5 x 7 film holder confusion

[aclark]

Barry, I agree it would be most practical to have an actual film holder when making the camera back, but understand your current problems. Good luck building the camera. I've made a few myself over the years. Great fun. And you have the choice of some great Australian woods to choose from.

Alan

[Barry Kirsten]

Hi Alan, it turns out that my two half plate Fidelity holders are in every external dimension identical to your 5x7 Fidelity holders. The differences are all internal and are to do with the guides that hold the film. This allows the one type of holder to accommodate different film sizes. So 5x7, half plate and I expect 13x18 metric holders would all be identical in outside dimensions. I feel I can now continue with confidence and finish the rear. So much for the published ANSI sizes for 5x7 holders! Yes there are some lovely Australian timbers and I have used some of them with much pleasure in the past. For this camera I'm using Huon Pine from Tasmania. It's a wonderful wood and has been used for many years for fine furniture and boat building. Using it for a LF camera goes against conventional wisdom of using hard, dense timbers like teak, cherry, walnut or even ebony, but I like calculated risks and I think this will work. Thanks again for your great help.

Barry

[Jimi]

So 5x7, half plate and I expect 13x18 metric holders would all be identical in outside dimensions.

Yes, that is the main takeaway - the outer dimensions are the same for all of these holders, while the inner dimensions differ, and those differences are marked with the according size in white, at least on the plastic holders I have encountered. Thus the general confusion.

Wooden ones are perhaps the same, but I can't say for sure.

[Barry Kirsten]

Jimi, what I (and others) found confusing was the published ANSI standard for 5x7 holders - they are so different from the actual sizes of available holders. I was prepared to follow the published ANSI measurements, but got wise in time to avert a disaster and decided to find out sizes of actual holders.

[Jimi]

As I have never read the ANSI, I am only speaking from my (limited practical) experience, so I wasn't aware that the various holders differ from that standard. It seems to me there are several levels of confusion here, which makes it even more confusing.