Distortion on VC 35mm 2.5 11 lens

[peter16]

Hi, I'm a recent rangefinder user. All I could afford for a first lens was the Voightlander 35mm 2.5 pancake, which is fine for 90-95% of the pictures I make. However when I am photographing close, say 5 to 20 feet away, objects with straight lines near the edge of the frame are being curved like the below examples. I'm considering burning my tax return for a pre-asph summicron. Would anyone be willing to post images similar to these below taken with the non asph summicron and showing how it handles straight lines close up such as these? I don't think Sean Reid's test images show this...Thanks in advance.
also what's the secret for being able to post over on rangefinder forum??

 

[Eric Rose]

It's hard to tell as you have some tilt that is affecting your images.

 

[peter16]

That's true Eric, but I guess I was figuring some folks could understand the difference between parallax distortion from tiling up and down and field curvature or barrel distortion making straight lines curved near the edges of the frames like you see on the top black line on the bus billboard, the diagonal black line of the shelving unit above the taken apart mac screen, or the left edge of the window frame on the bottom one.

Your pictures of the tall building in Malaysia have some tilt too but the lines near the edge don't curve, Were those made with a pre asph summicron? Do you have any closer up examples? If I am mistaken and there is a relationship between tilting up and down and barrel distortion and distance from camera to subject, I'm all ears.

 

[Eric Rose]

Not sure if that was a vailed insult, but I do know the difference between lens distortion and parallax distortion. My point was if you want to have us evaluate the lens distortion then it is best to eliminate all other forms of distortion.
Your lens does exhibit some barrel distortion but unless you have straight lines near the edges I would not worry to much about it.
I have a VC Color Skopar that has the same issue and for 99.9% of the shoots I have taken with it no impact on the image was noticed.

 

[Oren Grad]

In September 2002, Leica published a little book called Leica M-Lenses: Their soul and secrets, written by Erwin Puts, and including technical data on their then-current plus some previous-generation lenses. Among the included lenses is the v4 35 Summicron. The specified distortion curve for that lens shows extremely low linear distortion as fast 35's go, a fraction of 1% that becomes apparent only at the far edges of the image field.

As it happens, 35 is my most-used focal length for 35mm work. I don't have any relevant scans handy that I can post for you here, but I'm pretty sensitive to linear distortion and have used many different 35's extensively, including the v4 Summicron, and I'd say that that one is among the best in that respect.

I don't have experience or data for any of the earlier-generation 35 Summicron-M's, though, so can't speak to those.

 

[peter16]

Eric, wasn't sure if your initial comment was mildly condescending. If I was mistaken and overreacted, I apologize. The pitchers below still show some tilt, (seems nearly unavoidable w handheld rangefinder) but are a little closer to being straight. I know I shouldn't worry about it too much, and that none of these pictures would be transformed from humdrum to masterpiece without the curvature, but it does bug me a little. I'd almost adjust my initial #s and say it seems to effect 10-15% of my shots. You're right I should just not worry about it and be outside exposing film instead of resizing scans to post here! But as I said, I can't help but wonder if the summicron would make me sleep better at night.

Oren, Thank you for the comments, going to try and buy that book.

 

[Ko.Fe.]

It is not my business to suggest how is better to burn tax return. But 35mm Leitz prices skyrocket in 2017 to the levels it doesn't makes sense to buy this old lenses, which are often not in good shape IMO.

If most corrected on distortions lens is needed I suggest to check CV Zeiss ZM.

 

[Oren Grad]

Oren, Thank you for the comments, going to try and buy that book.

Thorsten Overgaard has it posted on his site:

http://www.overgaard.dk/pdf/Leica-M-Lenses-Their-Soul-and-Secrets_en.pdf

 

[Oren Grad]

FWIW, Ken Rockwell shares observations and measurements on linear distortion for quite a few M-mount 35's here...

https://kenrockwell.com/leica/lens-reviews.htm#35

...and here:

https://kenrockwell.com/voigtlander/35mm-f14.htm

 

[peter16]

Excellent – Thanks. Wish Ken Rockwell reviewed my VC 35 2.5 pancake so I could see the distortion numbers but it looks like he's saying the VC 35 1.4 has terrible distortion which may likely be what i'm seeing. Also very interesting to see that according to him not only does the asph have more distortion then then the V4, that the amount of distortion is not consistently tied to closer distance, ie. some lenses get worse as you get closer while some actually improve from 3m to 1m.

 

[Eric Rose]

The images I made in KL were either with a Nikkor 50mm f2 on a Nikkormat or a Zeiss 80mm on a Blad. The ones looking almost straight up were done with the Nikon.

I have a pre asph 50mm Summicron but haven't bothered checking any of my images to see if there is any curvature. If you were on my website all the photos taken in the Mexican cemetery were taken with either a 50mm or 90mm Summicron.

 

[ic-racer]

If you are planning some copying work in the future, get a macro lens, those are corrected better for distortion. Otherwise, I don't see anything wrong with the posted images. I kind of like the second one. Reminds me of my last week, rebuilding my last computer that will still run 10.6 and all the software that won't run on the new machines.

 

[Sirius Glass]

I see some barrel distortion. If I am concerned about distortion for a wide angle photograph I use the Zeiss Biogon 38mm lens which is not available for your camera. When I am back to my main computer and if I remember I will post one of its photographs.

 

[E. von Hoegh]

That's true Eric, but I guess I was figuring some folks could understand the difference between parallax distortion from tiling up and down and field curvature or barrel distortion making straight lines curved near the edges of the frames like you see on the top black line on the bus billboard, the diagonal black line of the shelving unit above the taken apart mac screen, or the left edge of the window frame on the bottom one.

Your pictures of the tall building in Malaysia have some tilt too but the lines near the edge don't curve, Were those made with a pre asph summicron? Do you have any closer up examples? If I am mistaken and there is a relationship between tilting up and down and barrel distortion and distance from camera to subject, I'm all ears.

Firstly, the distortion you are seeing is "barrel distortion", it has nothing to do with parallax and it isn't curvature of field. The converging or diverging is caused by the film plane not being parallel to the subject plane.
That seems like a fair bit of barrel distortion for a modern 35, more than my 20mm Nikkor which is a 50 plus year old design.
One RF 35mm I have used which displays virtually no distortion is the Jupiter 12, an FSU clone of the prewar Zeiss Biogon and a non-retrofocus design.

 

[peter16]

Firstly, the distortion you are seeing is "barrel distortion", it has nothing to do with parallax and it isn't curvature of field. The converging or diverging is caused by the film plane not being parallel to the subject plane.

I do like Hollis Frampton's quote "Any art hopes to provide intimations of perfection; to speak with some cogency of our conditions as human beings; to nourish our affections. Art can accomplish such ends only through accuracy, through exact definition, what Confiucius referred to as 'calling things by their right names.' I can recommend no higher ambition to anyone."

So Bravo, E von Hoegh, for pointing out that I was confusing 'barrel distortion' with curvature of field, and explaining to all of us what happens to straight lines when the film plane is not parallel to the subject plane. Yes, it does also seem to me to be a fair amount of barrel distortion for a modern 35, Good to know about the Jupiter, altho i'm looking for something that won't have any issues with sharpness or quality control.

But can anyone post images with closer up straight lines near the edge of the frame made with a 35mm pre asph summicron? Or tell me how to get access to post on the rangefinder forum?

 

[FujiLove]

I haven't noticed any issues with my 35mm 2.5, so I had a poke around Flickr to see if I could find some closeups with vertical lines along the edges. I can't see much on these:

Berlin by Arnaud POIRIER, on Flickr

Untitled by Arnaud POIRIER, on Flickr

DO NOT BLOCK by dcastelli9574, on Flickr

Historical Museum Moscow, Russia by Eugen von Arb, on Flickr

 

[FujiLove]

This looks like your's on the left edge:

000040 by nan wang, on Flickr

I wonder if there is quite a bit of variation between examples of this lens? Quality control issues maybe?

 

[E. von Hoegh]

I do like Hollis Frampton's quote "Any art hopes to provide intimations of perfection; to speak with some cogency of our conditions as human beings; to nourish our affections. Art can accomplish such ends only through accuracy, through exact definition, what Confiucius referred to as 'calling things by their right names.' I can recommend no higher ambition to anyone."

So Bravo, E von Hoegh, for pointing out that I was confusing 'barrel distortion' with curvature of field, and explaining to all of us what happens to straight lines when the film plane is not parallel to the subject plane. Yes, it does also seem to me to be a fair amount of barrel distortion for a modern 35, Good to know about the Jupiter, altho i'm looking for something that won't have any issues with sharpness or quality control.

But can anyone post images with closer up straight lines near the edge of the frame made with a 35mm pre asph summicron? Or tell me how to get access to post on the rangefinder forum?

Cofucious said quite a lot that I like.
As for the Jupiter, and FSU lenses in general, I have found the Contax - Kiev mount versions to be quite reliable, my J12 is sharp as anyone could want, the LTM versions, particularly the J9 are a different story.
I wonder if your lens was made with digital in mind? Because I have noticed large amounts of barrel distortion and lateral chromatic aberrations in later digital lenses, particularly zooms. These issues are easily corrected in the processing software, but are real problems when that lens is used on film.
One of the advantages of using a rangefinder is that retrofocus wide angle lenses are not necessary, hence far less distortion.
Your lens shows more distortion than any Nikkor WA I use, from 20 to 35mm, all of which are retrofocus designs from the 60s.

 

[Ko.Fe.]

FSU are often copies. J-12 is Biogon. Still made as Zeiss ZM. Sharp and low distortions.

LTM could be as sharp as Contax, but it has to be aligned. Which is second nature of FSU LTM .

 

[MattKing]

This looks like your's on the left edge:

000040 by nan wang, on Flickr

I wonder if there is quite a bit of variation between examples of this lens? Quality control issues maybe?

I would say that the item near the left edge of the example you posted is a mirror, and may not be parallel with the wall behind it.
There are so many sources of potential distortion in that scenario - I don't believe you can reliably glean anything from it with respect to the performance of the lens involved.

 

[Eric Rose]

OP, is there anything in particular you will be photographing that needs a highly corrected lens?

 

[peter16]

OP, is there anything in particular you will be photographing that needs a highly corrected lens?

Just what Chris Marker called "only fabulous materials: glass, plastic, terry cloth."
No, not really anything specific – beyond the general built environment shown in the 6 examples I posted.
Maybe it's just the nature of 35mm equipment to do this, I'm used to view cameras that don't.
Guess the only way to figure out how bad my current lens is to rent a zeiss biogon and use both to shoot a grid on a tripod.

 

[Oren Grad]

Maybe it's just the nature of 35mm equipment to do this, I'm used to view cameras that don't.

35mm lenses do tend to be optimized for other things, notably size, cost and/or speed. But 35mm lenses with low linear distortion for 35mm format do exist. It's reasonable to expect that you'll be able to find one that will suit you.

 

[Sirius Glass]

I see some barrel distortion. If I am concerned about distortion for a wide angle photograph I use the Zeiss Biogon 38mm lens which is not available for your camera. When I am back to my main computer and if I remember I will post one of its photographs.

Here are two examples of this lens which is rectilinearly correct.

 

[Patrick Robert James]

If I am not mistaken the 35mm Zeiss Biogon f/2 has super low distortion. I just looked at images from mine and it doesn't have any that I can see. I used to have a Summicron which I think was V3 (the one with the tab for the aperture) and I compared them after I bought the Biogon. Wasn't even close. Sold the Summicron.....