Choosing medium format lenses - what's in a name?

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My main interest is in folding cameras and the Rollei TLR range. One of the recurring questions that I am asked when I place cameras for sale on eBay takes the form: “I am interested in a folding camera for use. Which lens would you recommend?”

Those who has been engaged in photography for some years will appreciate that such a question is difficult to answer, and perhaps the following quotes from leading authorities on the subject form a good starting point to explain why.

“Camera lenses vary considerably in their ability to render fine detail sharply on the film or plate. Not only do they vary from type to type but individual lenses of the same make and type…can be very different in their performance, one from the other. One can find, for instance, a comparatively poor lens with the name Zeiss Tessar on it, or an exceptionally good Victar, but of course the better the reputation of the lens, the greater is the chance of finding a good one.” (“Pearlman on Print Quality” - Alec Pearlman.)

“…cameras with front-cell focusing, even high-quality Zeiss cameras, were rarely set to a true infinity focus even when fresh from the factory, and having the infinity focus set accurately is likely greatly to improve image sharpness.” “…the Zeiss Novar, … despite being a three-element lens, can produce first-class results if the focus is correctly set, and yields results indistinguishable from those of the more expensive Tessar in photographs taken in the middle aperture range, between f/8 and f/16. (“Collecting and Using Classic Cameras” - Ivor Matanle). This book by Britain’s leading authority on classic cameras should be on every photographer’s bookshelf. It is a mine of useful information.

“Up to apertures of about f/5.6 the use of a Tessar construction is somewhat of a luxury. Beyond about f/4.5 the Tessar construction used to be preferred for the higher standard of definition afforded. (“Optics, the Technique of Definition” - Arthur Cox).

As most folding cameras are equipped with three-glass or four-glass lenses, the above quotes are relevant, and they show that it is almost impossible to state with any certainty that one lens is better than another. However, in my experience over many years of using dozens of folders and twin lens reflexes as an amateur and as a freelance, almost all the lenses produced by the major manufacturers are capable of remarkably good results - provided they are in good condition and housed in a well designed and sound mechanism that has been used by a careful and caring owner. Very few of the folding cameras that I have bought have had damaged lenses, and that may be due to the fact that, in the case of folding cameras, the lens is fully protected when the camera is closed. The greatest enemy of the lens the over-zealous owner who is constantly wiping the front element with any old bit of cloth that happens to be handy. Such action invariably produces a myriad of fine scratches and a lens with such damage is useless. Light striking the lens is scattered in all directions and produces a fuzzy, low contrast and useless image.

Some time ago I sold an Agfa Isolette with a three-glass Apotar lens. The buyer tested it under identical conditions against a top Japanese medium format SLR with a six-glass objective. The resulting 15in x 12in prints were almost impossible to separate. Close examination of fine detail in the extreme corners of the prints revealed which print had been produced by the Apotar and which by the SLR, but even then there was very little in it.

Similarly, an article in Photographica World magazine in which a contributor tested several Agfa Silette cameras with 3.5 Apotar against a similar number of Voigtlander Vito cameras with Color-Skopar showed that the Apotar was superior in many respects, most notably in terms of colour rendering. Those results show that reputations or a large number of elements in a lens are no absolute guarantee of excellence.

My experience with Schneider lenses shows that they are all excellent, and, more importantly in the context of the quote from Alec Pearlman, consistent. I have used many Retina cameras with the Xenar or Xenon lenses and all of them produced top-class results. The same applies to the Xenar fitted to the Rolleicord, of which I have used several over many years. Unfortunately not many folding roll film cameras were equipped with Schneider lenses, and we are generally confined to the Novar, Apotar, Vaskar, Meritar, Tessar, Solinar, Xpres, Ensar lenses. Incidentally, the Ensar should not be overlooked.  For many years it was the Houghton Ross Ensign standard lens and it is capable of outstanding results. In my experience it is almost the equal of the Xpres and better than the later Rosstar.

In terms of the statement by Mr Matanle that many lenses were not correctly set to infinity focus, even in the factory, it is worth considering the following. The 75mm lens on a Rolleicord or on any medium format camera with a similar helical focusing lens, moves forward about 8mm to cover a focusing range from infinity to about 3 ft. But in a folding camera with front-cell focusing, the front cell has a forward movement of about 1mm in focusing from infinity to 3ft. Within that tiny range of movement there is a wide range of distance settings, and it follows that if the lens is not accurately set to infinity, it will be inaccurate at closer settings as well.

When time allows, I test with film all cameras that I offer for sale, and in about eight out of 10, the focus is incorrectly set. Moreover, setting infinity focus with ground glass at the film plane does not allow for the fact that film is flexible and may and usually does bow slightly inwards. I read on the internet, but cannot confirm, that for setting the focus on Rollei cameras before they left the factory, Franke and Heidecke used at the film plane a screen with a slight inward bow to allow for such film movement. It should also be remembered that folding cameras are about 50 years old and when they were made, film base was much thicker than it is now and was less likely to bow.

As I have said, medium format folding cameras are at least 50 years old. With Gauthier shutters (Prontor-S, SV and SVS) that almost always means a shutter service. Rangefinders are invariably inaccurate and need to be adjusted. If the matters that I have mentioned are not attended to, the best lens ever designed will not produce optimum results.

An important factor to bear in mind is that many lenses are condemned for poor definition when the real culprit is camera shake. Fast shutter speeds are no guarantee of a pin sharp negative. By all means use the fastest speed possible for hand held shots, but where circumstances permit, use some form of support. A good tripod is the obvious choice, but a monopod is an excellent alternative. A table top tripod with a ball and socket head, capable of being carried in the pocket or gadget bag, can also be used by pressing it sideways against a tree or wall. An efficient, cheap and eminently portable support is a length of chandelier chain, chrome or brass, to which a suitable tripod bush screw is fitted. The screw is fastened to the camera’s tripod bush and the other end of the chain is trapped under the foot so that it is taut when the camera is lifted to the eye or, in the case of a TLR, to waist level. The upward pull on the chain holds the camera remarkably steady.

I hope to add a further guide to buying and using medium format cameras.

 

 

 

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