Help Bronica s2a 6x4.5 back

Hello,

I have a new to me 6x4.5 back for my Bronica S2A but not sure how to compose on the WLF and would rather not waste some film to sort this. Any hints would be appreciated. Could not find any measures to make a mask. Are the frame lines on the WLF of any help? Thanks!

Jose

First thing to do when you get a new camera is to read the manual .
http://trondbaashus.org/filer/bronica/S2A_Manual.pdf



In the case of some cameras like some Kiev's it'll prevent you breaking them by doing things like changing the shutter speed before winding the film on .

With regard to framing with a 6x4.5 back , the horizontal lines on the screen will line up with the top and bottom of the frame if there about 43mm apart (or less than the 45mm as the name implies) .

EDITED TO LINK TO CORRECT MANUAL

Thanks for the reply!

Sorry if I was not fully clear, but the camera is not new to me, only the 6x4.5 back is. I did read the manual, the S2A one (the link above is for the S2) but could not find a reference to that. The frame lines are separated by 39mm, I've been using that as a guide, but not sure if it was accurate. I'll see how it turns out. My plan is to only use this back for Velvia, since I eventually would crop the 6x6 for some landscape aspect ratio and given its cost I can get 4 additional frames with the same value.

Check the opening on the film back , you don't need to remove the dark slide if it's loaded with film .
It should correspond with the lines on the focus screen position wise .
Size wise the markings on the focus screen might be slightly under that of the film back .
So 39mm spaceing on the screen can be 42mm (or so) on the film .

Most viewfinders are not 100% field of view , quite often some are about 98% , some even less , with slides that allows for what is lost due to the slide mount .
With camera makers it also allowed a bit of tolerence in alignment and reduced cost's .
A 100% viewfinder has to be exactly in the right position to what the film see's , or it's not 100% !


Sorry I gave a link to the wrong user manual , I have now corrected that for anyone else interested .

If there are lines in a finder related to some format, new lines for a different format would be located in proportion to the existing ones.
(Maybe though I missed the point of this thread.)

The groundglass is just ground glass, and there's a fresnel lens underneath it. If your groundglass lacks markings for 645, then remove it, and mark the underside of the glass with a pencil to show where the 645 framelines should be. The glass is the same size as the format, so just hold it up, centered over the frame gate on the 645 back to trace the lines. You can mark the whole frame or just the corners, if the lines interfere with your 6x6 composition.

The frame that holds down the groundglass is held in place by 4 screws. When you remove it, note the orientation of the groundglass and the fresnel. The glass should be frosted side down. I don't recall offhand which way the fresnel goes and sold my S2As some years ago.

If you haven't already done so, now would be a good time to clean the fresnel and the groundglass before marking them, and replacing the foam under the frame. The old neoprene foam tends to deteriorate and pull up on the groundglass, causing focus problems. Clean it all off. Naphtha is a good solvent for that. You can replace it with more neoprene light seal material (or just cut up an old mouse pad), or use Moleskin, of the sort you put on foot blisters, which won't break down as readily. As I recall, I had one layer of Moleskin on two sides of the frame, and two layers on the other, but test and figure out what works.

David A. Goldfarb said:

The groundglass is just ground glass, and there's a fresnel lens underneath it. If your groundglass lacks markings for 645, then remove it, and mark the underside of the glass with a pencil to show where the 645 framelines should be. The glass is the same size as the format, so just hold it up, centered over the frame gate on the 645 back to trace the lines. You can mark the whole frame or just the corners, if the lines interfere with your 6x6 composition.

The frame that holds down the groundglass is held in place by 4 screws. When you remove it, note the orientation of the groundglass and the fresnel. The glass should be frosted side down. I don't recall offhand which way the fresnel goes and sold my S2As some years ago.

Click to expand...

Thanks, this is very helpful. The backs’ opening look the same, only from inside we can check the difference, hence I having a bit of trouble currently since it is loaded with film, but making this marking (I was afraid to ruin something) will definetly help!

As regards the frame foam, I had it replaced on a CLA about one year ago, but thanks for detailing this method.

Different question… I’ve recently purchased another S2A, latter version with EC strap connectors. This camera is not accepting my 645 back. It does accept the 6x6 normally, but 6x4.5 doesn’t lock.

The same back locks with no problem on my other S2A.

Is there any incompatibility or how can I sort this?… Thanks in advance.

I don't think there's any incompatibility, but you could ask Frank Marshman. He's around on Facebook. He'd know. More likely, the latch mechanism is worn on the back or the camera that doesn't lock.