Please help evaluate what happened on this test neg with new Chamonix F2

[David Wolf]

Hello All,

I'd love to hear your thoughts about what may be the blocking the image at the top of this test negative, please. This view is as the image looked on the GG, so the top as seen here is the bottom of the image.

This is the first negative I've made with my new camera, so I'm not yet familiar with it's limitations ~ thus the test. One thought is the bellows may have obstructed the image? Though this would surprise me, given no one mentioned this during my info gathering as a potential issue with the lens I used here, or even much wider lenses.

Below are the details to help sort this out ~

Many thanks for your kind help!

David

Intention: tree in focus, background not

Chamonix F2
Universal Bellows
Caltar II-N 210mm, f5.6 lens
F16 1/3@1/30th

Camera pointed upward
F and R vertical
F small forward tilt
F moderate rise

Darkslide removed completely

[David Schaller]

When you tilted the camera upwards, then brought the back vertical, the bellows got in your picture. It's happened to me. It has nothing to do with your specific camera. You might try to recreate your movements on the camera, in your living room, and you'll see what happened. The angle was too extreme.

[Alan Klein]

I'm new to 4x5 cameras and have a Chamonix 45H-1. Just curious. Why did you tilt the front standard?

On a separate note, I have a big lens. I haven't had the problem you have had, yet. But I noticed that the lens will hit the bellows if I'm not careful.

[sharktooth]

It's possible you haven't inserted the film holder fully. There is a narrow rib on the upper end of the film holder. This rib engages with a slot in the camera back. Since you're new to this, the film holder may not have been inserted far enough for the rib to engage in the slot. Depending on the wear of the camera back and film holder, the engagement may be easy or difficult to feel or hear.

If the bellows is interfering, you can check for that by looking through the lens to see if you can see all four corners of the ground glass (from the front of the camera).

[Huub]

My guess would also be with David Schaller: it looks like your bellows got in the way. If your camera has a ground glass with clipped corners, make it a routine to check if you can see the complete diafragma of your stopped down, but still open lens when you look through these clipped corners. If your camera hasn't such a ground glass, look from the front of your lens into the camera and check if you can see the complete ground glass with some marging. This also works to check if you go beyond the image circle of your lens.
A bellows that intrudes into the image area can often be adjusted by putting some object between the bellows and the camera bed for instance.

[Doremus Scudder]

It's a good idea to use your front rise as much as possible before resorting to the "point up and tilt parallel" method of getting more rise.

That said, there should be a way to get the bellows from interfering even with extreme movements. It kind of looks like the bellows sag was somewhere close to the lens.

Recreate the movements and focus you had on the problem shot and remove the back to see what's in the way. There's probably a way of shifting the bellows around a bit that will solve your problem. Many cameras have bellows with a D-ring on top, roughly in the middle, so you can hook the bellows up to something to counteract the sag.

On similar shots in the future you'll need to check for this and correct it before exposing.

Best,

Doremus

[David Wolf]

Thanks to all for your helpful replies!

Looking through the lens as suggested, I now see the corners at the top of the GG (image bottom) aren't visible, corresponding to the loss of the image on the negative.

Is this an image circle issue, or a bellows issue? The Caltar II-N lens has a large circle of 294mm, so I'd be surprised if this is an issue of coverage? Although maybe at this angle (see below) most image circles would be obstructed?

If I gently lift up at the lowest point of the bellows in this camera position, I do see a some difference on the GG, with the upper (lower) corners just becoming visible. I don't know if using something to eliminate the sag, say, a soft bean bag, would be a viable solution ~ could be a little finicky, unstable?

Other than trying to support the bellows, would my only other alternative be to reduce the camera pointing upward + vertical tilt by raising the camera higher on the tripod (thus necessitating a ladder) and shooting at more of a level angle?

What do you think?

Thanks again!
~D

PS As for looking through the clipped corners of the GG, I'm not sure what to look for, and only see what appears to be a small dark arc ~ is this a partial view of the lens diaphragm?

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[Corran]

I've never had this kind of obstruction with front rise on a 210mm lens.

Question: on this photo, did you actually tilt the camera back and then tilt both the standards, as in the pic you have shown here in the post above? There is no reason to do this - just set the camera flat with the rear at 90 degrees and use more front rise. I have a feeling the extra gyrations of your setup there may have contributed to the issue. Secondly I would check that your "universal" bellows at the front aren't sagging into the image.

You only need to do that "tilt" in a situation where you run out of front rise - almost impossible with a Chamonix.

[Vaughn]

...PS As for looking through the clipped corners of the GG, I'm not sure what to look for, and only see what appears to be a small dark arc ~ is this a partial view of the lens diaphragm?

Look thru the clipped portion of the GG towards the lens -- if you can see the entire aperture, then you have nothing blocking the light and you will get full illumination to that corner. You will see if the bellows are blocking any of the light. One can look thru the cut-corners while closing the aperture to see what f/stop gives first fully illuminated the corners, and use that info to adjust movements and help determine one's optimal aperture for the image.

[ic-racer]

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[grat]

As others have said-- you're using practically no rise (in fact, you're using a bit of fall) on the front standard. Level the base, set front and rear to 90, and raise just the front standard. A little movement goes a long way.

[David Wolf]

Thank you, all!

David + Doremus ~ I recreated step-by-step the camera set-up as pictured, while looking thru the lens to the corners of the GG. Yes, I can see now the obstruction does come from tilting the rear standard to vertical while the camera is pointed upward to this degree.

Corran + Alan ~ I had tilted F&R to vertical to keep the lens and film planes parallel as I pointed the camera upward to gain height for my desired composition. I did this because it appeared the amount of F rise needed created an obstruction. I'll have to revisit the subject site to double check myself there ; )

Huub + Vaughn ~ Maybe it's my eyesight (I use magnifying "reader" glasses to view the GG, and add a loupe for fine focus), but I'm still having trouble seeing much of anything while looking thru the clipped corners toward the lens. Oh, well. I can see fine looking in the opposite direction, looking thru the lens toward the GG for obstruction.

ic-racer ~ Thx for the pics! So is that a bellows support you've attached to the Cambo? Very nice! Did it come with the camera? Could you show/tell more about it and how it's attached, please?

Thanks again to all! I appreciate your kind and thoughtful replies. Now I just have to improve my technique and get better acquainted with the camera ; )

All my best,

David

[Vaughn]

Try pulling your head back enough to focus your eyes on the back of the lens -- and you do not have to be under the darkcloth. I find it difficult to understand why you can not see the back of your lens thru the clipped corners (silly, but remember to open the lens).

Under the darkcloth and with the proper eyesight, one can also see a focused aerial image in the clipped corner, so one will know what is happening with the image in the corners...very important to me.

[Doremus Scudder]

David,

A few remarks:

First, If you have clipped corners on your ground glass, which I believe you do, you simply look through the empty space at the corner toward the lens, with the lens stopped down to taking aperture. If you can see the entire aperture, i.e., the full circle (which may appear oval in shape with really short lenses), then there is no vignetting. If you can't, there is something in the way or your lens simply won't cover that far (i.e., you are outside the image circle at whatever corner your are looking through. When applying front rise, it is only necessary to look through the bottom corners.

Another, similar method is looking back through the lens at the corners. I often find this easier, especially if the camera is placed rather high. Stop down to taking aperture and look back through the lens at the corners. If you can see the corners clearly, no problem. If you can't either something is in the way or you've run out of coverage.

Do set up your camera as you had it for the shot in question and take the back off so you can see if the bellows are in the way. You don't appear to have done this. If the bellows are the problem, and I believe they are, then figure out a way to get them out of the way. It's a common problem with long bellows like the Chamonix has. See my earlier post.

As for your movements: As others have mentioned, it is often easier to set up your camera level and just use front rise. The Chamonix has plenty. However, if you run out of rise, the method you are using is good, provided that you use primarily the front rise to get the job done. So, try the camera level first. If you run out of rise, leave the rise at its maximum height and point the camera up till your image is just a bit higher than you really want it. Tilt both standards back to parallel and then use the front rise to fine-tune.

Best,

Doremus

[AtlantaTerry]

This has all been a very good discussion of the bellows possibly getting in the way.
But I would like to add one more possibility:
David (being new to this) did not remove the dark slide completely.
Was enough lingering inside the sheet film holder to block some light?

I do NOT think I am right about this because if this happened, there should be more of a solid edge to the blocked light. But I just wanted to put it out there.