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.  

The Focus finder.

This is a wonderfully simple piece of darkroom equipment. Basicly it is a magnifying glass and mirror. It provides the user with the optimum sharpness for the enlargement by focusing on the grain of the negative. 

Also known as a grain magnifier it rests on the masking frame where it diverts a small amount of light from the projected negative to your eye as you look through the small magnifying lens. With one hand on the focusing control of the enlarger you gently turn the knob until the grain becomes sharp in the mirror. This translates to a sharp image at easel level; to maintain this accuracy a piece of waste photographic paper should be placed in the masking frame with the magnifier on top. It is easiest to focus on the grain with the enlarging lens set at its widest aperture and then re-checked at the working aperture. To make sure that the focus has not changed. 

Some focus finders can only be used in the central area of the projected image. This is because the angle of the light is more severe at the edges and corners. If you wish to check these areas to make sure that the whole negative is in focus you will need a magnifier that allows for this with a wider mirror and tilting aim.

Focusing. Soft prints why!

Ilford FP4+, Iso 125, developed in ID11
Printed on Ilford paper

There are reasons for your photographs to be out of focus. If we assume that the negative was sharp when it was exposed, it could be if you are using a glassless negative carrier that the negative may have popped and requires refocusing. Another cause is vibration, you need to make sure that you are not knocking the enlarger when you are exposing. If the enlarger is mounted on an uneven surface or rickety table this will not help nor will living near a main road with lots of heavy traffic.

If when looking at the photograph it looks  blurred, it has not been focused properly. You can cure this by using a focusing negative. To make one you need a negative of no value as you will have to scratch the emulsion in several places. It is simply a case of placing this negative in the enlarger and focusing until the scratches are razor sharp. Alternatively you can use a special focuser.

FP4+ developed in PMK Pyro method update

Zero camera, FP4+ developed
in PMK Pyro

The first permanent change is to go from two inversions every twenty seconds to one every fifteen seconds which is a reduction of two per minute. When I did this I wasn't sure if this would make the density of the negative less, as it turns out it has increased it, making for better toned prints. My conclusion is by decreasing the time between each inversion the developer in contact with the film surface is fresher for longer hence the increase in density. 

Zero Camera  FP4+ developed in PMK Pyro
Pelham bridge road Lincoln

I have also used an after-bath  (only with 120 FP4+) which does change the colour of the film base and seems to make them easier to print and at a softer grade. It has been suggested that the bath can reduce the sharpness of the negatives. Is this reduction noticeable? That's an answer you will have to find for yourselves as  I have only been using it so far with the film that's been exposed with the Zero pinhole camera, which is not known for it's ultra-sharp negative production. I will not be introducing it across the range of other makes of film I develop in PMK. I'm happy with the fine toned negatives it produces and see no reason to add the bath. 

Zero Camera FP4+ developed in PMK Pyro

Those of us who like to go against the mainstream will use it for creative or pictorial purposes but you need to be sure that the grain is sharp across the negative, it may add that extra something you are looking for to the final photograph.









Related posts:

PMK Pyro after-bath
PMK Pyro developer part B
PMK Pyro working solution