Lens hoods

Discussion in 'Large Format Cameras and Accessories' started by Krzys, Jan 23, 2010.

  1. Krzys

    Krzys Member

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    I have a 52mm hood for 50mm lenses, 35mm format, which I want to fit on my Nikkor-W 150mm for 4x5. Am I right to assume that there will be no vignetting and that the two formats are compatible as they are the same focal length?
     
  2. Ian Grant

    Ian Grant Subscriber

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    I use a Pentax lens hood for a 28mm Takumar on my 150mm Sironar, I think your hood might cause vignetting if you use any movements, and a 150mm is slightly wider anyway than a 50mm lens on a 35mm camera.

    Ian
     
  3. Jesper

    Jesper Subscriber

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    Personally I use the darkslide to shade the lens since I have it in my hand during exposure anyway.
     
  4. Krzys

    Krzys Member

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    Clever idea, Jesper.
     
  5. RalphLambrecht

    RalphLambrecht Subscriber

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    A 50mm lens and a 150mm lens don't have the same focal length.
     
  6. Ian Grant

    Ian Grant Subscriber

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    In this case Focal length is irrelevant it's the "Angle of View" that's important.

    Ian
     
  7. RalphLambrecht

    RalphLambrecht Subscriber

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    ...which differs with focal length. Six of one and a half dozen of the other.

    The maximum angle of view (a) can be calculated from the image diagonal (d), and effective focal length (f) as follows:

    a = 2 * arctan(d/(2*f))
     
  8. Ian Grant

    Ian Grant Subscriber

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    I think you've missed the point Ralph. He's comparing different film formats, a 150mm lens on 5x4 camera has a slightly wider angle of view than a 50mm on a 35mm camera, I use a 150mm on my 10x8 and that's even wider still.

    Ian
     
  9. RalphLambrecht

    RalphLambrecht Subscriber

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    Ian

    That was my question to him. He said 'as they are the same focal length'. Lenses with the same focal length have the same angle of view, independent of film format. Unfortunately, he didn't speak of two lenses with the same focal length, which is confusing. So, I'm not sure what he is after. I think you're probably right, and he meant 'equivalent focal length' and not 'same focal length'.
     
    Last edited by a moderator: Jan 23, 2010
  10. Ian Grant

    Ian Grant Subscriber

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    He wants to know if a lens hood for a 50mm Nikon SLR is OK on his 150mm Nikkor-W (5x4) lens without vignetting, that's unlikely if he uses any movements.

    Ian
     
  11. David A. Goldfarb

    David A. Goldfarb Moderator Staff Member Moderator

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    I think it's pretty clear that Ian understands the question, even if it's stated imprecisely.

    Try it, and it might work, but it might vignette if you use movements. If your groundglass has clipped corners, you can look through them and if you see the lens shade with movements applied and at the shooting aperture, then you'll have vignetting. If you don't have a clipped groundglass, look through the lens and see if you can see the corners of the groundglass, and that will tell you as well.

    The best hood option with a view camera is a compendium hood, but if you don't have or can't afford that option, you might look for a three-position rubber zoom shade, like the ones made by Hama.

    I think Robert Zeichner posted a good design for a barn door shade over on lfphoto.info a while back, which would be better than a three-position rubber hood. I sometimes use a 3" gel holder with spring clips and two barn doors (not as good as 4, but better than nothing) made by Voss that works well with lenses that don't have (currently) common sized filter threads.
     
  12. mikebarger

    mikebarger Subscriber

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    I do the same as Jesper. However, I have to admit to getting my shadow in the print recently.:smile:

    Mike
     
  13. RalphLambrecht

    RalphLambrecht Subscriber

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    A lens hood, designed for a 50mm lens will work on a 150mm lens without vignetting, but it may not provide adequate protections, because the 50mm lens has a much wider angle of view. The 50mm lens hood will allow light to fall onto the 150mm lens, which a properly designed 150mm lens hood would block off. Camera movements have no impact to vignetting due to lens hoods, because the lens hood moves with the lens.
     
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  15. RalphLambrecht

    RalphLambrecht Subscriber

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    Yes, I think we know what the OP means now: 50mm lens hood on a 150mm lens.

    Why would it? The hood moves with the lens when camera movements are used! Also, a 50mm lens hood allows for a much wider angle of view than the 150mm lens has!

    Vignetting is not the issue here, bright light falling onto the lens is.
     
  16. Ian Grant

    Ian Grant Subscriber

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    You are still neglecting the difference in format, so your comments are totally incorrect

    A Nikkor f1.8 50mm lens on a 35mm camera has an angle of coverage (diagonal) of 46° Nikons own figure, while they state the coverage of the Nikkor-W f5.6 150mm to be 60° at full aperture and 70° at f22.

    That's rather at odds with your comment and in fact the total opposite, it's why I use a lens hood designed for a 28mm SMC Pentax Takumar (35mm camera) on my 150mm Sironar and it's an excellent combination.

    So in view of the figures I think the OP should really look for a wider lens hood. The 150mm Nikkor W is closer in equivalence to a 38-40mm lens on a 35mm camera, the actual picture area is more like 52° compared to the 46° of a 50mm standard on 35mm.

    Ian
     
    Last edited by a moderator: Jan 23, 2010
  17. John Koehrer

    John Koehrer Subscriber

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    Aren't angle of view & angle of coverage on opposite sides of the lens? Front/back
     
  18. Richard Wasserman

    Richard Wasserman Member

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    I bet Krzys thought he was asking a simple question!
     
  19. Ian Grant

    Ian Grant Subscriber

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    The angle of view is what you capture with the camera, the angle of coverage is what the lens is capable of.

    Ian
     
  20. RalphLambrecht

    RalphLambrecht Subscriber

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    Ian

    My fault, you are correct. I recently had my brain serviced, and I don't think they put it back together right. The equation, posted by myself earlier proves your point too.

    Nevertheless, you and David said that camera movements were an issue. Why do you think that? The hood is moving with the camera. Either the hood is in the way or it isn't. Camera movements should have nothing to do with it.
     
  21. Ian Grant

    Ian Grant Subscriber

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    It's those German brain surgeons Ralph :D

    As the lens is shifted (up, down, left or right)you are using light from a more oblique angle, almost as if using a much wider angle lens, so the edges of the lens hood on that are furthest from off centre is likely to vignette.

    In Krzys case that would probably happen rather quickly with his 50mm lens hood on the 150mm assuming it's not vignetting without movements.

    Ian
     
  22. RalphLambrecht

    RalphLambrecht Subscriber

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    Understood. Thanks.
     
  23. sanking

    sanking Member

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    Hopefully you got a full 90 day guarantee for parts and labor?

    Sandy King
     
  24. RalphLambrecht

    RalphLambrecht Subscriber

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    No. The receipt said 'no fault found'.
     
  25. Ian Grant

    Ian Grant Subscriber

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    You should make claim then :D
     
  26. edtbjon

    edtbjon Member

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    Back to the OP's question. You should probably do alright, but with a view camera it's quite easy to check for vignetting yourself. It goes as follows, with a little bit of theory to start with:
    Start with a straight shot at infinity. Then the lens will be as close as possible to the film and thus the risk of vignetting will be the biggest. You don't say which camera you use, but at working aperture (typical f/22-f/32) check the corners of the ground glass. The best is if you have cut corners on your ground glass, but it will show on a ground glass without cut corners too. If there is any difference in what you see when the shade is on or off, you have problems. Try this again with maximum shift, but still at infinity. If in doubt, you can expose a couple (yes, only two) of sheets to make sure that you don't get vignetting, or if neccesary, maybe with one or two extra sheets decide when you need to take away your shade.
    Again, as there are so many different shades available, it's hard to say whether your particular shade will vignette or not and when it will do it.
    One thing is sure though, if the shade is safe at infinity it will be safe at any closer distance. It's all in the geometry of a camera.

    //Björn