vignetting on prints w/150 enlarging lens

[brian steinberger]

I've been getting slight vignetting on some prints that I've been making from 4x5 negatives on a Besler 45M and Dicrho 45s with a Nikon 150/5.6 lens. That lens should easily fully cover 4x5. It seems to me that there is a lot of space for the negative carrier to be positioned inside the circle in the enlarger. I can't exaclty tell when I'm perfectly in the middle. There always seem to be vignetting in atleast one corner. Any solution or suggestions? Thanks

[Wilbur Wong]

It is not clear to me if this is a new set-up to you, or this is a recent problem.

All of my Beseler negative carriers have 4 small locating pins on their bottom side which drop down into a circular cut out just above the focusing bellows - 4 x 5 both glass and glassless as well as smaller format carriers have these.

Are they present on your carriers. With them in place, there is only one central location for it to take (without rocking around the place).

I use a Beseler 45 v xl with a universal dichroic head. I don't know if there are any differences from the M. My enlarger has a second bellows above the carrier stage which allows the diffusion head or condenser head to be closer or further away from the negative stage. Do you have that option, and what position is it in? I don't know if that may be an influence, if you do try setting it as low as possible.

[Wilbur Wong]

BTW, I use an El Nikkor 150 mm f5.6 enlarging lens. I doubt it is a lens issue, and is more likely lighting. Perhaps your light source is what is not centered above the negative stage.

[Graham Patterson]

The Dichroic 45s head needs to be mounted with the upper bellows compressed to the 5x4 inch setting at all times (you have to take the format scale off). My 135mm lens and 5x4 carrier are fine. The carrier must have centering pins.

Have you dented the lower bellows, or dropped something inside? The only time I see vignetting is when I enlarge some roll-film panoramics that are 155mm long - I have to sacrifice some of the width because the light source is too small, but the lens coverage is fine.

[Andrew O'Neill]

Certainly not a lens issue as I used to have this same lens as well as the 135mm. (before they were stolen!). I got vignetting only when the light source was too far from the negative.

[brian steinberger]

Wilbur, my some of my negatives carriers have the whole you're talking about. They drop into the circular part you are talking about, but then they're still a little free to move. I've take off the scale and my upper bellow are fully compressed. So that is not the problem. Maybe I didn't install the dichro head right. Just a thought

[Wilbur Wong]

My carriers just wiggle a little bit, certainly less than a 1/16 inch

Your dichro head did you buy it recently, and is it new? There are several different "mixing chambers" available for mine, although I only own the generic 4 x 5 chamber since it has been seldom that I put smaller format negatives in here. The alternate mixing chambers would have larger light output, but are have a smaller coverage as I understand.

Understand I have never seen any of the other chambers, and it has been a few years since I set my system up.

(To be honest, my printing seems to be headed towards digital. Any one interested in a great wet 4 x 5 color dark room set up?)

[mark bridges]

Check upper bellows compression to the 5x4 inch setting, scale on the right hand side.

[Brian Ellis]

A couple very basic things that almost certainly aren't the cause of your problem but who knows , so - you do have the easel centered in the circle of illunination on the enlarger base board and you don't have the filter ring (if there is one on your M) partially turned so that part of it is blocking light, right?

[Scott Davis]

Also check the alignment of the light source to the film plane. The dichro heads don't have a very large circle of illumination beyond the carrier size, so if the head is off, it could be causing either vignetting or uneven illumination, giving the appearance of vignetting.