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 p.10 #19 · Voigtlander 35mm f/2 APO-Lanthar Review | |
tsdevine wrote:
Not saying the corners are perfect wide open, but I won't be shooting wide open where corner performance is critical. This was handheld using Fred's quick and dirty test. These are 100% crops. Not 100% sure which corner is which.
Plan to test more throroughly later.
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https://www.devine.photography/img/s/v-10/p2341556574.jpg |
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https://www.devine.photography/img/s/v-10/p2341556544.jpg |
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Out of curiosity, how many lenses to you find absolutely perfect in all regards, and do you find one lens manufacturer better than others?
Thanks for the corner crops Tim, very informative. Beautiful pictures of Longwood Gardens too!
That's a really good question. My standards for general daytime landscape is very different from astro. I find both my Canon 24-70 f/2.8 II and 70-200 f/4 IS II adapted to my a7R II to be just fine, even though neither is anything near perfect. The 24-70 is pretty crooked and has horrific field curvature from ~35mm onwards and quite soft at 70mm, and is progressively more tilted and swung towards the tele end. Noticeably decentered also. My 70-200 has over 100 microns of swing which varies across the zoom range, so it needed a compromise shimming adjustment. I typically use them stopped down a lot. F11 or 16 is not unusual. I'm happy enough with them, though I would be happier if Sony made a GM 24-70 II that matches or exceeds the 24-70 Z (both F4 and 2.8 are outstanding, and I don't mind either). I also have a set of seven Pentax 645 A lenses to use with my Mirex tilt-shift adapter and none are perfect wide open, but I don't care and always use them stopped down.
The quest to acquire a kit for astro was something else entirely, and it taught me about all kinds of things I never cared for previously. I'm looking for fast-ish prime lenses with low distortion, low field curvature, good PSF rendering off-axis, low LoCA, low vignetting and high resolution all by f/2.8, shouldn't be too large and heavy if possible (a tall order when wanting a fast lens) and should have a very nice manual focus feel. The optical behaviour of the lens must be as radially symmetrical as possible. I decided early on that I wasn't interested in shooting at f/1.2 or 1.4 for the stars. And I don't care at all for AF and don't have enough experience to make useful comments. I don't require weather sealing either.
I don't have much experience with Nikon at all or Canon RF (I'm more familiar with EF lenses). The Z lenses seem to be pretty alright but the by-wire focus feel is dreadful. Plus the Sony system has better prime lenses in all the focal lengths that matter to me. Roger Cicala holds Sigma and Canon in very high regard with regards to consistency, but my own experience has not inspired the same confidence. It depends. On average, I would say they are good and I'm just unlucky. Samyang/Rokinon and the newer Chinese lens companies are less consistent for sure. Cosina definitely stands out among the lens makers as a company I trust. Zeiss picked them to make their Otus lenses after all. Several of the newer Sony releases seem very good (GM50, GM35, GM12-24 etc.), but I don't own any Sony glass yet.
I studied Otus lenses and samples (28, 55, 85) of them for some time while shopping for my own kit, and eventually decided they are far too heavy and expensive and all suffered from poor PSF rendering off-axis. Many Sigma lenses seemed just as good for 1/3 or less of the price (28 1.4, 50 1.4, 40 1.4, 85 1.4), but still large and heavy. Many of those copies were rejected early on because of swing and tilt, before Joseph Holmes discovered that the sensor of these Sony cameras are crooked relative to the bayonet mount, and later we figured out how to shim the lenses in addition to the camera, increasing the otherwise-few-and-far-between number of good copies we can select from.
I also looked at the Leica SL APO lenses, because their MTFs are so beautiful. They are not small or light for what they are and if I were paying those prices, they had better be perfect, but they are not. The 35mm, which is supposed to be the best of the bunch, has awful coma and astigmatism. The PSF rendering gets awful pretty quick as you move off-axis. The 50mm is easily matched by the CV50.
The 35mm focal length family is most vital to me for wide-field astro work (stitching to get a wider field of view rather than use a 24 or 20 or 18 or 14mm lens, none of which I've found to be good enough), but for a long time none seemed to be good enough. The Sigma 35 1.2 changed that. I lucked out and got a great copy on my first try but I really don't like the size and weight. The modest field curvature requires compromise focus for everything to be in focus at F2.8. Field curvature is a nasty problem for astro work. If we could stop down to f/5.6 life would be significantly easier. I've also got the CV 65 and 50 Apo-Lanthar lenses, both were great on the first copy, though I've since looked at 5 more 50mms, because my copy has some asymmetric astigmatism, not unlike your CV35 but much, much less severe. All were very good, with little faults only a maniac would find that made it difficult to say if one copy of the species is better than another, but I still could tell the behaviour of individual copies apart with careful looking. I can live with mine quite happily, it doesn't affect my stars in an obvious way. Both my CV50 and 65 needed correction for tilt and swing adjustments but I no longer consider this a lens defect if I can DIY this. The Cosina A-L lenses have redefined what a great lens is to me, at prices that would still be a screaming deal if they were doubled.
Going by how good actual copies of the CV50 is, its published (measured I gather, not theoretical) MTF, and the CV35's own data, a good copy of the CV 35 should be just as amazing. These are "perfect" lenses to me, I don't need any more. Maybe the falloff could be a bit less for both, but then they will get larger and heavier. They are good enough. Little optical jewels! I'm pretty desperate to get a great copy of the CV35 and complete my kit for good. Shopping for lenses to do this is such a pain.
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