Photoshop Distortion Removal Same as Zero-D Lens?

[William Baroo]

I see there are various types of wide lenses out there. Some are labeled "zero-distortion" because they minimize distortion and leave straight lines and right angles alone.

On the other hand, software lets you correct distortion.

Is software correction as good as using a zero-D lens, or does it give inferior results? If it's just as good, I have to wonder why two types of lenses exist.

 

[Soocom1]

Depends on what your trying to achive.
One style of lens is Flat Field.
There are many and most do not know about how Flat Field works.
Outside that, I personally go old school and use perspective control on the lens or LF body.

 

[Ysarex]

I see there are various types of wide lenses out there. Some are labeled "zero-distortion" because they minimize distortion and leave straight lines and right angles alone.

On the other hand, software lets you correct distortion.

Is software correction as good as using a zero-D lens,

No.

or does it give inferior results?

Yes.

If it's just as good, I have to wonder why two types of lenses exist.

It's really hard and very expensive to design a wide angle lens to be distortion free. For DSLR cameras it's basically impossible -- difficult to do for mirrorless. Most folks don't need it because slight distortion won't show in most of what they photograph. Those who specialize in architectural photography need distortion free lenses. That's one reason back in the film days they used non-SLR cameras for that work.

 

[William Baroo]

That was a pretty good answer. Doesn't leave room for confusion.

 

[VidThreeNorth]

Here's the problem:

Case 1: You have "some" barrel distortion. I'm not going to say how much, I'm just talking theory. The barrel distrotion causes straight lines to curve in the photo. To correct for this in a print, you will have to stretch the outer part of the image. When you do this, the further out a pixel is in the image, the more it has to be stretched to correct the distortion. So maybe one pixel is stretch to cover two or three or more pixels in the final image. You lose detail (and probably sharpness too). What about starting with a fully corrected lens? Case 2: Well, that lens is going to be complex, and out from the middle will probably lose sharpness the further off-axis the image is anyway. Which is worse? Sorry, only way to tell is to try both and find out for yourself, or get someone reliable to do so for you. But in general, I would expect a high quality rectilinear (non-distorted) lens to do better.

 

[Ysarex]

That was a pretty good answer. Doesn't leave room for confusion.

Take a look at this old post: New Camera! Finally! -- I'm Impressed.

 

[Ysarex]

Here's the problem:

Case 1: You have "some" barrel distortion. I'm not going to say how much, I'm just talking theory. The barrel distrotion causes straight lines to curve in the photo. To correct for this in a print, you will have to stretch the outer part of the image. When you do this, the further out a pixel is in the image, the more it has to be stretched to correct the distortion. So maybe one pixel is stretch to cover two or three or more pixels in the final image. You lose detail (and probably sharpness too). What about starting with a fully corrected lens? Case 2: Well, that lens is going to be complex, and out from the middle will probably lose sharpness the further off-axis the image is anyway. Which is worse? Sorry, only way to tell is to try both and find out for yourself, or get someone reliable to do so for you. But in general, I would expect a high quality rectilinear (non-distorted) lens to do better.

I have two wide angle lenses that are distortion free -- the 14mm f/2.8 Fuji X and a Zeiss Biogon M mount. The key is mirrorless cameras. If you don't have to design the lens to clear the flopping mirror in an SLR you can design out the distortion.

 

[William Baroo]

Here's the problem:

Case 1: You have "some" barrel distortion. I'm not going to say how much, I'm just talking theory. The barrel distrotion causes straight lines to curve in the photo. To correct for this in a print, you will have to stretch the outer part of the image. When you do this, the further out a pixel is in the image, the more it has to be stretched to correct the distortion. So maybe one pixel is stretch to cover two or three or more pixels in the final image. You lose detail (and probably sharpness too). What about starting with a fully corrected lens? Case 2: Well, that lens is going to be complex, and out from the middle will probably lose sharpness the further off-axis the image is anyway. Which is worse? Sorry, only way to tell is to try both and find out for yourself, or get someone reliable to do so for you. But in general, I would expect a high quality rectilinear (non-distorted) lens to do better.

Thanks.

So here's another question: what's the difference between a rectilinear lens and a zero-distortion lens? Laowa sells lenses with both descriptions.

 

[William Baroo]

I found some info on Laowa's site. It uses the term "rectilinear" to describe lenses that have minimal, but not zero, distortion.

 

[Ysarex]

Thanks.

So here's another question: what's the difference between a rectilinear lens and a zero-distortion lens? Laowa sells lenses with both descriptions.

Rectilinear just means a lens designed with the intent that straight lines are rendered straight lines. Most of our lenses are rectilinear as opposed to say fisheye.
Rectilinear does not mean the lens will be without distortion. Prime lenses in the "normal" focal length range will be rectilinear designs and stand a good chance of having little to no distortion. Zoom lenses, wide angle lenses and telephoto lenses are much more likely to exhibit some distortion especially wide angle lenses designed for SLR cameras. The SLR mirror presented a unique problem; on a 35mm SLR a normal design 24mm lens would have it's rear element smashed through the mirror. A solution was required. That solution was complicated and came with a boat load of distortion: Pierre Angénieux. Since then lens designers have bent over backwards, twisted themselves into pretzels and spent big piles of $$$$ trying to beat down the distortion in these special lenses. They have had some limited success but otherwise have failed (good luck trying to find even 1). Enter then the modern mirrorless digital camera -- problem solved.

 

[VidThreeNorth]

I think that one of the lens companies was trying to use "Zerro-D" as a sort of trade mark for its wide and ultra-wide lenses. There was nothing special about the term. It was just their name for their rectilinear lenses. I do remember seeing a picture from one of these lenses. It had very slight, but visible barrel distortion. A company can make claims, but results are results. . . .

I had, and probably still have an old wide angle (probably 28 f2.8) which I tested and it actually was perfectly linear. It was also soft off-axis. Your money, your choice. . . .

 

[William Baroo]

I'm going to try a 15mm Laowa Zero-D lens and see what happens. I am hoping to be in Rome in November, and it sounded like a good lens for that particular destination.

 

[Ysarex]

I'm going to try a 15mm Laowa Zero-D lens and see what happens. I am hoping to be in Rome in November, and it sounded like a good lens for that particular destination.

Here you go: Laowa 15mm

 

[Rickbb]

True zero distortion photography was/is done on old school tilt/shift lens or bellows and a view camera that will let you control the perspective and key-stoning however you wish. Even then you can’t get rid of it all. Film/sensor plane is flat and all lens are anything but. Cant violate the laws of physics, they try, but in the end they just minimize it.

 

[Ysarex]

True zero distortion photography was/is done on old school tilt/shift lens or bellows and a view camera that will let you control the perspective and key-stoning however you wish. Even then you can’t get rid of it all. Film/sensor plane is flat and all lens are anything but. Cant violate the laws of physics, they try, but in the end they just minimize it.

No, I have a 100% distortion free lens (14mm f/2.8) that I use on my Fuji APS-C cameras. Distortion isn't just minimized it's not there.