Extension tubes vs. reverse adapter for macro: do autofocus and aperture control matter?
Asked 2/2/2012
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I want to try amateur macro photography without buying a dedicated macro lens yet. My current lenses are a Canon EF 50mm f/1.8 II and a Canon EF 24-85mm f/3.5-4.5 USM. I’m considering either extension tubes or a reverse adapter.
What are the practical differences between extension tubes and reversing a lens for macro? How useful is autofocus at high magnification, and how important is it to be able to control aperture?
Originally by Photography Stack Exchange contributor. Source · Licensed CC BY-SA 4.0
Photography Stack Exchange contributor
14y ago
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The answer to your first question is answered here. Both are good low-cost ways to get started in macro photography.
Autofocus is not very effective as you near 1:1 magnification. Most AF systems will struggle to find focus, you have such a narrow DOF anyway that holding focus is very hard. With anything that is not moving, you are far better to set up a tripod and use live view to focus, if you have it. Or manually focus, then move the camera to and fro to get the subject in focus.
If you have a macro lens, you may not use it at 1:1 as often as you think, in which case AF can be very handy. I use it when shooting bees - it's very hit and miss, but for me slightly more successful than manual focus.
If you use extension tubes or reversal ring, you will be forced to be a certain range of distance from your subject (you can no longer focus over a wide range of distances), so AF is not really useful at all.
Aperture is important. You have a very narrow DOF, so you will often want to stop down in order to get as much DOF as possible. Or if you are shooting hand-held you may need a wide open aperture to avoid blur. If you reverse a lens, or have manual extension tubes and aren't able to control aperture, it's not a killer blow, but it isn't ideal.
Originally by user4191. Source · Licensed CC BY-SA 4.0
user4191
14y ago
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Both extension tubes and reversing a lens are valid low-cost ways to start macro.
A reverse adapter is usually the cheapest option, but it tends to be less flexible. With a reversed lens you may end up with effectively fixed focus distance and magnification, especially on a 50mm. Image quality can also be less flat across the frame, which matters for flat subjects.
Extension tubes are generally more versatile. They keep the lens in its normal orientation, the manual focus ring still works, and some tubes preserve electronic contacts for aperture control (and sometimes AF). Cheap tubes are fine if you expect to focus manually.
Autofocus is usually not very important in true macro. Near 1:1 magnification, depth of field is extremely thin and AF often hunts or misses. Many macro shooters focus manually, often by setting focus and then moving the camera slightly back and forth. A tripod and live view can help a lot for static subjects.
Aperture control is more important than autofocus. In macro, you often need to stop down to gain a bit more depth of field, so being able to change aperture is very useful. If your lens needs electronic control for aperture, choose a setup that lets you retain that control.
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