I read this last night and spent the morning on it.
Vignetting is routinely measured in lens tests and 1-2 stops wide open is entirely normal for wides in any system. As such, I'd suggest perhaps more of a focus on measurement than subjective reviews would be helpful. Or, if it's important to continue thinking of ~1.5 stops of vignetting as quite bad, then avoiding measurements of ultrawides, wide primes, and certain lenses such as the
EF-M 15-45 would probably be a good choice.
Coming from fast (f1.4 primes) I did not expect to see vignetting at f3.5. I was wrong. I continue to feel the lens is fine. I assume your "avoiding measurements" should read simply "avoiding". To which I'll respond its too early for that. I bought this system for travel and will simply have to get used to this lens. Looking at my trip to Canyonlands, 12mm turned out to be my most used focal length. Wider and the perspective distortion becomes too difficult for me.
Depending on it's exact intent, the claim of "pretty much all apertures" made in this thread's first post may be poorly supported by measurements of the 12-35 and 12-60.
The only measurements I found of the 12-60, along with images, was the Lens Tip tests. After adjustments (SOOC jpeg). At f8 vignetting is -.8ev. Thats readily visible in the corners with a light sky, be it blue or grey. It also creates a large, though subdued, vignetted area that's creeps well into the image. I don't go past f8 with m4/3. Don't know what its like beyond that. Call me picky, call me spoiled but I see it and I'd prefer not to. And no I am not selling prints. This is purely amateur travel photography hoping I come back with more than a slide show. For those, I'd prefer not having to correct uneven lighting.
Took many shots of the sky and a blank wall this morning with all sorts of filters and hoods I generally use when filters are preferred (not often but were used in the shots out west that led to my initial post). Agree, without the ancient (thick) 58mm PL filter I was using, the vignetting is almost gone mostly acceptable by f8. But at f3.5 and 5.6 I need/want to deal with it. Unfortunately there's insufficient room to mount a 62mm step-up + 62mm pl with the stock hood is mounted. My usual screw-on hood exacerbates the vignetting. Will need to look at alternate hoods or another PL.
One possibility is the core concept you're looking for is cos⁴() falloff, which is routinely described in introductions to lens properties. So lots of options to choose from if one's so inclined. It's a simplification but is broadly applicable and often referred to as a law (
Gardner 1947).
This led to some interesting reactions. After the second read I embraced what Gardner said, "To determine the size of either entrance or exit pupil by computation is a tedious process." Conceptually I think I'm there. I don't need to understand the math or purchase an equipped lab and conduct experiments. But thank you as the paper led to other reads that were also new information for me.
For example, some
similar lenses measured to have one to two stops of vignetting are
- Canon 15-85
- Fuji 16-50
- Fuji 16-55
- Nikon 16-85
- Olympus 12-40
- Olympus 12-50
- Olympus 12-100
- Panasonic-Leica 12-60
- Sony 16-50 f/2.8
- Zeiss 16-70
However, it's a bit unclear from the above whether this is the correct range of stops.
I owned the Fuji 16-50 and felt it was a 17 at best. Distortion correction cropped out the vignetting. A degree of correction which appears unnecessary with the P12-60.
Not having to create lensfun profiles is one of the reasons I like SOOCs, though I'm not aware of any manufacturer which fully corrects vignetting (0.5-1 stop after correction when wide open is normal for wides). I actually don't think I've ever needed to fall back to raw with the 12-60. On the rare occasions I've wanted vignette correction on raws, which is usually with the 100-300 II, I've used both
darktable and
RawTherapee.
I've been shooting jpegs for quite some time with Fuji. Adjusting the GX85 jpegs to my preference has yet to be done. I know I'm not there with the defaults and adjustments will take time. From a lens corrections pov, again with the P12-60, the jpeg offers essentially no advantage vs the raw file. The Panasonic corrections provided to Adobe result in essentially the same corners. Makes sense. Not fully correcting when wide open I assume is that the corrections are fixed across all fl's. If that's the case, makes sense and is reflected with this lens.
Given IBIS and OIS vignette reduction isn't necessarily trivially automatable as the position of the correction groups and sensor shifts the location of the optical axis. There are also quite a few threads here about inconsistent mechanical vignetting due to IBIS shifting corners of the sensor close to the edge of or out of the image circle. Anecdotally that seems to happen more with Olympus than Panasonic (not sure about Fuji, Nikon, or Sony's implementations) and could be argued to be more of a feature than a bug.
Understood, would expect its more likely in low light and dark corners. Sort of an environmental vignetting correction. There are inconsistencies in my Canyonlands images. But I'm not going into IBIS and OIS effects. Life's too short.
