Joe has gone to a lot of trouble and applied some really inventive thinking to come up with his fixes. His glass is fuller than mine in that he sees acceptable results as reachable over a broader range of lenses and shutter speeds than I do, Still, his ideas should help under almost any circumstances.
How could two careful testers come to (slightly) different conclusions? Although our thinking is alike, we’re using different methods, lenses, and somewhat different implementations, with Joe’s fixes being more sophisticated and probably more effective than mine. There’s a difference in emphasis in our work; I’m trying mainly to analyze the problem, and Joe’s concentrating most of his efforts on fixing it. However, beyond that I think there are two reasons why we’re looking a bit differently at how successful a solution we can expect. First, the effect of shutter shock depends on something that for the most part goes unnoticed: the lens resolution.
I know some technically-interested photographers, among them Huntington Witherill and Mike Collette. Both have made guest posts – here’s Mike’s – in my blog about the a7R shutter shock. I’ve also been corresponding with other people about the problem. Recently, someone announced that, using the Witherill lens mounting method, that he had completely tamed the a7R shutter shock for a Canon zoom for all shutter speeds and all focal lengths out to 200mm. Well, I was amazed. Being from Missouri, I asked to see files from shots of ISO 12233 targets. When I looked at them, I saw that the lens was not resolving detail to the sensor’s pitch, or anywhere near it. Thus, the shutter shock motion was buried in the lens fuzziness. The photographer who claimed to have solved the shutter shock problem was completely right, for that lens. I’m pretty sure he would have had the problem with an optic of greater resolving power. I have been using some pretty special fixed-focal-length lenses for my testing. For example, in the last two tests, I’ve used the Leica 135mm f/3.4 APO Telyt on the a7R and the Zeiss 135mm f/2 APO Sonnar ZF.2 on the D800E.
The second difference is the target. I’m using the ISO 12233 chart at 600 to 900 pixels vertical extent, which is an extremely demanding test. I can see effects with that target that would probably never be noticed in ordinary photography.
For those two reasons, my results are very conservative — they portray the a7R’s shutter in the most glaring, hard-edged light and make its flaws stand out. You may wish to derate some of my conclusions to make them more applicable to your lenses, subject matter, and output resolution.
There are other possible contributing differences. In the latest iteration of my testing, I’m checking my highest shutter speed results against trailing-curtain triggered 1/13000 second electronic flash. I’m also using 5500K illumination for the continuously-lit images, which minimizes the effect of diffraction compared to tungsten lighting (I still have to quantify this — it may not be significant.)
[Edit 5/3/2014: Since I originally posted this, in addition to the methods described above, I have been employing slanted edge MTF testing to get information of shutter shock. Here’s a link to a representative set of curves for the a7 and a7R,]