Mechanische camera's

Kijk op het fotografisch universum door Erwin Puts

Testing 28 mm lenses

Wittgenstein noted that noting is so difficult as not deceiving yourself. He obviously referred to his ideas that perception is a process that can and will easily be controlled by what we know. (in Wittgenstein’s philosophy knowing is located in the use of language and we never know anything about things but can only discuss and perceive facts). Photography has indeed a strong relation to facts because the photograph can only show what is the case. Artistic intentions notwithstanding, a photograph does not show the intentions of the photographer, only a copy of the light reflections from a surface. What we see however is different from what there is.
This discrepancy has been a problem for reviewers of lenses, because it is very difficult to separate between what is there and what is assumed to be there, based on some previously acquired knowledge. When it is ‘common knowledge’ that Leica lenses are the best one can buy, it is difficult to look at the results without this knowledge in mind. That is why comparisons between lenses is often required to neutralise the observer’s bias. Or one should use neutral measurement procedures.
Recently I have acquired the new test chart from Image Engineering to complement my usual procedures. A limiting factor of all these test charts is the distance between the camera and the chart. It is between one and two meters, a distance for which most lenses are not designed. The classical test proposed by G. Crawley, is an alternative: take a picture from a brick wall at a certain distance and move away from that position in incremental steps and notice when the detail structure of the bricks starts to break down. A laborious procedure, but more insightful than a single landscape picture.
I am explaining this because I will start a lengthy test procedure with the new Summaron 5.6/28, the current compact Elmarit 2.8/28 and the current 1.4/28.
I will test the lenses on the MM-2 and on film. For the film I have selected the Ilford XP2 Super, a very fine grained emulsion with an extended dynamic range,
I am very curious about the results.