Graflex.org
Get help with your Graflex questions here

ground glass focussing loupe
Graflex.org Forum Index -> Speed Graphic Help
AuthorMessage
gerhard
Joined: 07 Apr 2003
Posts: 6
PostPosted: Fri Aug 22, 2003 2:22 am

Can anyone recommend a ground glass focussing loupe for my Graflex camera that can focus on the image of the ground glass instead of the Ektalite fresnel lens. Most loupes focus at the end of the tube they are inside of, I need it to focus beyond that point to the ground glass image. Regards, Gerry
Les
Joined: 09 May 2001
Posts: 2682
PostPosted: Fri Aug 22, 2003 2:31 am

I like old 50mm screw mount lenses.....Yashica, pentax, honeywell, etc..... They are cheap, coated and can be focused. Just test it at the show first since not all can focus at their filter flange, but if you get one that can, it will also focus 0.070" beyond it.

BTW This ides pops up on list serves and forums from time to time and it stirs a lot of theories.
Theory 1. You have to have your loupe focus on the other side of the glass, because that's where the image is.
Theory 2. You'll never do it accurately by sight because the ground glass itself effects the light entering the loupe, so you really aren't focusing where the aerial image is.

Theory 3, and the one I like the best...... All of the above may be true but film holder positions aren't anywere near that accurate and vary well beyond the minor tolerances trying to be held in theores 1 & 2.
_________________
"In order to invent, you need a good imagination and a lot of junk" Thomas Edison

<font size=-1>[ This Message was edited by: Les on 2003-08-21 19:38 ]</font>
gerhard
Joined: 07 Apr 2003
Posts: 6
PostPosted: Fri Aug 22, 2003 4:42 am

Nice idea on using old 50mm lenses. I've used this with 50 f1.4 Nikkor but didn't like the idea of carrying it around. Also there's the weight. At's a7 element lens, A loupe is 2. Have you ever thought of cutting the transluscent ring down to adjust it's focussing point. I have a Fuji loupe which has one of these but was hoping someone else had done this before I make the plunge. Regards, Thanks Les
45PSS
Joined: 28 Sep 2001
Posts: 4081
PostPosted: Fri Aug 22, 2003 5:29 am

I took my Eastman Commercial View with 12 inch Commerical Ektar attached to the Hardware Store (where I work, on a day off) and set it up on an unused checkout close to the reading glasses display and started testing on the trees on the far side of the parking lot. I easily found the power I needed to to pick out the leaves with at a distance of 10-14 inches from the ground glass. Spring hinge versions are more durable than the regular ones. I haven't decided if I will add a <a href=http://www.doneganoptical.com/catalog/behr/> Behr </a>clip on loupe or not. A 55S2 on 2.5 readers was recomended on another LF site.
Charles

_________________
While a picture may be worth a thousand words, a quality photograph is worth a million.



<font size=-1>[ This Message was edited by: 45PSS on 2003-08-21 22:34 ]</font>
Nick
Joined: 16 Oct 2002
Posts: 494
PostPosted: Fri Aug 22, 2003 7:12 pm

I use a rectangular magnifying glass. It easily gets into the corners if I want. Many people recommend linen testers. That's what I'm going to try next. The testers aren't very much money.
Barry Scholles
Joined: 23 Aug 2003
Posts: 3
PostPosted: Sun Aug 24, 2003 9:16 pm

Info for Gerhard on focusing loupe.

Gerhard from what I read in your question you have the fresnel lens mounted on the outside of the ground glass. This is first of all an incorrect position for it.

Leslie Stroebel's book "View Camera Technique" (fifth edition) pg 218 shows it mounted with the grooved surface of the fresnel lens in direct contact with the ground surface of the ground glass. In other words, inside the camera not outside.

I had a very direct discussion with Calumet on this issue since their instructions show it incorrectly mounted as I think your fresnel is.

You will get only one, very bright image with it mounted the way Strobel recommends.

Now for your loupe question. I have found an Agfa 8x or 10x loupe works very well with its clear portion completely taped up with black plastic tape. This will eliminate all extraneous light when focusing. The lens can be twisted to its longest position to focus on the ground glass.

Barry Scholles
bscholles@adelphia.net
45PSS
Joined: 28 Sep 2001
Posts: 4081
PostPosted: Mon Aug 25, 2003 12:42 am

Barry,
Sinar fresnels are on a frame that snaps in over the ground glass as an accessory.
Charles
All times are GMT