JanOriginally Posted by Sheiky
Your method will work, however it takes longer to get the same results. It is a method I used for a long time.
What I see as one of the real benefits of the ruler is that it tells you what your DOF is doing overall. I don't agree that the LensAllign would cost you +/- 1, I would agree your camera will vary that much though. You can be +1/-1 and you will still have quit a few pics in focus, just as if you were dead on. There will be two reasons for this, one is that your AF system isn't pin point accurate, when you move forward or back you end up with either shots that were a bit back focused at dead center coming in to sharp focus or vice/versa for front focus if you go the other way. The other reason is that depending on your lens, your DOF still covers the target.
I would also say, that with the 500mm the +/- 1 matters more than with many other lenses. The wider the lens the wider the DOF, and of course a wider DOF is more forgiving. With the 500mm if you are shooting birds or small wildlife it is a narrow DOF, the fine detail of an eye can be one of the most important aspects of a shot. Luckily, I have found that the big telephoto's are the easiest to get dead on of all the lenses. They are much more accurate and consistent than any other lens I own. If you are a little off one way or the other your keeper rate will start to fall.
I still think Bob's configuration will work. The only thing I see left is he hasn't incorporated a way to easily square and align the target. The lensalign uses two holes that you peep through to get alignment. I think there would be a way to overcome that, with a little surveying and carpentry know how.
Bob, one other note. If you decided to buy a lensalign, you wouldn't have to buy the $150 version unless you wanted to test at the longer distances. They also sell the ruler and face plate as add on's, so if you think you need them later you can order it separate.
Rick
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