Tariq Gibran
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 Re: Zeiss Loxia line | |
retrofocus wrote:
Tariq Gibran wrote:
Steve Spencer wrote:
edwardkaraa wrote:
philber wrote:
I beg to differ with the learned members above. The RX-1 proves how good a lens designed for a specific camera can be when Zeiss get involved (I am not sure if it is a Zeiss or a Sony-Zeiss lens). The Touit 12 shows how good a Zeiss lens can be even when designed for a very touchy camera (the NEX 7). The Sony-Zeiss FE 55 shows how good a lens can be for the A7 camera, even though I don\'t care much for it and will put mine up for sale tomorrow. My guess is that the Loxia will show that (a) Sony don\'t mis-design senor covers and glass toppings to the point that even forum members look like experts in comparison (no offence meant, yuo guys have forgotten more in a day than I\'ve leanred in a year), and (b) Zeiss know how to take those parameters into account.
Simply put, their 50 Loxia must outperform the FE 55, or Zeiss will look like complete fools, which is not their custom. Considering how many people thing highly of that lens, the Loxia should be interesting, to say the least. Forget the theory and glass toppings, they are not members of FM anyhow...:-)
I think you\'re over estimating Sony, Philippe. We have seen a lot of stupid decisions in the past, decisions that crippled their output unnecessarily and lost them a lot of clients. The decision to add the glass thickness goes back to the A700 and A900. All UWA are completely screwed by this decision. No Sony or Zeiss wide performs correctly in the image periphery. The decision to remove the mirror and replace it with a translucent one that stays in the optical path cost them their DSLR user base, including myself and many others on this forum. Even with perfect lenses like the FE55 you can see the weird effects of the sensor stack in the image periphery especially on highlights and blur discs. I guess we AA less camera users like the Leica M are spoiled because we are used to the benefits of a thin stack so we get sensitive when we see unnecessary image degradation caused by some stupid engineer at Sony. Add to that the lossy raw compression and no uncompressed format, the mirror like surface causing flare and ghosts everywhere... etc. As for the b part, I have no doubt whatsoever about Zeiss abilities, but the sensor stack will inevitably put many restrictions on the lens design, size and weight that need not be there in the 1st place.
Edward, I think you are right about some of the dumb choice Sony has made (e.g., the translucent mirror in the DSLR \"upgrade\"), but I don\'t think the sensor stack is quite as bad as you make it out to be. As I understand the issue from Roger Cicala\'s excellent analysis with Brian Caldwell and several others, the issues is not as simple as thin stacks are good and thick stacks are bad. That is basically true if we are talking about lenses designed from film cameras. One important point to keep in mind is that it is worse the shorter the exit pupil. So for film lenses, the problems of the sensor stack are reduced if the sensor stack is thin and the exit pupil is long.
Leica which has to deal with a lot of legacy lenses designed for film, when they started making digital cameras smartly made the sensor stack as thin as they could. This was especially important for them because many of these legacy lenses had very short exit pupils. One thing that Leica has also done, however, is that as they have come out with new lenses since going digital it is pretty clear they have lengthened the exit pupil.
Now if I understand Roger and Brian\'s analysis, however, if you design the lenses for the sensor stack a thick stack does not need to cause problems. I suspect the 55FE is a little under designed to handle the sensor stack fully. I expect, however, these new Loxia lenses to be fully designed to handle the stack, which incidentally won\'t make them bad candidates for any other possible mirror less formats. Almost all FF cameras and APS-C cameras too (other than Leica), have about a 2mm sensor stack according to Roger\'s tear down, and the one clear exception is an interesting one (earlier Canon 1 series cameras that had to deal with a lot more lenses designed for film). So, I don\'t think the sensor stack will completely ruin these cameras. They will work fine for lenses designed for the sensor and although the lens won\'t quite react optimally even older lenses with a long enough exit pupil will still do quite well especially at narrower apertures. The problems are worse at wider apertures as well as one might expect.
I think the question is more intersting put this way - what are the benefits/ advantages of having a thick sensor stack? We know the disadvantages - and I tend to agree with Edward on those. One possibility is simply cost, maybe versatility of application. The other, which Leica has shown in the past , is proper IR filtering. Others?
I woudn\'t be surprised if it is the same sensor stack as now being used also in the D810 DSLR. Simply for cost savings in the sensor production, it might be easier to have the same sensor sourced out both for mirrorless and DSLR cameras. For DSLR lenses the thicker stack doesn\'t seem to be an issue. Possible that the drawbacks especially with some wide angle rangefinder lenses weren\'t considered as being worthwhile to make a separate sensor production line with a thinner stack.
Yes, that\'s exactly what I was thinking. I do suspect there is even a performance hit with even SLR wides with the thick stack off axis though.
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