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Barrel Distortion with the 35mm Summitar on my M9


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I have a 35mm Summicron ASPH. I recently bought a 35mm Summitar in beautiful condition at a very good price. I wanted to compare them side by side, thinking that I might sell the Summicron and cover part of the cost of another lens of some sort.

 

I took a few vertical shots yesterday with the Summitar of a rectangular doorway, mostly to compare it for sharpness with the Summicron. This very informal test demonstrated that the Summitar produces a very sharp image. No real surprise there.

 

But I was very surprised by something else--barrel distortion. The vertical frames of the doorway bow out in the middle, more than my 28mm Elmarit ASPH or the Summicron ASPH.

 

Is this the nature of this lens? If so, I'm not sure I want to stick with it. Anyone else seen this on an M9, M8, or any M film camera?

 

I can post a photo to illustrate what I'm seeing this evening after I return home from work.

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I have a 35mm Summicron ASPH. I recently bought a 35mm Summarit in beautiful condition at a very good price. I wanted to compare them side by side, thinking that I might sell the Summicron and cover part of the cost of another lens of some sort.

 

I took a few vertical shots yesterday with the Summarit of a rectangular doorway, mostly to compare it for sharpness with the Summicron. This very informal test demonstrated that the Summitar produces a very sharp image. No real surprise there.

 

But I was very surprised by something else--barrel distortion. The vertical frames of the doorway bow out in the middle, more than my 28mm Elmarit ASPH or the Summicron ASPH.

 

Is this the nature of this lens? If so, I'm not sure I want to stick with it. Anyone else seen this on an M9, M8, or any M film camera?

 

I can post a photo to illustrate what I'm seeing this evening after I return home from work.

 

OK, now I know why no one has responded to my previous post--I misidentified my 35mm Summarit and called it a Summitar. Sorry. But my problem continues--what about barrel distortion with the Summarit. Any thoughts?

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According to the spec sheet, the lens shows 2% distortion.

 

I don't have either the lens or an M9, so I can't comment directly.

 

Two percent doesn't sound bad to me, though that would obviously make the lens less useful for an architectural photographer. If I'm reading it right, the diagram implies that it's a rather simple curve, so it should be pretty easy to remove in postprocessing.

 

Why don't you post an example so we can at least see what you're seeing?

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Why do you pose the same question in two different subforums? I don't see much need to follow it in two places, but I may be in the minority. :confused:

 

The spec sheet says it has barrel distortion, so I don't understand why it seems so off-putting to you. :(

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As Howard says, it's all in the specs : Summarit and Summicron asph hav a very different distortion diagram (first Summarit, then Summicron asph) :

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Here are figures for linear distortion of other Leica 35mm lenses:

 

v.4 Summicron-M: c. 0.2% barrel

v. 1 Summilux 'pre-ASPH': c. 0.2% barrel

Summicron-M ASPH: 6% barrel

Summilux-M ASPH: 1.4% barrel

 

'Barrel distortion' is when straight lines bulge, 'pincushion' is when they bend inwards. It is generally felt that figures around 1% are very good and not noticeable except in copy photography, while less than 2 seldom means trouble. We do usually have to accept a little more in strong wide angle lenses however. Pincusion distortion is far more noticeable than equal amounts of barrel.

 

The two first lenses above are old symmetrical double-Gauss designs. Leica's own graph, published in the promotional material for the Summarit lenses, show about 1.8--1.9% barrel distortion. Lens design is really a matter of minimising and balancing various problems, where eradicating one would lead to unacceptable levels in another. Leica are very good at this job, and their lenses do overall show much less linear distortion than the products of various big SLR camera manufacturers. Try some Canon or Nikon lenses, especially zooms, and you will see some distortion!

 

The old man from the Age of the 5cm Elmar

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The current Summicron has much lower distortion. I assume that its one of the design 'trade-offs' because the Summarit is an excellent lens in many ways (sharp, very low flare, etc.) but it does have more significant distortion levels. If you really want a distortion free 35mm then the Summicron asph. is the one to go for (the 'lux distorts more too).

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... Try some Canon or Nikon lenses, especially zooms, and you will see some distortion! ...

Examples FWIW.

 

Very noticeable at the wide end is the so-called "mustache curve," which can't be completely corrected without special software.

18-200 Nikkor at 18mm

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18-200 Nikkor at 200mm

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Keep the cron if it is perfection that you seek! :)

 

But not the version 4 for all its qualities. Here's the Round House Camden Town, London, looking like a jelly on a plate.......

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Thanks for the responses. Sorry to be late in getting back on the Forum, but was busy with work. I am attaching a file showing the barrel distortion on the Summarit 35mm. I didn't do my homework thoroughly enough to understand that the barrel distortion could be quite noticeable, even objectionable at times. I do like the lens a great deal otherwise, so I suppose I will hang in there and see how it goes and correct in CS4 as needed.

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Why do you pose the same question in two different subforums? I don't see much need to follow it in two places, but I may be in the minority. :confused:

 

The spec sheet says it has barrel distortion, so I don't understand why it seems so off-putting to you. :([/quote

 

Ho Co, I'm not sure why it matters, but here goes. First, I posted on the M9 forum and for the first day or so, got no response. Decided the 35mm Summarit might be more commonly used by M8 or M film users, so saw no harm in trying to stimulate a little discourse there as well.

 

I should have researched the lens more than I did, though I read everything I could about it on this Forum, Reid Reviews, and all the logical places and it was never mentioned. I was caught off guard because I assumed the barrel distortion wouldn't be much different on the Summarit than on the Summicron ASPH, when in fact it is 3.3X more of an issue with the Summarit. Had I known that, I would certainly have thought twice about it. Other than barrel distortion so far, it is a great lens. But I am very surprised that the barrel distortion wasn't minimized to a much higher degree than with the Summicron.

 

Sorry again for identifying the lens as the Summitar, when I meant to say "Summarit."

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Thanks for the response, Steve. I was beginning to think you might have given up.

 

As I said, the distortion can be a surprise when you're not expecting it, but as others said, it's a quick clean-up in post. And you could even make a PS preset for the lens.

 

That's why I posted the Nikkor 18-200 shots as a counter-example. For it there's no batch cure in Photoshop because every focal length needs a different correction. :(

 

 

I like the shot of a solid door to "Nothing," BTW. Certainly sparks curiosity about what goes on in there. "No, officer, there's nobody in here but us chickens." :)

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But not the version 4 for all its qualities. Here's the Round House Camden Town, London, looking like a jelly on a plate.......

Please. This is NOT linear distorton. It is something called perspective. It means that you have not held the camera level. You have pointed it slightly down. Don't blame the lens.

 

The linear distortion of the v.4 Summicron is quite impossible to discover by eyeball alone. You have to do a careful measuring of the geometry of the image field, and you have to be absolutely sure about the geometry of the subject too! Like most asymmetrical lens designs, the Summicron ASPH exhibits a good deal more distortion than its symmetrical, double-Gauss predecessor.

 

The old man from the Age of Undistorted Facts

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