Thursday, November 14, 2013

FoCal - Focus Adjustments on D4 part 1

 As with just about any nature/wildlife/bird photographer I am always hoping/trying for better focus.  I've tuned many of my camera+lens combos using the AF-Fine Tune / Manual Adjustment.  I've tried using a big printed Sign as a target as well as a printed target positioned at an angle.

A couple weeks ago I bought FoCal (on the recommendation of Andy), the computer assisted focus tuning software.  In a nutshell, you connect the camera to a laptop running this software, setup a test target for shooting, and then with the software (sometimes plus some manual intervention during the tests) you run tests and the camera takes test shots, the software/laptop analyze the results and then the software recommends an optimal AF Fine Tune setting.

The following example results are from my first few test runs, and before I learned all the possible things you can adjust in the test software to improve results.  These additional settings w/ the Pro Version include increasing the ISO to make sharper (higher shutter speed) test shots, as well as target optimizations which improve test results across photo samples.

The D4 tests are my camera and a few lenses.  The D300 and D7100 are my brother's cameras with his 80-400mm.




The software worked pretty well, even given that I didn't know all the options available w/ the pro version (ISO and optimization).  It was often able to establish a curve across the test focus shots, leading to a good recommendation for AF fine time value.

Here are the results in a table:
CameraLensQuality of Focus [QoF]
D480-400mm (#1)1270
D30080-400mm (#2)730
D700080-400mm (#2)620

While the D4 is a great camera, and I am happy with those initial results, it is interesting to compare the QoF/Quality of Focus results.

I was surprised that the 14-24mm scored so low relative to the other results.  My tests were not perfect by any means so, a new set of tests might show it performs better.

The gear I have has performed fairly well over time.  I've tried lots of things to make it work - tripod, higher ISO for higher shutter speeds, AF-fine tune, etc.

The results that are odd and seem out of place are my brother's results from the D300/D7000 w/ 80-400mm (his lens).  These results were lower than all of my results w/ my D4.  My brother's had concerns over focus and sharpness.  While it is tough to compare focus results of a D4 to a D300 or D7000,  I had better results with my 80-400, as well as my D7100 (results not shared here).

I'm very interested in what other people have recorded for the 80-400mm lens, as well as their D300's and D7000's.  Please post your results for QoF in the comments.

Over the next couple months I plan to test my 80-400mm on my brother's bodies.  And I plan to test his 80-400mm on my bodies.  These will provide some good tests to compare.

I'm also going to re-run my tests at higher shutter speeds via higher ISO settings.  This is part of the FoCal pro options. / Jon