Archived posting to the Leica Users Group, 2001/07/20
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]I would like to receive your newsletter. Thanks in advance. Roland Smith Oakland, California roland@dnai.com - ----- Original Message ----- From: "Erwin Puts" <imxputs@ision.nl> To: <leica-users@mejac.palo-alto.ca.us> Sent: Friday, July 20, 2001 10:28 AM Subject: [Leica] New Newsletter > In the past two months, while silent on the Lug (for obvious reasons), I > have produced a newsletter for a small group of people, who have a keen > interest in the optics, mechanics, engineering, secrets and use of > mechanical precision engineered 35mm camera systems. With these > afficionados I discussed topics like: a indepth test of the new Hexanon > 2/35 lens, the philosophical and ergonomical differences between the M6 > and the Hexar RF, the essence of the SLR and RF viewing systems, the > engineering arguments behind the Hexar/Leica incompatibility, the > artistic differences between Provia100, Kchrome 64, the issue of film > flatness, the concept of depth of focus, and so on. Find below an > excerpt from the latest newsletter. > If you are interested in receiving the newsletter, send me an email with > your address and topics you may wish to have discussed in the future. It > is free, no $18 fee for this service. > > > ### > Having established in previous newsletters that there is more to > Konica/Leica lens compatibility than the simple measurement of the > distance from flange to pressure plate, I did some further research, now > testing in real life with 100 ISO slide film all leica lenses from 24 to > 135mm on a calibrated M6 and a factory provided Hexar, which had the > distance from pressure plate to flange of 27.95mm, thus identical to > Leica but differing from the Konica specs. > As you recall, the Lug was very quick to some simple checks, which in my > view were done not to find the truth, but to 'prove' that nothing is > wrong. This view has been canonized in Nemeng's FAQ. > My results are different. I used a tripod, a high resolution test chart > and a measured distance of 4 meters. All Leica lenses on Leica body were > focused manually several times and the average setting on the distance > ring calculated. All lenses were within 3% of the factual distance and > the slides showed accurate focus under the microscope at the 40X > enlargement. The Leica lenses on the Konica body showed on average a > misalignent of close to 10% and that consistently over all lenses. > I did a special study of the 75mm lens, but not at the allegedly > critical setting of 1 meter (which is not that critical if you study the > shape of the curve). The 3 meter setting is more critical. I first set > the Leica body and the 75mm on the tripod etc. Made a series of pictures > and then I kept this distance setting carefully when using the lens on > the Hexar. Results (microscope) showed a loss of micro contrast, a drop > in edge sharpness and a loss of the very fine detail, including closely > spaced lines. Then I refocused the 75mm using the Hear RF system. > Results were truly bad: slides were unsharp and only the gross outlines > of the test patterns could be detected. I also used the 75mm/hexar at 1 > meter distance. Results were much more acceptable, but not really good, > but not knowing the other results could mislead you in assuming that > the focus was within range. > > I did this test three times on several days, using several films and > creating every time a new setting and so tried to eliminate any specific > bias. Of course this test is not conclusive, but it does indicate that > the Lug has been too quick to bury the subject. But as Bob Dylan used to > sing: sleep well, Mr President. > > The monster test of the BW films is underway. > I had some old rolls of Panatomic-X (20 years old), the film that > introduced high resolution acutance photography to 35mm users. I also > used the Maco UP25, 64 and 100, which are all versions of the classical > Adox high actance series of KB films. And an ortho 25, APX25, APX100 and > previous tests included PanF, TM100 and D100. > To keep it manageable I used one developer (the famous CG512) and tried > to develop to the same CI value. You need to do this as otherwise the > steeper curve of the APX25 may lead you think this film is sharper than > as example a D100, while in fact both are as sharp (seen as recording > the same information from the object) but the 25 has higher contrast so > the pictures have more punch, which could be sen as more sharpness. > All pictures were enlarged 14x. which in my view is the minimum to > differentiate meaningfully between films. > The shots were of a model in an old desolated factory, giving ample fine > details, tonal scale and resolution possibilities. > The Pan-X showed outstanding sharpness and acutance, but its grain > pattern was a bit rough but very tight. It resembled the grain pattern > of the APX100, which is a bit finer, and indeed the two films are close. > Finest details however were suppressed by the grain pattern. The tonal > scale showed quite subtle grey values, again till the threshold of the > granularity noise. The whole atmosphere is an image of very pleasing > tonality, gritty sharpness and details painted with broad strokes. > The UP100 (Adox KB21) has surprisingly fine grain, but on inspection the > grain is clumpier but the edge sharpness is low so the fineness is > bought at the expense of definition. Overall quality is still > commendable and while not up to todays standards, in its day it > certainly was a winner. The Pan-X and KB21 images indicate the > progress realized in 20 years of emulsion technology. In itself of > amazing quality, these films lag in all significant areas when compared > to todays super stars. But the differences are on the other hand more > evolutionary that revolution. > The APX100 gives images that suit the reportage style of location > photography very well. These images have a fine realistic imprint: some > what gritty, but with a smooth tonality and sufficient fine detail to > make the scene interesting. > The APX25 has a higher inherent contrast and so small details are > recorded somewhat more forcefully. Grain is absent, which adds a creamy > tonality to the scene, but on close inspection the recording > capabilities are just a small edge compared to the APX100 or PanX. The > finer grain does record the faintest shades of grey values, which adds > to the 3D impression of the scene. > The UP25 (KB14) is very close to the APX25. Grain is slightly more > pronounced, but much less so than PAnX or APX100. The tonal scale is > identical to the APX25. The intriguing characteristic of this older thin > layered, thick silvered emulsion is the edgy grain clumps, which, being > very fine, also roughen up the image structure. It makes the picture > very lively and especially for model photography and architectural > photography adds an effect that can be described as underscoring the > main story. > Compared to the PanF as example the KB14 is definitely less smooth and > its finer details lack the stark micro contrast of the PanF, but all > said, this film is a worthy emulsion, that deserves a try. On a normal > viewing distance, the main subjects literally jump from the picture. > The Ortho25 is a trouvaille: I had some films and asked myself: why not? > In the same setting, the prints proved excellent. The skin of the model > came out very realistic and I did not notice any strange grey values. f > course there was no red in he scene, so all other gray values are more > or less 'natural". Sharpness is excellent and grain very fine. The film > has a clear base and so looks very contrasty, even if the values are > close to normal. Not a film for every topic, but I am inclined to use it > more often and when using some filters can even add some additional > tonal scale. > Definitely a film to try and use for portraits, glamour etc. Take care > of red of course. But more versatile than mostly thought of. > > As a preliminary conclusion I have to say that the UP25 and Ortho 25 are > very potent films with a potential for intriguing results that need to > be explored. They are not as good as current top performers, but the > distance from a TP as example is less than often imagined. So it is as > easy to note that there is hardly any progress in BW emulsions in the > last decades or to state that we have advanced a big stride to deliver > superior results. > > If you habitually use enlargements below 10X, the difference are even > smaller. > > The lesson: try more film than you use now: it will add to your toolkit > and visual awareness. > > Next: > the PanF, D100, TM100, D400 (new). > > > Erwin > > > > > >