Graflex.org Forum Index Graflex.org
Get help with your Graflex questions here
 
 FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 

How to build a camera?
Goto page Previous  1, 2
 
Post new topic   Reply to topic    Graflex.org Forum Index -> Large Format Photography
View previous topic :: View next topic  
Author Message
ferlopezperez



Joined: 11 Feb 2003
Posts: 31
Location: Mexico City

PostPosted: Tue Feb 24, 2004 5:02 pm    Post subject: Reply with quote

Hi everybody, I've just started to draw my "frankenstein" camera, the idea of a mirror is wonderful to solve the focusing problem. The direct positive paper sounds great but it reminds me of my first attempt to build a camera (when I was 10 years old) it was a pinhole camera and used grade #3 kodak paper, the images were wonderful but they had to be reversed to obtain a positive image. If I put a ground glass on top, with a mirror in the middle, ┐how can I measure the distance to the film in relation with the ground glass? I guess it has to be the same distance, am I right? The camera I'm trying to build should be unique, the idea of 8x10 paper is something remarkable, but my lens is 150mm I think it won't cover the 8x10" image. Ideas like these ones are really valuable, most of all if you are new in the building-a-camera subject. Thank you all, if you have any other ideas I will appreciate them.
Back to top
View user's profile Send private message Send e-mail Visit poster's website MSN Messenger
Nick



Joined: 16 Oct 2002
Posts: 494

PostPosted: Tue Feb 24, 2004 5:50 pm    Post subject: Reply with quote

I agree if building something unusual would be more interesting then just building something easily available off the shelf. There is one Ebay seller that sells older Ra-4 roll paper. I picked up two rolls and it seems just fine. 8" wide and 275' long. Something like an 8x16 or 8x20 or anything 8x would be possible. It could be cut down to 4x5 for testing or smaller prints.

I don't think a shutter is an issue. Paper is fairly slow. The way I understand it paper is in the ASA 6 range. You'll need an 85 filter [or is it an 80?] so that slows things down even more. You'll also be making an in camera orginal so diffraction shouldn't be an issue. Figure F/32 or F/45 or even smaller.

For B&W wouldn't paper negatives be possible? Avoiding any need for a complex setup to flip the image.
Back to top
View user's profile Send private message
ferlopezperez



Joined: 11 Feb 2003
Posts: 31
Location: Mexico City

PostPosted: Tue Feb 24, 2004 6:02 pm    Post subject: Reply with quote

maybe the shutter is useful in order to use it in B only, just to control the opening and closing. The paper is available with my local film supplier, He has a stock of this and other old supplies. Do you think my 150mm schneider lens will cover an 8x10" area?
Back to top
View user's profile Send private message Send e-mail Visit poster's website MSN Messenger
t.r.sanford



Joined: 10 Nov 2003
Posts: 812
Location: East Coast (Long Island)

PostPosted: Tue Feb 24, 2004 6:37 pm    Post subject: Reply with quote

I'n pretty sure that a 150mm. "Xenar" will not cover 8X10 at infinity, though it surely will at 1:1.

Paper negatives certainly appeal; the trick is finding the right kind of paper. Kodak used to make a very lightweight base, "A" or "Ad Type" (good for prints that had to be cut accurately for pasting up on mechanical layouts), and art supply stores used to carry a "transparentizer" that could be used to make paper more translucent, as an aid to tracing drawings. If those products still exist and could be used in conjunction, something might be done.

Another possibility, of course, is to make the paper negative (as with the pinhole camera described) and then rephotograph it on paper stock at 1:1 to make what the photostat houses used to call a "second print." This would take care of the tonal reversal and the "flopped" image orientation.

It would, of course, do away with whatever advantage might be obtained from a contact print, but it also would prevent your having to deal with the paper fiber (though you might want that), and it wouldn't produce the typical "Callier effect" contrast enhancement experienced with condenser enlargers.

As for measuring from lens to film after introducing a mirror into the lightpath, a good deal would depend on accurate measurement before construction. Beyond that, you'd probably find it simplest to use a groundglass (or even a good enlarger focusing magnifier) to fix the final position of the sensitized-material support in the bottom of the body, then adjust the focusing screen on the top to conform.
Back to top
View user's profile Send private message
RichS



Joined: 18 Oct 2001
Posts: 1467
Location: South of Rochester, NY

PostPosted: Tue Feb 24, 2004 7:24 pm    Post subject: Reply with quote

Just a side note about the actual construction. Some interesting ideas may be found in the book: Primitive Photography by Greene. He also has some ideas about home made lenses and such. Gotta get back to work


_________________
----------------------------------------
"Ya just can't have too many GVIIs"
----------------------------------------
Back to top
View user's profile Send private message Send e-mail Visit poster's website
Display posts from previous:   
Post new topic   Reply to topic    Graflex.org Forum Index -> Large Format Photography All times are GMT
Goto page Previous  1, 2
Page 2 of 2

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


Powered by phpBB © 2001, 2005 phpBB Group