Some enlarging questions

[ic-racer]

I agree with this and your and Bob's comment about using longer lenses (that definitely helps, because you are trimming off the problematic part of the MTF), but I have one question:

You said, you're using this type of lens. But, this is a f=45mm lens and, therefore, not a 'longer' lens even for 35mm. What 'smaller format negative' are you using this lens for?

Minox and 16mm! In fact I just got a new-to-me Minolta 16 Type I two weekends ago.

Also, I use that 45mm lens for 16x20s from 35mm negatives as it is easier to center the 35mm frame on my 5x5 enlarger glass carrier, than it is to center the 35mm frame on the 10x10 glass Durst carrier. Even though the 80mm lens I'd use on the Durst 8x10 enlarger has a wide field, it is important to use the exact center if I want to use a wider aperture.

 

[ic-racer]

Ralph,
I wish I had the El-Nikkor data.
Do you have the El-Nikkor brochure at the bottom of this page? http://sites.google.com/site/inexpensivemacrophotography/6-enlarging-lenses
It has optimum magnification, mag range, degrees of coverage and lens construction info that is all useful. (but no MTF).

There are a bunch of El-Nikkor brochures at this site, but I can't get any to download: Dead Link Removed

 

[RalphLambrecht]

ic-racer

Thanks for the links. I did not have the brochure. It's very old (1978) but still valuable. EL Nikkor MTFs seems to be a bit of a mystery.

 

[Bob Carnie]

One item that for me is critical is the placement of the easel.

If it is not dead center to the lens, negative, bulb then one is always going to have trouble.

I have a little neat trick that helps.

I roughly size the negative to the height I want to print at.

I then take the glass carrier out of the neg stage and rack down the bellows so that I can see the circle of the condensors . I then position the four blades to the circle so they are dead nuts centered.
Then by moving the negative to fit the blades rather than move the easel I know I am centered in the carrier. I flip over the carrier and mask out the extra area around the rebate of the negative. I use black electrical tape for this.

I have around 8 glass carriers for the Omegas that I have done this for various sizes. Now I know the negative lens easal bulb are in a direct line and as stated above I use longer than normal apo lenses.
I find this works really well, If I am printing a show I use two enlargers at the same time with the easel taped down in both pristine positions with the head at the correct height.
I then get my tech guy to laser align the negative stage so I am comfortable that alignment is good.

I will not tear down the setup until the show is printed and this works really well for me.

 

[RalphLambrecht]

One item that for me is critical is the placement of the easel.

If it is not dead center to the lens, negative, bulb then one is always going to have trouble. ...

Then I'm in trouble, because I usually place the easel to create the most pleasing composition and ignore the center alignment altogether.

 

[Bob Carnie]

If you are falling outside the sweet spot and getting no problems I am envious.

Then I'm in trouble, because I usually place the easel to create the most pleasing composition and ignore the center alignment altogether.

 

[RalphLambrecht]

If you are falling outside the sweet spot and getting no problems I am envious.

Bob

I might, but image composition is still more important than ultimate sharpness.

There is nothing worse than a sharp picture of a fuzzy concept.
Ansel Adams

 

[ic-racer]

What Bob said plus you then shift the negative until it matches the easel. Now the NEGATIVE is centered to the lens and you can do whatever you want with the easel.

This is my method:
I have a sheet in the easel with an X in the center and an outline of the Versalab laser such that the laser is centered over the X. I shine the laser on the front lens element and when I see the circular diffraction pattern, I know the laser is exactly under the lens and the sheet with the X in the easel is exactly under the lens. Now turn the enlarger light on without a negative carrier and I shift the light box right or left (the Omega has about one cm of play) to center it. Finally when I put the negative in the glass carrier, I fiddle with it until it is exactly centered on the paper. At this point the lens, lightbox and negative are all aligned. Now the easel can be moved at will.

I don't do any of that for small prints, as the image of the lightbox is bigger with respect to the negative and the lens coverage is bigger when doing a small print.

 

[jpberger]

Is it not also the case, especially with large colour prints, that stopping down beyond 5.6 or so will give reduced sharpness due to diffraction?

 

[Bob Carnie]

Ralph , I think you know me too well , I hate cropping and think its a method of salvaging poor camera capture.
In fact I hate cropping so much I refuse to do so for any client walking in my doors.

You have now opened another can of whoopass:munch:

Bob

I might, but image composition is still more important than ultimate sharpness.

There is nothing worse than a sharp picture of a fuzzy concept.
Ansel Adams

 

[RalphLambrecht]

What Bob said plus you then shift the negative until it matches the easel. Now the NEGATIVE is centered to the lens and you can do whatever you want with the easel. ...

That does not work with all negative holders, and I hate to 'disturb' the negative once everything is set up.

 

[RalphLambrecht]

Ralph , I think you know me too well , I hate cropping and think its a method of salvaging poor camera capture.
In fact I hate cropping so much I refuse to do so for any client walking in my doors.

You have now opened another can of whoopass:munch:

Can of worms for now, but yes.

I strongly believe in setting up a proper composition in the viewfinder, but some has to be done afterwards in the darkroom for two reasons:

1. Why ignore an opportunity for creativity and optimization?
2. My camera is not flexible enough to change the negative proportions, and who says they are the right ones for all images?

 

[msoumya60]

Marek has already answered ur questions. I would like to add that it is not advisable to stop down the lens by more than 2-3stops for 2 reasons- if there is any fungus in the lens- stopping dn will result in a softer image, secondly it may cause the negative to bend, if u have a glass less carrier. Conversely too short an exposure time makes the print difficult to control.


Over exposure + correct or under development results in flat prints. Conversely under exposure + correct/over development results in contrast prints. So u have to strike out the balance. To correctly answer the question I need to see the negative.

The greatest advantage of B/W prints is that you can control ur prints.Control the fore ground with a dodger & later increase the exposure of the back ground if necessary.