Is there a difference between mechanical, first curtain or full electronic silent shutter for scanning?
My thought is that the more you can reduce or eliminate camera vibrations the sharper the final image. Especially since my exposure times range from 1/4 sec to 1/60 second at f13.
A73
Sigma 105mm f2.8 DG DN.
Viltrox video lignt.
Thanks
FW
A sturdy setup helps to reduce vibrations. Electronic shutter in combination with timed exposure should also help. To find the best conditions for your setup, take a few exposures at different settings and check if you can see any difference.
Longer exposure times are not bad per se, they can effectively prevent adverse effects from flickering backlights or vibrations that fade out, e.g from shutter vibrations.
The least vibration is likely electronic shutter. I use first curtain shutter with a delay of several seconds after actuating the shutter remotely. Can’t help but notice, adjust your setup to stay away from stopping down past f/8. There is virtually no usable depth of field at 1:1 magnification at any useful aperture, but there is definitely diffraction past f/8, and it will significantly affect sharpness. Also, the marked aperture of the lens, for example f/8, is for infinity focus. Your effective aperture at 1:1 could be as much as two stops further, or f/16, if you are extending the lens alone, for lenses in a classic design. A number of modern macro lenses work by shortening the focal length as you magnify, so the effective working aperture varies and is hard to calculate by traditional means. Ideally your camera and lens combo reads out the actual effective aperture and not simply what is marked. With a Nikon D850 and Nikon micro-nikkor lens, you get the actual effective aperture.
I will do a test for myself comparing the mechanical vs electronic shutter. All things being equal I would assume less moving parts equals less vibrations. I will also check sharpness, depth of field and the effects from diffraction.
I will get back with the results.
Thanks for your input.
FW
My setup:
Sony A73
Sigma 105mm 2.8 DG DN 1:1 macro
Electronic shutter.
Essential Film Holder.
Viltrox L116T video light.
LPL copystand.
Camrote (remote camera app. for adjusting camera settings and shutter release)
I did a test copying several different films covering a variety of subject matter at apertures ranging from f8 to f13.
I did notice a slight improvement at f8 over f13. Some scenes were more noticeable than others. I wouldn’t be too worried about it for doing general photography.
However when doing any copy work, the original will always lose some clarity just by copying it.
There’s no reason to give up any clarity if you don’t have to, so going forward, in an effort to keep copying resolution to the absolute highest I will continue at f8.
I would also recommend the max aperture range of f2.8 to f8 for any other critical work such as portraits, landscapes, field macro work or wildlife.
FW
Agree. I use the Sony a7iii as well but with the 90mm Sigma Macro lens. After testing the lens, I determined that for my scans, the best aperture for edge-to-edge sharpness was f/13. I’m certain it’s not as sharp as a dedicated scanning lens but it produces acceptable results for a personal collection that will mainly be viewed online. I do have to say that I am always astounded when people insist on using f/2.8 or even f/1.4 for scanning. It’s rarely the lens’ sharpest aperture and the depth of field in macro shooting leaves no margin for error.
I did some testing with my A73 and Sigma105 f2.8 macro DG DN. I tested scanned 35mm negatives using a range of f4 to f16 and the best aperture is f8 for sharpens. I could see the difference in finer details as I went through the range of f stops and diffraction occurs after f8. You can use smaller f stops it all depends on how fussy you are.
I just got the A7r3 and will test it for best sharpness. Not sure if the higher resolution will change when diffraction effects image quality. Will get back with results.
F
This isn’t a consideration for you with your A73 but a friend found a difference in dynamic range and noise between his mechanical & electronic shutter with a very difficult slide, the shadow detail was crucial to the image, the best result was from the mechanical shutter. It seems that this is because with some older models of camera the electronic shutter only records 12-bit RAWs, not 14-bit.