Bronica SQ-A film flatness

[sjb79]

Hi team,

I've been shooting some 6x6 in the Bronica recently and have noticed a lot of fuzziness towards the edge of frame even though the centre is pin sharp (usually). My first thought was that the film was not being kept flat in the magazine. Is there any way to solve this problem? I've attached a photo to show the problem, the tree on the right is sharp in the centre but oof at the top. Any help or advice appreciated.

 

[sevo]

Pressure plate springs reasonably firm? In doubt buy a second magazine and adjust the spring tension on the bad magazine to match the firm one.

 

[sjb79]

Thats a good place to start, thanks for your reply.

 

[PRJ]

The problem with a lot of 120 cameras is the film path bends the film backwards. If the film is left in the camera for any length of time, it can take the shape of the bend, then bow away from the pressure plate. It will usually be the second frame you shoot after letting the camera sit. There really isn't anything you can do about it, except to use the camera a lot!

Old TLRs and Rollei SLRs pulled the film straight through the camera so they never suffer from distortion of this type.

 

[Fixcinater]

That looks more like an element being flipped in the lens than film flatness.

Are the negatives sharp where the scan isn't?

Are you sure your scanning process holds the film flat?

 

[sjb79]

The problem is with the negatives. You can see the blurry edges with the naked eye. Shot a test roll yesterday using a combination of handheld and tripod. Also tried not advancing the film until i was ready to take a shot but the problem persisted. Next option I think is to buy a replacement back.

 

[sjb79]

Can you explain what you mean when you mention a flipped element in the lens? Like the lens had been built incorrectly? Thanks.

 

[Fixcinater]

If there are signs of the lens being opened (scratched heads on screws, marks on the spanner rings around elements), it may have been repaired improperly and had an element installed backwards.

You can flip some elements and have everything mount back up perfectly, so you wouldn't know until you test it on film or look very closely at a high quality ground glass installed at the film plane, if the camera design allows for such a thing.

Are there signs of entry on the lens or are those points mentioned pristine?

 

[sjb79]

I've had a look and the screws look pretty clean, there are a couple that look like they might have been loosened, doesn't look the lens has been opened up at all though. But it gives me another option to look at so thank you.

 

[nikon_sam]

Maybe try focusing on a high contrast scene that has sharp lines or objects on it and is well lit...focus as you normally would then check the edges, if all is sharp in the viewfinder it's not the lens.
Try adding a thick piece of paper to the pressure plate on the next test roll. See if that helps direct you in the right direction...