Are high end rangefinder lenses better than SLR lenses? Would I notice?

Question

I have been thinking about getting a Nikon Df, one of the factors being the reportedly excellent image quality possible. An alternative would be to get a high-end rangefinder, like the Contax G2. Ken Rockwell says that the lenses on the G2 are "far superior" to DLSR lenses:

The optics of the Contax G2 are equal or superior to Leica lenses, and far superior to Nikon or Canon lenses. Part of this is due to the Contax G2's design allowing rear lens elements to get closer to the film plane than in Leica, which allows lens designers more freedom to design better wide lenses, For example, the Contax G Zeiss 21mm f/2.8 has much less distortion than the LEICA ELMARIT-M 21mm f/2.8 ASPH, and both are much better than SLR lenses.

Is there some mechanical/physical reason why rangefinder lenses are better than DLSR lenses? Would I notice the (alleged) superiority in my photographs?

Answer 1

Would I notice the (alleged) superiority in my photographs?

If a difference exists, then possibly. The best way to notice the difference would be to take photographs with each combination of equipment under tightly controlled and standardized conditions. A well equipped lab is an ideal starting point and a test chart will make an excellent subject for determining lens superiority.

The superior photos won't be appreciably better than the unsuperior photos -- neither will be very interesting relative to most other photographic subjects because photos of test charts are objectively dull. But at least it will be possible to sleep at night due to owning technically superior equipment.

The limitation of the question is that quality is bounded to small format cameras. No "35mm" style camera is going to offer the technical potential of a medium format camera and no medium format camera is going to offer the technical potential of a large format film camera...a 4" by 5" large format film negative provides the ability to capture orders of magnitude more detail than is possible with the most expensive "35mm" lenses and bodies...even with a cheap (in camera terms) setup.

Of course, a large format film camera comes with tradeoffs that will limit the ability to capture particular subjects in particular settings. Everything in photography comes with tradeoffs and the important ones are rarely economic: e.g. waiting for or making the right light will have a more substantial impact regarding superior photographs than lens quality.

Answer 2

Your quote basically covers it... With a DLSR, you have to be able to fit the viewing mirror (that bounces the image onto the viewfinder screen) between the lens and the sensor (or film, in old film SLRs). That means that the rear lens element is some way away from the sensor/film, which means that the optical design gets complicated for short focal lengths (especially where the focal length is less than the mirror gap). With a rangefinder or mirrorless system, there's no mirror to get in the way, so you can get the rear lens element much closer.

(Historical note - there was at least one old short focal length Nikon SLR lens where you had to lock the mirror up and use a separate viewfinder because the rear element would have hit the mirror otherwise).

At longer focal lengths it's unlikely to be a major factor.

Answer 3

I do not think the Nikon Df can really be compared against Contax G2. One is a digital camera, the other a film one. Apples and oranges...

It is true that having to accommodate the moving mirror limits lens design at the wide end, but while this was true when Biogon was first introduced it was largely overcome by current designs.

I would be more concerned about resolution - the scanned 35mm film will underperform a 16 MP full frame camera - and the hassle of having to develop and scan film.

If I was looking for a rangefinder form factor and I was not decided on film camera just for the heck of it (which is a good enough reason) I would consider something like the Fuji X-Pro2, it has all the benefits of Contax G2 and more.