enricosavazzi Posted June 4, 2019 Share Posted June 4, 2019 I retired in February 2019 and moved to Valdemarsvik, a Swedish village at the end of a fjord on the Baltic Sea. This is a rather tame fjord compared to Norwegian ones, but nonetheless the only true fjord on the East coast of Sweden. We might be moving away in a few months if my wife decides to take a new job, so I decided to stop postponing landscape photography before I miss my chance. First a VIS landscape: An unusually clear UV landscape with full-spectrum Sony A7 II, CoastalOpt 60 mm and Baader U: Then I put on a Pentax Super Takumar 28 mm f/3.5 (3rd variant) with 750 nm NIR-pass filter. The picture is stripped of color in post-processing: The ominous black cloud visible in the NIR picture turned into an approaching thunderstorm and I had to pack up the photo equipment and head home. I arrived home just in time to avoid a torrential rain. I managed to take a couple quick UV shots with the Super Takumar, but results are quite fuzzy. I will have to try again to see if it was a focusing problem, or the lens is unsuitable for UV imaging. Link to comment
enricosavazzi Posted June 5, 2019 Author Share Posted June 5, 2019 Continued: I went back to the lookout point today, and got much better UV shots with the Super Takumar 28 mm f/3.5. The problem was indeed focusing. The only reliable way to focus in UV with the Alpha 7 II is by using the maximum live view magnification with the lens fully open, then stop down (to f/8 for the test pictures below). Other methods are simply not reliable with this camera. As usual I shot hand-held at ISO 800 and 1600 with exposure times between 1/60 and 1/20 s. Results were quite similar at both ISO settings. Straight from camera with rear-mounted Baader U, same custom color balance as pictures with the CoastalOpt 60 mm in the preceding post. The image is almost completely monochromatic, indicating that UV transmission of this lens drops sharply below about 380 nm. Same picture, desaturated and with tweaked contrast and luminosity: So this lens is usable if the 380-400 nm band is sufficient. It is not the sharpest UV lens, but sharp enough for a 28 mm lens produced between 1966 and 1971. Link to comment
Andy Perrin Posted June 5, 2019 Share Posted June 5, 2019 I love the CoastalOpt/Baader U photo in the top three. Link to comment
enricosavazzi Posted June 5, 2019 Author Share Posted June 5, 2019 I love the CoastalOpt/Baader U photo in the top three.The CoastalOpt 60 mm Apo and the UV Nikkor 105 mm are pretty much alone in their class. One cannot go wrong with either, or both. One (well known) problem that makes our choice among legacy lenses more difficult is that, within several brands, wideangles of the same focal length and speed have often been made and re-made in multiple variants using different optics. The Super Takumar 28 mm f/3.5 in M42 mount, for example, has been made in four variants that use two wildly different optical schemes (potentially different in their performance in UV imaging). This limits the usefulness of lists of lenses like the ones in our UV lenses sticky, since the information in this list is often insufficient to make sure which of the variants of a lens model has actually been found to be usable. Pictures of the actual tested lenses would help, together with information (when available) on how to tell the different variants apart. I am beginning to test a small number of legacy 28 mm and 24 mm lenses for full-frame, some already in the sticky list, others not, but I don't expect miracles. Another problem I am having, for example, is that the Enna Lithagon, Ultra-Lithagon and Super-Lithagon 28 mm f/3.5 and 24 mm f/4 are available in a variety of different barrels, but I have found no information on their optical schemes. They might be optically the same, or they might be different. Link to comment
rfcurry Posted June 6, 2019 Share Posted June 6, 2019 Enrico, From lensvademecum: "Lithagon f4.0 24mm auto or preset. 7g/7c.Ultra Lithagon f3.5 28mm auto or preset 6g/6c En001.Photokina 1956. This was noted as a novelty in MCM Jan 1957.Lithagon f3.5 35mm preset 4g/4c En002.Lithagon f2.8 35mm auto or preset. 6g/5c. This seems to be new in Dec 1959." Note: The vademecum uses g/c - glass/component - instead of the more familiar element/group. Link to comment
enricosavazzi Posted June 6, 2019 Author Share Posted June 6, 2019 I am actually waiting for delivery of a Lithagon 24 f/4 and Lithagon 28 f/3.5 to test. The Ultra Lithagon 28 f/3.5 is on my list if other lenses are not satisfactory. A Super Takumar 28 f/3.5 variant 1 is also on its way. It uses a very different optical scheme than the variant 3 I just tested. 35 mm f/3.5 is an easy focal length today, with multiple good choices available. Link to comment
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