Extension bellows for Sinar P2 8x10

Discussion in 'Large Format Cameras and Accessories' started by reggie, Oct 16, 2007.

  1. reggie

    reggie Member

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    Hi:

    I have a Sinar P2 8x10 and I need to add ext. bellows onto it. I also have a Sinar P 5x7, so I should be able to use the front standard from it to support the extra bellows. Does anyone know what bellows I should use for the ext? Can I use the 4x5 square bellows? Does it not vignette? I have never seen and 8x10 ext. bellows, so I assume that I use a smaller bellows for this.

    Sorry for the beginner question, but I just got this camera and I'm not sure of all the accessories for it.

    -R
     
  2. David A. Goldfarb

    David A. Goldfarb Moderator Staff Member Moderator

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    The normal way of doing this is to add an extra standard (like an F/1/2 front standard, which is also called a "Multipurpose Standard") as an intermediate standard and 4x5" bellows between the intermediate standard and the front standard. In situations where you really need that much bellows, it shouldn't vignette, but it depends on how much extension you have, the lens, subject distance, etc.

    My 8x10" P has an extra-long 40" bellows, but it may be a custom bellows. A Sinar collector looked at it and said he hadn't seen one before.
     
  3. reggie

    reggie Member

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    I plan on doing close-up photography, 2x or 3x. I usually do still lifes during the winter months, nice indoor projects. So, I will need longer bellows. My subjects will be anywhere from 3" high to 5" high or so. I will want to fill as much of the 8x10 glass with the subject as possible and in come cases even magnify beyond the edge of the glass so I'm phogographing a portion of the subject.

    I haven't done the math see what the lens to subject distance and lens to film plane distances are, so I'm not entirely sure of the bellows length that I"ll need. I have to research the numbers in some of my reference texts. But I can start out with a 300mm lens and a subject 3" high and I want a 3x magnification so that it is 9" tall on the gg. I don't know for sure, but I think that would mean placing it 12" in front of the lens and placing the film plane 36" behine the lens - does that sound right? I will go look it up.

    Thanks.

    -R
     
  4. David H. Bebbington

    David H. Bebbington Inactive

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    David is correct that a multi-purpose standard (or any Sinar front standard or 4x5" rear standard) will do the job. There is also an older component that looks like this:
    http://cgi.ebay.de/Sinar-helpstanda...oryZ8277QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
    This is too light to be used as a front standard but on the other hand is fine for its intended purpose joining two bellows together and does not make the camera too heavy. If you want 36" (900 mm) bellows, you should be fine taking the 8x10" bellows to near its full 600 mm and then adding a 4x5" bellows extended to 300 mm. Any more than this and you will probably find out why people sometimes go to the expense of a custom bellows like David's. The handy thing about the auxiliary support in the picture is that it is very easy to raise, lower, swivel and tilt it quickly to minimise vignetting.

    Regards,

    David
     
  5. reggie

    reggie Member

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    I did the math. Using the formula (from my trusty Focal Encyclopedias):

    S=F * (M + 1)

    where

    S=lens to film plane distance
    F=focal length of lens
    M=magnification ratio

    So, with a 300mm lens and a 3x magnification ratio (because my subject is 3" high),

    S=300 * (3+1) = 1200mm = 48 inches

    If my subject is 5" tall and I want a 2x magnification, I would need 900mm or 36" of bellows draw.

    My 8x10 bellows goes out to about 24", so I will need 12" to 24" of ext. I imagine I will easily get the 12" out of the eBay item (if it fits a P2). However I can't imagine 2 of these extensions would work due to vignetting. I may have to go with a custom bellows in the 36"-40" range. I wish Sinar made an ext. for their 8x10 bellows.

    Another option is using a much shorter focal length lens. E.g.

    F=150mm
    M=3

    S=150*(4) = 600mm = 24 inches, an unextended 8x110 bellows.

    Does anyone have experience using short FL lenses for macrophotography on plate cameras? I wonder if a 150mm lens (at least one that I own) will project a circle big enough to cover 8x10 at 24"? I am also concerned about subject distortion when shooting closeup with such a short lens.

    Can anyone point me to someone who makes custom bellows? I know I've seen someone on the 'net, but I can't recall who it was.

    Thanks to both Davids for the input. I appreciate it.

    -R
     
    Last edited by a moderator: Oct 17, 2007
  6. Struan Gray

    Struan Gray Member

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    Camera Belllows in the U.K. (http://www.camerabellows.com/) can make any bellows you like, but you will probably have to supply a pair of bellows frames (easy enough: just buy a ratty bellows on eBay).

    Sinar made a special bellows for just this situation, which fit their 8x10 standard on the rear and a 5x7 standard on the front. On the rail would be mounted an 8x10 standard, then a 5x7 standard in the middle, and a 4x5 at the front for the lens. You use a normal 5x7 bellows to connect the intermediate 5x7 standard to the front. I have even seen pictures of systems where the there was a further 4x5 bellows out in front of the 8x10-5x7-4x5 combination.

    Another advantage of the 8x10-5x7 bellows is that it allows you to use big portrait lenses on custom lensboards that fit the 5x7 standard.

    I have seen a trickle of the 8x10-5x7 bellows on the German eBay site. They don't sell for much more than the usual 8x10 bellows, but they don't turn up so very often (once or twice a year). Camera Bellows could of course make you a similar one if you send them an 8x10 and a 5x7 frame.
     
  7. David H. Bebbington

    David H. Bebbington Inactive

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    The answer is yes, yes and yes! A symmetrical lens (e.g. Schneider Symmar in all its variants) seems to work well at macro distances, effective coverage is greater at close distances (150 lens should be fine for 10x8" at 1:1) and subject distortion can be a problem (depending of course on how 3-dimensional the subject is). A 210 or 240 lens may offer a handy gain in magnification without so much distortion.

    Regards,

    David
     
  8. GeorgesGiralt

    GeorgesGiralt Member

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    David,
    Having tried a Symmar at quite large magnification and disliked the results, I asked optics specialists and they told me to reverse the lens. The longest distance in the couple subject/lens and film/lens should face the front element of the Symmar.
    I haven't had time to test this yet, but you may find this information interresting...
    Last but not least, I've seen a picture of an 8x10 Norma with the 8x10 bellow connected to a 8X10 standard (so it may be a special bellow) then another 8x10 bellow, connected to a 5x7 standard and the 5x7 bellow connected to the multi purpose auxilliary standard with a 4x5 bellow connected to the front standard. The lens was looking like a WWII bazooka... and had a support at mid barrel between the Norma rail and the barrel.
    I kindly suggest you keep this camera home and do not use it into the streets.... But you may want to test the cops behavior in your vicinity....
     
  9. roodpe

    roodpe Member

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    That was Reinhart Wolf who used an 8x10 sinar norma with a 1200mm ronar lens to shoot the buildings of nyc.
     
  10. David H. Bebbington

    David H. Bebbington Inactive

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  11. GeorgesGiralt

    GeorgesGiralt Member

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    Well the Symmar I own is on a size 1 Compur. If I'm not wrong, the cells have the same thread front and back, so you just have to reverse them.
    I have to try this, so I do not know if it works.
     
  12. reggie

    reggie Member

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    Well, I ordered the stuff I need to the bellows ext. I got a baseplate, a 2nd rail clamp, a multi-purpose standard and a 4x5 square belows. I hope all this stuff fits ok.

    I also contacted Camera Bellows in the UK about making a 36" new bellows and they wanted GBP 165 for it. I need to supply the bellows frames. Hopefully Sinar will have them as I never see them come up on eBay.

    David, if you're watching tis thread, do you reccomend a 40" or a 36" bellows?
    How do you deal with the sag? Do you have those rings onthe bellows to take up sag?

    I'll check with CB to see if they can make an 14" - 18" 8x10 ext bellows rather than a full bellows. I'll see if they can make leather bellows.

    Thanks.

    -R
     
  13. David A. Goldfarb

    David A. Goldfarb Moderator Staff Member Moderator

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    Well, 40" is what I have, and it works. To reduce sag, I just rotate the bellows occasionally, and it seems to hold up pretty well. Or if that's not convenient to do at a particular moment, I just support the bellows in the middle with something, like a large sponge or a small box.
     
  14. Sparky

    Sparky Member

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    Reggie - if, as you say, your 8x10 bellows extend to 24" or so (I would think they'd go longer than that!) - then you should be good to at LEAST 54" with a 4x5 bellows extension. I think the opening in the frame holding the bellows at the joint is around 5.5" square - isn't it? So that should mean that you'll be able to pull just around 30" of bellows draw (or close to it) on the 4x5 part before it starts impinging on the image - the way it appears to me at least.