Sunday, 26 March 2017

Enlarging lens revisited

Recently black and white photography magazine has been celebrating it's two hundredth edition which gave me impetus to rediscover what was in some of those back issues. While thumbing through one issue, an article about enlarging lenses caught my eye, reminding me that I have been meaning to revisit the subject.

I have written a couple of small articles: Enlarging lens and which aperture  I re-read both before writing this one so as not to repeat myself. But that is not going to be easy as the main issue with enlarging lenses is quality. The rule of thumb is to choose a lens of six or more elements. The Componon-s and Rodagon are two modern designs that work very well - they are two quality makes of the few still available new.

Looking down a focus finder at F5.6- F8
In the 1970s Nikon special optics division set about producing a darkroom lens second to none ( Apo-EL-Nikkors ). It was done in a one off batch, releasing a number to the market over a ten year period until they were all gone. It has been said that at the end of this period they did consider doing another run but stopped doing so because they would have had to sell the lenses for £12,000 each. I do not know if this figure is true or not. If it is, it will have made the original runs price in the thousands and therefore out of the reach for most of us.

The enlarging lens has one job to do and that is to project the the image from the negative to the paper perfectly. The one hindrance to good enlargement method and creativity is poorly maintained or ignorantly used enlarging lens practice. It is not good enough to think if you close the lens right down, like you would a camera lens, that you will increase the sharpness of the image. The rule again is to close the lens down by two F numbers. In a lot of cases this produces the optimum sharpness. One stop more may result in a softening of the grain structure. This does not mean that you will notice a softening of sharpness with the mark one eye ball as the image is projected onto the paper. Like a lot of things in photography the kit is made to a greater quality than can be seen in normal life.

Focus finder
Enlarging lenses should not be treated as second class citizens as they are several time better in quality than the camera mounted counterparts. They do their best work in a very narrow range of magnifications. For 35mm negatives the lens is optimized to 10x its size which equates to an enlargement of 10x8. As you go up the format scale this decreases 6x6cm lenses 6x and 5x4in 4x magnification. As you push past the optimal point it increases the possibility's of grainy photographs. This is not to say you should not push beyond this point as experience has shown. You can negate this by using ultrafine film developers.

Grain at f11

How do you see which is the best apertures to use? You need to complement your lens with a good focus finder. This magnifies the grain of the negative so you can see it. The best way to use the finder is to have the enlarging lens fully open. Place the finder in the middle of the baseboard. While looking down it at the grain, adjusting the bellows until it separates into little defined specks. This will mean that you now have fine focus.

While still looking down the finder shut the lens down a stop at a time. There will be a point where the look of the grain go's slightly soft and becomes softer the more you close it down. You should remember that you are still at optimum focus. To test this you can try to adjust the sharpness in most cases it will get worse and become to difficult to regain any sharpness until you go back to the optimum aperture.

Grain at F16 looking down the focus finder.

What has been described above is my experience with one of my 35mm enlarging lens. I will point out that it is not a well known make. It is one I use often. The softening of the grain in the focus finder is not transferred to a softer looking image on the baseboard that can be detected with the naked eye but you will start to question whether it is affecting the quality of your images. The only way you will know is to borrow or buy a better quality lens and do a comparison.

When considering buying a lens you should spend as much as possible to ensure that you get a good to very good lens. Knowledge that the lens is not what you expected will impact on your photography subconsciously.