[ldbates]

I recently bought a 645, and I assumed it would come equipped with a split-image microprism screen (UC-21), since that was the standard screen back in the day as far as I could tell from my research. Unfortunately my 645 came with just a plain, no grid, no nothing focusing screen so focusing is a bit of a chore. I'd rather not have to rely on eye-balling it or zone focusing if I don't have to. I did some quick searches for a UC-21 and a UB-21 focusing screen, and the prices are $80-$100 and there aren't a lot of them around.

All that to say, I know standard 645 screens don't fit into a 645N, but the 645N screens are more affordable and more readily available, which brings me (finally) to the question in the thread title. Does anybody know if I can mod a 645N focusing screen to fit a 645? If you've done it, is it more trouble than it's worth? Should I just shell out for one of the 645 screens I've found? Alternatively, if anybody knows of a place online that isn't eBay that might sell a 645 split-image screen, that'd be fantastic!

[jslifoaw]

I'm under the impression that it's actually the 645N (and D/Z compatible) screens that are the most expensive (those with manual focusing aids being the AA-82 and AB-82). Those are very uncommon and when they pop up, they might go for $200 or more.

The UC-21 is usually less expensive, at around half the price as you stated.

[TDvN57]

Yes you can fit the split focus screens for the 645n into the 645z if you "shave" off the little nib on the focusing screen.

I've been using my 645z with the slightly modified split screen for about 5 years now.

[ldbates]

I'm under the impression that it's actually the 645N (and D/Z compatible) screens that are the most expensive (those with manual focusing aids being the AA-82 and AB-82). Those are very uncommon and when they pop up, they might go for $200 or more.

The UC-21 is usually less expensive, at around half the price as you stated.

Gotcha. While I was looking at dozens of different items last night, some of the letters and numbers of all the 645 variations may have gotten mixed up in my brain. Thanks for the response!

Yes you can fit the split focus screens for the 645n into the 645z if you "shave" off the little nib on the focusing screen.

I've been using my 645z with the slightly modified split screen for about 5 years now.

So shaving off the nib is definitely possible, that's good to know! I'm wondering if you can take a screen designed for a 645N (or NII, NIII, Z, etc) and retrofit it to work with the original 645. I can't find any measurements online of the screens themselves, so I'm curious if anybody's tried it and what their experiences are.

[TDvN57]

Gotcha. While I was looking at dozens of different items last night, some of the letters and numbers of all the 645 variations may have gotten mixed up in my brain. Thanks for the response!

Sorry I can't help you with the original 645. I used to have one in the 80's, never bothered to take it apart to see the "bits".

[marco_gea]

I have fitted a Beattie Intenscreen focusing screen to my Pentax 645 (original manual focus body), and it is a marked improvement (brighter, easier to focus) over the OEM one that was in the camera.
Metering seems unaffected (I will cross-check with my hand-held spot meter as soon as I get the chance).
They are still available new in a number of versions (horizontal vs. diagonal split prism, with or without grid lines) at affordable prices: Beattie Intenscreen for Medium Format - Morco Limited

Marco

[yurihuta]

I recently bought a 645, and I assumed it would come equipped with a split-image microprism screen (UC-21), since that was the standard screen back in the day as far as I could tell from my research. Unfortunately my 645 came with just a plain, no grid, no nothing focusing screen so focusing is a bit of a chore. I'd rather not have to rely on eye-balling it or zone focusing if I don't have to. I did some quick searches for a UC-21 and a UB-21 focusing screen, and the prices are $80-$100 and there aren't a lot of them around.

All that to say, I know standard 645 screens don't fit into a 645N, but the 645N screens are more affordable and more readily available, which brings me (finally) to the question in the thread title. Does anybody know if I can mod a 645N focusing screen to fit a 645? If you've done it, is it more trouble than it's worth? Should I just shell out for one of the 645 screens I've found? Alternatively, if anybody knows of a place online that isn't eBay that might sell a 645 split-image screen, that'd be fantastic!

Given the relatively higher cost of the UC-21 screens lately - might I suggest you buy a 645 parts body to salvage the screen from? There are several on the big auction site now - and some come with a 120 film insert and other accessories that can be used on your current 645.

I've done just this in the past with 645N bodies only to learn that some of them were fully functional and it seems the seller just did not bother to clean things up and try the magic mid-roll rewind button on them.

As others have pointed out the original 645 screen has one tab while the 645N/645NII screens have two tabs. No idea if the thickness of the actual screen is the same. The split image 645N screen - AB-82 - is rare and for the money you pay for one of those, you can get a fully functioning original 645N body.

[itsdoable]

I have done exactly this, and you just have to remove the tab on the 645N screens. This does make it trickier to install and remove the screen (because the supplied tool grabs the tab), but you just have to be careful.

The 645N screens are a little over 1 stop brighter, so you have to compensate on the P645 by setting the ISO to 1/2 the film speed.

Also keep in mind that "AF" screens can trade off some contrast / focus snap for brightness, as you are suppose to use the "AF" system instead of the focus screen. But I found the 645N screens to work quite well for manual focus on the P645 (non-N). In bright light, you may find the original 645 screen to be more contrasty and snap into focus better than the 645N screens, but I found the difference minimal, the brighter screen was more useful in general, especially in lower light. But as you want to use the focus aids (Split / Micro prisms), then they work the same.

[trixtroll]

I recently bought a 645, and I assumed it would come equipped with a split-image microprism screen (UC-21), since that was the standard screen back in the day as far as I could tell from my research. Unfortunately my 645 came with just a plain, no grid, no nothing focusing screen so focusing is a bit of a chore. I'd rather not have to rely on eye-balling it or zone focusing if I don't have to. I did some quick searches for a UC-21 and a UB-21 focusing screen, and the prices are $80-$100 and there aren't a lot of them around.

All that to say, I know standard 645 screens don't fit into a 645N, but the 645N screens are more affordable and more readily available, which brings me (finally) to the question in the thread title. Does anybody know if I can mod a 645N focusing screen to fit a 645? If you've done it, is it more trouble than it's worth? Should I just shell out for one of the 645 screens I've found? Alternatively, if anybody knows of a place online that isn't eBay that might sell a 645 split-image screen, that'd be fantastic!

Are you still looking for a focusing screen? I’ve got a “parts” 645 that has a bad shutter, but I’m pretty sure the focusing screen is still in it.