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  1. #21
    Ole
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    For a fixed 2x magnification, you need an extension of 3x focal length.

    Make your camera 405mm long with +/- 5cm wiggle room, get an old Schneider Symmar 135/5.6 convertible, unscrew both cells and put them back on the opposite side of the shutter.

    In that magnification range there's little (at least affordable to a student) that outperforms a reversed Symmar. Get the 135 in a #0 shutter, not the 150 in a #1 shutter: The #0 has the same threads front and back, and you need to reverse the lens. The 135 has an image circle of 190mm at infinity, thus 380mm at 1:1, and 570mm at 2:1. That should be sufficient, I believe.
    -- Ole Tjugen, Luddite Elitist
    Norway

  2. #22

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    Quote Originally Posted by Murray@uptowngallery View Post
    150 mm lens at 1:1 is 300 mm bellows extension because 150 mm at 150 mm is infinity focus.

    I haven't figured out the math for 2X - whether it's double the 1:1 (600) or just 1 more f.l. longer (450 mm).

    All nominal numbers above...

    Use that equation that looks like a bunch of fractions something like 1/f = 1/s + 1/o

    Uses image and object distances,
    I see that you haven't looked at that little spreadsheet I gave you. It contains all of the relevant magic formulas and does the calculations up to 2:1. Look in the flash on lens tab.

    You're back on my lazy brainless blockhead list.

  3. #23
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    Yah, I took a look, and I realized it took more than a look, so I haven't studied it yet.

    LBB list, huh? Flattery...indeed.
    Murray

  4. #24
    Murray@uptowngallery's Avatar
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    But my response DID include a correct answer behind one of the curtains...

    Whatchoo doing reading myreplies, anyway? ...you know they're gonna give you an ulcer...
    Murray

  5. #25
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    I'm afraid you're going to spend a bunch of money on this project and end up with an unusable POS. Believe me, I know it's tough but come up with the jack for a Calumet C1. The heavy ones are cheap, like $200 for a beat up job. Patch the bellows and you'll have 34 inches of bellows extension and a solid camera that you can actually transport and use for non macro work as well. Unless building it is really important to you... Good luck whatever you do. Best. Shawn
    Last edited by Shawn Dougherty; 06-08-2007 at 07:18 PM. Click to view previous post history.

  6. #26
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    1) One man's POS is another's treasure. If he's already doing 4x5, he might not be satisfied with a science project. If he's adaptable, he might be.

    2) Look at mamutphot.com or Google the name for ULF cameras. There are some pretty weird contractions people are using...for example it's only 2s3, but Dan Fromm's Pushmi-Pullyu Dr Dolittle cam is something like two mating
    2x3 cameras, from the description (I haven't seen it).

    3) Do pinhole 8x10. See/ask about macro compensation for pinhole diameter calculation (http://www.huecandela.com/hue-x/pin-...%20Wellman.pdf) becasue pinhole is far less critical regarding focus this will alleviate alot of headache with getting filmplane to match ground glass. After the adjustment period of adapting to pinhole, a lens that is decreed to be a POS by one person may look just fine.

    4) If you DO proceed with DIY 8x10 with lens and ground glass, the most critical thing for you will be matching film plane position with ground glass position. A standard 8x10 filmholder has a filmplane setback of 0.260", so you put a 0.260" spacer on your ground glass so it sits the same distance back from the mounting plane the filmholder sits in. There is a tolerance of 10 or 15thousandths on that 0.260" also. Further reading or asking will advise whether it's worth the trouble to offset the 0.260 + or - for film thickness, or just accept that film thickness is within the spacing tolerance above.
    Murray

  7. #27

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    There is a big difference between a DIY ULF and a DIY 8x10 or 4x5. 8X10 monorails are almost a dime a dozen. You might pay more for shipping then for the camera.

    ULF are relatively rare and not that cheap no matter what they look like.

    I have little doubt that it'll take a great deal of luck to build a long bellows 8x10 for less then some of the old 8x10 monorails.

  8. #28

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    Quote Originally Posted by Murray@uptowngallery View Post
    But my response DID include a correct answer behind one of the curtains...

    Whatchoo doing reading myreplies, anyway? ...you know they're gonna give you an ulcer...
    Murray, thanks for the kind expression of concern. Once upon a time my wife suggested that I should change jobs before I got an ulcer. I didn't and I didn't.

    Now we know more about the causes of most gastric ulcers. Helicobacter pylori. If you're not infected with it you almost certainly won't develop a gastric ulcer.

    And your posts are often interesting.

  9. #29

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    Quote Originally Posted by Murray@uptowngallery View Post
    <snip>

    for example it's only 2s3, but Dan Fromm's Pushmi-Pullyu Dr Dolittle cam is something like two mating
    2x3 cameras, from the description (I haven't seen it).

    <snip>
    Murray, look here: http://www.apug.org/forums/forum147/...ng-camera.html

    One could do the same with a pair of 4x5 Graphics, but since there are inexpensive and fairly long 4x5 monorails around the only reason to do so would be to have a long 4x5 camera with no movements and a focal plane shutter.

    I did what I did because I already had two 2x3 Graphics and didn't want to carry a third 2x3 camera. If I'd had the money I'd have bought a proper 2x3 monorail, shelved the Century, and been done with it. Take the hint, send money.

    Cheers,

    Dan

  10. #30

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    Thanks for the replies again everyone, I hadn't checked this post for a while.

    I've done a bit of looking around in the little time I have whilst doing Uni and i've come up with a few options.

    1. The original PVC pipe plan is doable - I can easily and cheaply get it large enough.

    2. Box sliding - not as portable or adaptable for what I want.

    3. there are some great camera technicians at uni who are happy to help
    me out (they constantly make bellows for our 70 plaubel and linhof 4x5's).

    I've also got some copy camera lenses which have plenty of coverage for 8x10 especially at these magnifications.

    unfortunately i only have 150, 210 & 300mm lenses so bellows lengths wil be longer than originally intended.

    By the way, yes I'm using 4x5, no I haven't built a camera yet but am fairly handy with other photo stuff I've made.

    I now have a good understanding of various formulas for mag, object/lens distance, effective DOF etc. (just covered it more in depth at uni).

    Thanks again.

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