Digiscans: Does the Sony A7RM2 electronic shutter mode affect image depth?

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alpshiker Regular Member • Posts: 476
Digiscans: Does the Sony A7RM2 electronic shutter mode affect image depth?

Can I share some experience and benefit from other's as well?

For the purpose of copying slides and negatives, am switching from the former setting which consisted of an A7R on a light box with flash illumination, to the A7RII with a LED panel. The flash was useful to eliminate the shutter vibration. But with the M2, shutter vibrations aren't noticeable and the continuous light is more comfortable to work with, although I might have to find a more evenly lit panel than the Kaiser slim lite plano that I just got, which is good on colours however. To further benefit from the A7RII, I am considering the silent mode for its total absence of vibration. But I have seen mentioned here and there that this mode will switch from 14 bit to 12 bit read out. Synchronous LED light can also be a problem, but probably not for long exposures.

I should probably make some comparison tests for myself to see if something is lost in the process, but my question is : does the silent mode always sample the images with a lower gradation? Or does it switch to that lower bit sampling only when the speed, or the frame rate, are too high for its processing to cope with?

What I have to copy is for one part an archive of family negatives. Even the 12 bit mode should be overkill for this purpose.

But I have also an enormous stock of 120 and 4X5" slides. I am astonished when I see how these Fujichromes have retained their original colours after 20 to 30 years in a closet. At the time, I had scanned the keepers using a drum scanner, and later an Eversmart. The drum had 12 bit and the flatbed 14 bit input, but both were only 8 bit output files capable. So there is not much latitude for post editing those scans, mostly from Velvia, Provia and Astia, without getting banding, blocked shadows or washed highlights. Even grain removal will make banding appear in the sky and working the 8 bit scans in 16 bit does not make too much sense.

So, if I can find the time to redo this job, shooting and editing those 14 bit digi-scans in 16 bit (if this assertion is right) with the enormous density range provided by the Sony and a custom camera profile, will bring another depth to the old images. The scanners were also limited to 2540 dpi, and scanning a 4x5" in that resolution would take 40 minutes for a 380 MB file (I had an early SCSI model that could not be upgraded). Now with the 42 MP sensor and image stitching, it takes less than a minute to digitalize 8 crops, generating a 250 MP file from a 4x5". But it takes certainly more time to edit! Flare is also well under control with the camera, and results are comparable if not better sharpness wise, to what a drum scanner produces, with the additional benefit of RAW. The samples are promising.

Sony a7R
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