Creating a 4x5-->3x4 reducing back

Discussion in 'Large Format Cameras and Accessories' started by Jeremy, Jul 9, 2005.

  1. Jeremy

    Jeremy Member

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    I'm really enjoying the 3.25x4.25 film size (the film dimensions are great!), but I really felt limited tonight when I went out to do some shooting where some more movements would have really helped.

    Can anyone give suggestions on how to make a 3x4 back for a 4x5 camera? I was thinking I could get a piece of 1/4" plywood (or other such material) sized the same as the rotating camera back of the 4x5. Then I could just unscrew the 3x4 back from my Crown Graphic (I think this is possible as I just see 4 screws holding it on, but there could also be some glue) and screw it centered onto the plywood with the appropriate hole cut in the middle. Any problems forseen?

    Also, if anyone has a 3x4 graphic with a good grafloc back for parts let me know so that I don't have to butcher the crown and I can have a back-up camera, but if I can't find one then I would rather have the field camera....
     
  2. Nick Zentena

    Nick Zentena Member

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    Why? 3x4 film isn't cheaper then 4x5. Just shoot 4x5 and crop later.

    No. Okay. Which 4x5 camera is this for? I made a new back for my Ansco 5x7 by just cutting some hardboard to the right size. Cut the opening. I then took the hardware and mounted it on the hardboard. Done. You need to make sure the film plane doesn't move. Take depth measurements off the ground glass. You'll want to make sure it's perfectly square. But nothing really complicated.
     
  3. Jeremy

    Jeremy Member

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    Other than the fact that I have 900 sheets of 3x4 in the freezer, 3x4 film is also $10 cheaper/50 sheets than 4x5 film in what I shoot (Efke 100).

    The camera is a Shen Hao 4x5.

    I am not sure I follow, why do I need to take depth measurements off of the ground glass? If I just screw the 3x4 grafloc back onto the hardwood the ground glass and film plane won't change in relation to each other. Or do you mean to make sure that whatever I get to screw the 3x4 back onto is completely flat and does not introduce a slant into the film plane?
     
  4. Nick Zentena

    Nick Zentena Member

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    Just to make sure you haven't moved the film plane some how. If the inside of the ground glass measures the right distance then it should be fine.
     
  5. Oren Grad

    Oren Grad Subscriber

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    Jeremy -

    You are correct. If you use the back assembly from the 3.25x4.25 Crown intact, then the ground glass to film plane register is preserved and you don't need to worry about it.

    And yes, you can just unscrew the back from a 3.25x4.25 Graphic - I did it once to satisfy myself that a project like yours would be possible, though in the end I didn't go through with it.

    Good luck...
     
  6. Greg Davis

    Greg Davis Member

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    I made 4x5 and a 2x3 reducing backs for my Kodak Master 8x10 by using the backs from Crown Graphics. I bought the hobby plywood available at craft stores for the job. Get a thickness that is just too thin and buy two pieces of it. Look at which way the warping curves and glue them together to cancel out the bend. I put an extra piece of plywood between this part and the camera back so I can get my fingers under the film holder to pull it out. And don't forget the light trap on the camera side of the whole thing.

    -Greg
     
  7. Troy Ammons

    Troy Ammons Member

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    I would look on Ebay for a 3x4 crown. They are not that popular, and the prices I have seen are fairly low, especially without a lens.
     
  8. Jeremy

    Jeremy Member

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    I've been looking on eBay for one, but the cheapest I have found with a graflok back so far has been $150.
     
  9. Oren Grad

    Oren Grad Subscriber

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    Why does it need to have a Graflok back? You don't need one to use 3.25x4.25 sheet film in holders - the plain spring-back will do fine.
     
  10. Jeremy

    Jeremy Member

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    Because I also have a 6x9 roll film back that I like to use for the occasional color negs and to use it I need a Graflok back.
     
  11. Oren Grad

    Oren Grad Subscriber

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    Sorry, a bit of brain fog on my part. Roll holders that are compatible with the 3.25x4.25 Graflok fitting are not especially common, it didn't occur to me that you might already have one.
     
  12. noseoil

    noseoil Member

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    Jeremy, there's a guy in town here I bought my 4x5 Graflok back from (for the B&J 8x10 to 4x5 back), I will ask for you. He may or may not have one, but will check. Don't have his number, so I'll have to contact a friend who will contact him for me. Might take a day or two, but I'll let you know. tim

    Link to my back mod http://www.apug.org/forums/showthread.php?t=16763
     
  13. Jeremy

    Jeremy Member

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    Thanks, Tim, I appreciate it--I'm still hoping you'll get around to an article about your 4x5 pinhole.

    No worries, Oren. I'm actualy really lucky as my 3.25x4.25 Graflok 120 roll film back was frankensteined from something else as it also has the pin rollers to obviate film flatness worries.