Bronica SQ - vignetting or light leak ?

[awaken77]

I recently bought Bronica SQ set (including Zenzanon-S 80/2.8 , AE metering prism and 120 back).
First roll revealed some problem - dark "stripes" along the edges of the frame.
They can be seen on the exposed area of negative only, not in the spaces between.
Since it was an expired film, it is possibly damage of the film itself.


However, on the next film rolls, problem still exist, altough not so obvious.
Here it is on the right side - looks like vignetting along the edge of the frame.


Here it is less prominent, on the right side too.


I thought it can be a light leak in the back, but light leaks usually appear like light stiripes, not darker ones, right?

[dances_w_clouds]

The light leaks appear darker because you know what light does to film. Vignetting would be circlular.;

[Q.G.]

Originally Posted by dances_w_clouds

The light leaks appear darker because you know what light does to film.

Yep. The OP and i do.
If it receives more light, for instance due to a light leak, the end result will be lighter. Not darker.

Originally Posted by dances_w_clouds

Vignetting would be circlular.;

Vignetting takes the shape of the thing that is causing the vignetting.
Just like any shadow (which vignetting is) takes the shape (outline) of the thing that is casting the shadow.
So it is only circular if the things that is causing it is circular. And there are other things that might cause vignetting that are not.


Awaken7,

It could be a processing thing (too much agitation).
Or something inside the Bronica not moving out of the way properly.

[dances_w_clouds]

Originally Posted by Q.G.

Yep. The OP and i do.
If it receives more light, for instance due to a light leak, the end result will be lighter. Not darker.



Vignetting takes the shape of the thing that is causing the vignetting.
Just like any shadow (which vignetting is) takes the shape (outline) of the thing that is casting the shadow.
So it is only circular if the things that is causing it is circular. And there are other things that might cause vignetting that are not.


Awaken7,

It could be a processing thing (too much agitation).
Or something inside the Bronica not moving out of the way properly.

PARDON ME

[Andy K]

How bright was the light where you loaded the film? Also are these scans of prints, negatives or transparencies? If there is a curve in film it can affect the scan of a neg or transparency.

[dances_w_clouds]

Originally Posted by Q.G.

Yep. The OP and i do.
If it receives more light, for instance due to a light leak, the end result will be lighter. Not darker.



Vignetting takes the shape of the thing that is causing the vignetting.
Just like any shadow (which vignetting is) takes the shape (outline) of the thing that is casting the shadow.
So it is only circular if the things that is causing it is circular. And there are other things that might cause vignetting that are not.


Awaken7,

It could be a processing thing (too much agitation).
Or something inside the Bronica not moving out of the way properly.

That makes sense film exposed to light gets lighter ????

[Q.G.]

Originally Posted by dances_w_clouds

That makes sense film exposed to light gets lighter ????

Take a picture of something out in the open sun, casting a shadow, make sure the sun itself is also in the frame.
Now what would you say would be light(est), what would be dark(est) in the picture?

And/or take a look at the pictures the OP posted.
See how, for instance, the shade below the sunflowers is darker than the nutated sunflowerheads, and ask yourself whether that really would be because the film receives more light coming from the shades.

[dances_w_clouds]

Originally Posted by Q.G.

Take a picture of something out in the open sun, casting a shadow, make sure the sun itself is also in the frame.
Now what would you say would be light(est), what would be dark(est) in the picture?

And/or take a look at the pictures the OP posted.
See how, for instance, the shade below the sunflowers is darker than the nutated sunflowerheads, and ask yourself whether that really would be because the film receives more light coming from the shades.

The truth rears its ugly head. If he had a camera where the shutter opened in the center the dark marks would be from a slow shutter with Not enough light getting to the edges. Even @ this late hr it makes sense. I don't know if any cameras have a shutter that splits up the center though. But we got off topic here sorry awaken77

[Q.G.]

Originally Posted by dances_w_clouds

If he had a camera where the shutter opened in the center the dark marks would be from a slow shutter with Not enough light getting to the edges.

That's along the right lines, yes.
A Hasselblad, for instance, has two baffle doors in the rear that flap out of the way. If they don't do that quick enough, or not completely, they shade the film.
I don't know the Bronica well enough to know how it shields film against light when the shutter in the lens is open. But whatever it uses not opening fast enough (or not completely) could cause this.
The fact that it gets better after some exercise might indeed point in the direction of a mechanical problem: gummed up lubricants, getting better when used again.

A central shutter (a.k.a. leaf shutter) in the lens (which this Bronica has) also opens from the center, but will not vignet in the same way. Not even when it doesn't open completely. Due to its position, it simply acts like an aperture, and not opening completely would lead to an evenly less exposed image.
So that would not be it.

[awaken77]

Originally Posted by Q.G.

A Hasselblad, for instance, has two baffle doors in the rear that flap out of the way. If they don't do that quick enough, or not completely, they shade the film.
I don't know the Bronica well enough to know how it shields film against light when the shutter in the lens is open. But whatever it uses not opening fast enough (or not completely) could cause this.

I thought about that (slow mirror movement). but... I always use mirror lock-up feature on Bronica, so this is not an issue.

as for light leaks - they look dark on the negative, but light on the positive.
here is what I got on my Iskra, typical leak in the camera body