Nikon D200 + Nikkor 17-55 f/2.8 @ 55mm — ¹/1250 sec, f/2.8, ISO 400 — full exif

During the three-month ordeal of autofocus problems with my Nikkor 70-200 f/2.8 zoom, between suspecting a problem and finally having it fixed by Nikon, I learned a lot about SLR autofocus — how it works, and how best to test it.

There are plenty of autofocus test charts available on the web, but all of them were severely deficient in one way or another, so I ended up making my own. Its development progressed over time as I tried different approaches, discarding what didn't work and refining what did. (The chart I used in November shows elements of both.)

After Nikon finally fixed my equipment and I was able to retest it with the final version of the chart, I was pleased not only with how well my equipment worked, but also with how easily and confidently my chart allowed me to confirm it.

So, I'm finally ready to release my chart, with copious and verbose instructions on how to use it, as another of my photography-tech posts:

Jeffrey's Autofocus Test Chart

If you at all suspect you have autofocus issues with your lens or you body, I encourage you to check it out.

Some of my other photography-tech posts are highlighted in the box at right.