Frame averaging is so easy with Sony: a pixel shift shot will do it (4 shots, half the noise, see example and how-to), or you can use the remote and run off N frames effortlessly in a second or so. Piece of cake. Most other cameras can do something similar.
Prerequisite: physically touching the camera is a non-starter for frame averaging, because disturbing the camera by one micron is too much. Electronic shutter is mandatory to guarantee no vibration.
Fujifilm makes frame averaging difficult, with a poorly conceived feature set:
1. There is no wireless remote, so you cannot use one to quickly make multiple exposures with zero vibration. The wired remote exerts a force on the camera, no matter what.
2. Multiple exposure mode requires that you press the Menu/OK button for each frame—who thought that one up?
3. The pixel shift mode can in theory be used, but 16 frames is not workable in any practical sense: far too many frames taking too long (high risk of blurred details), and massive storage requirements. Not viable. And I’m after the average of the frames and one single frame as an alternative, not 16 huge files.
Fujifilm has designed a camera that makes frame averaging quite difficult. But it might be a moot point, given my update below.
Phone/tablet manual solution
Fortunately, there is a solution via Bluetooth, albeit a full manual kludge: the Fujifilm camera remote app on phone or tablet. It is an 4th rate science-fair solution: (a) requires two devices, (b) more power draw on both devices, (c) makes me pair/unpair/re-pair and cannot use any other Bluetooth device at the same time, (d) requires me to manually change shutter type and IBIS and ISO and raw-file type (14 bit => 16 bit), (d) iOS updates likely to break the app sooner or later, (e) it doesn’t stop down and stay that way for all exposures, (f) it doesn’t guarantee identical exposure or optimal exposure. And after all that, I have to switch everything back for regular shooting. Quite the mess.
In spite of all that, I tried the remote shutter release on the iPhone with satisfactory results, averaging 8 frames at ISO 3200 and confirmed excellent results. So it might be viable outdoors. But it is needlessly labor-intensive—changing all the settings and then having to manually take each frame as quick as I can. And then changing all the settings back if I want to shoot regular frames as I was. Then quitting the app so it doesn’t keep running in the background. And then back on the computer, having to do it all manually (but see my automated frame averaging script for Photoshop, which takes-out most of the tedium once the TIF-from-RAW layers are stacked).
UPDATE: I ran another test, and what I found is that the Fujifilm GFX100S cannot reliably keep the sensor in the same place frame-to-frame (IBIS off, electronic shutter, app used to make exposures so zero physical contact); fractional pixel movements occur frame to frame. As a result, frame averaging is useles, blurring all fine details.
Roy P Writes:
Two other items: One, you can use your phone as a wireless remote for your GFX 100S, although the Fujifilm app is buggy and poorly written. It keeps losing the Bluetooth connection and it’s slow. It’s supposed to give you a much more competent Live View experience, but I gave up after a few tries. It works better as a remote control, so it’s better than using the self-timer.
DIGLLOYD: the Fujifilm app "works" but IMO is a totally unworkable POS just because of the Bluetooth connection hassle—unreliable and lots of screwing around to make it work. And download speed of JPG is so slow as to be useless for any practical work. Plus holding a phone to take pictures is a clunky experience at best.
Below, image from Frame Averaging Case Study: Patriarch Grove Pre-Dawn.