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Rear shutter vibration answers

 
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BobW AZ



Joined: 23 Feb 2006
Posts: 2
Location: Phoenix, AZ

PostPosted: Thu Mar 09, 2006 3:31 pm    Post subject: Reply with quote

Tested the 1/10 setting of the rear curtain shutter with camera tripod mounted, 127mm lens, bellows extended about 1/3 to 1/2, a mid range f stop. Shot same scene and setup with curtain shutter and lens shutter then compared the negatives with a loupe. Result: oddly enough the foreground was indistinguishable but there was noticeable loss of sharpness in the background areas. I would have thought the opposite would be the case if there were camera movement, since it would seem that closer objects would be more affected by movement. The loss of sharpness looks more like a very significant change in f stop resulting in loss of depth of field but the exposure is very close, though not exactly the same, maybe one stop off? I'm going to have to repeat the test and double check the f stop setting to make sure I did not inadvertently move it between exposures
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glennfromwy



Joined: 29 Nov 2001
Posts: 903
Location: S.W. Wyoming

PostPosted: Mon Mar 13, 2006 2:58 am    Post subject: Reply with quote

Think of camera movement as moving a long pole. At the point of origin. the film plane in this case, there is very little movement. As the subject distance increases, so does the effect of movement. Just as wiggling a long pole. It moves very little at your end and a bunch at the other. The effect increases significantly as lens focal length incrases, also. OR, you may have moved the aperture lever......
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