Can anyone spot what’s different with the bug to the left compared to all other bugs I’ve shot up until this point? No, it isn’t that it’s a type of bug I haven’t shot before, it’s all about the size.
Last weekend I tried out my new setup that I’ll be using on most of my bug hunts from now on. I’m still using my macro lens (Nikon 85mm f3.5) but I’ve now added a full set of Kenko extension tubes as well. The set contains three pieces (12, 20 and 36 mm) and when using all of them with my macro lens it gives me a magnification somewhere around 2:1. That means that the bugs will be about twice the size compared to what I’ve been able to capture previously.
When I got the tubes I also decided to make a second change to my setup. As you all know (you do know, don’t you? Otherwise go and do your homework) I use a SB-400 that I hold in the hand that isn’t busy holding the camera. However, I realized that it would simply be too difficult to hold the camera with just one hand with both lens and tubes attached. So I put a LP160 with my Lumiquest Softbox III on camera. It’s not ideal since the light will now be head on; it does however free up both hands, something that’s essential when trying to keep things steady.
I’ve only used this setup on one outing so far but I can already tell that I’ll need to go back to school. It took me quite a while before my technique felt good enough with my previous setup. Now it’s even more important to really perfect the technique; when you keep getting closer every little movement will produce motion blur in the pictures. Not only that, the DOF will get even shallower, so getting focus perfect will be even more critical.
I think my biggest problem might have been motion blur, especially when there was more ambient light around. That might seem counter intuitive but hear my out. Yes, more light means you can use a faster shutter speed but things are more complicated than that. I shoot most of the photos at f16 - which produces a very shallow DOF at 2:1 – and that robs a lot of light. The fact that I’m using extension tubes robs me of some additional light as well; adding an extra distance for the light to travel until it hits the sensor will naturally do that. So even in strong sunlight I need a fairly slow shutter speed to expose the background correctly. I tried quite a few shots at 1/100 and those are the ones where I notice the most motion blur. In the future I’ll probably stick to 1/200 (fastest sync speed for my camera) unless I really need the extra light or if I have a position that lets me keep things very steady. When the scene is mostly lit by flash this problem goes away. Even though I have to use the flash at a fairly high power (I was alternating between 1/4 and 1/8) the flash duration will be a lot shorter than a 1/200 shutter, hence freezing motion a lot better.
Another change that came about from using extension tubes, one that surprised me, was that the working distance became greater. I guess I didn’t read up enough on things but I kind of thought the working distance would be shorter instead. Having a greater working distance might seem like a good thing, and sometimes that can be true, but I would probably have preferred it the other way. I don’t really feel that I have much trouble getting close enough to the bugs, so the greater distance doesn’t gain me much. By getting closer instead the flash could be used more efficiently and some of the motion blur could be eliminated, or at least reduced – the farther you are from the subject, the greater the impact of any change in position. There’s nothing to be done about this however, it’s a quirk I have to get used to.
These factors all add up and I’ll definitely have to work in order to improve my technique to mitigate them. I also feel that I’m losing a bit of sharpness when using the extension tubes; not surprising when you add something between the lens and sensor. Yet another factor that makes it even more important to maximize my chances of recording as good data as possible.
All that being said (was quite a lot, wasn’t it?), I’m looking forward to seeing what kind of results I can get with this setup. It’s exciting to be able to get even closer than before and subjects that were previously too small to be interesting can suddenly be seen in a new light. This has been a pretty technical post so feel free to ask questions if anything is unclear.
Now go and check out the large versions of all these shots below so you can see the details properly (in the last one you can see the motion blur very clearly).