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View Full Version : Super Wide Angle Lenses? -- Distortion?



JZ
3-Jan-2005, 14:06
I'm a fairly big fan of Clyde Butcher's (http://www.clydebutcher.com) photography. He says he uses very wide lenses, which is apparent when you visit one of his galleries. What I didn't realize at the time was just how wide. On his website there are a few that list a 21mm on a 8x10 and a 47mm on a 5x7 or a 90mm on a 8x10... My question is, why aren't these images distorted? At this focal length, shouldn't these images be a fisheye perspective?

Thanks.

Ernest Purdum
3-Jan-2005, 15:31
I couldn't get the link to work, so I can't comment on the images directly. I can, though, discuss the subject in general.

True distortion is not caused by the use of extreme wide angle lenses. There is apparent distortion in which spherical objects at the edge of the image appear elongated into ovals. This isn't really distortion because the lens is accurately portraying the way the objects look when viewed at that angle. Our eyes don't give us this view because we turn them and our heads to look at something at our sides.

A fish-eye lens purposely uses enormous barrel distortion to obtain a peculiar view with well illuminated corners. I don't recall any having been made for general-purpose large format use, although there have been some big ones made for scientific purposes. If omeone knows of one, maybe he'll mention it.

Mr. Butcher may be carefully avoiding any objects in the cormers of his images which would appear strange when viewed.

ramin
3-Jan-2005, 17:32
Ernst try this: www.clydebutcher.com

Darin Cozine
3-Jan-2005, 20:02
Yeah, I met Clyde at the View Camera Conference in Monterey. Very nice guy. His prints were stunning. I had asked him some advice on how to better capture the feel of a location. I had told him that I shoot in 4x5, and my widest lens was a 65mm.. he replied that I needed a shorter lens, like a 47mm.

Well I must say that I was a bit discouraged from his advice. I think that Clyde is a great photographer, and his vision is the key to his success, rather than a specific lens.

But in answer to your questino, there is no 21mm lens for 8x10 format. I think 47mm is the widest lens that covers 4x5. I'm not sure about 8x10, it's not my format.

Darin Cozine
3-Jan-2005, 20:26
Oh, sorry your question was about distortion. Most lenses are designed to be rectilinear, which means that straight lines stay straight. Fisheye lenses disregard normal lens design in order to allow for extreme wide-angle views.

Ole Tjugen
4-Jan-2005, 01:40
The widest LF lenses ever made were the classical Goertz Hypergon, which covered 5x the focal length. So a 60mm would be the shortest for 8x10".

I couldn't find any reference to focal lengths on Clyde Butcher's website, but I expect it's hidden away down there somewhere.

For myself, the widest lens I've ever felt the need for was a 90mm on 5x7"; besides I'd need a new camera to use anything shorter...

ramin
4-Jan-2005, 08:05
Large format lens designers seem to have more freedom to control distortion due to the size of large format cameras compared to an SLR camera. That is why we donít see the typical distorted look of a say 20mm lens on a Nikon 35mm in no large format lens. If you come from photojournalism you will miss this in LF photography. Lenses for rangefinder cameras like Leicas and Contax are better corrected than SLRs again due to the lack of the mirror box in rangefinders. Another fact is that we all choose lenses with large image circles and we use the ďbest part of itĒ

Love to learn more on this topic since I am a wide angle lover myself and for the moment I have nothing wider than the 110 SS. At the moment I am in the process of deciding between a 72 SA and the 47.

Cheers

arthur berger
4-Jan-2005, 08:23
out of curiosity, I checked out this site and under the sub heading of photo journal I found the answer to your question. He meant 121 mm Super angulon on his 8x10 camera( so it says in the explanation). This is the widest he used on 8x10. and on 5x7, a 90mm was the widest lens he used according to what I gathered from the journal.

Ellis Vener
4-Jan-2005, 10:51
<quote>That is why we donít see the typical distorted look of a say 20mm lens on a Nikon 35mm in no large format lens.</quote> Just curious but have you ever used a 58, 55, 47 or 45 mm lens on a 4x5? i have and with a 47mm you have plenty of near far/relationship distortion: round table tops turn into increasingly oblong footballs the closer they are to the camera and strectched even more as they go into the corners; severe "ship's prow" effects with skyscrapers in a skyline. It is very much like using a 15mm or a 13mm on a Nikon 35mm SLR.

Ellis Vener
4-Jan-2005, 10:51
"That is why we donít see the typical distorted look of a say 20mm lens on a Nikon 35mm in no large format lens."

Just curious but have you ever used a 58, 55, 47 or 45 mm lens on a 4x5? I have and with a 47mm you have plenty of near far/relationship distortion: round table tops turn into increasingly oblong footballs the closer they are to the camera and strectched even more as they go into the corners; severe "ship's prow" effects with skyscrapers in a skyline. It is very much like using a 15mm or a 13mm on a Nikon 35mm SLR.

Darin Cozine
4-Jan-2005, 16:56
LF lenses are not devoid of distortion. Most LF lenses are intended to be rectilinear as much as possible, but there are allways tradeoffs in lens design.

Also dont confuse distortion with perspective. If you point any camera up at a building, the sides of a building will converge. This will have an effect on circles looking misshapen and other oddities. Try drawing a grid on a foam core board. Then lay the board on the table you mentioned and see if the lines are still straight. They may not be parallel anymore, but they should remain straight in any rectilinear lens.

Schneider has information on distortion published for their lenses online.

Mark Sawyer
4-Jan-2005, 17:46
Some excellent points here on perspective vs. distortion. Here's how I go through it with my high school students while we're working with pinhole cameras, some of which are very wide angle.

Human vision has a relatively narrow angle of view. Stand in front of a very long straight wall, maybe ten feet away, and you can't perceive the whole thing from end to end. Look at the part right in front of you and the top and bottom are parallel. Look to the left and you'll see the wall disappearing to a vanishing point. Look to the right and you'll see the wall disappearing to another vanishing point. Nowhere can your eyes detect a curve in the straight wall.

Now take a piece of paper, and draw a rectangle. Inside the rectangle draw the whole wall, including the parallel lines in front of you and the vanishing points on both ends.

What you have isn't the distortion of optics, it's the distortion of condensing a wide field of view into a narrow field of view. Well, that's not 100% of the distortion you see in a pinhole photograph, but it's a good part of it...