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  1. #71

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    Quote Originally Posted by Bill Burk View Post
    I used to think of the Pentax Super Takumar 35mm f/2.0 (with 67mm filter ring) as a rectilinear wide angle lens. Was I mistaken? Or is this really an attribute of that lens?

    After it was stolen, I "replaced" it with the Olympus Zuiko 35mm f/2.0 lens. I wasn't thrilled that I was introduced to barrel distortion. So I never really took a liking to that lens, and I kept thinking I should get the shift lens... not at all for the shift feature... but because I had the impression it was bound to be rectilinear.
    I'm wondering about this, too. I inherited my father's OM equipment, among which is the OM 35mm shift lens (and a few other goodies).

    My experience so far has been that the faster and/or wider the lens, the less likely it will be rectilinear. I have the 35/2 Nikkor-O, and it seems pretty good - but I don't use it for architecture.
    Last edited by E. von Hoegh; 11-20-2012 at 11:18 AM. Click to view previous post history.

  2. #72

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    Quote Originally Posted by Bill Burk View Post
    I used to think of the Pentax Super Takumar 35mm f/2.0 (with 67mm filter ring) as a rectilinear wide angle lens. Was I mistaken? Or is this really an attribute of that lens?

    After it was stolen, I "replaced" it with the Olympus Zuiko 35mm f/2.0 lens. I wasn't thrilled that I was introduced to barrel distortion. So I never really took a liking to that lens, and I kept thinking I should get the shift lens... not at all for the shift feature... but because I had the impression it was bound to be rectilinear.
    It depends on how it was designed of course. One always hopes a shift lens is designed with architecture in mind, meaning it would be well corrected for distortion, but it depends on the lens. Take the Nikkor PC-E lenses for example. The 85mm and 45mm are virtually distortionless as expected (particularly in the 85mm focal length). The 24mm has visible barrel distortion near the edges. The Canon 24mm TSE-II on the other hand has virtually zero distortion.

  3. #73
    RalphLambrecht's Avatar
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    Quote Originally Posted by Ian Grant View Post
    ItA better example although MF not 35mm would be a comparison of the 38 mm Biogon on the Hassleblad SWC with the 40mm Distagon for the regular Hasselblads.
    goodpoint!i have the latter, not the former. is there any significant difference?From someone who has bothkeeping in mind that the distagon is a fle design, it might actually be better, at least close up.
    Regards

    Ralph W. Lambrecht
    www.darkroomagic.comrorrlambrec@ymail.com[/URL]
    www.waybeyondmonochrome.com

  4. #74
    Poisson Du Jour's Avatar
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    Quote Originally Posted by Michael R 1974 View Post
    It depends on how it was designed of course. One always hopes a shift lens is designed with architecture in mind, meaning it would be well corrected for distortion, but it depends on the lens. Take the Nikkor PC-E lenses for example. The 85mm and 45mm are virtually distortionless as expected (particularly in the 85mm focal length). The 24mm has visible barrel distortion near the edges. The Canon 24mm TSE-II on the other hand has virtually zero distortion.

    True also for Canon's TS-E 24 f3.5L first geneation PC lens. These lenses are designed from scratch to be free of distortion; they have to be: why build a PC lens for architecture if it is going to have distortion as a visible fault?
    .::Gary Rowan Higgins

    A comfort zone is a wonderful place. But nothing ever grows there.
    —Anon.






  5. #75

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    A side jump, I know, but aren't virtually all modern wide-angle large format lenses retro-focus designs? Reduced angle at which the the lens must illuminate the corners is the obvious advantage and was already mentioned. I don't know if this outweighs any disadvantages to the design or if it's more about catering to buyers. My point is that there are no mirrors or other obstacles between the lens and film in view cameras so retro-focus designs must be pretty decent if current production wide-angle lenses are all of this design.

  6. #76

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    Short focal length view camera lenses are not retrofocus designs. Infinity focus is achieved when the rear nodal point is one focal length away from the film plane. This is why the flange focal distance (essentially the distance from the lens board to the film plane when focused at infinity) is fairly close to the focal length of the lens. They are are more or less symmetrical in design around the diaphragm - which is another way you can tell they are not retrofocus designs. A retrofocus lens is asymmetrical in design, with a negative element/group at the front. The purpose is to move the rear element further away from the film plane than it would normally have to be for a given short focal length, so that there is room for say a reflex mirror to swing up and down behind the lens. There is no such obstacle in a view camera - although obviously retrofocus wide angle lenses could reduce the need for accessories like bag bellows. The disadvantages are complexity, size, weight (lots of elements) and - usually - distortion.

    Compare the designs of a typical RF 21mm lens (Zeiss, Leica etc) or even a 75mm 4x5 lens with a high quality 21mm SLR lens. In the highly corrected RF lens you'll find maybe 8 or 9 elements, 7 or 8 elements in the view camera lens, and up to twice that amount in the SLR lens. Compare say the Zeiss 21mm f/2.8 ZF SLR lens with a Zeiss 21mm f/2.8 Biogon RF lens. Both excellent, sharp lenses. But the Distagon uses twice the number of elements to get there, and still exhibits some visible distortion.

  7. #77

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    Quote Originally Posted by Old-N-Feeble View Post
    A side jump, I know, but aren't virtually all modern wide-angle large format lenses retro-focus designs? Reduced angle at which the the lens must illuminate the corners is the obvious advantage and was already mentioned. I don't know if this outweighs any disadvantages to the design or if it's more about catering to buyers. My point is that there are no mirrors or other obstacles between the lens and film in view cameras so retro-focus designs must be pretty decent if current production wide-angle lenses are all of this design.

    No.

  8. #78

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    Quote Originally Posted by E. von Hoegh View Post
    No.
    Please try to be more succinct.

  9. #79
    AgX
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    Quote Originally Posted by AgX View Post
    In case is true that Parfocal lenses have less abberations, the ability with Varfocal lenses to focus with a long FL and to zoom then back to a short FL, and by this gaining higher focussing acuracy, might compensate in some cases for any better lab-performance of Parfocal lenses.
    I just relized that I mixed up the terms Parfocal and Varifocal in that posting!


    The correct version:

    In case is true that Varifocal lenses have less abberations, the ability with Parfocal lenses to focus with a long FL and to zoom then back to a short FL, and by this gaining higher focussing acuracy, might compensate in some cases for any better lab-performance of Varifocal lenses.

  10. #80
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    Thank you AgX for the change. It's true that there is an advantage to being able to focus 'at telephoto' and then zoom back to 'wide' but, to tell you the truth, sometimes I feel better re-focusing at that 'wide' length. Chalk it up to paranoia perhaps but I really wonder how accurate even Parfocals are with regard to 'holding that precise focus' at all focal lengths. I guess that is what it must really be on my part: paranoia.

    Thank you for the clarification, AgX, and also to the others for the necessary addenda to my original question. There is so much to gain on this forum from many with different dimensions of knowledge out there. - David Lyga

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