OK, I think I have finally sorted out the problems I was having with image stacking (see Image stacking revisited: macro photograph a sow bug—take 2). Above is a portrait of an immature drumming katydid (Meconema thalassinum) that I compiled from a stack of 41 images. The insect was approximately 1 cm long. I think this is the best stacked image I have produced.—it looks completely sharp and focussed.
In my previous attempt (Image stacking revisited: macro photograph a sow bug—take 2) I felt the resolution of the final stacked image wasn’t right—that the image didn’t look “crisp” enough. I also speculated whether the lack of resolution was due to the lens or my technique. I assumed it was my technique, and sure enough, it was. You see, when I took the sow bug photo I used a home-made macro stand—basically just a wooden base to which I could mount the camera (on the bellows) with the specimen on a small platform in front of the lens. Having both on one stand made it easier to set-up the shot and I thought it would make it easier to be able to do this sort of photography on a regular basis. I knew that the camera shutter could result in a tiny amount of vibration, but I wasn’t concerned because I was using electronic flash which would freeze any movement
What didn’t occur to me was that over the course of 40+ photos the vibration of the camera shutter, plus any vibration caused by operating the bellows, could possibly cause the tiny subject (in this case the sow bug) to shift position ever so slightly. The bug wasn’t pinned in place, so I think that is exactly what happened.
In the case of the katydid photo above, I did two things different that I think were important. Firstly, I didn’t use my wooden stand; instead I mounted my camera, lens and bellows onto a sturdy tripod. I then mounted the (dead) katydid onto a metal bracket which was firmly taped to my kitchen counter (I dream of having an actual studio). By doing so I isolated the specimen from any vibration caused by the working of the camera and also kept the specimen from moving for any other reason. As you can see from the photo above, it worked.
Below I have included one of the 41 pictures that were stacked to create the final image, so that you can compare the two to see the difference in depth of field.
Now that I am finally getting some good results from image stacking, it is time to get back to some regular macro photography. I’ll continue to play around with image stacking and I especially want to work out techniques for stacking pictures of live critters. So you can expect to see more stacked photos, and more technique discussion in the future. But I don’t want stacked images to dominate this blog. Besides, I have a real urge to shoot some more aquatic critters soon…
The technical stuff:
Camera: Olympus E-620 digital SLR
Lens: Zuiko 50mm F1.8 reversed on an Olympus OM auto bellows
Settings: manual exposure (F5.6 @ 1/125 sec)
Lighting: Olympus RF-11 ring flash (manual; 1/8 power)