Bolex EBM viewfinder - black shape / curve inside?

[Lewis Hart]

hi guys, just noticed inside my Bolex EBM viewfinder, there is this curve of blurry darkness on the right hand side, looks like something is in the way? - not sure. 

the camera looks to me to be super 16'd film gate is of the s16 aspect ratio / 12+mm in size so I think it is? (picked it up cheap / untested the other day with a nice 16-100 - with no power, seems to run fine on first look),

im not sure if the s16 makes a difference to the viewing through the viewfinder? looks a odd shape anyway, not too fussed as long as its not on the film which it shouldn't be technically? 

same with a lens off or on, impossible to photograph but you can see on the right there is a slight curve.  any clues?

I thought it was the shutter as sometimes the shutter sits in front of the gate when you stop the EBM, but when I run the camera it stays there, so im pretty sure its something inside the viewfinder itself? 

 https://imgur.com/a/549JR13

thanks ahead

lewis

[Lewis Hart]

Found out that the optics haven’t been recentered / lens port.

is there any advice out there on how to correct this, I imagine it’s relating to the lens Mount being shifted over to cover the larger image circle / aspect ratio?

lewis 

[Dom Jaeger]

Re-centering the lens port won't remove an obstruction in the viewfinder, since it looks to be before the ground glass image. A lens vignette due to an offset lens port would only affect the ground glass image. It could just be that the viewfinder optical path hasn't been modified for an enlarged ground glass image but if someone has done a DIY S16 conversion, who knows what they may have done wrong.

You might want to take it to a Bolex specialist to see what the viewfinder issue is, and look into re-centering the mount or what else may be needed. It's not usually a DIY job to shift the mount over, unless you are a machinist. A shoddy DIY gate enlargement could also cause scratching, so maybe have that checked before you waste film on it.

[Lewis Hart]

13 hours ago, Dom Jaeger said:

Re-centering the lens port won't remove an obstruction in the viewfinder, since it looks to be before the ground glass image. A lens vignette due to an offset lens port would only affect the ground glass image. It could just be that the viewfinder optical path hasn't been modified for an enlarged ground glass image but if someone has done a DIY S16 conversion, who knows what they may have done wrong.

You might want to take it to a Bolex specialist to see what the viewfinder issue is, and look into re-centering the mount or what else may be needed. It's not usually a DIY job to shift the mount over, unless you are a machinist. A shoddy DIY gate enlargement could also cause scratching, so maybe have that checked before you waste film on it.

Thanks for your reply Dom

yes it’s difficult to ascertain what it’s caused by, if it’s purely cosmetic or not 

Les Bosher said that the camera appears to be set to standard 16 for a few images I sent to him, and moving the Mount across 1mm would likely sort it.

it’s not lens vignetting as it’s there with it not even on, and zooming in, it doesn’t move at all, does appear to be inside the viewfinder itself actually because when I flick the prism door up inside the lens Mount, of course it’s black through the viewfinder, 

but when I point a bright light into the lens Mount I can still see the curve, so that would mean likely it’s one of the optics inside the viewfinder (up to and before the front prism) and not to do with the lens Mount position ?

any other ideas?

needs to be looked at for sure 

 

 

 

 

 

[Lewis Hart]

Unfortunately camera repair shops here are few and far between, there’s a few in London who don’t do bolexs

les Bosher is far away from me but does repair them, he’s extremely busy he said.

a thought though, I did take off all of the front Mount screws today to see if I could shift the Mount across, Les said it would be a few MM to the right if so, 

but he said the Mount could shift easily, but all I found was that the film gate, and whole assembly was together, including what looked like the front prism all attached together.

im 100% no technician so I put it back before I caused any damage.

@Dom Jaegerif you know any technicians in the U.K. do let me know

Lewis 

 

Edited August 23, 2021 by Lewis Hart

[Lewis Hart]

Got a better photo here.