Strange Issue with GF 100-200? Sharp at f/5.6, but blurry at f/8!
p.1 #1Strange Issue with GF 100-200? Sharp at f/5.6, but blurry at f/8!
I'd heard this was one of the least sharp native lenses for GF (which is a very high bar!) but I wanted to try it out anyway so bought it used from another user here on FM. It is reasonably small and light, and feels well made. The lens collar is really nice and easy to remove, though I do wish they'd cut the foot for Arca Swiss.
But this copy of the lens is performing very strangely.... it is reasonably sharp wide open at f/5.6, but it is very blurry stopped down to f/8! f/11 is slightly better than f/8 but it is never gets as sharp as it is at f/5.6.
I'll attach some test shots below. All taken on a sturdy tripod using the lens foot on a windless day with a 10s timer and stabilization turned off. I tried both autofocus and manual focus, and I updated the firmware for both the lens and the camera body (GFX100S). I took multiple shots over several days to make sure they were not user error and they all look like this.
I've never heard of a lens being sharper wide open than it is with the aperture closed down by one stop, so could any other GF100-200 owners please chime in?
Here is a link to the full 100MP resolution album: https://ibb.co/album/tzdZD6
GF100-200 @ 100mm and ISO 100
GF100-200 @ 153mm and ISO 100. Note that the positions of f/11 and f/16 are switched in this set, sorry!
GF100-200 @ 200mm and ISO 100
But this copy of the lens is performing very strangely.... it is reasonably sharp wide open at f/5.6, but it is very blurry stopped down to f/8! f/11 is slightly better than f/8 but it is never gets as sharp as it is at f/5.6.
I'll attach some test shots below. All taken on a sturdy tripod using the lens foot on a windless day with a 10s timer and stabilization turned off. I tried both autofocus and manual focus, and I updated the firmware for both the lens and the camera body (GFX100S). I took multiple shots over several days to make sure they were not user error and they all look like this.
I've never heard of a lens being sharper wide open than it is with the aperture closed down by one stop, so could any other GF100-200 owners please chime in?
Here is a link to the full 100MP resolution album: https://ibb.co/album/tzdZD6
GF100-200 @ 100mm and ISO 100
GF100-200 @ 153mm and ISO 100. Note that the positions of f/11 and f/16 are switched in this set, sorry!
GF100-200 @ 200mm and ISO 100
Jul 14, 2026 at 03:51 PM
p.1 #2Strange Issue with GF 100-200? Sharp at f/5.6, but blurry at f/8!
Two possible reasons:
#1: Shutter shock. Can't magnify the images so I have no idea of what shutter speeds you used.
#2: Focus shift. Some lenses move focus slightly when stopping down, because of spherical aberration.
Edit: It's also possible that such a slow lens actually is sharpest wide open, at least partly because of diffraction softening when stopping down. But then it should be worse at f/11.
#1: Shutter shock. Can't magnify the images so I have no idea of what shutter speeds you used.
#2: Focus shift. Some lenses move focus slightly when stopping down, because of spherical aberration.
Edit: It's also possible that such a slow lens actually is sharpest wide open, at least partly because of diffraction softening when stopping down. But then it should be worse at f/11.
Jul 15, 2026 at 07:43 AM
p.1 #3Strange Issue with GF 100-200? Sharp at f/5.6, but blurry at f/8!
I found out the hard way to never use this lens with mechanical shutter. Once I switched away from mechanical shutter and used electronic shutter, sharpness issues disappeared.
Jul 15, 2026 at 08:19 AM
p.1 #4Strange Issue with GF 100-200? Sharp at f/5.6, but blurry at f/8!
Hmm, something looks off to me. I don't remember seeing focus shift like that, and my copy performed similarly from f5.6 to f11. I think the first priority is to determine if the focus is moving versus nowhere being in sharp focus. You can try taking shots of a ruler or rug (anything where the focal plane is easily visible) to see if it's shifting stopped down. Or try manually focusing at f8, though it will be difficult. There's a button dance necessary to manually focus stopped down.
I agree with the others saying to use electronic shutter only for testing a telephoto.
I agree with the others saying to use electronic shutter only for testing a telephoto.
Jul 15, 2026 at 11:07 AM
p.1 #5Strange Issue with GF 100-200? Sharp at f/5.6, but blurry at f/8!
I used to have similar problems with my first,brand new copy of GF 100-200/5.6 on GFX 100s.It was sent back to Fuji service somwhere in Portugal and after 2 months it came back with even worse optical performance.Finally Fuji replaced it with the new lens.
Jul 16, 2026 at 02:14 AM
p.1 #6Strange Issue with GF 100-200? Sharp at f/5.6, but blurry at f/8!
Thanks everyone. The issue was in fact shutter shock and I can't believe that hadn't occurred to me. With some pixel peeping I noticed the same issue with the 32-64 if I punch in more, so it just really does not like 1/80 to 1/200 shutter speed or so! Turning on IBIS/OIS does seem to help a bit when using mechanical shutter but still not as sharp as electronic shutter. A little annoying that I'll have to remember to switch from ME to ES when using those shutter speeds...
Oddly the 100-200 is still sharper at f/11 than it is at f/5.6, but it is much closer now and both are usable. Phew!
Oddly the 100-200 is still sharper at f/11 than it is at f/5.6, but it is much closer now and both are usable. Phew!
Jul 18, 2026 at 05:42 AM
p.1 #7Strange Issue with GF 100-200? Sharp at f/5.6, but blurry at f/8!
Just use EFC? The only drawback is for bokeh with high shutter speeds, over 1/500 or so. But it's hard to get that fast with an f5.6 lens in normal shooting at base ISO.
For really long lenses, Canon 100-400 and Fuji 500, I find full electronic shutter can be necessary; EFC isn't enough.
For really long lenses, Canon 100-400 and Fuji 500, I find full electronic shutter can be necessary; EFC isn't enough.
Jul 18, 2026 at 12:03 PM
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p.1 #8Strange Issue with GF 100-200? Sharp at f/5.6, but blurry at f/8!
"use ES" is INSANE cope for a $2300 lens made to be used on cameras whose sole advantage in its niche is having a mechanical shutter.
Jul 18, 2026 at 12:16 PM
p.1 #9Strange Issue with GF 100-200? Sharp at f/5.6, but blurry at f/8!
There's been such bank-and-forth about this lens over the years that I've retested my 2019 copy on several occasions and at several subject distances. After reviewing a couple of hundred images, here goes.
Around 200mm, I could never find a case where central definition was higher at f/11 than f/8; almost always there was the usual slight softening at f/11, and the couple of cases where f/8 and f/11 were similar centrally had questionable focus. Centrally between f/5.6 and f/8 there is little difference. On a high-quality shorter lens we should see visible difference, so there's that against this zoom.
The corners definitely benefit from f/8, and in some cases, f/11. The corners with most lenses benefit from stopping down two stops, so I regard this result normal.
All the above was on a substantial tripod with ES. Handheld or on a monopod one should use EFCS and stabilization. The effect of EF on bokeh depends both on aperture and on the distance of the exit pupil from the sensor. It can indeed be seen with a short lens at a very wide aperture, but with a long, slowish f/5.6 lens it's an utter red herring.
With a light tripod and mechanical shutter the risk of movement would be reduced by mounting the camera directly on the tripod rather than using the lens collar. And with sub-one-second exposures stabilization would likely help, defying blanket strictures about stabilization on tripods.
Maybe all of this is "INSANE cope." Maybe not.
Around 200mm, I could never find a case where central definition was higher at f/11 than f/8; almost always there was the usual slight softening at f/11, and the couple of cases where f/8 and f/11 were similar centrally had questionable focus. Centrally between f/5.6 and f/8 there is little difference. On a high-quality shorter lens we should see visible difference, so there's that against this zoom.
The corners definitely benefit from f/8, and in some cases, f/11. The corners with most lenses benefit from stopping down two stops, so I regard this result normal.
All the above was on a substantial tripod with ES. Handheld or on a monopod one should use EFCS and stabilization. The effect of EF on bokeh depends both on aperture and on the distance of the exit pupil from the sensor. It can indeed be seen with a short lens at a very wide aperture, but with a long, slowish f/5.6 lens it's an utter red herring.
With a light tripod and mechanical shutter the risk of movement would be reduced by mounting the camera directly on the tripod rather than using the lens collar. And with sub-one-second exposures stabilization would likely help, defying blanket strictures about stabilization on tripods.
Maybe all of this is "INSANE cope." Maybe not.
Jul 18, 2026 at 04:09 PM
p.1 #10Strange Issue with GF 100-200? Sharp at f/5.6, but blurry at f/8!
johnvanatta wrote:
Just use EFC? The only drawback is for bokeh with high shutter speeds, over 1/500 or so.
I don't know about the later models, but both my 50S II and the previous 50R automatically switched from EFCS to MS at speeds faster than 1/640, so no bokeh issues.
I only use pure electronic shutter on a tripod (because the readout speed is waaay too slow for hand-holding anyway), and that I have a custom bank for. So nothing really to remember.
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Edit: Regarding the general performance of the 100-200, it's somewhat questionable if you use it for landscape and other distant scenes. It seems optimized for closer range, where it's both very sharp and has nice bokeh.
Just use EFC? The only drawback is for bokeh with high shutter speeds, over 1/500 or so.
I don't know about the later models, but both my 50S II and the previous 50R automatically switched from EFCS to MS at speeds faster than 1/640, so no bokeh issues.
I only use pure electronic shutter on a tripod (because the readout speed is waaay too slow for hand-holding anyway), and that I have a custom bank for. So nothing really to remember.
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Edit: Regarding the general performance of the 100-200, it's somewhat questionable if you use it for landscape and other distant scenes. It seems optimized for closer range, where it's both very sharp and has nice bokeh.
Jul 19, 2026 at 05:32 AM
p.1 #11Strange Issue with GF 100-200? Sharp at f/5.6, but blurry at f/8!
I also experienced shutter shock for the first time with this lens on a tripod. EFC was an easy solution with the setup Makten suggests. I had really mixed results with the 100-200. I liked it better with 1.4x on and found that it needed a little more post processing to look good. I ultimately moved on to adapted options instead and traded away the 100-200.
Jul 19, 2026 at 04:52 PM
p.1 #12Strange Issue with GF 100-200? Sharp at f/5.6, but blurry at f/8!
SGinNorcal wrote:
I liked it better with 1.4x on and found that it needed a little more post processing to look good. I ultimately moved on to adapted options instead and traded away the 100-200.
May I ask what you are adapting? I'm occansionally using the Canon EF 70-300L and Sigma 100-400/5-6.3, but while both are very nice lenses, the need for cropping is very unpredictable and ruins too many images. So I mostly use them in 24x36 mode, which I don't like simply because of the dreaded 3:2 ratio. I wish there was a 4:3 crop too.
Edit: Both are also very iffy with every adapter I've tried, including my current Fringer. It locks, and it looks to be in focus, but when examining, it was slightly out of focus. Not to mention OIS on both are quite random. Extremely good at times, but then extremely bad at other times. Makes it not-very-fun to use.
The 100-200 at least behaves as a native lens. My only gripe with it, is that the range is a bit too short. Especially at the already slow speed (which makes cropping not-so-fun either).
I liked it better with 1.4x on and found that it needed a little more post processing to look good. I ultimately moved on to adapted options instead and traded away the 100-200.
May I ask what you are adapting? I'm occansionally using the Canon EF 70-300L and Sigma 100-400/5-6.3, but while both are very nice lenses, the need for cropping is very unpredictable and ruins too many images. So I mostly use them in 24x36 mode, which I don't like simply because of the dreaded 3:2 ratio. I wish there was a 4:3 crop too.
Edit: Both are also very iffy with every adapter I've tried, including my current Fringer. It locks, and it looks to be in focus, but when examining, it was slightly out of focus. Not to mention OIS on both are quite random. Extremely good at times, but then extremely bad at other times. Makes it not-very-fun to use.
The 100-200 at least behaves as a native lens. My only gripe with it, is that the range is a bit too short. Especially at the already slow speed (which makes cropping not-so-fun either).
Jul 21, 2026 at 01:48 AM
p.1 #13Strange Issue with GF 100-200? Sharp at f/5.6, but blurry at f/8!
Makten wrote:
May I ask what you are adapting? I'm occansionally using the Canon EF 70-300L and Sigma 100-400/5-6.3, but while both are very nice lenses, the need for cropping is very unpredictable and ruins too many images. So I mostly use them in 24x36 mode, which I don't like simply because of the dreaded 3:2 ratio. I wish there was a 4:3 crop too.
Edit: Both are also very iffy with every adapter I've tried, including my current Fringer. It locks, and it looks to be in focus, but when examining, it was slightly out of focus. Not to mention...Show more →
Of course! When I want a zoom in this range, I use an Fringer adapted Canon EF100-400L2 with the baffle removed. At certain apertures and focal lengths it has minor vignetting to which I have a preset to make a light crop in C1 quickly. Some hassles of using a FF lens on a Gfx but not a tall statement to say its matches or exceeds image quality, AF of the 100-200 with more reach. The OIS is not quite as good but functional. I also have two Contax primes, the 140/2.8 and 210/4 that are more or less in this focal range. While not an apples/apples comparison, they both produce a more interesting look to my eye. All 3 lenses are faster aperture and the 140 is smaller. That may sum up my experience with the 100-200, just not a motivating reason to use it with those 3 alternates. I can see where a pro, moving quickly, might choose the native, but not me.
SGinNorcal wrote
I liked it better with 1.4x on and found that it needed a little more post processing to look good. I ultimately moved on to adapted options instead and traded away the 100-200. Edit: Both are also very iffy with every adapter I've tried, including my current Fringer. It locks, and it looks to be in focus, but when examining, it was slightly out of focus. Not to mention...Show more →
Of course! When I want a zoom in this range, I use an Fringer adapted Canon EF100-400L2 with the baffle removed. At certain apertures and focal lengths it has minor vignetting to which I have a preset to make a light crop in C1 quickly. Some hassles of using a FF lens on a Gfx but not a tall statement to say its matches or exceeds image quality, AF of the 100-200 with more reach. The OIS is not quite as good but functional. I also have two Contax primes, the 140/2.8 and 210/4 that are more or less in this focal range. While not an apples/apples comparison, they both produce a more interesting look to my eye. All 3 lenses are faster aperture and the 140 is smaller. That may sum up my experience with the 100-200, just not a motivating reason to use it with those 3 alternates. I can see where a pro, moving quickly, might choose the native, but not me.
Jul 21, 2026 at 11:57 AM