I took a Nikon D4, mounted the 105mm f/2.8 Nikon G ED lens, turned off VR, and mounted it on a RRS TVC-34L Versa Series 3 tripod and a RRS BH-55 ball head. I extended the top two leg sections, but not the bottom one. I left the column in the down position. My first… [Read More]
Archives for November 2013
Sharpness testing, part 4
Well, I thought I was done with the preliminaries, but it occurs to me that the standard deviation is going to vary linearly with exposure. I wrote some code to check that and correct for it. Then I came up with a way to simultaneously correct for overall exposure variation, and exposure variation caused by… [Read More]
Sharpness testing, part 3
Before I deal with all the uncontrollable and semi-controllable variables involved in making actual test photographs, I did some simulation to make sure the target would work the way I thought it would under completely controlled, albeit unreal, conditions. I wrote this Matlab script: I ran it, and plotted the results. As expected, more low-pass… [Read More]
Auto-bracketing on the M240
I went for a walk this morning, and took along what is becoming my constant companion when I don’t have anything particular in mind, but I think that a picture might jump out in front of me: the M240 with the 28mm Elmarit-M ASPH. No EVF. Small, light, and unobtrusive. The 28 is pretty soft… [Read More]
Sharpness testing, part 2
I wrote a little Matlab program to generate the targets: And, yes, all you Matlab experts, I know it can be coded a lot more efficiently, even by me. I wrote it this way so that any Java or C programmer could figure it out. Here’s what a close up of the first four layers… [Read More]