#154. "RE: Testing of D800 with Reikan's FoCal application" In response to In response to 150
I have also just started testing with FoCal. I have done several tests and am now trying to standardize my testing protocol before testing again. I have a D800 and a D4. My preliminary results show consistency of focus for all camera/lens combinations ranging from 97.6-99.8% which seems good.
My tests with my 70-200 VR1 also show the sharpest aperture at f/2.8 on both the D4 and D800. Actually, my 70-200 has an unexpected inverted bell curve.
Here are some questions that I have regarding the testing protocol. I am using FoCal Pro version 126.96.36.199. 1. Should Target Optimization be turned on? I think so. 2. Does Color Temp really matter? I am testing with two Elinchrom studio strobes using the modeling lights at max setting. I am now setting the color temperature in FoCal at 3000K vs 5200 originally. 3. Should I be using mirror lockup? I haven't been. 4. I left the battery grip on my D800, is that OK? 5. I have the illumination consistently between 8-9EV using my studio lights. I check it with a light meter. Is the variability between 8 and 9 significant? 6. I printed the targets on 8X10 Luster paper. I know they recommended matte. I don't see any reflections or luster with my setup. What are your experiences using different paper? 7. I have been using the default AF Consistency Constraint of 6%. Is that what you are using or should it be tighter? 8. I have done one set of tests allowing non-centered alignment to test the left, center and right focal points. Has anyone else done this? My first test results on my D800 with 24-70mm showed -11, 1, -14. Yikes! I want to finalize the protocol before retesting. 9. What distances are you testing various lenses at? FoCal suggests the 25-50X the focal length. 10. For 200-400mm lenses what target size are you using? 11. My optimization tests normally peak around 2000. What is focal measuring? What is this number?
Thanks in advance for your input.
John Herrel Nikonian from South Carolina See the light, capture the essence!