep boosting the ISO up to the maximum the camera will allow, then check out the results carefully on a larger screen (not the camera LCD, for dog’s sake!) In my experience, the highest usable setting for decent results is two stops below what the camera can achieve, so if your camera’s maximum is ISO 6400, you may want to avoid anything higher than 1600, but use your own judgment. Again, the amount of gradient or dark areas and the end usage may dictate your limits better than an overall rule.
And on occasion, you can take a horribly grainy image and do something creative with it. Simply converting to monochrome may make it acceptable, solely because we expect B&W images to be grainy sometimes, from experience with very old photos. A little later on, I’ll have a tutorial on selectively smoothing portions of an image in an editing program, a slick little trick.
Hopefully this was helpful in at least some way, but more advanced stuff will be along. Good luck!
I’m supposed to be working on the weekly post right now, but I heard a noise outside and, since it was nearly 11 PM, I thought I’d check – you only get one chance to be eaten by a bear, you know? Though despite my cavalier attitude in the preceding sentence, I was cautious and went out slowly, checking the area with the headlamp carefully, finding nothing at all that might have made the noise. Doesn’t mean much – could have been a falling branch or something of that sort. But on returning, right alongside the door into Walkabout Studios I found a small frog, surprising me a little even though it shouldn’t have. I managed to capture it and bring it in for a studio session, for which it was not at all amenable.
This is a spring peeper (Pseudacris crucifer,) and while it’s February, it’s also supposedly 10°c out there and raining gently, though it feels a couple of degrees warmer to me. Peepers definitely get an early start in the spring, or in anything that seems like it, so this wasn’t as odd a find as I initially thought upon seeing it. This is one of only two frames taken in the shallow dish that I use as a ‘setting’ for studio work with little critters, and I only managed two because this little guy wasn’t having it, and would pause for no more than ten seconds, usually less, before leaping away. Which is why I was doing this in the bathroom, since this provided a lot fewer places to hide. The first frame that I obtained was this:
Yeah, that’s a small scrubbing brush on my sink – the peeper continually leapt away towards the wall over the sink, and so I surmised that it was aiming for altitude, trying to climb higher, and switched over to another setting.
This is almost an acceptable natural setting, if I crop out the teal planter edge peeking in, and if you’re ignorant of the plant species, which is a neverdie (Kalanchoe crenata) and native to Madagascar, which these frogs are not. It was what I had available indoors that might serve to disguise the background, but the frog wasn’t any happier on this and kept leaping to new positions, so I gave up after a few minutes and went to return it outside. There, I thought I’d make one last attempt, and carefully coaxed it onto the coral bark Japanese maple, thinking it might be okay for a short while in the tree. Set the transport container down, switched on the camera and the flash, turned back and… gone already. Nowhere in the tree, and the ground around it was ideal camouflage for something the size of a smaller coin, so I figured I was done with this subject.
On a whim however, I decided to check out some of the other trees, because the conditions were kind of encouraging to peepers, and this did indeed pay off.
This is a neighboring tree, actually the dead one that nonetheless served as a favored roost for one of the Carolina anoles throughout the summer and fall. Just a little too far to be the same frog seeking shelter from the annoying paparazzi, and actually the second of three that I found with only casual searching; I even heard a couple of sporadic calls.
I figured I’d take a few minutes because it really wasn’t bad out and there wasn’t anything that I should have been doing instead, and found something dangling from another tree, firing off a few frames of this new subject.
Seeing the pale grey color with the legs dangling and watching it twist in the tiny breeze, I figured this was probably only a molted exoskeleton, but after a few moments it reanimated and scrambled back up the web strand it was dangling from.
Some form of tiny crab spider (Thomisidae,) though I wasn’t shooting with the macro lens nor inclined to do a full study, so this is all we have. Spiders are surprisingly cold-hardy as well, often reappearing at temperatures even lower than this. Had I not already released (lost) the peeper, I would have collected this spider to provide a meal to the frog, just to show there were no hard feelings. Well, towards the peeper – the spider would have been shit out of luck.
Finally coming back inside, I stopped right near where I’d first found the frog and checked the Magic Bucket, the trash can right outside my door for all the smellier, fume-ridden things I produce with my various pursuits – it only had a couple of paper towels and a small dead beetle in it, but as I shook it gently, this little guy popped out.
Yep, another Carolina anole, which means that even in winter I should be checking this damn thing regularly. No idea how long it might have been in there, so I carried it over to the greenhouse (where several of its brethren are already spending the winter) and dropped it off inside – there would at least be a certain level of warmth maintained by a small heater, as well as plenty of water and whatever little insects happened to be available, especially since on the warmer days we open the vents, and the citrus trees are still blooming and attracting pollinators.
Once again, we find ourselves (that’s the royal “we,” not [necessarily] including you) on Darwin Day, without anything prepared to show for it. I have long maintained that we should be celebrating the scientist on some other day than his birthday, since the dead of winter is a hard time to find topical content. The fictional readers that I insist are real shoot back that I’m being too narrow-minded on how to interpret Darwin’s contributions and am, instead, just shitty at planning ahead.
Aha! say I in return, in this inner monologue that would never take place in real life, Natural selection hasn’t anything to do with planning, but with pinning down the singular trait that just barely squeaks by. And so a tailor-made post is actually counter to the entire concept, a lot more like that nonsensical and self-indulgent ‘religion’ that, despite the plethora of evidence that species are not very well designed at all, still gets bandied around, probably because of the traits that wiggled us as humans through the selection process. Thus, to celebrate this day properly, what we need is something that allows this post to survive, if only by millimeters. And since the selection process for all content is, solely and entirely, “me,” well…
In the days running up to (and including) Darwin Day, came several demonstrations of how natural selection actually works. Really. Stay with me, here.
Back in January, I snagged this image of a camellia blossom right alongside the front door.
The camellia (Theaceae) bushes bloom quite early, generally while it’s still winter, and this one in particular shows a distinct difference in color between the cold season and the warmer months when we expect to see flowers – you can see a hint of the variegation that they display now, but they will go solid pink in spring. And as the temperature climbed into the “only chilly” territory, it nonetheless attracted a European honeybee (Apis mellifera) to pollinate it, making it the first of the year in my personal observation, which might have been more notable had I actually posted it back on January 9th when it was taken.
Despite this response in the winter months, however, camellia blossoms don’t actually tolerate sub-freezing temperatures, and the heavy snow and persistent cold temperatures that we received recently changed the appearance of the flowers drastically, so they looked like this yesterday:
The question remains, can the reproductive process that the flowers facilitate survive the temperatures if the pollination occurs before such temperatures arrive? And I cannot answer that, because I thought of the question specifically for Darwin Day and not back in January when I could have marked that particular branch to see what happened. Yet, while all of the opened flowers were affected in the same way, some of the later buds (like the one at right, also taken yesterday) are beginning to emerge, showing no signs of damage from freezing, so we have to surmise that the enclosing leaves are better proof against the cold temperatures. This suggests that camellias found a niche of being the first to attract pollinators, with virtually no competition, as soon as the weather is warm enough, but still capable of handling the variable nature of, well, nature, specifically temperatures toying chronically with freezing.
You think I’m reaching, don’t you? Psscchhfftt. This is selection at work. And speaking of pollinators…
The winter speedwell (Veronica persica) blossoms always arrive about this time, though they’re so tiny and occur in such small patches that they’re easy to overlook. These obviously aim for certain pollinators too, though I doubt it’s honeybees, given the size – they’re about the same diameter as a bee, so I’m not even sure they could support the weight of one. I really should’ve staked these out to see what does visit them, while the weather was warmer, but yesterday when I shot this it wasn’t Darwin Day, so it didn’t occur to me. I could do it today, but then I’d probably never get this post done, and thus it would defeat the purpose ironically.
Close by, a sudden movement on the liriope attracted my attention, and only a moment’s examination netted this guy:
Whatever does pollinate the winter speedwell stands a chance of being preyed upon by the Carolina anoles, since they don’t waste any time getting active as soon as it’s warm enough, either. I can’t say that this is the first I’ve seen this year, since several days in January got warm enough (generally, sunny and above 12-14°c) to bring them out in search of the early-appearing insects. It’s a cutthroat world out there.
Still speaking of pollination…
Looking out at the pond this morning, we saw these two Canada geese (Branta canadensis) hanging out on separate little islands in the pond – the one on the left definitely seems to be settled in, and was snoozing when we first spotted them. You can also see that the beavers have been working these islands over too, which as yet remain nameless, but this may not be for very long.
Given that this one was asleep while the other was standing and watching, I’m guessing this is the female, and she certainly seemed to be settled in. We’ve had plenty of geese visiting, several distinctive regulars, but to date no one has shown any indication of wanting to build a nest, though we’re hoping this is a good sign, and it’s an ideal spot for one: decently subtle, but completely isolated from predators, and of course very handy to the food. I considered it still a little early for mating season, but not by much.
Did you catch the past tense in there?
A little after this when I looked out the downstairs bathroom window, which has a good view of the north end of the pond that sits well to the left of this spot, I saw two geese side-by-side, head to tail, dipping their heads in the water almost in unison, and I wondered if this wasn’t courtship behavior. In only seconds, this was confirmed as they mated, and so this is a very good sign, especially since a little later on we found them both back in the same spots. We’ll be monitoring this development closely.
So there, see? Selective pressures produced a post that suffices and survives, possessing the traits necessary to maintain. Not at all an excuse to just throw up some recent pics, but topical and demonstrative. Isn’t nature wonderful?
The day is quite warm today, as in, no jacket required, and The Girlfriend and I were checking out the property, mostly tallying the beaver activity, which will come along in a later post since it’s on video. But right near where the ibis had snagged the suspicious, eel-looking thing, I was remarking about wanting to drag a net through the shallows in the spring to see what could be dredged up, when I spotted something, again, suspicious-looking, and fished it out of the debris at the edge of the pond. It was an exact match for the ‘eel,’ what I could make out in the earlier pics anyway, and changed my mind about the species.
The little legs, at least, indicated that this was a salamander of some kind, but the lack of dorsal and ventral fins added to that. I wasn’t at all familiar with this species, especially not one as big as this, and it was big:
That’s 38cm in length, so I can perhaps (probably not) be forgiven for mistaking it for an eel, since my experience with salamanders has been with specimens less than a third this length, with much more noticeable legs. However, this is likely a two-toed amphiuma (Amphiuma means,) and they can get much, much larger than this – like, better than a meter! They are also occasionally, colloquially, referred to as, “conger eels,” so I’m not the only one making the mistake, though granted, comparing myself to the ‘locals’ isn’t doing me any favors
A better look at the forelegs, and we’re being generous to call them, “legs,” really. But we need a closer look at the ends of them, so we crop much tighter and go full-res:
Now we can just make out where the name comes from, but it’s probably safe to call these, “vestigial.” We’re not going to see them climbing trees with these, is what I’m saying.
This is exactly their habitat, though, and I’m a little surprised not to have found any before this, but I’ve also done very little in the pond, and will likely be correcting this in the spring when the water’s a bit warmer. Meanwhile, looking this up has made me realize that I don’t know a lot about the various salamanders in the area, though the vast majority of species in NC are all mountainous, and often very specific portions thereof to boot.
A look at one of the hindlegs, as well as what appears to be some damage from a potential predator. It’s possible, given the location and its presence right near the surface, only partially hidden in the debris, that the ibis had found this one too, but discarded it as being dead too long. Or perhaps it had gotten interrupted, since we were under deep-cooling to frozen conditions while the ibis was hunting – my specimen doesn’t seem too degraded.
Anyway, that’s one mystery solved, and another set of goals for the spring. And maybe dinner tonight…
Today we’re going to talk about something that nearly every modern camera has, some better than others, but also has its faults; specifically, so you know when it might become undependable and when to shut it off.
Autofocus has come a long way since its first application, but it still remains easy to fool in certain circumstances. Let’s begin with a little understanding of it. The most basic property is, it needs a certain amount of light to work – once the view gets too dim, the autofocus sensor within the camera body cannot adequately resolve the contrast that it needs, which is why nearly all lenses available today have a maximum aperture or f5.6 or larger (in some cases, f6.3, which seems to define the limit.) It’s better if the lens has an even larger aperture, which in the seemingly-reversed terminology of lenses/apertures is a smaller number, like f4 or f2.8. Zoom lenses will often be listed as a range of numbers – in the example at right, f3.5 to 4.5 (the “1:” can be replaced with “f” – all of this is explained here.) What this means is, the lens has a maximum aperture of f3.5 at the shortest focal length, one end of its zoom range, and f4.5 at the longest, the opposite end. These are, however, only the maximum apertures, while the lens may reach f22 or f32 throughout its zoom range as a minimum aperture. The reason only the maximum aperture is listed as a basic specification is to show how much light it can admit, and autofocus benefits from this. Autofocus sensors work by adjusting the lens focus until the maximum contrast is achieved.
But what exactly does this mean? Well, sharp focus is actually about contrast between different colors or brightnesses within the image. A sharp image has nice, distinct, and very specific delineations between these contrast areas, while an unfocused image blurs these distinctions and the contrast becomes a gradient, muddy and indistinct. The only thing autofocus does is adjust the lens focus until this contrast is as high as possible – within the sensor’s active area, of course.
[Caveat: Some Nikon cameras have a ‘phase-detection’ autofocus that instead relies on two microlenses with some separation between them working together in a form of depth perception, or old rangefinder focus aids if you’re familiar with those. I have not had the opportunity to use this at all, much less at length, so I can only go on the claim that this is supposed to be faster and more reliable than contrast detection, though I imagine some of the situations below would still provoke issues or failure to focus.]
Too little light, however, means that the sensor cannot distinguish the contrast well enough, and may ‘search’ by continuing to focus the lens in and out, or may select the nearest region with contrast that it can detect, or it may simply balk and not do anything. This is why lenses with those larger apertures (smaller f-numbers) are more sought after, because they let in more light and allow better focusing (even manually.) Even then, it doesn’t always work.
[Note, too, that the lens remains at maximum aperture for the focal length in use, regardless of the aperture setting chosen by the photographer, until the shutter is tripped, in which case it closes down to the chosen setting in milliseconds right before the shutter opens. This way, the autofocus and the viewfinder receive the maximum amount of light to focus. This has the added benefit of maintaining the shortest depth-of-field until then as well, making it easier to know when focus is on the correct spot.]
So too little light will prevent autofocus from operating effectively – and so will too little contrast at the chosen focus point. Should a subject have only subtle contrast or color variations, or blend in too well with the background or foreground, the autofocus can easily get balky. Autofocus assist lights exist on many cameras and some flash units, and these add light as needed, often in infra-red so the light isn’t noticeable, but you’ve likely seen how your smutphone will use illumination to focus and can even see it in action on the phone screen. However, these lights usually have a very limited range – a few meters at most – and can still be thwarted by a low-contrast subject. The solution to this, fairly often, is to look around in the immediate vicinity to see if something the same distance away has better contrast and use that to lock focus onto, then re-frame the shot and trip the shutter.
Autofocus can have several different settings, however, and any photographer doing action shots of any kind usually selects a mode that means the autofocus will attempt to keep up with the action – this means that picking another subject, or portion thereof, and trying to reframe will simply cause the camera to change focus as it detects this ‘action.’ Changing autofocus modes can help, but might cause a precious delay when trying to get the shot.
There are also cases where a subject is very small in the viewfinder and moving too much to keep well centered within the AF area, and so the autofocus then tries to grab something else with adequate contrast; this happens a lot in my field when tracking a bird in the air and it crosses the horizon line, which is larger and features more contrast.
One solution, which is active on my camera bodies, is to assign a particular button on the body to stopping autofocus – Canon, at least, allows this to be set on most bodies that have an AF button near your right thumb. Once focus is achieved (and the subject is not changing distance from the camera too rapidly,) holding down this button stops autofocus entirely while it is held, preventing focus searching. Naturally, this only works if focus is adequately sharp when the button is pressed.
As mentioned, a very small subject can cause autofocus to ‘get confused,’ since its sensor area might be receiving contrast from the subject or its surroundings, especially with handheld cameras that can twitch a little too much while aiming (magnified several times over with longer focal lengths.)
Normally these are discarded and so I have no examples handy, but this was recent…And most notably (and frequently from a nature photograph’s perspective,) something in the foreground or crossing in front of the subject can cause autofocus to try and select that instead: foliage and branches, or other subjects passing in front of the chosen one, or the chosen one passing behind any such obstructions. And you’ll notice, with the example at left, that the branch has higher contrast from the background than the body of the ibis, though not the beak.
What to do about these? Well, there are several options, though none that will handle or be useful for every situation. One of the first is, if there is a focus limiter on your lens, this can help prevent the long focus search when AF can’t lock on, racking all the way out to ‘infinity’ and back down to closest focus, during which you may lose sight of your subject entirely and even lose it out of the frame. This is most useful with long focal lengths, and such a limiter switch is found more often on those.
An appropriate AF mode for your subject matter helps a lot, as well as knowing how to switch them quickly. Most cameras have a ‘Single Shot’ mode where the lens will autofocus only once until it locks onto a particular distance/subject, and will hold this until the shutter is tripped; in order to get it to re-focus, the shutter button must be released (lift your finger) and repressed. Then there are different forms of active or tracking autofocus, intended for moving subjects, where the camera attempts to predict where to keep adjusting based on the previous movements. Certainly, some of these are better than others depending on what kind of subjects you pursue, but none that I have ever tried are free from issues and just plain inability to focus.
One of the more distinctive options that you should be prepared to exercise, at any given time, is simply turning the autofocus off. When the camera is doing nothing but focus hunting without ever locking on, or when you’re not particularly sure the focus actually locked onto what you intended, or if the key focus point is very small and distinctly different from the surrounding area (this happens a lot with macro work,) just turn it off. For this reason, I encourage everyone to know where the AF switch is on their lenses or bodies, and be able to find this by feel without even looking; lens manufacturers don’t exactly help this by being inconsistent with where the switches are on the lenses, or not making them distinctive enough to locate dependably by feel (much less switch on and off with gloves on, for instance.) But when you need it, you need it, and it should be considered a viable option the moment you can’t achieve autofocus.
For this to work, however, you need to be able to see clearly in the viewfinder. Most cameras have a diopter dial on the side of the viewfinder window, and you use this to adjust the viewfinder view until its the sharpest that it can be to you. The best way to do this is to use autofocus to lock onto an easy subject with very distinct contrast and sharp lines, preferably on a tripod, and then adjust the diopter dial until the view is sharpest. And be aware that it’s still possible to bump this damn dial and fudge your setting, which you may not realize until its crucial.
There’s also the idea of focus bracketing, which means, taking several frames while making fine adjustments to the manual focus in between; I use this all the time when doing sun or moon shots, to ensure that focus is as tight as possible (it does not help that the Tamron 150-600 that I’m using for such shots has a very twitchy focus ring, where infinitesimal tweaks can have more radical affects than they should.) Some cameras even have this as an option, while many lenses allow you to tweak focus manually even while set for autofocus, which can be handy for pinning down that tricky subject, as long as the lens does not keep competing with you to select something else as soon as you’ve pinned down the focus that you want.
A small variation of this technique with macro work is to switch to manual, get close to the ideal focus, and then move the camera until the focus is perfectly sharp, which really only works with the very short depth-of-field that macro magnifications provide. This is fine with tripod work, especially with a macro slider that allows very fine adjustments to distance, but it’s a lot trickier handheld; nonetheless, I do this quite often, solely from the convenience of getting the shot immediately, but I also fire off several frames to try to ensure that at least one of them is bang-on.
A smaller aperture to increase depth-of-field can help reduce or eradicate those situations where focus wasn’t quite as precise as intended, though this is not something to rely on – a high depth of field reduces how quickly or noticeably something goes out of focus, but if the image is not focused properly, it can still be visible.
And while we’re on the subject of macro work, any method where you can increase the amount of light to focus with can help a significant amount, which is why I do ‘macro studio’ work on a desktop with bright LED lamps, even when the image lighting is provided by a flash unit, and will use auxiliary focus lighting in the field wherever possible.
On occasion, you may find that autofocus just doesn’t seem to want to work correctly, regardless of the conditions; personally, I’ve found that either poor contacts between the camera and lens, or an unclean focusing mirror are the most common culprits, and I’ve addressed these in detail in this post. Since then, I’ve also stumbled upon the discovery that poor contact with the camera battery occasionally throws some balkiness, usually fixed by either reseating the battery or by cleaning the contacts on that.
Hopefully you’ve found something herein that will help improve your autofocus performance or results. Once again, good luck with it!
Finally, we have the video that I kept mentioning and never actually producing, but when you see the length of it, you might understand. I actually had 42 separate video clips set aside just for this compilation, though I don’t think I used all of them. At the same time, I started cataloging all of the video I’ve been shooting into a spreadsheet, so I can find specific clips a lot faster.
So let’s go to the video first – headphones are recommended because of some of the quieter sounds captured:
As I said, there was about a month of observations in there, though not every night, but a couple of really active evenings when I hadn’t bothered to bring down the camcorder convinced me not to forego this anymore. The juveniles have become inordinately bold, as you can see, but we’re fairly certain they’re still not sure that it’s actually human beings doing all this, or that we’re that close – the headlamps (and their terrible vision) may prevent them from realizing this. When the pond had frozen over we’d gone down a couple of times in the day, and the nutrias that had been out made haste for safety across the pond, at one point to my great amusement because a couple of open patches of water existed, but not a complete path back to the woods where their lodge sits (somewhere – I haven’t located it yet.) One adult and one juvenile were there and scampered off, first swimming across the open patch, then scrambling onto the ice to run the rest of the way. The juvenile made it onto the ice without issue, but the fat damn adult had to make several tries because it kept breaking away the edge of the ice and got left far behind its offspring. Even the highly recognizable sound of the corn being distributed failed to halt their escape, but as I said in the video, it would appear that they consider the water “safe,” since they can dive and not many of the things that might prey on them can negotiate it (we don’t have alligators around here, unfortunately – I’d have even more of a blast with those to chase.) While the juveniles can get a fair turn of speed on land, the adults seem only able to manage a fast waddle, so they’re much more vulnerable.
The current status of the night video rig deserves a gander:
I’ve covered the flashlight holder on the underside before, and even the parabolic microphone, but now they’re all mated together onto a monopod, which greatly increases both the stability and the quality of the sound captured. Most especially, the near-eradication of the traffic noise (and most other background noises as well) has made the parabolic mic a worthwhile addition, even if it can’t capture the lower registers very well; this might actually be serving as an inherent low-pass filter.
[Quick notes on all that. Many mics have a low-pass filter that cuts out the lower frequencies, which is where a lot of the background noise actually sits, especially wind and traffic, though the lavalier mic that I have attached to the parabolic dish has no such setting – it might still be built in, since it’s intended for speech capture during interviews and such. Meanwhile, to capture the lower registers well, a parabolic dish needs to be a certain size because the longer wavelengths of those sounds either fail to focus adequately or bypass a smaller dish entirely; I’ve heard that a meter-wide dish is best, but the one I’m using falls way short of that mark (28cm at its widest,) and noticeably dropped out the lower registers in tests. For nature audio, being able to capture a wide range of frequencies is ideal, but a big dish like that would be impossible to manage. The tradeoff here, losing the lower pitches but being this selective over the directional aspect, is one I can live with handily.]
All in all, though, this took hours of work, not counting the time spent capturing the video clips themselves. It did not help that, before I even sat down to do editing, I’d capture more behavior that I wanted to include, and things just kept stretching out in that manner. Still, not just having the ability to capture and edit decent video, but having such readily available subjects, has been a huge leap forward in my efforts. I’d say I really couldn’t ask for more, but I could – more eagles in the area, or the aforementioned gators, for example – but that would just make me a greedy bastard, while my plate is full enough with all of this. And it’s not even spring yet.
Nonetheless, my takeaway right now is, produce videos of fewer clips, more often, and reduce the oppressive projects in that manner. We’ll see how that goes…
“Hey, you mook,” I hear you saying, “that was last year’s weekly topic. We’re done with that now.” But no, not when we’re greeted with this this morning.
That’s a white ibis, or American white ibis if you prefer (Eudocimus albus,) perched in a tree on the edge of the pond, and while it’s not the first I’ve seen in North Carolina, all the others have been strictly coastal, which that doesn’t exactly describe our locale. Not that I’m complaining, mind you.
I slipped out the door quietly to snag these shots, hoping not to spook it. These are cropped of course, not representing what I could see in the viewfinder, but the behavior certainly wasn’t that of a bird getting ready to flee. Check out that negligent grip with one toe. And the blue eyes, natch.
I came in after getting enough detailed frames, intending to let the ibis feel comfortable and pondering (only in idle amusement) what to feed it to keep it around. The ibis had that well in hand, though, and dropped down into the yard on the edge of The Bay and began poking around, so back out I went. It was snowing very gently while this was happening, not enough to count really.
For those of you keeping track at home, The Bay is a small semi-circle of the pond edge to the right of the ‘apron’ where the ducks and geese and nutrias and beavers all come up to get corn, actually a little closer to the house than the apron but usually half-glutted with pond plants throughout the summer. [We have to use these terms to communicate what’s going on or where to spot some particular critter, so we’ve developed a collection of geographical terms for the property features.] I was unconvinced that the ibis would find anything to eat there at this time of year, but I’m not an ibis nor conversant enough with their habits, it seems.
That long beak evolved to poke through the mud in search of small crustaceans and shellfish, thus the coastal habits, and not something that it’s going to find here. Nonetheless, it came up with something that it juggled for a little bit, and I kept firing away.
What I took, from my view through the viewfinder (and a 600mm focal length,) to be a cluster of roots or debris looks, on close inspection of the frames afterward, suspiciously like a salamander. Let’s go in as close as we can manage:
This is full resolution, the best I was going to achieve in the conditions (or at least, that I’d chance from what I considered a safe distance,) and that still looks like a salamander in its beak. Nor was the ibis inclined to drop it and move on, instead juggling it around until it was in the right position and gulping it down.
[Salamanders would not be the slightest bit active in these conditions, but they would be buried in the mud staying moist and waiting for spring, so this isn’t a farfetched capture at all.]
After what I considered to be enough frames and, again, trying not to frighten it off, I came back inside to unload the memory card and prepare some choices for this post. The Girlfriend soon came down and got me again, because the ibis had moved off to another portion of the yard, one with a better view, and was still foraging.
Now we’re to the left of Duck Island and the apron, a good 15 meters from the previous hunting ground – or at least, the ibis is. I was down in the middle of the backyard, having crept closer while the ibis was intent on the thing it has in its beak here. This is full-frame, to give you an idea of my view at the time. The ibis was playing with something long and floppy, and I was almost convinced that it only had a rotting leaf from a pond plant or something. But we’ll go in closer.
We’re once again at full resolution now, and the intervening plants and stems in the way aren’t helping. Yet, that doesn’t look like a rotting leaf at all, and there weren’t that many pond plants in the immediate vicinity that have would long thin leaves of this nature. The slick two-tone coloration, the faint appearance of what may be ribs, the rounded end, and the thicker apparent shape of the thing in its beak certainly suggest something else, and to my mind, that’s, “eel.”
Now, I don’t recall ever seeing an eel at any time in my history, much less here on the pond itself, and it doesn’t strike me as the habitat for them. But that S-bend is suspicious, and nothing else seems to fit the bill (a ha ha) – the ibis certainly seemed convinced, because it juggled this one too for perhaps two minutes before snorking it down whole, and doing that thing that waders do to settle the food distinctly in their crops. I would have shot video, but video handheld at 600mm would have been nausea-inducing and the resolution is three times as good in still photos anyway.
You can see some swelling in the crop area (mid-neck) here, as the ibis favors me with a condescending look. Okay, probably not, just checking on me to ensure that I’m not up to no good, since I’d crept closer while it was wrestling with the snack. Still, it wasn’t inclined to fly off, and after a few more frames to ensure I had something sharp, I let it be.
Of course, I could have done without the intervening vegetation, but not a bad little portrait for my troubles. Will this guy stick around? I would have been inclined to think this was a once-off encounter, but the ibis also seemed to snag two good meals within a half-hour here, so who knows? We’ll be happy to add it to the denizens if it’s so inclined.
The question remains, can the reproductive process that the flowers facilitate survive the temperatures if the pollination occurs before such temperatures arrive? And I cannot answer that, because I thought of the question specifically for Darwin Day and not back in January when I could have marked that particular branch to see what happened. Yet, while all of the opened flowers were affected in the same way, some of the later buds (like the one at right, also taken yesterday) are beginning to emerge, showing no signs of damage from freezing, so we have to surmise that the enclosing leaves are better proof against the cold temperatures. This suggests that camellias found a niche of being the first to attract pollinators, with virtually no competition, as soon as the weather is warm enough, but still capable of handling the variable nature of, well, nature, specifically temperatures toying chronically with freezing.
Autofocus has come a long way since its first application, but it still remains easy to fool in certain circumstances. Let’s begin with a little understanding of it. The most basic property is, it needs a certain amount of light to work – once the view gets too dim, the autofocus sensor within the camera body cannot adequately resolve the contrast that it needs, which is why nearly all lenses available today have a maximum aperture or f5.6 or larger (in some cases, f6.3, which seems to define the limit.) It’s better if the lens has an even larger aperture, which in the seemingly-reversed terminology of lenses/apertures is a smaller number, like f4 or f2.8. Zoom lenses will often be listed as a range of numbers – in the example at right, f3.5 to 4.5 (the “1:” can be replaced with “f” – all of this is 
But what exactly does this mean? Well, sharp focus is actually about contrast between different colors or brightnesses within the image. A sharp image has nice, distinct, and very specific delineations between these contrast areas, while an unfocused image blurs these distinctions and the contrast becomes a gradient, muddy and indistinct. The only thing autofocus does is adjust the lens focus until this contrast is as high as possible – within the sensor’s active area, of course.
