On Sharpness, ISO and Shutter Speed

Started Nov 29, 2013 | Discussions thread
ferrellmc Regular Member • Posts: 106
Re: Create a base image with no shutter vibration

Steen Bay wrote:

ferrellmc wrote:

Jack Hogan wrote:

Good idea. People with affected cameras and strobe/lights will want to try it.

I did the test with the A7R, the results are here, scroll down to part II:


I found that there is no discernible difference between an image taken with a strobe while the shutter was open for 10 seconds ie. no shutter vibration and a normal exposure with shutter vibration. I checked with a 35mm FE lens and a Nikon 85mm 1.4 and metabones adapter. I also did not see any difference in the A7R mounted on a sturdy tripod or resting on a table top. Both had image quality matching the strobe image with no shutter vibration.

I feel very comfortable in my conclusion that the A7R is not losing image quality due to shutter vibration.

Comments, criticisms, suggestions welcome.

Shutter vibration/shock isn't an issue at 1/3 sec. The critical shutter speeds are between 1/40 and 1/250 sec, or so (worst at 1/80 to 1/100 sec).

I tested 1/5  1/3  1/10  1/20  1/40  1/80  1/160  1/320..... None looked discernibly different with either lens: 35mm FE28 or the 85mm 1.4. The camera was mounted on a Really Right Stuff tripod, not a rink-dink one.

Here is a summary screen capture:

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