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-   -   Heavy Distortion FUJIFILM XF 23mm f/2 R WR Lens (http://www.rangefinderforum.com/forums/showthread.php?t=168051)

bushwick1234 04-04-2019 04:56

Heavy Distortion FUJIFILM XF 23mm f/2 R WR Lens
 
I was going over a series of images shot last year with my X-T1 and the Fuji XF 23mm f/2 R WR lens bought at B&H last year, and was impressed by the amount of distortion of all backgrounds, specially of buildings. Most of the times I could not correct the distortion with Adobe LR. Or is it only me?

retinax 04-04-2019 05:20

Are you certain you see lens distortion and not perspective? This comes up quite often. That things further away are depicted smaller, making rectangles into trapezoids etc., is not something that lenses do, it's a result of seeing a three-dimensional world from one point. I don't see why you couldn't correct lens distortion of whatever level in LR.

bushwick1234 04-04-2019 06:12

Unedited file.

Dogman 04-04-2019 06:14

I've never experienced distortion with my 23/2. I recall Lenstip's review of the lens indicated virtually zero distortion, even in uncorrected Raw files. Also, LR automatically corrects the Raw files from the 23/2 by applying Fuji's lens profile.

EDIT: You posted image shows the perspective distortion retinax mentioned. It's present in all lenses, more pronounced as they get wider.

BernardL 04-04-2019 06:19

Perspective: straight lines that are parallel in real world are recorded as converging lines, straight but not parallel. The rules of perspective have been established by Brunelleschi and Alberti in the 15th century.

Distortion: straight lines in real world are recorded as (more or less) curved.

shawn 04-04-2019 06:37

If you are looking for perspective and volume deformation corrections then DXO Viewpoint gives a lot of control.

https://www.dxo.com/dxo-viewpoint/

Shawn

willie_901 04-04-2019 07:45

As others mentioned, keeping the camera square to the subject will eliminate converging verticals (also called keystoning). We see converging verticals when lines that are | | in reality render as / \ . This has nothing to do with lens quality. All you can do is tilt the camera until the converging vertical edges render as lines. In many cases (tall buildings) this is impractical. You can't get the camera high enough and still frame the subjects of interest.

The X-Pro 1 has an electronic level that helps eliminate horizontal tilt. You can check for vertical tilt by inspection using the optional grid overlay in the EVF display. I'm not sure the converging verticals are easy to detect in the OVF.

Most post-production software will correct for converging verticals. However this results in a crop. The larger the correction the more the frame becomes cropped. Im my experience correction converging verticals is very easy when there is no horizontal tilt. Automate correction works well in Adobe products. But when both planes are off, proper corrections can be tedious.

Kudos to Shawn for mentioning a volume deformation. This always occurs because it impossible to project three-dimensional objects into a two-dimensional plane without error. So lens quality is not a factor. Volume deformation is often observed when spherical objects render as ellipsoids or square objects render as rectangles. When you are close to objects and, or they are at the frame edges, volume deformation is most obvious.

Newer versions of Photoshop will minimize volume deformation (link).

shawn 04-04-2019 08:30

Here is a DXO tutorial for their volume corrections. Works well and is easy to combine with their other corrections too.

Shawn

bushwick1234 04-04-2019 10:20

Thanks for the suggestions, but I returned the lens already. And the camera as well.
DXO is not for free, right? And there are many lenses that don't have distortion at all. Isn't it a paradox to have to purchase extra software to correct lens design flaws? To me the heavy distortion displayed by this lens is a serious flaw.
Quote:

Originally Posted by shawn (Post 2879629)
If you are looking for perspective and volume deformation corrections then DXO Viewpoint gives a lot of control.

https://www.dxo.com/dxo-viewpoint/

Shawn


shawn 04-04-2019 10:35

Quote:

Originally Posted by bushwick1234 (Post 2879683)
Thanks for the suggestions, but I returned the lens already. And the camera as well.
DXO is not for free, right? And there are many lenses that don't have distortion at all. Isn't it a paradox to have to purchase extra software to correct lens design flaws? To me the heavy distortion displayed by this lens is a serious flaw.

No, because those corrections have nothing to do with a 'flaw' in the lens. That is the reality of all wide angle lenses, even an optically 'perfect' lens will have perspective and volume deformations.

Optical lens quality distortions are combinations of barrel and pincushion distortions. Your image isn't showing that. Your image is showing perspective distortion which was caused because you didn't have the lens level and square with your subject. You were shooting with the camera pointing down, the top of your image is closer to the sensor than the bottom of your image. You would get that same distortion with any lens of that focal length if it was held at the same angle.

As an easy example of this take out the camera on your phone. Hold the camera up to a framed picture on your wall, tilt the camera top torward/away from the frame and watch how that changes the perspective distortion on the screen. That is what happened in your picture.


You can correct that (to a point) in LR but you needed to use the transform controls. The real solution is of course to understand where the distortion came from so you can avoid it next time. A different camera + lens won't solve this.

Shawn

Dogman 04-04-2019 10:55

This is a job for Sinar, Linhof, Deardorff, etc.

Dogman 04-04-2019 10:58

Quote:

Originally Posted by bushwick1234 (Post 2879683)
Thanks for the suggestions, but I returned the lens already. And the camera as well.
DXO is not for free, right? And there are many lenses that don't have distortion at all. Isn't it a paradox to have to purchase extra software to correct lens design flaws? To me the heavy distortion displayed by this lens is a serious flaw.

As has been pointed out, the lens is not showing a flaw whatsoever.

slantface 04-04-2019 10:58

That image posted looks totally fine and what I'd expect from the 23mm. I don't understand this original post as it seems you are after lens qualities that don't really exist. How do you shoot normally if that image is "too distorted" to the point of returning the camera/lens? Do you shoot only longer/tele focal lengths that are more to your liking?

Sorry, just confused on this whole thing...

BernardL 04-04-2019 11:48

Quote:

Thanks for the suggestions, but I returned the lens already. And the camera as well.
So you ask a question on a forum, and less than 6 hours later, as several people are trying to explain to you that your image is OK, you draw your own conclusions and return the lens.

bushwick1234 04-04-2019 11:49

Quote:

Originally Posted by slantface (Post 2879694)
That image posted looks totally fine and what I'd expect from the 23mm. I don't understand this original post as it seems you are after lens qualities that don't really exist. How do you shoot normally if that image is "too distorted" to the point of returning the camera/lens? Do you shoot only longer/tele focal lengths that are more to your liking?

Sorry, just confused on this whole thing...

I shoot street mainly, and try to get as close as possible to my subjects. And I live in NYC where we have streets packed with buildings. As was pointed out here earlier, you can't always correct distortion on LR and crop images afterwards. This image isn't fine: look the top right of the vertical window frame, look the green subway fence that is not parallel but deviates apart. Some degree of distortion is natural. There are many! wide lenses without this huge amount of distortion. And I expected this 23mm to be one with little to none distortion.

bushwick1234 04-04-2019 12:05

Another photograph shot with X-T1 and 23mm f/2 with heavy distortion. When I try to correct the image using LR I have to crop and the head gets trimmed off.

13Promet 04-04-2019 12:13

As already pointed out, the distortion visible in your shot does not depend on the lens at all: it's perspective.
If you crouched a bit ad kept the sensor plane parallel to the fence, you'd get no distortion.

Or - from the standpoint you shot from - by using a tilt-shift lens, but that's another story and not really convenient for fast-paced sreet photography.
And anyway you'd need to understand perspective first, which you don't really seem to be keen on.

Ah... it's not a good habit to ask questions when you don't consider answers.
Especially if they are 100% consistent with each other ;)

13Promet 04-04-2019 12:15

Quote:

Originally Posted by bushwick1234 (Post 2879709)
Another photograph shot with X-T1 and 23mm f/2 with heavy distortion. When I try to correct the image using LR I have to crop and the head gets trimmed off.

This is even funnier: you're pretending the lens to straighten your bent shot :D

shawn 04-04-2019 12:41

Quote:

Originally Posted by bushwick1234 (Post 2879703)
I shoot street mainly, and try to get as close as possible to my subjects. And I live in NYC where we have streets packed with buildings. As was pointed out here earlier, you can't always correct distortion on LR and crop images afterwards. This image isn't fine: look the top right of the vertical window frame, look the green subway fence that is not parallel but deviates apart. Some degree of distortion is natural. There are many! wide lenses without this huge amount of distortion. And I expected this 23mm to be one with little to none distortion.


Lens distortion would mean the window frame wasn't a straight line, or that the subway fences weren't a straight line but were curved.

This is an actual example of lens distortion from the Fuji 35mm f2:



In your pictures you have straight lines. The lens isn't distorting the picture.

That your lines aren't parallel to each other is perspective distortion. That distortion is not due to the lens at all. What you are seeing is the result of your camera being tilted relative to the subject. Nothing more.

Any same focal length wide angle lens will have the same perspective distortion if the camera+lens is tilted relative to the subject.

The wider you go, the more obvious it becomes.

Shawn

bushwick1234 04-04-2019 12:41

Quote:

Originally Posted by 13Promet (Post 2879712)

Ah... it's not a good habit to ask questions when you don't consider answers.
Especially if they are 100% consistent with each other ;)

Am not closed to opinions. And I am not saying Fuji is bad. After I tossed my X-T1 along with the 23mm f/2 I purchased again the X100, but this time the faster focusing X100F, which is not giving me the "perspective" concern you mention.
And after researching a bit I found out that the 23mm f/2 has indeed a tendency to distortion (trying to avoid the term flaw and issue). I should have done the research before I bought the camera-lens combo. :)

shawn 04-04-2019 12:45

If you aren't getting it with the x100 it is because you are now holding it level. The X100 will absolutely give the same perspective distortion if it is tilted.

Shawn

nightfly 04-04-2019 12:45

I think from a practical perspective, you might be better off using a full frame camera which will allow you to use a less wide angle lens to get the same angle of view with less of what you are perceiving (and I agree) as distortion.

I understand the technical arguments here and they are probably technically correct.

However I also get that to you the images don't look right. Because a 23mm lenses feels distorted where a 35mm lens would feel more "normal" and less distorted.

This bugs me about APS-C and smaller also.

nzeeman 04-04-2019 12:54

this is some joke post,right? i dont even know where do you see distortion on this one-can you explain us better?
Quote:

Originally Posted by bushwick1234 (Post 2879709)
Another photograph shot with X-T1 and 23mm f/2 with heavy distortion. When I try to correct the image using LR I have to crop and the head gets trimmed off.


retinax 04-04-2019 13:11

Quote:

Originally Posted by nightfly (Post 2879718)
I think from a practical perspective, you might be better off using a full frame camera which will allow you to use a less wide angle lens to get the same angle of view with less of what you are perceiving (and I agree) as distortion.

I understand the technical arguments here and they are probably technically correct.

However I also get that to you the images don't look right. Because a 23mm lenses feels distorted where a 35mm lens would feel more "normal" and less distorted.

This bugs me about APS-C and smaller also.

Sorry, but this is nonsense. Please convince yourself with a comparison of different formats with lenses with identical fov shot side by side.

shawn 04-04-2019 13:15

If you have the same FOV and the same distance from the subject you don't get a difference in perspective distortion because of sensor size.

A FF 35mm would have the same perspective distortion as a 23mm lens on APS-C at the same distance from the subject.

DOF would be different though if shot at the same aperture.

Shawn

nightfly 04-04-2019 13:32

Wouldn't a 23mm lens exhibit more barrel distortion than a 35mm lens?

shawn 04-04-2019 13:37

Barrel distortion is an optical defect of the lens, it is not inherent in the focal length.

Shawn

LCSmith 04-04-2019 14:06

I see the distortion. My understanding, which may be flawed, is that makers of these kinds of lenses do not worry much about distortion since it is usually corrected by the camera software or in post. At least, that was the logic behind the faulty design of one lens I used to have, a Sony FE 28 f/2, whose inherent distortion was widely known and accepted.

EDIT: The distortion I see has nothing to do with perspective. It is in the curved lines.

Dogman 04-04-2019 14:10

I know this is pointless but....

Try something. Take a picture of a building straight on with the camera held perfectly level and not tilted either forward or backward. Then take a picture of the same building with the same camera/lens combination with the camera tilted upwards. I betcha a nickel you can see this same "distortion" in the second picture no matter what lens you use.

The only way you can avoid this is to always shoot pictures level and dead straight without any tilt. Or you can invest in a large format camera with full swings, tilts, rises and falls that allows for perspective control. (Thus my post about Sinar, Linhof, Deardorff, etc.)

LCSmith 04-04-2019 14:14

Quote:

Originally Posted by Dogman (Post 2879736)
I know this is pointless but....

Try something. Take a picture of a building straight on with the camera held perfectly level and not tilted either forward or backward. Then take a picture of the same building with the same camera/lens combination with the camera tilted upwards. I betcha a nickel you can see this same "distortion" in the second picture no matter what lens you use.

The only way you can avoid this is to always shoot pictures level and dead straight without any tilt. Or you can invest in a large format camera with full swings, tilts, rises and falls that allows for perspective control. (Thus my post about Sinar, Linhof, Deardorff, etc.)

It's not about the converging parallels. The lens distortion is obvious in the first picture. The green subway railings look like they were bent by superman. That's lens distortion.

Corran 04-04-2019 14:15

lol, did B&H take back the camera/lens that you said you purchased last year, despite there being no problems with it except your misunderstanding about distortion?

Dogman 04-04-2019 14:20

Quote:

Originally Posted by LCSmith (Post 2879735)
I see the distortion. My understanding, which may be flawed, is that makers of these kinds of lenses do not worry much about distortion since it is usually corrected by the camera software or in post. At least, that was the logic behind the faulty design of one lens I used to have, a Sony FE 28 f/2, whose inherent distortion was widely known and accepted.

EDIT: The distortion I see has nothing to do with perspective. It is in the curved lines.

The 23mm f/2 Fuji WR lens is fully corrected optically, not by the software. At least according to both LensTip.com and Opticallimits.com in their measurements of the lens. The distortion in the two photos posted here is totally due to the tilting of the camera, not any distortion in the lens used.

LCSmith 04-04-2019 14:26

Quote:

Originally Posted by Dogman (Post 2879740)
The 23mm f/2 Fuji WR lens is fully corrected optically, not by the software. At least according to both LensTip.com and Opticallimits.com in their measurements of the lens. The distortion in the two photos posted here is totally due to the tilting of the camera, not any distortion in the lens used.

I am not an expert on lens design or on Fuji lenses. So, for all I know, you may be right.

What I do know is that tilting the camera does not cause undulating lines, like those green subway rails. In all discussions of lens distortion that I have seen, that is exactly what they are talking about -- curved lines that should be straight.

shawn 04-04-2019 14:31

1 Attachment(s)
I just imported the picture into lightroom and put a grid up over it after rotating the picture so the slats are vertical. Only one slat is fully visible, it is straight. The attached is at 300% view.

Shawn

LCSmith 04-04-2019 14:35

Quote:

Originally Posted by shawn (Post 2879742)
I just imported the picture into lightroom and put a grid up over it after rotating the picture so the slats are vertical. Only one slat is fully visible, it is straight. The attached is at 300% view.

Shawn

Shawn, I am talking about the horizontal lines, not the verticals. Sorry, I should have been more clear. The "railing", as it were, of the subway grate. It curves in just slightly, along with the horizontal lines of the sidewalk and bottom of the grating, etc. There is a slight bend in the lines.

If I were a digital shooter, I am not sure I would worry too much if my lenses had distortion. What does it matter? It can always be corrected. Lens distortion is a much bigger problem for film shooters.

shawn 04-04-2019 14:38

1 Attachment(s)
Nope, they are straight too.

Shawn

LCSmith 04-04-2019 14:45

Agree to disagree!

gavinlg 04-04-2019 14:59

There's 100% no lens distortion on that photo, it's 100% perspective distortion that is totally seperate to lens design and will happen with any lens. 110%.

maryland_fotos 04-04-2019 15:39

Bushwick, I still only see perspective distortion in both your photos. For your requirement you need a perspective control lens. It is true that perspective distortion can be annoying, and right, you end up losing a good chunk of the photo correcting it in software. But that's what perspective control lenses are for. I don't know about the Fuji system. For Nikon I have a 28 3.5 and a 24 3.5 that both handle this kind of a scenario. I know Canon has tilt shift lenses that do the same thing.

Or one tries to align the camera to a plane parallel to the one that the offending lines are in. Not always feasible though.

kkdanamatt 04-04-2019 17:38

Bushwick is trying to avoid perspective distortion?
Simple solution: set up a large format view camera on a tripod; employ tilts, swings, rises and apply the Scheimpflug principle.


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