Sony Camera Upgrades - Color and Pixel Shift

[silvergelatin]

I am gradually upgrading pieces of my scanning system (ordered a Scanlight and will likely trade in my 70mm Macro Art lens for the 105), and am considering trading in my A7RII for either the III or IV. The main reason is to have pixel shift available to get better color, shadow detail, and reduced noise. Most threads I have read seem to focus on spatial resolution, but I’m more concerned with the other benefits.

Obviously the IV is the more serious upgrade on paper, since the sensor is newer and higher res, but does it actually provide better color and noise performance compared to the older models? For example, if I ran a four shot pixel shift with the III and the IV, would there be any advantage to the IV other than spatial resolution?

 

[koraks]

Pixel shift has come up a couple of times in this context here on Photrio, but I don't recall anyone reporting any significant practical benefit.

 

[silvergelatin]

Pixel shift has come up a couple of times in this context here on Photrio, but I don't recall anyone reporting any significant practical benefit.

Those threads seem to focus on spatial resolution and not the other aspects.

 

[koraks]

Okay, gotcha.

 

[Ardpatrick]

I can't answer your question, because I haven't tried it. But I've been reading quite a bit online about camera scanning and pixel shift myself. My guess is the difference between the III and the IV would be minor, beyond the colour benefit they both derive from pixel shift in general. There does seem to be fairly wide consensus about the benefits of pixel shift for colour, but the evidence around spatial resolution is less conclusive. Something I haven't seen discussed widely for example, which would be a consideration for your new set-up, is the resolving capabilities of the lens you're using. Can the lens resolve anything close to the 240 megapixel file the AR7 IV produces?

 

[loccdor]

There really shouldn't be much noise to speak of from any version of the camera at the low ISO you would use for film digitization.

Color reproduction improves by using pixel shift vs. not. How much, I haven't tested, but others will have results online you can look at.

The IV version of the camera has a half-pixel shift 16 shot mode for 230 MP files. I've never tried such a mode, my Pentax K-1 (first version) has 4 shot mode. I'd expect diminishing returns and huge files. If the resolution is truly there, then expect to struggle a lot with film flatness, parallelism, diffraction, and focus, in order to achieve it. It would also slow down the rate at which you can digitize a roll.

With film digitization, you'd need an extremely contrasty negative/positive for the shadow detail of your digitizing camera to come into play. I don't think this will matter much for 99% of circumstances.

Pixel shift was the deciding factor when comparing a 50MP camera without it to a 36MP with it in the same price bracket. Your III and IV cameras seem to be pretty close in price and one has quite a few more megapixels. If you're primarily a 35mm shooter, I'd personally go for something with pixel shift cheaper than both of them, unless you consistently use very high resolution film. If you shoot tons of medium format, maybe it will be useful for you.

 

[Ardpatrick]

To add - if you’re after improved colour the light source will be really important. I use flash (as opposed to continuous light sources) and I know that some but not all cameras that do pixel shift can work with flash.

Whatever about the relative CRI merits of continuous vs flash, at least I know I’m not suffering with camera shake whilst shooting very highly magnified images when using flash. For critical sharpness flash is hard to beat.

 

[4season]

I very much like the pixel-shift feature, not just for the added resolution, but for the way it can eliminate aliasing artifacts. But to date, it hasn't seemed particularly useful for scanning film. Maybe if I were dealing with microfilm or microfiche, or wished to digitize high-res halftones?

Negatives don't seem to challenge the digital camera at all with regard to colors or dynamic range. Likely that 8-bit JPEG would provide more than adequate coverage. Nevertheless, scanning can be rewarding, as there can be a good deal of useful detail in shadows and highlights, albeit tonally compressed.

Slides can be more challenging in terms of dynamic range, and to date, my efforts to extract additional shadow and highlight detail have been met with very modest success: There simply doesn't seem to be much data there, and what little there is is often heavily compressed.

Fujifilm Instax prints have been a pleasant surprise though: There can be a decent amount of tonality in the highlights which isn't always immediately apparent when viewing the original print.