645 Print Size/ Pentax 645 Screens

What size of print will show more of the total image of a 645 shot? Would it be 4x5 or 4x6? I've seen them print 645 to 4x6, but this size seems a bit wide for this format. I know 645 is not a perfect fit for either, but I'd like to know what people are printing to. Technically what size of print would show the total image without some cropping?

Also I've heard the focus screens are different between the original 645 and the later 645N and NII cameras. What changed for the N models that won't allow you to use an original model screen? Or is it possible to install a 645 screen in a N model? Reason I ask is I have both a 645 and a 645N. I only have a manual focus lens I can use on them, and manually focussing on the N model is quite difficult compared to the original with the split prism. I know with the N, I'd need a AB-82 screen, but they are both expensive and difficult to find new or used.

My experience is with Mamiya, but I believe that the Pentax 645 dimensions are similar.

The ideal image size from 645 would be 4 x 5 1/3, which of course is fairly "custom".

Actually, of the standard sizes, 5x7 is probably closest to the same aspect ratio. 11 x 14 isn't far off either.

The focus screens are not interchangeable between the 645 and the 645N. I bought mine from japan exposures. I am very pleased that I did.

The 645 format fits quite well into the 8x10 paper size, notm perfectly, but better than 35mm. There is not so much wastage.

What I really like about the 645 format is the 3:4 aspect ratio. If you take an 8x10 piece of paper, and make a 1" border around the entire print, you get a 6x8" print area, which is a perfect 3:4 aspect ratio. Plus, the print looks fantastic in your hands.
Same goes for 11x14, where if you take 1" border around the print area, you end up with a 9x12" print, also perfect 3:4 ratio.
It almost works for 16x20 too, but in order to stay true to the aspect ratio, you'd have to make a 13.5x18" print, which leaves a 1.25" border on the long side instead of 1" as with the other two.
If you really dislike 'wasting' paper, you could always import 12x16" paper from Europe, a common size there.

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Originally Posted by Thomas Bertilsson

... If you take an 8x10 piece of paper, and make a 1" border around the entire print, you get a 6x8" print area, which is a perfect 3:4 aspect ratio.

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That is the way I do it too. The 1" border looks gorgeous!

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Originally Posted by Thomas Bertilsson

Same goes for 11x14, where if you take 1" border around the print area, you end up with a 9x12" print, also perfect 3:4 ratio.

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Modeling industry uses 9x12 as its standard for photographs. The legend has it, it came from the fact fashion shoots were often done with 645. perhaps this is the reason. I use this 9x12 with 1" border all the time as it meets my vision quite well.

Actually, 645 and 6x7 (and 6x8) works quite well to print on 8x10 and 11x14 with very little cropping. Keep in mind, the film opening on most neg carriers (on enlargers) do crop a bit, so you'll have to take that into consideration as well as minor framing errors when shooting.

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Originally Posted by tkamiya

Modeling industry uses 9x12 as its standard for photographs. The legend has it, it came from the fact fashion shoots were often done with 645. perhaps this is the reason. I use this 9x12 with 1" border all the time as it meets my vision quite well.

Actually, 645 and 6x7 (and 6x8) works quite well to print on 8x10 and 11x14 with very little cropping. Keep in mind, the film opening on most neg carriers (on enlargers) do crop a bit, so you'll have to take that into consideration as well as minor framing errors when shooting.

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Yes. I've seen a lot of 9x12 work in model portfolios, so one might opine that this is where the demand for 645 format came from.

My enlargers show the full neg area, btw. It's strange they would crop the neg.

The Pentax 645 frame is 56 x 41.5mm. So if you magnify the short axis by 4.896x to fill 8", the long dimension exceeds the paper by 0.79".

The Bronica ETR(S/Si) has better frame dimension at 55x42mm, and the Mamiya 645 even better frame dimension at 55x43mm, for filling 8x10 with minimal image loss

Quote:

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Originally Posted by Thomas Bertilsson

Yes. I've seen a lot of 9x12 work in model portfolios, so one might opine that this is where the demand for 645 format came from.

My enlargers show the full neg area, btw. It's strange they would crop the neg.

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Yes, I actually heard from a local modeling studio person that's their standard. I read about it's relation to 645 somewhere on photography related forum. It makes sense, doesn't it?

On my D2, on all format, 35mm, 645, 6x7, and 6x8, the hole on the neg carrier is ALWAYS little smaller than the frame size on the negative. It always crops a little. I find it strange that yours doesn't... I always account for this when I shoot. I also account for a need of 'waste space' around what I want to put on paper as to leave a clean borders around the images, I need to cut-off enough so that I don't get fuzzy borders.

Which all gets involved when OP tries to print full frame with no wasted neg space onto a paper. He really won't be able to do it unless he wants to print almost like dirty border type printing.