Re: REIKAN FOCAL 1.2 Free Download
Nelson Suggs
I didn't test extension tubes (what focal length was detected), for adapted Sony/Canon lenses, Nikon camera body reported as different lenses (from Nikon ever made ) with correct focal lengths, and also had some shifts on Z7. The official answer from Nikon (when I asked) for AF shift on DSLR was "spherical aberration". But when I asked why again AF shift on Z7 they didn't have the answer. When I saw here:
I didn't test extension tubes (what focal length was detected), for adapted Sony/Canon lenses, Nikon camera body reported as different lenses (from Nikon ever made ) with correct focal lengths, and also had some shifts on Z7. The official answer from Nikon (when I asked) for AF shift on DSLR was "spherical aberration". But when I asked why again AF shift on Z7 they didn't have the answer. . .
Starting with my art 35mm, the focal setup is exactly as prescribed, very careful placement, lighting, distances etc. The test was run 3 times and gave completely consistent readings of -16 adjustment, however when that is dialled in, the lens is clearly backfocussing, probably by that amount ar thereabouts - i.e. in everyday use (albeit a new lens to me) there was no identifiable problem, and I was expecting at most a plus or minus 1 or 2 for real fine tuning.
It's also worth saying that there is NO correct AF Fine tune for some lenses. Some zooms are significantly different zoomed in and out. Some lenses (my 85/1.4 is awful) are significantly different for close and far. I'm a big proponent of testing it where you use it, i.e. at the focal length and distance, as well as close and far and in and out to see how it varies, but give a lot of weight to the place you use it.
Forget about it with D lenses - use the target and your eyes to set the needed AF adjustment, the AF tests consistently failed with Focal using D lenses. Pretty good with all G lenses, make sure to calibrate zooms at the widest focal length. Pretty good with all Sigma Art lenses, 24mm to 135mm tested.
Pretty good with D lenses except for the 105mm and 135mm DC lenses, calibrate AF on those by hand if needed. Pretty good with all G lenses, make sure to calibrate zooms at the widest focal length. Pretty good with all Sigma Art lenses, 24mm to 135mm tested.
Pretty good with D lenses except for the 105mm and 135mm DC lenses, calibrate AF on those by hand if needed. Pretty good with all G lenses, make sure to calibrate zooms at the widest focal length. Mixed results with Sigma Art lenses - most of them got a below average "fit" rating during calibration, two of the lenses (50mm and 85mm) both said they needed greater than -20 calibrations, but I found they were very accurate (focusing on an eyeball at f1.4) in the -18 to -20 correction range.
That said, calibrating a prime is one thing, calibrating a zoom is futile. If you calibrate for one focal length, the other ranges will not focus as accurately. This happens with some zooms out of the box. So, caveat emptor!
Started at Noon... kept going until 5 p.m. trying various focal lengths, tripod distances from target and aperture settings... EVEN TRIED IT ON TWO COMPUTERS, MY DELL 12 GIG Desktop and my Notebook that has 8 gigs... both gave the same results.
I found that the process was simple and intuitive, although, particularly with long lenses, the recommended A4/US Letter size printed target was too small in the LiveView display to work. Printing it at a larger size cured this however. You do need to be prepared to move the camera and tripod to accommodate different focal lengths, although for underwater use, with mostly wide-angle or macro lenses this is perhaps less of a problem.
aa06259810