Designing a Macro Bracket, pt.4
Continued from Part 1, Part 2, and Part 3
I still have a few minor things to overcome with the bracket — the raised post on the end comes off, but the screw is too long to mount anything to without it. I’m considering a few possible ways to work around this, but I’ve spent a lot of time talking about the bracket, and I’d like to move on. I’ll definitely mention what I’ve got when I have a final solution.
So, the next phase is lighting. This is the whole point of the macro rig: dump enough light on the subject to get a good exposure, and dump it in an aesthetically appealing way. There are over-the-counter macro lighting solutions that work quite well, some of them better than what I’m making here. The MT-14EX ring light and MT-24EX twin light are quite good, but they’re really, really expensive. I love macro photography, and as long as there’s something to shoot at 1:1 my 100mm macro lens doesn’t really come off the camera, but I can’t justify spending hundreds of dollars on something I can only use for macro. So I use traditional flash units, which are less expensive and very versatile.
I already have a Vivitar 285HV, a cheap and popular manual-only flash. I’m considering upgrading it, if budget allows, but that’s not certain yet. The ideal flash for this rig is lightweight, for obvious reasons, with enough power to get a fast flash pulse, and has TTL metering. A flash will give you hard, ugly light, so it also needs a diffuser of some kind.
The flash pulse is important for freezing motion: I shoot a lot of bugs, which are very active and very fast. Basically the lighting scenario I’m in most often is one where I’m shooting with a shutter speed close to my camera’s fastest sync speed, or around 1/250, with an aperture of at least f/8, and usually f/11 to f/14, on an ISO of 100 to 200; the flash fires at 1/16th power, because it’s so close to the subject. Without a flash, these settings would give you an unexposed black frame, except on the brightest of days.
So imagine, in slow-motion, what happens as you press the shutter with these settings: For a long 1/250th of a second, almost no light is falling on the sensor. Then, the flash fires a burst of light, and for the 1/16,000th of a second that it’s pulsing, light floods into the camera and the sensor records that image, which by itself is a full exposure. The flash turns off, and the sensor is no longer receiving any light. At the end of that 1/250th of a second, the shutter closes, and the sensor sends its data — all of it recorded in that 1/16,000th of a second — to the camera’s image processor.
The pulse duration of a powerful flash on a low setting is going to be much better at freezing motion than the fastest shutter speed your camera can do. Unfortunately, Canon doesn’t release its speedlites’ flash pulse duration, and even for the third-party companies that do, there are different ways of measuring it. So there’s a bit of guesswork here; I think the only real thing we can do is assume that any moderately powerful flash is going to be fast enough, and choose between them on other grounds. It probably rules out small low-power flashes, and it definitely rules out constant light sources like LED lamps.
TTL isn’t critical, and I don’t feel like I need it at all for my non-macro stuff. It would be nice so I don’t have to adjust the power level if I’m shooting a little further back, or decide to use a circular polarizer, for example. E-TTL 2 can make finer adjustments than just the one-stop power levels of the Vivitar 285HV. It also offers rear-curtain sync — that would let me slow the shutter speed down to let more ambient in, and capture motion trails to show movement. These are generally convenience things, but I’d like to have them.
Two things I don’t care about: Electronic zoom heads are a complete non-factor for me. High-speed sync is actually something I want to avoid using. It sounds like a great idea, using ambient as the main light, and high-speed sync as fill, but the way it works is to use thousands of low-power pulses through the entire exposure; when the subject is a fast-moving insect, that’ll give a blurred picture — like a strobe effect, but probably too close together to look cool.
Considering these things, I’d like to upgrade to the 430EX II if I can afford it. I go back and forth on the Yongnuo YN-465 and YN-467; I’d like to see a comparison to an official Canon flash in terms of build quality and reliability. Considering they cost less than half as much as the 430EX II, I’m willing to cut them a little slack, but I want good odds of getting more than a single season out of them before I drop money on one. Really it’s the international shipping that gets me: if there were a supplier in the US who would handle replacements under warranty, I’d be much more likely to buy one. This all depends on my job situation, too, which is either seriously improving or completely disappearing in the next few weeks, and I don’t have any idea which yet. No new toys if I’m unemployed. Fortunately for me, the flash I have works fine — this is an entirely optional upgrade for me. (I wouldn’t get the Vivitar as a macro flash if I were doing it again, though: it’s too heavy, it has a beveled head that’s hard to mount things on, and it’s expensive compared to more modern competitors. On a super-tight budget, I’d go with the manual YN-460 or YN-460 II as a first flash, or on one of the E-TTL flashes I mentioned above.)
As for the diffuser, that’s important for controlling the quality of the light. If you’re already familiar with Strobist-style lighting, you know this already, and it’s true for macro as well. The diffuser — basically a small softbox — is important because it makes the light bigger. The greater the angular size of the light source, the softer the shadows it makes. It also ‘spreads out’ the intensity of the lighting, so you can capture more detail in reflective surfaces without getting blown-out highlights. The plastic caps, like the Gary Fong-type diffusers, are no good here. They’re designed for indoor use, and send light out in every direction to bounce back onto the subject. Outside, with nothing to bounce light off of at macro scales, they’re just sending perfectly good light off into the void.
Right now I’m using the DIY flash diffusers described here on Myrmecos, albeit using a larger yogurt cup for my larger flash. It may be a bit too large, so I might remake it soon to be a bit shorter, but I’m getting great light from it. I’m using translucent vellum paper ($0.25 per sheet at my local stationary store) as the diffusion material, though Roscoe makes some professional materials for this exact purpose. That would be more durable, and more heat resistant as well — though the general idea is to get the diffusion surface far enough away from the flash head to catch light from a wide area, so I’m not too concerned about the heat.
Spring flowers
The appearance of small plants and flowers in the past two weeks has been a huge relief. I’m not much of an indoor photographer, and with the change of weather I’ve finally been able to get outside again. I’ve gotten a few good ant shots already, but with my macro rig in a transitional state (to put it nicely) I’ve been changing things up by shooting some flowers in natural light. I uploaded several to my gallery this morning.
Prints of all these images are available through the links.
Designing a Macro Bracket, pt. 3
Continued from Part 1 and Part 2
In my previous post, I mentioned that I was considering using a cheap straight flash bracket in my macro rig this year, instead of something like the thick stainless steel plates I’ve been using. I ended up ordering this aftermarket Metz flash bracket, and received it this afternoon.
I’m glad I did. The bracket was $7 shipped, so it’s technically a few times as expensive as the steel plates, but it’s also a few times as effective. The screws are thumbscrews, so I don’t need a screwdriver to secure or remove any part of the rig. The surface is non-slip, so I can use it in portrait orientation with the flash slipping down. The length is adjustable, which is great. I’m convinced that to get these qualities from a purely DIY solution would end up costing much more than $7 in tools, even if I’d be saving in materials. (more…)
Designing a Macro Bracket, pt.2
Continued from Part 1
I’m sort-of coming to the conclusion that it’s not worth making the plate myself. There are several straight brackets, some with cold shoes (or even hot shoes, with a PC terminal) for under $10 on Amazon and eBay. I feel like they’d be a lot more secure than the pre-drilled metal braces I’ve been using, and lighter, for only a few dollars more. I’m still looking for a good inflexible plastic plate, though.
I’m looking at brackets like this: a cheap Opteka and this Nikon. They’re designed for a compact camera to use as a plate. I’m guessing that this is the sort of thing I’ll be able to get for cheap on eBay, from a Fotodiox or one of the Hong Kong distributors.
Having a shoe on a store-bought bracket is actually not a selling point for me. I don’t want the flash to be fixed in one spot, and I’ve been using a mini-ballhead, with the flash mounted on a short TTL coil cord. I’d like to keep using that, although I don’t have a TTL flash. For one thing, it’s very adjustable. For another, the connection is much more secure than a PC sync cord, which slips out of the camera’s terminal very easily. I’m also hoping to move up to a TTL flash this summer, but I’ll post on that separately.
Designing a Macro Bracket
I’m starting to think about my macro rig for 2010, now the weather’s getting nice enough to go outside again. I have a good general idea of what I want to do, given my budget constraints and what worked or didn’t work last year.
(In my head, what I call the “rig” is everything involved: the camera, the lens and any tubes/rings/diopters that get you to macro magnifications, the flash(es) and related modifiers and cords, and the bracket that ties it all together.)
If you’re just thinking about a macro bracket for the first time, it’s a pretty simple build. It’s basically the part of the rig that connects everything: usually a long flat plate that screws into the camera’s tripod mount, with some sort of mount for the flash on the other end. The value comes from getting the flash away from the lens axis, to add depth and texture to the subject. The trade-off you’re trying to minimize is the added weight of an off-axis light, and the hand-shake and fatigue that it introduces. (more…)
WhiBal and color temperature
I picked up a WhiBal color balance card and, though I haven’t had the chance to do any really critical (or even really interesting) photography the past few weeks, it’s already given me great results with some easy, casual shots. White balance is one of those subtle things that’s hard to get right, but really stands out when it’s wrong. Fairly or not, when I’m looking a photographer’s work, it’s the first thing that gives me an impression of their technical skill.
The card is a small, neutral piece of plastic that you use to determine an accurate white balance, either with a custom white balance before shooting, or as a batch setting in post-production. It comes in several sizes; I got one about the size of a business card, because I do a lot of macro and wanted a smallish one, but for larger scenes Amazon carries a 3.5″x6″ Studio size, and there’s a wider variety directly from the manufacturer. It comes with a stand, a lanyard, and a thin, cheap-feeling case; they also make a really small one that attaches to your keychain. One nice aspect of the card is that the color comes from the material, not a printed surface, so any scratches won’t affect its effectiveness. There’s a sticker on one side that’s used for setting white and black points in post, and it has an autofocus target as well.
The WhiBal looks like a typical Kodak gray card used for exposure (in that both are gray rectangles), but the two are used for different purposes. A gray card has a standard 18% reflectivity, so your camera’s light meter gives you a consistent exposure with them. But they’re not entirely neutral in color, and they aren’t even the same color in different types of light — so using a gray card for white balance will give you the wrong color temperature, and it won’t even be a predictable amount of wrong in different situations. On the other hand, the WhiBal isn’t 18% gray, and using it for exposure will be a bit off; I’m not sure by how much, or how consistently, but I’ll bet you could experiment with exposure compensation to meter off the white and black sticker.
In a RAW workflow, you use the WhiBal by placing it in the scene you’re shooting, adjust the angle so you don’t see any glare on the stickers, and taking a shot of it. Then you go on shooting as normal. If the lighting conditions change, take another shot. Once you’re in post-production, you can use the “click white balance” tool of your digital darkroom on the card, and then copy that setting across all the images in those lighting conditions. All the software I’ve used has a batch-copy tool to make this simple. It’s supremely easy and consistent — it takes about five seconds to shoot the card, and another five to set the entire shoot’s white balance.
By the way, in case you’re interested, I’ve measured the color temperature of my Vivitar 285HV flash as 5750 degrees, with a tint of -2 in LR. My 40D’s on-camera flash measures 6400 degrees, with no tint adjustment.
The image of the robin above was balanced using the WhiBal card, and for the photography I do — which is very nature and animal oriented — it’s a great example of the card’s impact. Auto white balance was totally off. The Daylight setting I was shooting in was just slightly too warm, and like many images I’ve taken in the fall and winter, the dried leaves just looked subtly wrong. It’s not terribly visible in the comparison image, but it’s something that’s bothered me for a long time, and I picked this specific image because the WhiBal’s setting made the colors of the dead foliage feel “right” for the first time.
So the verdict is good. It’s easy to use, tremendously helpful, and not terribly expensive, even for a low-budget photographer like myself. I wish I’d gotten one earlier.