I am kind of picky about focus but this enlarger really does need a tune up. It's pretty old and I am, at minimum, its third owner. I got it from my uncle who bought it from somebody else. The thing just needs to be cleaned up. I have spent a lot of time doing just that. This is one of the final steps, getting it all aligned correctly.
Working in movie theaters kind of makes me picky about focus but I know perfection has its limits. The lens, the film gate, the lamphouse, the screen and the film, itself, all contribute to how well you can get a picture to focus. You can tinker for a long time and never get the picture 100% perfect no matter how much you try. The machine just has its limits and there is also a point where extra effort stops paying off. For all the work you do, you will only make a small improvement over what you have already achieved. There comes a time when you just have to say, "Good enough!"
The SMPTE test film I am using was contact printed from a glass negative on a pin-registered film duplicating machine. I'm sure it is as good as can be had. (It had better be! The stuff costs $180 for 50 ft of it! $3.60/ft.)
I have tried three different lenses. I have a Componon ƒ-4.5 which came with the enlarger when I got it. It's okay but it's old and it's seen better days. I also borrowed an El-Nikkor and a Componon-S ƒ-2.8. They are much better. I have been using the Componon-S to make my adjustments with but I'd be hard-pressed to tell the difference between it and the Nikkor in a blind A/B test. I am planning to buy a new lens for myself, after I return the borrowed lenses to their owner. That, I figure will cover the optics end of the problem.
The negative holder is probably the last avenue of attack I plan to take. Right now, I have the standard, glassless negative holder that came with the enlarger. Yes, I know that the film can buckle and warp inside the enlarger. (It peeves me off to no end!
) For now, I have been sticking negatives down with non-residual film tape. I align the film in the gate and tape one end down. Then I pull the film taut and tape the other end down. It's as good as I can do for now. I plan to get a glass negative carrier as soon as I can find a good one that doesn't cost an arm and a leg.
As it stands, right now, I have "acceptable" results.
I have the enlarger cranked all the way up to make an 11x14 print. As I understand, that's about the limit of what this lens can do with 35mm film, anyway. As I crank it down to make 8x10 or 4x5 things will become less and less critical. Right?
With the lens all the way open to ƒ-2.8 you have to squint to see the difference in focus, edge-to-edge or top-to-bottom, unless you are using the grain focuser. Using the "scope" you can tell the difference pretty quickly. If you fiddle with the focus knob you can find a good middle ground where everything is acceptably sharp.
If I keep the lens stopped down to smaller than ƒ-8, I can get the image sharp all over, even at 11x14. If I stop all the way down to ƒ-16, the image appears tack sharp all over. (i.e. We're taking advantage of the lens's depth of field at small apertures.)
So, if I'm making an 11x14 print, if I don't mind having a two minute exposure time, I suppose I can stop the lens way down. Right?
At this point, I think I'm going to lock down all the settings and call it, "good enough." I've been working on this thing, on and off, for nearly a week. Without a glass negative holder, I don't think I can do any better than I already have.
Besides, I have an Omega D-II sitting on the bench waiting for a good tuneup!
I'm going through this process as well with D-2.
Something I never hear people talk about (and not mentioned in service manual either) and I am concerned as well is.... the enlarger head height. I'm finding, the higher the head I make it, more sag I experience which affects front to back alignment. I'm adding thickness to the baseboard to mitigate this. But is there a standard on what height I use? Minimum, maximum, middle, or most used? I think, it's far more critical to get film and lens parallelism correctly than that of with baseboard because of depth of focus issue, but as long as I'm at it, I would like to do it correctly.
Also, assuming one is not using APO lens, is it really reasonable to expect edge to edge sharpness as an end result?
Adding to this thread as it is related to OP's concerns.
tkamiya, By all means, do jump in. Aligning enlargers is the overall point of this topic. Right?
By the way, as far as I understand, alignment of the head to the baseboard is not as critical as alignment between the lens and film plane. Yes, it is important. When aligning an enlarger, getting everything plumb to start with is important but you have a few millimeters of play in either direction. Within the head, itself, you only have a few microns worth of play.
Example:
Film is somewhere between 130µm and 150µm thick. Let's call it 140µm. So, depending on film, you might have .140mm of leeway to get your focus sharp.
If you are using a 50mm lens to make an 8x10 print from a 35mm negative there should be somewhere in the neighborhood of 1.4mm worth of play at the baseboard. If you crank the head up to make an 11x14 print from the same negative, you will have just a hair more than 2mm worth of play at the baseboard.
So, if you use a regular spirit level that's more than enough accuracy to make the head-to-baseboard adjustments. However, when you go up to the enlarger head, you're talking about distances of just a few microns. Adjustments which might be invisible to the naked eye might very well throw the whole thing out of kilter!
