X100F vs XF 23mm f/1.4 - Is there something wrong with this X100F?

Hello

I'm currently testing a X100F, and I also have an X-T2 and a XF23mm f/1.4 lens which I've owned for a long time. In the last week, while using the X100F, I started noticing in some pictures that the images are noticeably softer on the sides (both sides and corners). I then just ran out and did a quick test against the local brick wall with the X100F and X-T20 with the 23/1.4, both at ISO 800, f/5.6 and 1/125 shutter speed, and the images were taken within 5 seconds. Both cameras were in the same position (more or less), but due to the slight difference in effective focal length, plus the X100F's distortion, the images aren't completely identical.

Regardless of technical perfection, there is a huge and clear difference between how the X100F and XF 23mm f/1.4 performs at f/5.6. I've owned the X100T previously, and never really noticed anything like this on it... Then again, maybe the 24 megapixel sensor of the X100F shows more of the shortcomings on the X100-series lens.

Anyway, I've attached several screen shots of my comparison in Lightroom, and also attached full resolution jpeg's that has been exported from Lightroom. Default LR sharpening settings were applied on both images, so there aren't any processing done to these images, except I had to boost the exposure by +1 on both to make the image slightly brighter.

Has anyone else done a similar comparison?
The X100F actually seems a bit sharper in the center, but in the outer zones of the image the images completely fall apart.


Zoomed out


Center 100%


Left Center


Left Bottom Corner


Left Upper Corner


Right Center


Right Bottom Corner


Right Upper Corner

Full resolution jpeg's can be downloaded from these links:

XF 23mm1.4 R http://indergaard.net/wp-content/uploads/2017/07/XF23_1_4.jpg
X100F: http://indergaard.net/wp-content/uploads/2017/07/X100F.jpg

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Website: http://www.indergaard.net
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Thanks for that detailed comparison. I'm surprised at the edge quality of the X100F at f/5.6. I was considering the camera for a walkaround, but I think I'll stick with my X-E2 and 23mm f/1.4. Maybe some 100F owner will demonstrate better performance?

JS Burnie said:

Thanks for that detailed comparison. I'm surprised at the edge quality of the X100F at f/5.6. I was considering the camera for a walkaround, but I think I'll stick with my X-E2 and 23mm f/1.4. Maybe some 100F owner will demonstrate better performance?

Click to expand...

I'm very surprised myself. I wasn't expecting this much difference at all. I was maybe expecting visible differences from f2-f4, but I expected that by f/5.6 the performance would be about the same... I wasn't really looking for a flaw, but I simply started noticing in a lot of architectural and landscape snaps I made with the X100F at f/5.6, even without zooming in! So I just did a quick comparison...

I have 3 days left in my return period for the X100F, and if this is normal, this baby is going back for a refund, no question about it. I absolutely love the form factor of the X100-series, but, the performance difference is just too drastic. It would basically render the X100F a camera I would only consider using on 1-2 people in the center of the frame, and I would never feel good about using it for anything else where edge-to-edge sharpness matters.

I usually always shoot my Fujifilm lenses at f/5.6, as that's where most of the XF-lenses sweet spot is. By f/8, on most of the XF lenses, the center resolution starts to drop, but stopping down to f/8 only marginally improves corner performance.

For me there is no difference, but I am not a pixelpeeper :-D

J.

joebat said:

For me there is no difference, but I am not a pixelpeeper :-D

J.

Click to expand...

You don't need to be a pixel-peeper to see it.
It would even be visible in an A4 / 8x12 print side-by-side if you looked closely. And that is a rather small print size for landscapes.

I've also owned the X100S and X100T previously, and I can't remember seeing such IQ degredation out towards the edges of the frames on those cameras. But they are also 16 megapixels - not 24.

Never owned an X100 series, but doing testing at about 10 feet with the XF23 f/2 at 2/2.8/4 (gave up), didn't match the XF23 f/1.4 at 1.4. From everything said about the X100t/f versus the 23f/2 (supposedly better) the above samples don't surprise me at all.

Unfortunately, yours is not a bad copy—this comparison just isn't flattering to the X100 series lens. The XF 23mm ƒ/1.4 is a particularly sharp and impressive lens.

I did a similar set of tests for my review of the X100F and came to the same conclusion. The 23mm ƒ/1.4 is in a different league, optically.

That being said, it's also a significantly larger lens, and that's where most people find the X100F to be preferable; they're willing to give up some raw optical prowess in favour of a more compact setup, and that's perfectly reasonable.

The X100F is capable of taking very sharp photos, but typically not close up and certainly not shooting wide open. That's just one of the trade-offs for having X-Trans III in a compact body.

I've owned the X100S, T, and F, and the F was the first one I didn't keep. It's the ideal form of this camera and it's virtually perfect now, but for the reasons I talked about in the review I determined that for my usage there wasn't a situation where an X100F would be a better choice than my X-Pro 2.

joebat said:

For me there is no difference, but I am not a pixelpeeper :-D

J.

Click to expand...

I owned the S, T and I now have the F since a month or so. It's plenty sharp and I also find myself rarely pixel peep corners. Even with sunset photos the sun is typically somewhat centered in the image. Same thing for people.

I would also expect Apples and Oranges to taste somewhat different...

What you are seeing is not a lens problem (or not one specific to your lens), but it's the field curvature of the X100 lens. It has had this from the beginning. So when you photograph flat brick walls, the X100 doesn't give you the edges you expect (because the focus lies in front of the wall). To get the corners sharp, you would have to go to f/11 or even further.

In real world situation this can be a problem, but it also can be an advantage. It's just important that you (the photographer) knows about it and knows how to deal with it

MariusMasalar said:

That being said, it's also a significantly larger lens, and that's where most people find the X100F to be preferable; they're willing to give up some raw optical prowess in favour of a more compact setup, and that's perfectly reasonable.

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Exactly. Besides, the 23 1.4 costs about 70-75% of the X100F which is a fully featured advanced camera with a nice 23mm lens, whereas the 23 1.4 is "only" the lens itself.

MariusMasalar said:

Unfortunately, yours is not a bad copy—this comparison just isn't flattering to the X100 series lens. The XF 23mm ƒ/1.4 is a particularly sharp and impressive lens.

I did a similar set of tests for my review of the X100F and came to the same conclusion. The 23mm ƒ/1.4 is in a different league, optically.

That being said, it's also a significantly larger lens, and that's where most people find the X100F to be preferable; they're willing to give up some raw optical prowess in favour of a more compact setup, and that's perfectly reasonable.

The X100F is capable of taking very sharp photos, but typically not close up and certainly not shooting wide open. That's just one of the trade-offs for having X-Trans III in a compact body.

I've owned the X100S, T, and F, and the F was the first one I didn't keep. It's the ideal form of this camera and it's virtually perfect now, but for the reasons I talked about in the review I determined that for my usage there wasn't a situation where an X100F would be a better choice than my X-Pro 2.

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Thanks Marius.

Yeah I've started looking at my images from the X100S and X100T. They seem to have the similar characteristics. It's just much more noticeable on the X100F due to the increased resolution (24mp vs 16mp). The short-comings are basically magnified due to the increased resolution.

The X100F is sharper in the dead center than my 23/1.4. But outside of the center things change very quickly. I absolutely love the form factor of the X100-series, but I'm not sure if I can justify owning it, cause I would always know the X-T2 with the 23/1.4 would do so much better even stopped down. And I do a lot of architecture and landscape photography where across-the-field sharpness matters.

How / when do you think it's an advantage? Just curious.

uMad said:

What you are seeing is not a lens problem (or not one specific to your lens), but it's the field curvature of the X100 lens. It has had this from the beginning. So when you photograph flat brick walls, the X100 doesn't give you the edges you expect (because the focus lies in front of the wall). To get the corners sharp, you would have to go to f/11 or even further.

In real world situation this can be a problem, but it also can be an advantage. It's just important that you (the photographer) knows about it and knows how to deal with it

Click to expand...

I would also be interested in how you can see field curvature to be an advantage?
I've delt with many lenses that have field curvature (Leica Summilux 50mm 1.4 ASPH, Leica Summilux 35mm 1.4 ASPH FLE, Noctilux 50mm 0.95 ASPH) and there is never an advantage to having field curvature - regardless if you are shooting landscapes or portraits at wide-open aperture.

For landscapes and architecture you can never use field curvature to your advantage.
For portraits at wide-open aperture field curvature can sometimes introduce zones in the image (the outer zones and corners typically) that fall in and out of focus all over the entire image. This is absolutely NOT something you would want for portraiture either, as the out-of-focus backgrounds should be smooth and be out of focus constantly, not in and out of focus in a wavy looking pattern. The Summilux 50 and Noctilux 50 that I've used before had these issues, and they're not always easy to deal with, and there is zero advantage to it.

whenever you want some outer regions sharp and they are closer to you than the main subject. This can happen with landscapes or cityscapes. (of course there can be other situations where it's not an advantage but a disadvantage. That's way I said know about it and learn to live with it maybe even use it)

uMad said:

What you are seeing is not a lens problem (or not one specific to your lens), but it's the field curvature of the X100 lens. It has had this from the beginning. So when you photograph flat brick walls, the X100 doesn't give you the edges you expect (because the focus lies in front of the wall). To get the corners sharp, you would have to go to f/11 or even further.

In real world situation this can be a problem, but it also can be an advantage. It's just important that you (the photographer) knows about it and knows how to deal with it

Click to expand...

And for some reason particularly noticeable at 5.6. Don't know why. Maybe the leaf shutter but if I want 'landscape' sharp I shoot f11. If I'm shooting mid near and want something tack sharp towards edge I move the focus box ie don't focus and recompose.

uMad said:

whenever you want some outer regions sharp and they are closer to you than the main subject. This can happen with landscapes or cityscapes. (of course there can be other situations where it's not an advantage but a disadvantage. That's way I said know about it and learn to live with it maybe even use it)

Click to expand...

Oh that's interesting! So perhaps an advantage for street shots, inside churches, etc, where walls or other detail are running parallel to the lens / focus point axis. I was using my X100 in exactly this situation yesterday. Must check out the results.

peter konzuk said:

uMad said:

What you are seeing is not a lens problem (or not one specific to your lens), but it's the field curvature of the X100 lens. It has had this from the beginning. So when you photograph flat brick walls, the X100 doesn't give you the edges you expect (because the focus lies in front of the wall). To get the corners sharp, you would have to go to f/11 or even further.

In real world situation this can be a problem, but it also can be an advantage. It's just important that you (the photographer) knows about it and knows how to deal with it

Click to expand...

And for some reason particularly noticeable at 5.6. Don't know why. Maybe the leaf shutter but if I want 'landscape' sharp I shoot f11. If I'm shooting mid near and want something tack sharp towards edge I move the focus box ie don't focus and recompose.

Click to expand...

Yeah that's what I don't understand either. Field Curvature is normal in most lenses when they are wide-open and maybe up until f/2.8-f4.0. But by f/5.6 (which is equivalent to f/8 on FF), which is the sweet-spot for most of Fujifilm's XF glass, I would never expect field curvature to be as noticeable as this.

Attached is a full-resolution jpeg exported from Lightroom, where I used the X100F to shoot a more realistic scene at f/5.6. This was before I started digging into this, but this is one of the images where I started to see that the center was pin sharp and the outer zones of the image quickly become noticeably softer. Look at 100% in the center of the trees, then out towards the left and right edges of the trees, the leaves are noticeably softer on the left and right sides. The trees were perfectly in line with each other. There was no focus and recompose (I never focus and recompose). Already here the X100F's lens shortcomings would be visible in a medium sized print. f/5.6 on a APS-C sensor has the same depth of field as a FF sensor at f/8 with the same equivalent focal length, and that should be plenty to achieve even sharpness on this subject.


X100F, f/5.6, ISO 400, DR 200%, 1/1700 sec

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Just postulating, but is this just an inevitable consequence of what is in effect a pancake lens, sitting very close to the sensor? Also that the X100 series was never designed with flat-field photography in mind, but the complex 3-D structure of "street"? May be complete BS of course, but some questions for the forum to ponder perhaps

borgein said:

Member said:

peter konzuk wrote

And for some reason particularly noticeable at 5.6. Don't know why.

Click to expand...

Yeah that's what I don't understand either. Field Curvature is normal in most lenses when they are wide-open and maybe up until f/2.8-f4.0. But by f/5.6 (which is equivalent to f/8 on FF), which is the sweet-spot for most of Fujifilm's XF glass, I would never expect field curvature to be as noticeable as this.

Click to expand...

You would have thought but if you do a search you will find others who have made the same observation at 5.6 and also have noted the defocus seems a little more pronounced a bit in from the edge. Perhaps this article explains it especially if the x100 displays the moustache pattern of field curvature.

I couldn't find an MTF graph for the X100 series. Anyone seen one?