Scanning and ETTR

As it’s come up in a separate thread. When digitizing negatives using a camera I’ve seen it suggested to expose to the right. When using a scanner each image pretty much gets exposed at the same level, and then if you have an additional scan to boost shadows in slides this seems to be about another stop. So it looks like with scanners the exposure is fixed (presumably based on some features of the hardware). If you do multiple scans on negatives I’ve never seen any particular difference in the results.

So my question is, given that exposure on scanners appears fixed, has anyone done any tests with ETTR on a negative vs an average exposure when digitizing using a camera, and and found a significant difference ? I’m thinking here for well exposed negatives in the first place.

I used a camera to digitize all my film negs several years ago. I think I had the camera set to evaluative metering, but the brightness range of an image of a negative isn't very great -- much less than that of an image of an outdoor scene. Looking at some examples, I see that the shutter times vary from 1/20 to 1/50.

Don

That’s pretty much what I’ve done on the few times I’ve used a camera rather than a scanner. It did concern me for slides at least that the camera corrected the exposure (so an underexposed slide would be given a stop or two more to correct it), but generally it did a good job. I’d never seen the need to use anything other than the metered exposure - I suppose it would be simple enough to set up - metered and ETTR exposure and see what the difference is.

I digitize negs with a GFX 100S and a Rodie 105/5.6 HR DIgaron. I use ETTR with a magenta filter for B&W negs. Can't hurt, might help, although the noise from the grain is the long pole in the tent.

And I wish all my negs were consistent enough that I could use the same exposure for everything.

Is the magenta filter to remove the green and improve resolution ? Does it make much of a difference ? I don’t do much B+W but I’ve seen suggested (with a scanner) to use just the blue channel for the image.

The magenta filter -- actually a Rosco minus green -- is to equalize the raw channels and improve the SNR. It doesn't make that much difference. If you just use the blue channel you get less diffraction but half the resolution. Maybe just the blue channel and pixel shift? But with 100 MP and the Rodie HR, I'm getting most of what's there out of the negs.