On Sharpness, ISO and Shutter Speed

Started Nov 29, 2013 | Discussions thread
Anders W
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Re: good idea, change light level to get different shutter speeds
In reply to Jack Hogan, Nov 30, 2013

Jack Hogan wrote:

RussellInCincinnati wrote: Hope nobody reading this thread thinks that shutter shock has any practical significance.

Well, I don't know whether what we are seeing is shutter shock, that is just one of a number of possibilities.

One might add that regardless of whether these samples reflect shutter shock or something else, shutter shock is well known to cause problems of a kind that certainly matters. Here is a report on my first encounter with manifest as opposed to subtle shutter shock:

http://www.dpreview.com/forums/post/52507678

I now know a number of ways to work around such manifest problems as well as more subtle ones. A report of how I do that can be found here:

http://www.dpreview.com/forums/post/52603448

This thread exposes that we have to get to a test bench to see even a 10% change in resolution. How in an ordinary world scene would somebody ever notice this in anything but extreme telephoto work, when even then the variables of what camera you have, what lens you have, what aperture you're using, accuracy and depth of focus, post-processing noise reduction, lens field curvature, inherent scene contrast and "edginess", post-processing sharpening, light level and effective sensor ISO, overall camera shake, presence or absence of various kinds of stabilization, flare level and subject movement will in all likelihood overwhelm "shutter shock" effects.

True. Although some of us use a tripod for many of our captures and work with perfectly still subjets (landscapes;-). So after seeing some surprises in the curves, the first question that came to my mind was 'is my technique better than DPR's? Followed by 'should I be attempting to avoid certain shutter speeds, when going for maximum resolution? - maybe I should run a few tests with my camera and my setup'.

I think you should. Better safe than sorry. If you haven't run into any problems yet, that suggests that you probably have no shutter-shock problems of a really serious kind. This, however, does not mean that you don't have any shutter-shock problems at all. Even when the blur is slight, it can easily be on the same order of magnitude as the difference between a really good lens and one that is only so-so. Personally, I prefer having the performance of the really good lenses I paid for.

We can only speculate at this stage, so it would be best to leave it to someone who can do proper targeted testing as far as these cameras are concerned. But since this is the first time that I have seen curves like this I thought others may find them interesting and possibly help explain some of the anomalies.

Lots of tests have already been carried out, primarily with mirrorless cameras (above all MFT cameras) but also with SLRs. Of course that doesn't mean than more and even better tests are not welcome.

What the evidence presented in this thread (and some others before that) primarily suggests is that DPR has to do something about the way they shoot their studio scene samples. The studio scene samples should show the image quality of which the camera is capable under the best of circumstances, and in quite a few cases, they currently do not manage to do so. If a camera has shutter-shock problems, it may be important to discuss and exemplify that elsewhere in the review, but not in the studio scene samples.

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