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View Full Version : How long should my bellow really be with a 11x14 ?



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tim k
09-14-2010, 03:23 PM
I am in the early stages of building/designing a 11x14 flat bed. I have some specs from the builders on-line, but in the real world, how long are you guys really stretching out.

I'm a stick and stone landscape guy. Don't think I'd ever want to chase bugs or flowers up close. I don't have any lens yet, but in my 4x5 I have a 90, 150, and a 210, and I feel pretty happy with them, and don't feel the need for more. Most of the time its either the 150 or the 210 so I guess I'm usually pretty close to normal.

So, what do you guys think? Is 3 feet going to be enough.

RalphLambrecht
09-14-2010, 03:38 PM
Tim

Do the calculations yourself. The bellows extension 'v' is calculated as:

v = (u*f)/(u-f)

where 'u' is the focusing distance, and 'f' is the focal length of your lens.

frednewman
09-14-2010, 04:37 PM
Hi tim k - The Canham 11x14 camera has 48" of bellows. It all depends upon your longest lens. If you are using even a 600mm lens like the Fuji, 36" of bellows should be fine.

Fred Newman

tim k
09-14-2010, 04:49 PM
Ralph, is this one of those "teach them to fish" answers?

I came out with something over 400 feet, is that too long?

Then I did it right and came up with 40".

Thanks

tim k
09-14-2010, 04:56 PM
Fred, sounds like if I do 40 inches I'd be safe.

Thanks

RalphLambrecht
09-14-2010, 05:57 PM
Ralph, is this one of those "teach them to fish" answers?

I came out with something over 400 feet, is that too long?

Then I did it right and came up with 40".

Thanks

Yes, but apparently, you've mastered it!

rrankin
09-14-2010, 06:02 PM
If you plan on ever selling it, then I'd say most 11x14 users are going to expect a meter or more of bellows on that size camera.
Cheers,
Richard

keithwms
09-14-2010, 06:37 PM
For 1:1 macro images (with non-tele lenses) you need bellows length twice the focal length. That is a pretty good estimate of maximum bellows length you'll need (although I think there is a lot of good work to be done in LF/ULF beyond 1:1 and we shouldn't automatically cede that territory to smaller formats).

http://www.apug.org/forums/forum44/55675-bellows-extension.html

tim k
09-14-2010, 09:20 PM
So, thinking out loud. With a 480mm I'm good for 1:1 with 40 inches. With a 600mm I'd need closer to 4 ft for 1:1.
40 Inches is starting to sound about right.

Jim Fitzgerald
09-14-2010, 10:40 PM
So, thinking out loud. With a 480mm I'm good for 1:1 with 40 inches. With a 600mm I'd need closer to 4 ft for 1:1.
40 Inches is starting to sound about right.

Tim, I've done quite fine with 36" of bellows. Remember the lens coverage increases as you get closer and extend your bellows. I've done some nice 1:1 with my 12" Gerogon.

Now for my 14x17 I'm thinking 48".

Jim

Ian Grant
09-15-2010, 12:42 AM
The bellows extension has less to do with the lens choice and is more to do with the actual design of the camera. You need to decide whether the camera is to be double or triple extension, that's compared to a standard lens for the format. Double extension allows 1:1 focus with a standard lens.

Typically a 10x8 camera with a 300mm/12" lens has an extension of approx 24"-27" and a triple extension version around 36". Scale that up for your 14x11 camera and 36" may well be practical without the hassle of adding an additional extension rail.

Ian

John Jarosz
09-15-2010, 06:13 AM
What will you be doing with the camera? A 600mm lens on my camera (extends to 36") won't focus to give a head & shoulders photograph. Sure, you can get head & shoulders with a shorter FL lens, but you have to decide if that's what you want.

John

Michael Kadillak
09-15-2010, 09:53 AM
When you contemplate how long your bellows should be on your 11x14 please consider how heavy your longest lens would be at this focal length and make sure that you design your support members to handle and "balance" this weight properly. This includes materials deflection properties and insuring that your tripod screw is sufficiently sturdy. A bit of research as to the range of weight of the optics that you could utilize would be well advised. The numbers could surprise you.

Personally I would make sure that my rail proportions for the front standard were at least as stout as the Deardorff V11. If you need some dimensions for the V11 I would be more than willing to provide you with some data.

tim k
09-15-2010, 02:49 PM
Michael, I would love to know the width and height of your front rails. The bed design that I have in mind is similar to your v11, but a little more like an Ebony. As long as you got your tape out, it would be interesting to know the back width, and the bed length. Thanks for the offer.

tim k
09-15-2010, 02:58 PM
Ian, its going to be triple (the bed plus front and rear sliding rails). Three is only one more set of rails, doesn't seem like much more work. Its the same design as the 4x5 that I built.

John, I have no Idea what I'm going to use the camera for. I'm not into people. Most everybody I know runs from me when they see a camera. I just want to not be limited by design.

tim k
09-15-2010, 03:03 PM
Jim, thats reassuring, if I understand it right, with your 12" lens focused 1:1 with 36" bellows you still have an extra unused foot of extension.

Michael Kadillak
09-15-2010, 09:51 PM
Tim:

The Deardorff V11 front rails are 1 9/16" wide and have a metal side plate affixed to it that has the drive gears along the bottom of the wooden rail for forward and rearward motion. This metal plate has flush mount screw driven into the side plate and adds structural stability to the rail. This front rail is 3/4" thick. The real rails are the same proportions. Let me know if you needs pics or have other questions. I use a 35" Red Dot in Ilex #5 with the V11 and it handles it with ease.

Jim Fitzgerald
09-15-2010, 10:44 PM
Jim, thats reassuring, if I understand it right, with your 12" lens focused 1:1 with 36" bellows you still have an extra unused foot of extension.

Tim, that is right. I just use a lens that will give me what I need as far as close ups go. I love shooting close up with ULF.

Jim

Ian Grant
09-16-2010, 12:21 AM
Ian, its going to be triple (the bed plus front and rear sliding rails). Three is only one more set of rails, doesn't seem like much more work. Its the same design as the 4x5 that I built.


Makes sense to use an extension rail. The issue then is making bellows that don't sag, and 2 or 3 ring tabs can help enormously.

I'm about to make a set of large bellows for a De Vere Monorail and looked how the originals were made, as well as those on my two Agfa Ansco 10x8's as all have very minimal sag. While the stiffeners on the original De Vere bellows are quite thin it uses three cloth layers this seems to give the additional stiffness preventing sag, the original bellows would have been made by Camera Bellows - now Custom Bellows in Birmingham, UK.

http://www.lostlabours.co.uk/photography/cameras/images/aa009.jpg

Ian

tim k
09-16-2010, 08:23 AM
Michael, thanks for the sizes. I'm a little surprised, in the pictures I've seen they don't look that big. In my design they were going to be quite a bit smaller than that. I think I'm going to do a little upgrading, based on your suggestion.