Half plate to 4x5 conversion

[smudge.g]

Hi all,
I had been looking for a way to use a recent purchase of a 'modern' 4x5 film holder on my 1900s Butcher & Sons National view camera, which is the slightly outdated 1/2 plate size. Having found very little on how to proceed, I decided to sacrifice one of the 2 plate holders that came with the camera. Having removed the brass clips and hinges holding the 2 halves together, I found to my amazement that the 4x5 film holder just slotted right into the grooves inside the book style plate holder. I just needed to add a mahogany spacer between the 2 original halves and make it a bit more robust by refitting one of the dark slides, sightly reduced in length. The distance required from rear standard edge to the ground glass seems about roughly the same with this new holder but does this distance really to need to be exactly the same to enable photos to be in focus or is there some latitude in this? I measured about 8mm from the original holder and the new one might be about 1mm wider. Before I test it, just need to make a 4x5 mask for the ground glass!!

[Vaughan]

Hi all,
The distance required from rear standard edge to the ground glass seems about roughly the same with this new holder but does this distance really to need to be exactly the same to enable photos to be in focus or is there some latitude in this?

That distance needs to be very accurate because it directly affects focus.

Half-plate to 4x5 film adaptors are available used. https://www.ebay.com.au/itm/155708136091

Note that these particular adaptors convert half-plate to 4x5 plate, with another adaptor to convert 4x5 plate to 4x5 film. With these you could get into 4x5 dry- or wet-plate photography as well as 4x5 cut sheet film.

[smudge.g]

Many thanks, I think some tests are in order to see how close it is! Thanks for the info, I am new to LF so its all a learning curve upgrading from Mamiya TLRs!!

[Vaughan]

If you are new to large format I would not recommend mucking around with hacking backs and plate adaptors. Keep it as simple as you can.

[Steven Tribe]

Your responder has got it right! The back with the ground glass and the plate holders are matched to ensure the determined focusing distance will be duplicated when the plate holder is inserted. The referenced listing shows the “correct” method! A bit expensive though. Metal 4x5 film sheaths are readily available - fortunately Kodak Eastman printed what they are on every single metal sheath they made! Making a wooden/plastic insert is easy woodworking.
I enclose an example of some of mine. The plate holder is a 1/2 plate, but the insert is for a lantern slide format and the photo of the rear film sheath is a 5x7” film size. The thickness of the wooden insert must match the thickness of glass plates originally used with the camera.
Actually, there are sources of 1/2 glass plates.

[r_a_feldman]

Here are pictures of a 4x5 reducing back I made for my half-plate Okuhara. I used pieces of exotic hardwoods that I had from other projects. The back has ears to mimic those on the original book-form film holder. I carefully measured the depth of the film plane in the book-form holder and duplicated that thickness in my back.

[Vaughan]

Wow great idea.

The evil genius in me is looking, on one side, at all those cheap-because-nobody-wants-them Japanese wood whole plate cameras on eBay, and looking, on the other side, at the WP-to-5x7 adaptor you're going to make next.