So this is the first of a bunch of questions that I have regarding my DSLR scanning workflow. First of all, here’s my setup:
Nikon D610 + 60mm 2.8 D Micro (at f/8)
DUNCO Copy Stand
Essential film Holder
I am shooting mostly Medium Format.
While trying the DSLR scanning for the first time last week, with my camera set on ‘A’ (Aperture Priority), LED set on 100% Brightness, sometimes the camera sets the shutter speed to 1/30, then for the next frame to 1/60 and then maybe even 1/100. And I’m wondering, will this cause inconsistencies in the brightness between the 10 scans of one roll? Since my LED is always on the same brightness setting and I am not changing the ISO or aperture? Or does it indeed depend on the brightness/exposure of the negative (dark scene vs bright scene) ?
Keep the SAME exposure for the entire roll . This will cut down on variance during processing. Beware auto exposure, as the small settings changes throughout the roll will create unwanted variance.
This also means that you’ll have to use the thinnest negative as the reference for exposure in order to prevent burnt highlights. You could also measure an unexposed piece of the film and set exposure manually to “overexpose” about 2 stops. Try how much your camera can take without burning highlights.
I shoot in manual mode only. First, you need to determine the optimal aperture for your lens. Set it and don’t change it. Second, set your ISO to the lowest natural setting for your camera. From that point on, those settings will never change. The only variable is shutter speed (and the power of your light sources but that is immaterial. Since the target is fixed, the shutter speed is just the final variable. You expose the shot for as long as it takes. In that way, all your scans are consistent.
The advice is all good. Aperture priority at f/5.6 or 8, ISO fixed anywhere between 50 and 200 (you won’t notice much difference).
Visually find your thinnest and most dense frames from the roll and pick a shutter speed somewhere in between.
Set lens to manual focus and use the camera’s digital zoom-in feature on the center of the negative frame to get most accurate focusing.
Take test shots of just those two frames.
Then, take a close look at the histograms of both shots to make sure there is no clipping on either one.
If you get clipping on either of the negative frames, adjust the shutter speed up or down for that roll.
You can also adjust the contrast in-camera somewhat to spread out or contract the histogram if you want.
My setup is a Nikon D700, Micro-Nikkor 55mm, Nikon bellows, Nikon negative/slide adapter, and a high-CRI LED flood lamp pointing at the negative adapter.
Personally, I leave shutter speed at auto rather than to set it fixed for the roll, and adjust the auto exposure up or down to center the histogram. Works OK for me.
I know all this. My question was, SHOULD I choose ONE shutter speed for the entire roll or is it gonna vary between the frames? Like for instance, indoor shot: shorter shutter speed. sunny shot: longer speed… ?
I would say that the aperture and ISO should remain constant but you can vary the shutter speed to obtain the proper exposure. Remember, you are shooting in a controlled environment but the original shots varied. Some may be in direct sun, some in the shade, and others indoors. I adjust my shutter speed to get a good exposure without clipping the whites or the blacks. Your aperture is set at the sharpest for your lens and the low ISO gives high detail with minimal noise. The shutter speed is changed to get proper exposure.
No. Shoot totally in manual mode. You have a controlled environment so you want all the variables to be determined by you. First, determine the lens’s sharpest aperture and set it there. Don’t change it. Second, set your ISO at the lowest natural setting. Mine is ISO 100. Don’t change it. Third, set your lighting however you want but don’t change it during a roll. Fourth, use your shutter speed to properly expose each frame in turn. Once you get your system set up, there usually isn’t much you have to adjust between frames.
Test a normal negative at base ISO, the sharpest aperture for your lens (you should have tested it for that when you bought it), and vary shutter speeds at third stop intervals over a six stop range. Base the range on a camera meter averaging or matrix reading of the normal negative. Run it through NLP, and examine the results, looking for the exposure that yields the best processing. When you find the right one, lock it down in 100% full manual ISO, f/stop, and shutter speed.
This is how we did it back in the days of slide duplication. The light source was a constant. The film speed and color balance for a given emulsion of duplicating film were constant. So for a given emulsion, the color correction filtration and the exposure needed to achieve black in the duplicate were the same. We only made changes to correct color or lighten/darken a smidge. But 95% of the time, we used our base exposure. I’ve found NLP to be the same ball of wax.
@Nate, what is the benefit of constant exposure (same iso, aperture and shutter speed) for all negatives of a film, if the film contains negatives that have been unevenly exposed, some negatives being thin, others dense?
You also recommend mild ETTR, which, in combination with the above, would deliver well positioned histograms for the thinnest negatives, but not for dense negatives.
I agree with Digitizer.
Aperture constant (optimal). ISO constant (base). Lighting (constant). Shutter speed (variable). Exposure mode (ETTR manual).
Exposure can be constant but only if the whole roll is uniformly exposed. For this, basing your fixed exposure on an unexposed negative +2 stops can work well. If some frames in a roll are under or over-exposed, using a constant exposure for an entire film roll will result in there being no compensation applied for the less than perfectly exposed frames. If this is the case, each negative needs to be individually exposed.
Think of camera scanning as just capturing sets of data and measuring them. The more variables were are able to eliminate while capturing the data, the cleaner the data set will be, and the better we will be able to use the data.
For instance, by keeping exposure fixed during capture, we can actually measure that some negatives in the roll are denser than others. This is useful to know and could be used in future algorithms.
Or currently, if you want to match negatives using the “sync scene” feature in Negative Lab Pro, it works best if the camera scan captures were done at the same exposures, otherwise the variance in the scans could create unexpected results.
So there is some clear benefit to keeping the exposure level fixed (although much of this potential is still being added to Negative Lab Pro) and will become more important in future version.
On the flip side, I don’t think there is that much to gain trying to optimize exposures for each individual shot. Perhaps you could very slightly improve the signal-to-noise ratio on a very dense shot, but for me at least, I think having the consistency in the data is more useful.
But of course, this is only my suggestion, please do what works best for you and your setup!
I would like to add my system and to also reiterate the recommendations others have made.
Keep the main settings constant:
ISO, best low base setting for your camera.
Aperture (testing will determine best sharpness just before diffraction degrades image quality).
Quality light source. Avoid cheap inconsistent slide viewers, craft store tracing pads, etc.
Other specs to consider:
Shutter speed, adjust for correct exposure. Check histogram in live view. If the entire roll is consistent you can consider an aperture that shows correct or a slightly over exposed setting, and fire away.
Electronic shutter to reduce vibrations.
Delayed shutter release.
Direct tether to PC or an app.
White Balance. My Viltrox light is set to 5600k and camera WB is at an equivalent setting, Daylight.
I use Camrote that connects to camera via Bluetooth and I select all these setting without touching camera and can view histogram to confirm exposure.