Close-up: Chasing (and Hopefully Photographing) Butterflies
Everyone seems to be attracted to butterflies to one degree or another. Most every outdoor or nature photographer has tried shooting them at one time or another too. If you are a frequent reader of this site, this may well include you. Getting good results though can be a challenge. Butterflies are small. As with other macro subjects, not only do you have a shallow depth of field and often less than optimal lighting to contend with, these guys are alive and frequently skittish.
One of the most important issues with butterfly photography is working distance. Try to move too close enough to get the shot you want and you are apt to scare them away if the focal length of your lens is too short. While it's not impossible to get good shots with a short lens, the luck needed to do so means you aren't likely to get many. A 105mm macro is really the minimum for productive results. My favorite lens for butterflies is currently Nikon's 70-180mm zoom micro (macro). Especially with the 1.5x cropping factor of current Nikon DSLR's, this makes a killer zoom range equivalent to 105mm to 270mm on a film body. When attempting to find a lens that will work well for you, try out your equipment ahead of time. Find yourself an imaginary or stand-in butterfly (anything of approximately the right size) and try various combinations of lenses, extension tubes, diopters, teleconverters, and so on to see what will work best. Make note of how close you need to be with each to get a given sized image so you can compare your options.
Butterfly photography is one situation when I generally use fill flash. This helps keep shutter speeds fast enough to hand hold so you can keep up with yuor moving subjects. Auto-focus can sometimes be advantageous, but more often than not you will be better off simply leaning in and out with your body to achieve focus. A bracket that allows you to raise the flash slightly above the camera can be helpful. If you are focused too close to the font of your lens, your lens hood can actually shade your subject if the flash is too low. Be careful that your flash is set to not overpower your subject. A powerful flash held too close will result in quite harsh lighting and black, shadowed backgrounds.
Depth of field can be an issue with butterflies. While their wings are indeed flat, it is often awkward to position yourself where you can benefit from this fact. Add to this the fact that they tend to move around and you will want to have your lens at least moderately stopped down to ensure sharp focus. Be careful about your background though. Look for situations when the leaves (or what have you) behind the butterfly is far enough away to render as noticeably more blurred than your subject. The ideal scenario is one that permits you to be positioned perpendicular to the plane of the butterfly's wings, with some separation between him (or her) and the background. If you have concerns about what will end up sharp, focus on the eyes and antennae. Don't forget to take some from unusual angles though such as looking directly into the face of one or even from underneath.
When considering the background, be on the lookout for bright spots where the sun peeks through that can ruin an otherwise good shot. A viewer's attention is automatically drawn to the brightest part of the frame. If the wind is blowing, flowers and other plants in the frame might create distractions as well. One more reason to ensure your shutter speed is fast enough.
Once they hatch from their chrysalis, butterflies don't live very long. Their wings are also quite fragile and will become damaged quickly. In your rush to get a shot, take a few moments to examine your subject. Tears in its wings may not detract from it too much when you're right there, but those tears will show in the image you end up with for all of eternity. Small imperfections will inevitably become more noticeable when the print is hanging on your wall. Don't neglect good composition guidelines either. Consider giving some space around your subject and perhaps allow them some room to look into.
Exposure for butterflies can sometimes be a challenge. Very few are medium toned. Especially if you are spot metering, be sure to compensate for white and black butterflies or any that come even close to that. You will likely be disappointed if both come out as gray.
Don't be stingy with your shooting either. Whether you are shooting film or digital, take lots of shots. Butterflies move quickly, sometimes the exact second you press the shutter release. It can often be difficult to say for sure that you got the shot until you have a chance to see the result. The instant feedback of digital can be quite helpful for this, but keep in mind that it can be difficult to adequately evaluate your images on a tiny LCD screen. Better to have too many good shots than to find out later that you missed the moment you were trying to capture.
You can find butterflies just about anywhere. Mountain wildflowers always make great backgrounds, but they generally aren't required for great results. Your own backyard or the local park might be worth a look. Many cities now have butterfly houses that provide a veritable smorgasbord of subjects to shoot. Here in Seattle we are blessed with two such facilities. The Pacific Science Center on the grounds of Seattle Center has a year round Tropical Butterfly House and the Woodland Park Zoo has a seasonal "Butterflies and Blooms" exhibit featuring North American species. Such locations are great since you can go back time and again to practice your technique or to try out new equipment. Regardless of where you go though, try to go early in the day. Butterflies are cold blooded and will be much less skittish before they warm up too much. Outdoors, you can often get quite close on a cold morning and may even find specimens with their wings covered in dew.
Watch your subject's behavior too. Often, even if you scare a butterfly away temporarily, it will return to the same flower or other perch if given the chance. Butterflies act almost as if they are camera shy so try not to startle them. Move slowly and be patient and you will up your odds of getting what you are after.