Enlarging lens questions.

[venchka]

I just returned from a 10 hour trek and wagged home an Omega D5-XL Dichroic enlarger. :cool: :) You bet I'm excited!

The enlarger came with two lenses: a 150mm/5.6 Componon-S and a 50mm/3.5 Komuranon-S.

No question that the Componon-S is a keeper. The only question I have is if there is an optinum f-stop for the lens?

The Komuranon-S is an unknown quantity. I suppose it falls into one of 2 categories: OK for practice but replace as soon as possible OR a sleeper of a lens that works as well as my talents will ever need.

Your thoughts?

[Stephen Willard]

A general rule of thumb is the middle apertures are optimal. So if you have a 150mm f5.6 lens, then I would guess its smallest aperture is f45.0 with an optimal aperture range between f11 to f22.

Most enlarger lenses do real good when you are making small prints. What separates the men from the mice is when you go to make big stuff. Here is a great test I do when I buy a new enlarger lens. First align enlarger table, lens board, and negative holder so they are all parallel to one another. Host the enlarger head to it highest point and put in a negative of a photograph of a newspaper. The negative needs to have razor sharp text from edge to edge. Using a grain focuser, inspect the edges of the image. A high quality lens will degrade very little at the edges.

I had a Rodenstock 240mm lens that produced very sharp images, but I was unable to focus it at the edges when I was printing my first 16x40 panoramic print. I ordered a Nikkor 210mm. The Nikkor won by a long shot and was very sharp at the edges as well as razor sharp in the center.

Hope this helps...

[vinny]

Test it. I had a 135 componon-s and a 135 rodagon that i tested from 8-22. F11 was sharpest on both at 16x20 enlargments. Many folks wouldn't be able to tell the difference. I kept the rodagon cuz it has illuminated apertures.

[Michael Graves]

Komura was (is?) a Japanes manufacturer that did a lot of aftermarket and OEM lenses for some of the second-tier camera manufacturers. The Komuranon enlarging lens was a decent, albeit not outstanding lens. It was better that the introductory Beslars and Omegarons of the day, but not really on a par with Nikkor, Componon or Rodagon lenses. You should be able to get reasonable results from your 50mm up to 8x10 or so...perhaps 11x14. At that point in time the presence of grain in the enlargement starts to blatantly give away the differences between great lenses and also-rans. Grain in the center of the image on a prime quality lens is crisp and well defined. The lesser lenses don't project the grain so crisply and it it is muddier. This effect gets progressively worse out to the edges. While you might think muddying up the grain would be a good thing...in reality it just makes the lack of sharpness that much more apparent.

[Mick Fagan]

I picked up a 150 Componon S about a year ago. After some testing I found the the best overall aperture for this lens, was f11 1/2 with my negatives, which are Tmax 100, FP4+, HP5+.

It is really quite good from f5.6 1/2 through to f8 1/2, at f11 it really starts to shine across the whole neg. At f16 1/2 it is just starting to look less sharp on the edges, by F22 slightly more degradation is happening. We are talking gnat's hair differences though.

Realistically, it's marvellous from f8 through to f22 1/2.

You should test it.

Mick.

[robert amsden]

I just returned from a 10 hour trek and wagged home an Omega D5-XL Dichroic enlarger. :cool: :) You bet I'm excited!

The enlarger came with two lenses: a 150mm/5.6 Componon-S and a 50mm/3.5 Komuranon-S.

No question that the Componon-S is a keeper. The only question I have is if there is an optinum f-stop for the lens?

The Komuranon-S is an unknown quantity. I suppose it falls into one of 2 categories: OK for practice but replace as soon as possible OR a sleeper of a lens that works as well as my talents will ever need.

Your thoughts?
The best f stop for the schnieder is f8. I have a 75 mm komutanon, very good lens, it has a resolution in excess of 228 line pair,very sharp lens.

[robert amsden]

I picked up a 150 Componon S about a year ago. After some testing I found the the best overall aperture for this lens, was f11 1/2 with my negatives, which are Tmax 100, FP4+, HP5+.

It is really quite good from f5.6 1/2 through to f8 1/2, at f11 it really starts to shine across the whole neg. At f16 1/2 it is just starting to look less sharp on the edges, by F22 slightly more degradation is happening. We are talking gnat's hair differences though.

Realistically, it's marvellous from f8 through to f22 1/2.

You should test it.

Mick.
Look thru a 25x microsight at the grain and stop down I found f8 to be the sharpest.

[ic-racer]

Two answers, EASY and NOT-SO-EASY.

The EASY: Do as suggested, watch as you stop down with the grain magnifier (be sure to check center AND edges).

The NOT-SO-EASY: There is a way to calculate the required aperture for enlarging in a manner similar to that required for view camera focusing. The equation is similar and is as follows:

N_max ~ 20 / (1 + m) sqrt(dv),

Where N_max is the largest aperture number you can get away with without being overwhelmed by diffraction (this will minimize your lens aberrasions)
m is the magnification
dv is the distance on you enlarger column in millimeters from sharp focus on the highest and lowest point on the negative (usually the center vs the edge)

The above equation just considers diffraction and fuzzy circles from things being out of focus. It says nothing about lens aberrasions and lens quality etc. Check the MTF curves here and you will see that the edges DO get better as you stop down. (ie f11 better than f8) http://www.schneideroptics.com/pdfs/photo/datasheets/componon-s/componon-s_56_150_2.pdf

Bottom line: I have that same lens (Componon-S 150mm 5.6) and I use F11 with a non-glass carrier on enlargements from 11x14 to 16x20.

Good find with that enlarger!!

[Mick Fagan]

Robert Amsden, I take your point about f8 possibly being the sharpest when looking through a magnifier, but have you actually printed using f8 and/or other apertures for comparison?

I have a series of test prints from different negs at different sizes with full frame enlargements, yes f8 is quite sharp, but with two different 150 Componon S lenses, my practical experience has been that from f11 onwards, they both made their best full frame enlargements.

Very interestingly, my 150 Componon S works best fully stopped down for unlargements. This is where the full frame image is actually smaller than the film format itself!

Mick.

[ic-racer]

Very interestingly, my 150 Componon S works best fully stopped down for unlargements. This is where the full frame image is actually smaller than the film format itself!

Mick.
OT: Unenlargements in themselves are an interesting topic. I don't do them, but my Durst manual recommends a lens of focal length similar to the diagonal of the print. I have not tried it yet, but I know my 300mm will not focus a 4x5 image from an 8x10 negative. But I bet the 150mm would work fine. They did not say anything about reversing the lens. Do you reverse your lens?

[Dan Fromm]

<snip>
Very interestingly, my 150 Componon S works best fully stopped down for unlargements. This is where the full frame image is actually smaller than the film format itself!

Mick.The word you're looking for is reductions. As ic-racer suggested, the lens should be reversed.

[Mick Fagan]

Yes, they are reductions of the original, but I believe that technically, the correct word is, "delargements". However in the lab we called them unlargements, sounded a lot better.

One of the more interesting things we used to do was photocopy work. Often and usually, we used the 8x10 Toyo monorail or sometimes the Toyo 4x5 monorail for photocopying work, depending whether it was for repro magazine work or a physical picture we would use either slide or colour neg.

Sometimes though after doing an 8x10 tranny for magazine work, we would be asked by the owner of the work for a colour slide for a slide show regarding their work they had been asked to do. We used to pull out the 360 enlarging lens for best coverage, attach it to an extension cone and drop the bellows attached lens stage to almost the maximum. At this stage we just covered, plus a bit, the dimensions of a 35 mm slide. We either used 4x5 print film for a slide, or, if it was a transparency original, we used dupe E6 film. The resolution was amazing.

On my own enlarger, a DeVere 504, to make smaller than the film size prints with 4x5 film and my 150 Componon S enlarging lens. I can do this by extending the bellows to maximum, with this I can get slightly smaller than S/S, which is pretty neat for no real fiddling. For a ½ size or further reduction, I need to add an extension I have had made up.

As long as the lens is stopped right down I get extremely good prints. I've never needed to reverse the lens and whilst it may be technically better, I'm not sure it's a warranted step.

Mick.

[ic-racer]

Yes, they are reductions of the original, but I believe that technically, the correct word is, "delargements". However in the lab we called them unlargements, sounded a lot better.

One of the more interesting things we used to do was photocopy work. Often and usually, we used the 8x10 Toyo monorail or sometimes the Toyo 4x5 monorail for photocopying work, depending whether it was for repro magazine work or a physical picture we would use either slide or colour neg.

Sometimes though after doing an 8x10 tranny for magazine work, we would be asked by the owner of the work for a colour slide for a slide show regarding their work they had been asked to do. We used to pull out the 360 enlarging lens for best coverage, attach it to an extension cone and drop the bellows attached lens stage to almost the maximum. At this stage we just covered, plus a bit, the dimensions of a 35 mm slide. We either used 4x5 print film for a slide, or, if it was a transparency original, we used dupe E6 film. The resolution was amazing.

On my own enlarger, a DeVere 504, to make smaller than the film size prints with 4x5 film and my 150 Componon S enlarging lens. I can do this by extending the bellows to maximum, with this I can get slightly smaller than S/S, which is pretty neat for no real fiddling. For a ½ size or further reduction, I need to add an extension I have had made up.

As long as the lens is stopped right down I get extremely good prints. I've never needed to reverse the lens and whilst it may be technically better, I'm not sure it's a warranted step.

Mick.

I'm not going to criticize the way you are doing it, I think it adds another way make the reduction or what ever we call it. I know some of my lenses will just not form a clear image when used for reduction. What you are saying is that by stopping all the way down you get almost a 'pinhole' effect and you can make the reduction without reversing the lens or choosing a lens focal length based on the diagonal of the reduction.

I think can see how this would be feasible as you only need to get 5 lines/mm resolution or so on the print.

[Mick Fagan]

Yes it is an interesting thing to do. I'm not 100% sure where you are coming regarding the smaller than the diagonal of the format.

My 150 is as near to the actual diagonal of the format, which measured on my ruler, is a 153mm diagonal length, on the image on my negatives. As for the 8x10 ones we did in the lab, we used a 360 mm lens, which is longer than the actual image diagonal measurement on the film. If my memory is correct, the diagonal on an 8x10 sheet of film is about 320mm give or take a millimetre or two. I don't use 8x10, so I'm going strictly on memory here.

I was in the darkroom earlier this evening and decided to check out just how small an image I can focus correctly too, using 4x5 film. My lens stage drops over 400mm from the film stage, which is a great help, by lifting the table up, or stacking the easel, I can get down to a nominal 6x7cm neg size. To further reduce the image I add an extension to the enlarging lens carrier, which enables me to make a full frame image effectively the same size as a 35mm film gate.

When I go to this step, I stop the lens right down, and, as you say, effectively have a pinhole set-up, which gives me a very good image. As to the reversing of a lens for better resolution, or whatever, I don't know as I haven't had the need to do this.

Fun stuff.

Mick.

[Ralph Barker]

As a side note, you'll probably need to mount the 150mm Componon-S in the longOmega lens cone (4.5" or so, IIRC). If the lens cone wasn't included with the enlarger, there are a few places at which they can still be found.

[ic-racer]

Yes it is an interesting thing to do. I'm not 100% sure where you are coming regarding the smaller than the diagonal of the format.

Simple, when doing a 4x5 inch to 6x7cm reduction, use a lens for 6x7 format! So use a 100mm, not 150mm. I had been enlarging for 30 years and did not know this trick until I saw it in the manual for my Durst.

Ideally you would reverse the lens, but since Durst doesn't make a lensboard for a reversed lens, they don''t mention reversing the lens and it is not a big issue in my opinion.

[Mick Fagan]

Great, you learn something new every day.

However I'll stick with my method, it works and I only have to drop the lens stage further away from the neg stage.

Mick.