Focusing becomes critical – this is no time to rely on your camera’s autofocus. My Canon 40D generally has a great autofocus, and the ultrasonic motor in my 100mm macro lens is smooth and fast . . . but it’s still no match for a flying bumblebee. The key is to focus fast and then snap a couple shots as you incrementally adjust the focus ring. With a focal plane of a couple millimeters, it’s nearly impossible to tell through the viewfinder whether you are focused on the bee”s head or just a stray hair on its back that is pointed towards the camera. And the autofocus obviously has the same problem. In addition to the fact that when you try to focus on an object that is moving in and out of the focal plane, the autofocus will never manage to get a good lock – it will scan the macro focus range, not find anything, then focus way out in standard mode at which point it probably picks up a tree or something in the background. There goes your beautiful bumblebee photo, because by the time you get your bearings and crank the focus ring back down to macro range it’s gone.

I”ve saved the best for last though . . . I had been frustrated with my inability to create depth in my photos with my macro lens since everything that needs to be in focus has to be in the same plane. Turns out you can trick the eye substantially by rotating the camera. Keep the plane of the lens perpendicular to the subject, but just rotate the camera so that your object spans diagonally across the image. It means thinking a little differently about composition, but it works.

Your other option for creating depth of course is artificial lighting (so that you can use smaller apertures and increase your focal depth). Your flash is not likely to help because the barrel of the lens will cast a shadow on the subject at close proximity. That’s why camera companies make ringlights which mount to the end of the lens. Unfortunately, ringlights are expensive and have a serious drawback – they create perfectly flat lighting. Oh, and they are heavy and bulky, though they do have the advantage of interfacing perfectly with your hotshoe. Anyway. The solution here is to mount a couple LEDs on flexible “antennae” that you can switch on and off. Attach them to your camera, and you should have a perfectly flexible miniature studio for dynamic lighting of small things This is my next project, I’ll keep you updated on how it goes.

By the way, the above photos were taken at the Cincinnati Nature Center – a privately owned and amazingly well kept nature preserve that is open to the public. It’s beautiful and secluded, tucked away in Milford . . . I highly recommend it

And yes, I know that I’m getting double apostrophes in my posts and that some of my old images have disappeared . . . working on that – I switched servers recently (upgraded to a dedicated system! ) and it’s screwing with my WordPress installation. Anyway, hopefully just a temporary issue!

Most photographers know that outdoor photos have the most “natural” color rendering, while photos under incandescent lights (ie standard house lights) look yellow, and photos under fluorescent lights look greenish. Many photographers are forgetting this concept as cameras get better and better at auto white-balancing, but it’s an important thing to understand nonetheless. And of course, it’s the whole reason you have to (or should) white balance your photos. The reason photos look different under different lights is because the light sources have different spectra. Light is made up of waves of different wavelengths, and these wavelengths are perceived by your eye to be different colors. Back to the extreme case of a red light, all objects will look red because the light emits the red wavelength (around 700nm wavelength if you’re interested), and an object can only reflect or absorb red – its quite unlikely that the object will absorb red and emit a different color (it’s possible, but these are the exceptions to the rule).

You can probably start to see why it’s important to have a balanced light source – if your light doesn’t emit anything in the green wavelength range, then green objects have nothing to reflect and will look black. Your brain is really good at tricking your eyes though. So when we’re inside and the room is light by incandescent lighting we don’t stand around and wonder why everything looks so yellow – our brain figures out where the light is coming from, takes stock of the color of the light source, and uses that information to filter the colors of every other object we look at. A camera, however, doesn’t have that luxury (though it certainly tries hard with the auto whitebalance) . . . and we don’t have that luxury when we look at a photograph. The photo looks yellow because the scene WAS yellow, and our brain tricked us into believing that it wasn’t.

So what’s the big deal if our brain tricks us? Let’s take a look at some spectra of light sources. Here is a typical incandescent bulb plotted as relative intensity of light at the various wavelengths (mapped as colors here so it”s easy to look at):

Not the black line running across the graph – that’s what a perfectly balanced spectrum would look like. So you can see the incandescent spectrum is severely lacking in the blue range, about right in the greens, a little high in the yellow, and fairly high in the reds. Your eye perceives blue and yellow to be opposites, and green and red to be opposites (more on that some other time, for now take my word on it). So the fact that incandescent lamps (and by the way, this includes quartz halogens as well!) have too little blue AND too much yellow compounds our perception of the scene being yellow. The bigger issue though is that blues and purples just plain don’t look right in incandescent lighting because they have very little incoming light to reflect (a huge problem for photography). And if your object has an optical brightener (which reflects in the UV by the way), it will look dingy under a tungsten bulb.

Ok, how about fluorescents? Fluorescents work differently than tungsten based bulbs – instead of heating up a metal which then emits energy from all of its electrons evenly, fluorescent bulbs stimulate a set of materials at specific energy levels which then fluoresce with a characteristic wavelength. There are lots of coatings and other modifications added to fluorescent bulbs, but here is what the spectrum typically looks like:

Woah! What’s going on there? Each of the peaks in this spectrum represents the characteristic fluorescent wavelength of one of the components of the bulb. And the valleys? These are spots where we don”t know of any economical materials that fluoresce at that wavelength. So it’s no wonder things look green under fluorescent light (note the large spike in the green wavelengths). But we can always white balance the photo to pull back the green. The more important issue is that there are many colors in the fluorescent spectrum that simply don”t exist (or exist at VERY low levels). So for example red objects and certain bluish-green objects will never look right in fluorescent light. And as before, the problem only gets worse in a photograph (remember, if the object didn’t have any light to reflect you won’t be able to recover or bump up that color in the photo – the color simply won’t exist!). The most devious part about the fluorescent spectrum is that it is often difficult to predict if a particular object will look ok or not – the missing wavelengths are very specific, so one bluish-green object might look fine, while one with a slightly different hue looks terrible!

Alright, so are there any solutions? Well, not really. At least not for photography. Stick with tungsten (incandescent) bulbs, and turn them up really bright (the advantage of using quartz halogen bulbs is that you can make them very bright) so that you at least get some blue light for the camera to pick up . . . and then white balance. Or shoot outside, that’s of course the best solution

For daily use in your house there actually is a great solution, but a word of warning – don’t use these lamps for photography! GE has come out with a new type of incandescent bulb called the Reveal, which does an amazing job of eliminating some of the characteristic yellow cast of tungsten lights. And while your brain is quite good at tricking your eyes, it’s very impressive the difference these bulbs can make in your house – eliminating dingy yellows and brightening blues colors.

So why not use the GE Reveal lights for photography? Let’s take a look at the spectrum for this bulb:

Ew, what happened there? GE added a material to the coating of this bulb which absorbs (primarily) yellow light. So there is less yellow in the resulting spectrum (and thus yellow objects look less yellow, and blue objects look more blue), but there is clearly not any more blue which as I mentioned earlier is the real problem with incandescent bulbs. In fact in a bit of a conundrum, it appears the GE Reveal might actually have LESS blue than a traditional incandescent! So it may work wonders on tricking your eye and brain, but it certainly won’t do any favors for your camera. In fact, because the spectrum is now non-uniform, you may actually have a more difficult time white balancing.

So there you have it. Buy GE Reveal light bulbs for your house. Don”t use them for photography

So for anyone out there who is wondering what fall foliage in New England looks like to a colorblind person, and to keep people from telling me I just haven”t seen the right fall colors to appreciate them, I took a backpacking trip in the Adirondacks last fall and took some photos. The first photo is what my camera captured, no adjustments. Beautiful I”m sure, but to me I can just tell that there are some red and orange trees, nothing special. In fact, I recall the scene looking more like the second photo. I actually had to stop and think “gee, there”s a tree with red leaves over there. I bet color-sighted people would think that”s pretty”. The third photo is my approximation of what the scene would have to look like in order for me to think “wow, that”s a bright red tree”. But even after the adjustments, I don”t think I”d call the color “amazing”. I”d like to assert that the third image represents the color adjustment required to make the world look to me like what the rest of you see naturally . . . but if I”m being honest I can only guess at what that looks like.

So you can see why fall colors just don”t impress me much. And this probably explains why I really crank up the saturation on some of my photos . . . I”m just trying to make it look like I think it should. I suppose you”ll just have to believe me that my photos capture the way the world really looks. But even if you don”t believe me, that”s my prerogative and task as a photographer – to show you the world the way I see it.

I suppose I should mention that there are multiple types of colorblindness, and that I am red-green colorblind. That’s the common type (affecting something like 10% of all males, believe it or not) and in my case is known scientifically as protanomaly (there is another type of red-green colorblindness, deuteranomaly which makes up a portion of that 10%, but they are often difficult to distinguish).

Ok, so what is colorblindness? Well people have 4 types of light receptors in their eyes: 1 type of rod, and 3 types of cones. Rods are proteins that are sensitive to a broad spectrum of light (ie all colors) – whenever light reaches a rod, it sends a signal. That means that rods can’t discriminate between colors, just intensity of light. Rods are active in low light because they’re really sensitive. Your ability to discriminate colors in the dark would be similar to what a monochromat sees normally (monochromats don’t see any color, but this is less than 1% of cases of colorblindness).

Cones, on the other hand, are sensitive to a particular portion of the light spectrum. Generically we would say that there are red cones, blue cones, and green cones . . . though that’s not entirely acurate, it’s close enough. This is why TVs, computer monitors, cameras, all sorts of image capturing and reproducing devices use RGB color – because those are the same color primaries that your eye sees. Whether you believe it or not though, EVERYONE is colorblind to certain colors. There are way more colors in the spectrum than what you can reproduce using only red, green, and blue primaries. But since humans can’t distinguish the colors, there is no need for a computer monitor to reproduce them either.

Anyway, back to being colorblind. Colorblindness is (usually) a genetic condition, and it is sex-linked (the DNA that codes for your cones is located on the X chromosome). Because males only have one X chromosome (males are “XY”), they only have one copy of the code for cones . . . if that one copy is defective, you’re colorblind. Females have two X chromosomes (females are “XX”), so unless both copies are defective, you’re color normal. By the way, there is good evolutionary reason for males to be prone to colorblindness and females to be color normal – females traditionally gathered food and needed to know the difference between a red berry and a green one, while males who were hunting benefitted from being colorblind because they can see through color-based camoflauges.

So most colorblind individuals have a “deformed” version of one of their cones (usually either the red cone or the green cone, with red cone deformations being more common). Now, the spectrum for all the cones overlap slightly, but a deformation causes the spectrum of that cone to shift closer to to one of the other cones. For example, a deformed red cone is a bit more sensitive to greens than it should be, and a little less sensitive to reds than it should be. As a result, reds don’t look as saturated or bright as they should, and some green colors can actually look red.

The part that confuses most people is that a bright saturated red still looks red to a colorblind person because there is SO MUCH red that the colorblind red cone picks up enough of it to send a signal. A very washed out red or a very dark desaturated red doesn’t have much red energy in it and thus can be missed by the defective red cone. By the same token, bright saturated greens give a strong signal to the green cone, and even if they set off the defective red cone a little the signal is swamped by the signal from the green cone . . . the colorblind brain still interpruts the color as green. Funky brownish greens or washed out greens though produce a low signal from both the normal green cone and the deformed red cone, which results in a confused signal reaching the brain.

Net, there are certain sets of colors that are easy for a normal-color person to distinguish, but look the same to a colorblind person. And when these colors are set next to eachother, the normal-color person detects a nicely contrasting image while the colorblind person sees only “noise”.

ice coated vines in the sun

We got one heck of an ice storm in Cincinnati this past week. Actually, these things are getting to be a regular occurance around here in the winter. Must be global warming or some such thing :p

Anyway, as much as I hate the cold, and as much as I hate the way Cincinnati people drive in the winter, ice storms do have an upside – they make for some great photography. There is something really cool about things that are entirely encased in ice, like the clematis in my backyard (left). Photographing clear objects (like ice or glass, etc) comes with a unique set of problems. Namely, they are transparent.

Obviously you and I can see things like ice and glass in the real world. So why don”t they look the same on camera? It”s largely due to motion – as we move around a transparent object, we see light reflections from different angles. Our brains integrate these different views to create a mental image of the ice or glass, etc which is considerably different from the instantaneous image that our eye sees. Cameras, for better or worse, do not have the advantage of a brain. They capture the image exactly the way your eye sees it, without the benefit of additional knowledge about how transparent objects behave.

The result of all this is that most photos of transparent objects either can”t be seen, or are covered in glare. But the way your brain thinks a transparent object should look is more like the photo of the ice above. So what”s the difference? Notice where the highlights are located on the vines (and where they aren”t). When photographing a transparent object, the light must either come from only the edges, or only the center. If you have even lighting, you will not see the ice. If you have a large lightsource behind you, you will only see glare. In the case of the above photo, the sun was above the ice that I wanted to photograph, and it was blocked out of the bottom half of the image by a hill behind the vines – the sunlight could only hit the very top edges of the ice, and as a result the ice is well defined.

I know, the sun”s reflections show up at the bottom edge of the ice, but that”s due to the refractive index of a thick piece of ice. Trust me, the light is hitting the top edge of the ice, and that”s why you can see the edge. You”ll probably also notice that I took a photo of the sun, which is normally way to bright to show up in a photo without completely washing out the foreground. I accomplished this using Auto Exposure Bracketing (a standard feature of most SLRs) and combining the three resulting exposures with Photomatix Pro, a program for creating HDR (high dynamic range) images. More on HDR later, but suffice it to say that it allows you to capture a larger range of contrast than standard images (in much the same way that your eye interprets a scene with very high contrast).

Oh, and in case you”re curious, the hexagonal spots in the upper right of this image are lens flare. Usually lens flare is a bad thing, but personally I like it in some images. The same thing causes the shiny beams from the sun and the sun reflections (usually a good thing), though many photographers would consider any lens flare large enough to create a defined hexagon to be bad. It”s a personal thing though – I don”t think it detracts from the photo in this case, and if anything it reinforces just how bright that sun was.