Enlarger lens coverage question

[MattKing]

There's a little "marker guide" on the 45 models that shows where the upper bellows should be for a given film format. It's on the right side as you face the enlarger. It's held on by 2 screws and easily removed, so you're enlarger may be missing it.

But while having the upper bellows extended might explain why you were have light falloff with the 135mm lens, it should have been worse (not better) with the 105.

That guide is only applicable to the Beseler condenser heads - not the OP's Aristo cold light head.

I don't recall whether the guide is applicable to the Beseler colour heads.

 

[Chadinko]

I've been buried under jobs that require digital (darned art directors and marketing folks) so I've not had a chance to go back in and play with the enlarger. I will have time this weekend to do some printing, so I'll report back after I do.

 

[mgb74]

That guide is only applicable to the Beseler condenser heads - not the OP's Aristo cold light head.

I don't recall whether the guide is applicable to the Beseler colour heads.

Good point.

I'd also suggest making sure the diffuser disk beneath the cold light head is present and not discolored.

 

[cheekygeek]

Correct me if I'm wrong, but in addition to knowing the format & enlarger lens focal length, the aperture used on the enlarger lens is also relevant, particularly when it comes to corner coverage/quality.

 

[Ian Grant]

Correct me if I'm wrong, but in addition to knowing the format & enlarger lens focal length, the aperture used on the enlarger lens is also relevant, particularly when it comes to corner coverage/quality.

Of course it is and it's more critical with some designs/types than others, however unlike camera lenses enlarger lenses are optimised for a flat field and also a more limited focus range which helps significantly.

4 element Tessar type designs and cheaper budget Triplets are better stopped down while 6 element lenses are significantly sharper in comparison at the corners at wider apertures.

Ian

 

[Chadinko]

Are you referring to sharpness in the corners or exposure in the corners? I almost always expose stopped way down so I can have more time to dodge and burn. but I wouldn't expect the aperture to make a difference in coverage, only sharpness.