View Full Version : Ground glass / film alignment Graphic and Linhof
I measured the depth of film in a 4x5 cassete: it appears to be 0.210 inch. In t he Graphic ground glass frame, the deph of the glass in the frame is 0.150". Thi s means that the ground glass of 0.060" should be installed with the ground side to the viewer (and smooth side to the lens). Is this correct? I also measured L inhof Technica III (not Grafloc) groundglass: the depth is ca. 0.215-220, which is 0.010- 0.005" more than the standard cassette. Is this withing tolerances? In the Linhof, the ground glass is installed ground side towards the lens. However , the metal part holding the ground glass has a lit to it , indicating that a 0. 070 ground glass of slightly smaller size can be installed with the ground side to the viewer. Any comments or suggestions? I have not seen these distances and tolerances discussed.
Are your photos sharp already?
Sean Billy Bob Boy yates
No info on tolerances, but it's always been my practice/experience to have the ground side towards the lens and the smooth/unground side towards the viewer.
Regardless, as Ellis points out, why worry if your negs or chromes are currently sharp?
The ground side of the glass should face the lens.
As I recall, the depth should be .192" +/- .007. A fresnel or after market scre en may change the depth required. Didn't the early Technicas require a special film holder? If so and if that was of a di fferent depth, then you would have to know their stated dimensions.
I can't speak for the Linhof, but regarding the Graphic, I have been looking into this because I have several models of different vintages. It is my understanding that the Crowns and later Speeds had Graphloc backs with factory-installed Fresnels in front of the GG...and these backs were constructed accordingly to allow for the Fresnel.
FOR PRE FRESNEL MODELS (early Graphloc and old Graphic backs), there was only the GG with the frosted side of the GG toward the lens.
For the Fresnel models, the order of placement was sent to me as follows:
<The correct order from front to back is: <Camera Lens <Smooth side of fresnel <Rough side of fresnel <Rough side of ground glass <Smooth side of ground glass
If you buy a used Graphic, it is worthwhile to inspect your back and determine if it was designed for a Fresnel, and if it has been removed (or visa versa a Fresnel added), some adjustment must be made.
If I am off base on this, please let me know.
Sorry-- the order of elements didn't print because I had them in brackets...
Here they are:
The correct order from front to back is: Camera Lens Smooth side of fresnel Rough side of fresnel Rough side of ground glass Smooth side of ground glass
(Well they don't paste in ?) I type them in...
Camera lens Smooth Side of Fresnel Rough Side of Fresnel Rough side of Ground Glass Smooth side of Ground Glass
You will find the ANSI standards for film holder depth here: http://home.sol.no/~gjon/lffaq.htm
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