diamond engagement ring

I’ve been gone for awhile thanks to having one heck of a busy summer. I’m sure you can guess from the photo to the left, or perhaps from the post title . . . but one of the things keeping me busy was getting engaged And considering that I was single at the beginning of the summer, a lot has happened in the past few months! (a lot of good stuff I might add)

Don’t worry, there are plenty of photography relevant stories from the summer. But you’ll have to forgive me if I’m still feeling rather proud of the fact that there is now a beautiful young chemical engineer who wants to spend the rest of her life with me Ok, before I make anyone sick . . . yes, I took the photo of Linda’s ring to the left. And I learned a lot of valuable lessons while trying to pull it off.

I captured that photo on my trusty Canon 40D with my 100mm macro lens.  The ring is sitting in it’s black leather box, which lead to lesson number 1: when photographing a ring, pull it as far out of the box as you can while still keeping it upright. I took a bunch of photos with the ring about halfway down in the little slot that holds it, and they generally look like crap. Count on losing about 50% of the circumference of the ring that’s still showing because it will be in shadow . . . which means I got a lot of silly photos of 1/4 of the engagement ring. The ring box does make a really nice backdrop since it’s dark, provides both a base and a backdrop, and casts a shadow that lets the band gradually fade out of view . . . just be careful that the nice shadow doesn’t swallow your ring.

For lighting, I used a bare bulb off to the camera left. I knew I was working with my macro lens which limits light intake, so I went with a really hefty bulb quite close to the ring – funny when you think about it, the light source was several times larger than the ring, even from the camera’s perspective. You have to be careful with lighting like this, as it’s quite easy to end up with significant lens flare. Canon lenses are generally exceptional at reducing lens flare thanks to little diffraction grooves that line the inside of the barrel . . . but even the best lens can succumb in situations like this. Make sure everything around your scene is draped in black to minimize stray reflections.

Speaking of stray reflections, we’re photographing metal and diamonds. I assumed that a lighting setup similar to the way you would light metal and glass would work pretty well. Namely, you want to minimize reflections everywhere except the very edge of the subject, which means positioning your light so that only the edge of the subject is lit in such a way that edge reflections are directed into the camera (using the rule that the incoming angle of light is equal to the reflected angle of light). This all worked fine in theory, but as you can see from the photo, diamonds are much more complex than most pieces of glass. And their legendary propensity for reflecting light wreaks havoc on a photographic setup. Due to the numerous facets as well as the incredible refractivity of diamond, there is almost no way to completely control reflected light. Of course, if I did a perfect job of it, the diamonds probably would have looked like glass . . . which I suppose defeats the purpose. Anyway, I think the little rainbows in the photo work quite well . . . though I’m still upset that I couldn’t do a better job of creating distinct edges.

engagement photo

Ok, last lesson I learned and a fun photo. I tried capturing some HDR series with my macro lens. This did not work out so well. In spite of using a good tripod and a remote trigger, I just couldn’t keep the focus coherent between multiple exposures. I’m not entirely sure why this happened, especially since I had the lens set to manual focus. But something about the extreme differences in visible objects in the scene as the exposure changed made it impossible to line up the frames and get a decent image. Basically the dynamic range in the scene was too big even for a high dynamic range image. I guess that makes a significant statement about the brilliance of Linda’s diamond

I think maybe if I had stepped the HDR in smaller increments and taken more exposures I could have gotten something to work with. But then of course I would have risked shifting the camera as I adjusted settings in the menu. So I’m at a bit of a loss for a practical solution. I mean literally the dark exposure developed all the texture of the leather box, but there was no ring in the photo; the middle exposure developed the shape of the ring, but there was no box; and the light exposure developed a beautiful reflected rainbow from the diamonds, but you couldn’t even make out the edges of the ring.

Perhaps this is why I’m always disappointed by the photos of diamonds in catalogs though And perhaps why I never thought I liked diamonds. I have to admit though, I really like the look of a diamond on Linda’s finger . . . I may have to buy her more. You know, to practice my photography skills

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

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.