Quote Originally Posted by Todd Ovick


I have a question that is somewhat related to this post,....


I will be performing these AFMAs when I receive the lensalign mk II.


Does anyone know if having a UV filter on the lens while performing this test makes any difference?


Todd


I never take the filter off and have never noticed a problem that I could associate with it. For example the problem I was talking about above, all of my results were consistent with each other. Meaning that that if I repeated the same test over and over the result was exactly the same. In fact I did over 800 shots in this set of tests. The AF system of the camera was focusing the same place each time.


I have heard people say you should remove it, and its always because of other problems they are having.


But my thinking is this. If you are getting some really wild results and think your lens is bad. Then take the filter off to test. But if you are going to have this filter on in real life shooting, and your lens with the filter on is consistent with itself (meaning for instance you have a prime lens and it is showing a group of shots that average a back focus). Then you should leave the filter on and simulate your real life shooting set up so that when you go out to take pictures it will be the same as you calibrated for.


Think about it this way, what good would it be if the filter did make the lens back focus or forward focus. Then you took it off and made your settings, then you put the filter back on and make it inaccurate and go out and take pictures. You end up with a lot of out of focus pics.


Rick