From Tim Jackson’s Nikon D70 Site.
Grab the PDF print out of Tim’s Focus Test Chart here and test the focus of your D70 or a particular lens.
Until reading Tim’s PDF, I wasn’t aware that there was a back-focusing issue with some D70 cameras; however, I was aware of some photographers complaining about getting a bad copy of a lens, due to issues with back-focus or front-focus.
I wanted to know what this was exactly and how to test for it. This has become important to me for two reasons:
- I can see it now. As my ability to critically analyze a photograph has improved, I notice when the focus is slightly off from where I, or another photographer, has intended it to be; and
- Because I don’t have the money to collect lenses, I buy and sell according to my current photographic needs. Whether purchasing new or used, I’d like to see if I have a good copy of a lens, and/or need to have my camera re-calibrated for any focus issues.
Tim’s PDF explains how auto-focus works, and what back-focus and front-focus issues look like. He also provides a DIY test chart and clear instructions how to use it. He also points out that focus issues are most likely due to operator error, rather than camera or lens problems.
There are some who disagree with Tim’s approach, but he appears to provide substantive answers to those arguments. I don’t have the background for a definitive conclusion to this back-and-forth, but Tim’s approach seems reasonable to me. I’ll likely do further research.
To summarize, Tim’s Focus Test Chart and explanations are a good read and something I’m looking forward to trying with my camera and lenses.
