So I just bought a replacement back for my Speed Graphic, and it came with Groundglass significantly more scratched up than my older piece. Here's the problem. The older piece came with a frensel, the new one did not. Can I use the Frensel with the older piece in the new back? It looks like the older one is the "Grafloc (with the two metal arms)" while my new one is the "Graphic back" (no metal arms, just black springy things)... Any thoughts?
-a
Not sure on descriptions here, the grafloks are generally from pacemakers which are newer than the old spring backs if that what you are describing here. I would guess the spacing for the Frensel is the same for both backs and interchangable. The Frensel goes between the ground glass and the lens. Ridges against the rough side of the ground glass, smooth sides on the outside. The spacing is set up for the thickness of the Frensel. K
AFAIK, Graflex offered fresnel lenses as an option for cameras with Graflok backs, not for cameras with Graphic backs. The fresnel shifts the point of focus, so a Graflok focusing panel -- not the back, the back is held to the camera body by screws, doesn't come off easily; the focusing panel comes off easily -- made to accept a fresnel is not identical to one made to be used without a fresnel. If you add a fresnel to a focusing panel NOT made for one, the fresnel has to go behind the ground glass (photographer side, not lens side).
The GG and fresnel, if present, sit on bosses at the edges of the focusing panel's gate. High bosses to put the GG in the right place if there's no fresnel, low ones if there is supposed to be a fresnel.
I don't know 4x5 Graphics very well, mine are all 2x3s. But on the 2x3s the Graflok back's focusing panel comes off easily and the Graphic back's doesn't. In other words, I don't believe that focusing panels interchange between the two types. Could be mistaken, though.
shapirophoto, you should learn more about your camera before you squander more money and effort. Wander over to www.graflex.org, read the FAQs and look around the site. If you still can't figure things out -- the site isn't that well-designed and Graflex Inc's terminology isn't easy to learn -- ask for advice on the help board. It is populated by grumpy old men who know their stuff. You might also buy a copy of the book Graphic Graflex Photography; it was published in many editions, you want one published after 1949.
The Pacemaker Speed and Crown Graphic models offered fresnel screens on the spring back as an option. You have a couple of choices. You can mount the fresnel on the outside of the ground glass, as Dan suggests. You can trim the fresnel to fit inside the glass, but not between the glass and frame. You can machine the focus panel to accept the fresnel without throwing the focus out of whack. My question is: Why on earth did you not just buy a new ground glass for your existing back?
Gotcha, well the deal was, the back on the camera (the entire back unit) was working improperly. It didn't affect image quality, but it was very difficult to insert the film holder and would shift the camera sometimes on the tripod.Originally Posted by Glenn Thoreson
With that said, I bought a new back off ebay for like 20$ and it works 10x better than my old one. So. There. ;-)
Yes, you can separate the fresnel and ground glass and pair the best of the two. Not sure what you are looking at, but I have removed broken or scratched GG and replaced them and swapped the spring back with Grafloc backs.
Jim Chesky
Old Dog Studio
"I shoot with old dogs, I have an old dog, I am an old dog."
This thread got me thinking so I took a fresnel and ground glass from a Polaroid MP-4 and put it on my Speed Graphic and took a 1 degree spot meter reading. I used a light bulb as my light source. Then I removed the fresnel and took a reading of the same light source with just the ground glass. Guess what? The reading with NO fresnel was higher (brighter). Go figure.........
Taking a reading off the glass with most normal meters and spot meters is not a valid way to test a ground glass, in addition, there is more to a screen than just brightness, it includes even dispersion of the light across the full surface of the screen.
Really good ground glass is about evenness and then brightness.
Posting Permissions
Reply With Quote
Bookmarks