Internal Bellows Reflections

[ic-racer]

I believe I'm getting internal bellows reflections. My photocopy stand is not setup right now, but I'll post some examples shortly.

I wonder if others that had this issue and solved it could chime in.

I do have a bag bellows that may focus with my 300mm lens. I don't have a compendium shade. I use the darkslide to shade the lens. But the pictures in question seemed to cause the internal reflections from a big semi-overcast sky. Perhaps I need to be more diligent to in these cases (where the sun is not actually hitting the lens) and still shade the lens with the darkslide from above.

[rfesk]

Yes, it is possible. Depends at lot on the bellows material and how close it is to the light going through the lens. Even film reflects some light back towards the bellows and lens so it can't be 100 percent eliminated. A bag bellows is the best option.

[Bernice Loui]

Flare from stray light inside the bellows is a given. In the past, there have been "miracle" bellows materials that claim to reduce stray light inside the bellows.. skeptical at best.

~Use a lens with a smaller image circe at a given reproduction ratio to limit the amount of stray light hitting the inside walls of the bellows.

~Use an adjustable lens shade to effectively limit the image size projected to the film recorder and stray light hitting the inside walls of the bellows.

The amount of internal flare thus contrast reduction due this stray light bouncing around inside the bellows can be more than most suspect.
This is one of the reasons why always trying for a lens with the largest possible image circle is not always wise.


Bernice

[neil poulsen]

With what camera?

[Alan9940]

I have found that you need to provide some sort of shading above the lens, especially on overcast days. I use the darkslide.

[Kiwi7475]

We just need bellows made with this stuff:


http://sitn.hms.harvard.edu/flash/2019/back-black-new-blackest-material/

[ic-racer]

I see "Black 3.0" on the internet, but it seems a little shady. I's expect 'the blackest paint' to come from 3M or some chemical company, not "Kickstarter," so I'm skeptical that "Black 3.0" is just black paint packaged in 'internet hype.'

If "Black 3.0" does what it indicates on the internet, I'd need to just paint the inner parts of the fold with a line of paint. It is the inner fold of each pleat from which the light reflects. I can see it clearly when I remove the ground glass.

By the way camera is a Shen-Hao 8x10 with its original bellows. Lens is a 300mm W 5.6 80 degree lens used with no compendium shade.

Currently I use the darkslide and I shade the lens standing in front of the camera. This works when direct sunlight shows on the lens because I can see the shadow of the darkslide.
Problem is the negatives in question were exposed with "Bright Overcast" that does not cast a shadow. It might be hard to know when the darkslide is in the angle of view.

Maybe some flexible arm with single barn-door on top, that I can set in place before the exposure, might be easier than adjusting a complete compendium shade.

[ic-racer]

I took a photograph of the negative but it does not show well. It shows better on the print. On some other negatives it is more of a box but it is fainter. This print shows it most prominently.

210701

210702

[Balazs Szabo]

Hi there,

I'm having similar issues and wondering if (and how) you managed to sort out yours.

Please see an example below.

220903

Many thanks,

Balazs

[ic-racer]

I made this, but due to COVID surge, had very little time for photography this last summer to use it. The few times I went out I was working in a wooded area.
https://www.largeformatphotography.info/forum/showthread.php?161427-Show-Your-Compendium-Shade-on-a-Field-Camera-Thread&p=1580047&viewfull=1#post1580047

[Neal Chaves]

If you both just showed me the negatives and said nothing about bellows, I would say it was "bromide drag" during processing. I've had lots of experience with light leaks and bad bellows and doesn't look like this.

The top right corner on Balazs could be a light leak, but I also see the same dark streaks as in Ice-Racer's

[Joe O'Hara]

Just looking inside the camera at the matte black surfaces can be misleading. The problem is that the light that scatters onto the film and degrades the low values is mostly the tangent rays, i.e., those just grazing the surface at a low angle. Take any "flat black" cloth or painted surface and tilt it so that it is almost parallel to the light source and you will see what I mean. They never look quite so "black" then. Internal reflections in the lens don't enter into it: with modern MC lenses it is only an issue if the light source (usually the sun) is in the image or just outside it.

It is, I'll admit, a big PIA but the only good solution IMO is to use a lens shade that cuts off all of the light outside the image area, in other words, if it were any smaller, you would get vignetting. Real fanatics (I'll not name names but some may have some guesses) have recommended using an 8x10 with a reducing back for smaller format film. I am not among those but I use a rectangular Lee shade on all occasions regardless of the light conditions.

Edit: Just noticed this was an old thread. I stand by my comments anyway.

[r.e.]

I use a rectangular Lee shade on all occasions regardless of the light conditions.

Hi Joe,


You may be have a prior version, but is this basically the Lee hood that you're using? I have the Lee100 holder. I've been considering this, but it's pretty expensive.



https://www.youtube.com/watch?v=ZfVE75XTwjo

[Bernice Loui]

Using a lens with far excessive image circle for a given film / imager format aggravates the problem of stray light bouncing around inside the bellows.

Some view camera folks are obsessed with using lenses with the largest image circle possible.


Bernice

[Balazs Szabo]

If you both just showed me the negatives and said nothing about bellows, I would say it was "bromide drag" during processing. I've had lots of experience with light leaks and bad bellows and doesn't look like this.

The top right corner on Balazs could be a light leak, but I also see the same dark streaks as in Ice-Racer's

Yes, the top right is a leak from the edge of the flap of the holder.

I thought about the streaks possibly being caused by bromide drag, but this is tray developed, so they wouldn't be straight lines IMO. With insufficient agitation I remember getting blotchy highlights, and so I just can't explain the straight lines.

I get them regardless my agitation patterns and I also tried brush development only to find the same lines. I agitate continuously for the first 2 minutes ( 1 minute alone results in the aforementioned blotchiness ) working with a highly diluted developer (hc110 at 1:79) and then 15 sec every minute.

I'm open for suggestions ��

[Balazs Szabo]

I made this, but due to COVID surge, had very little time for photography this last summer to use it. The few times I went out I was working in a wooded area.
https://www.largeformatphotography.info/forum/showthread.php?161427-Show-Your-Compendium-Shade-on-a-Field-Camera-Thread&p=1580047&viewfull=1#post1580047

Thanks, I'm experimenting with a simple retractable rubber hood, but with movements employed and a wide angle lens the only real solution will be a compendium hood, indeed..

[Balazs Szabo]

Just looking inside the camera at the matte black surfaces can be misleading. The problem is that the light that scatters onto the film and degrades the low values is mostly the tangent rays, i.e., those just grazing the surface at a low angle. Take any "flat black" cloth or painted surface and tilt it so that it is almost parallel to the light source and you will see what I mean. They never look quite so "black" then. Internal reflections in the lens don't enter into it: with modern MC lenses it is only an issue if the light source (usually the sun) is in the image or just outside it.

It is, I'll admit, a big PIA but the only good solution IMO is to use a lens shade that cuts off all of the light outside the image area, in other words, if it were any smaller, you would get vignetting. Real fanatics (I'll not name names but some may have some guesses) have recommended using an 8x10 with a reducing back for smaller format film. I am not among those but I use a rectangular Lee shade on all occasions regardless of the light conditions.

Edit: Just noticed this was an old thread. I stand by my comments anyway.

Hi Joe,

Thank you for taking the time to comment.

The inside of my bellows is indeed quite reflective, even at normal angles.. At low angles it seems almost glossy :(

A quick question about the Lee hood: I don't see how the length of this is regulated without the usual metal structure on the outside ?

Thanks again,

Balazs

[Balazs Szabo]

Using a lens with far excessive image circle for a given film / imager format aggravates the problem of stray light bouncing around inside the bellows.

Some view camera folks are obsessed with using lenses with the largest image circle possible.


Bernice

What you're saying makes sense. Unfortunately I can't afford having 2 or 3 lenses of the same focal length and then choose based on the necessity of movements.

With that said I don't think 398mm is an overkill, although still significantly bigger then the ic needed to cover 8x10.

Lens hood it is then, I guess .. :)

[Joe O'Hara]

Balazs-- I use the previous "wide angle" Lee filter, which has a 4x5 aspect ratio. I agree the new version is insanely expensive-- more than many of us spend on our main lens!

We put up with lens shades so that we can use lenses with large ICs, so that we have movements available to us. Otherwise, why use a view camera?

The bellows that mine is made from is stiff but flexible. You just pull it out to the length you need and collapse it back for storage.

[r.e.]

Lens hood it is then, I guess .. :)

Given that you're in Italy, you should be able to find a more attractive price on a Lee Hood than the U.S. price. However, note that the Lee needs a Lee Holder to work. If you need the name of a European reseller, send me a personal message.

[Rod Klukas]

Internal refections is an issue. Remember that a wide angle bellows is designed for wide angle lenses. There are often no pleats with wide angle bellows. The pleats of standard or long bellows are designed for more than just flexibility. They are designed to capture and block bouncing light.
While it may be convenient to use one bellows you should know and be aware that the internal flare with a longer lens, may require a speed/isa change to try to dampen the effect.
In black and white films using the Zone system we often went down 1/3 to 1/2 stop, if needing to use a W/A bellows with a longer lens to try to compensate for the contrast change that would manifest itself when using this bellows/lens combination.

Hope this gives some insight.

Rod