Is In Focus … in Focus?
Back in the day, I had a Vivitar 80-200. My photos were soft and I swore it wasn’t me but how to quantify my belief? I got a newspaper, taped it to the garage door, leveled out my camera to the newspaper and took some shots. When the film came back, I could see that what I thought, was true. Photographers still wonder if they are getting all they should be from their glass. These days some shooters now that we have an AF system question whether if the AF is delivering all the lens has to offer. There isn’t a day the question doesn’t hit my desk, “do you calibrate your AF system?” Since my system is delivering, and I know that because of the 28foot by 18foot prints made from my files, I’ve not bothered. My images are sharp. But with so many asking, I wanted to quantify what I know. After seeing this excellent piece in Rangefinder I decided to do a little testing (I will refer to this piece later).
I decided to test the AF in my D5 with five lenses: 24f1.4, 50f1.4, 105f1.4, 300PF and 800f5.6. Cutting to the chase, I made no changes to the Set Up > AF Fine-tune after testing for this body and these lenses. Will I test more lenses and more bodies after this? Nope! There are two reasons why: one, I’m not having focusing problems and two, the testing is a pain in the &$#$!) Now if you want to test for yourself because you see focus issues in your photos (you see them, not read about them), here’s how I did my testing.
First, I went and got from B&H the SpyderLensCal Autofocus Calibration Aid which is far superior to a newspaper! I then set up the Sypderlenscal as you see in the lower photograph. The white arrow points to a built in level which works really well. I did double check it was all plum with my laser plum from the garage (which came in handy the whole time). Then I set up the camera with the 24f1.4 first. Using the same laser level I plummed the camera back so the dead center AF sensor lined up perfectly on the center square on the Spyderlenscal (red square in above photo). Once that was accomplished, which is time consuming, I shot at three different distancces from the Spyderlenscal wide open, f/8 and f/22. I did this same thing for all five lenses. After I got all done and went to tare down everything, I noticed the angle calibrator had moved from its default position (red arrow). Argh, I’d knocked it! So after putting gaffers tape on that point so it wouldn’t move again, I did it all over again (I left some set up details out, you get them all in the Rangefinder link above).
Five hours later, I was in PhotoMechanic looking at my results. It confirmed what I already knew, I didn’t need to use the AF Fine-tune. When you do this testing and you find an issue? As the video says so well, you have to make an adjustment in the AF Fine-tune, shoot the test again and check. You might have to do that many times if you have an issue. So now I can honestly say that for at least my D5 and these five lenses, I have tested and don’t need AF Fine Tune. If you have any doubts, I recommend you go through the pain and find the answer for yourself and your gear, is in focus, in focus.