View Full Version : 5x7 T-distance

11-Dec-2012, 01:04
I am in the middle of making a 5x7 Plate holder and I need someone to confirm that the T-distance for a 5x7 is 0.228. I have seen a few other measurements but this seems to be the US standard. Thoughts?

Daniel Stone
11-Dec-2012, 01:15
This website claims it to be .228 as well



Jim Jones
11-Dec-2012, 07:54
The T-distance is indeed .228" +/- .010" according to the 1951 ASA standard. Keep in mind this is the distance to the back of the film slot, not to the emulsion. The slot is .012". This leaves a sloppy tolerance for the actual position of the film. A film or plate holder loaded from the back instead of from the front can minimize this slop.

11-Dec-2012, 12:55
so if the holder loads form the back should the t distance be .216?

Jim Jones
11-Dec-2012, 16:14
Yes, or a wee bit more. While the slot is .012", film varies from maybe .004" to .010" with (I believe) .007" being common.

11-Dec-2012, 20:34
thanks Jim!

12-Dec-2012, 00:05
Stupid follow up question then the focus screen should be set such that the imaging surface is at the same point correct? If there is a fresnel in front of the screen, one would still want to set the matte surface of the screen to that dimension.