ho_co Posted January 22, 2011 Share #61 Posted January 22, 2011 Advertisement (gone after registration) ... According to Leica, they took the original optical layout and re-did the computations... I'm not sure that's correct. I think Erwin initially said it had been recomputed, and that's what I would have expected. But he recently said that it is simply the previous formula, with the rear group broken out. Link to post Share on other sites More sharing options...
Advertisement Posted January 22, 2011 Posted January 22, 2011 Hi ho_co, Take a look here 35MM SUMILUX. I'm sure you'll find what you were looking for!
01af Posted January 22, 2011 Share #62 Posted January 22, 2011 ... [1] Erwin initially said it had been recomputed ... [2] But he recently said that it is simply the previous formula, with the rear group broken out. Erwin's statement [1] is correct; statement [2] is false. Link to post Share on other sites More sharing options...
ho_co Posted January 22, 2011 Share #63 Posted January 22, 2011 Cite a source, ONEaf. Otherwise you're just repeating yourself, and that's a waste. Link to post Share on other sites More sharing options...
jaapv Posted January 22, 2011 Share #64 Posted January 22, 2011 Err.. In general it appears very difficult to me to make a design change to a lens without recomputing it... Link to post Share on other sites More sharing options...
lct Posted January 22, 2011 Share #65 Posted January 22, 2011 Cite a source, ONEaf. Otherwise you're just repeating yourself, and that's a waste. Well said Howard but what are Erwin's sources if i may ask? Link to post Share on other sites More sharing options...
jaapv Posted January 22, 2011 Share #66 Posted January 22, 2011 Erwin's sources are Leica, Solms. Link to post Share on other sites More sharing options...
Xmas Posted January 22, 2011 Share #67 Posted January 22, 2011 Advertisement (gone after registration) Erwin's sources are Leica, Solms. Hi Jaapv Jurnos can be imaginative too, trained to have both ends of their tongues move in synchronisation. I think it has been recomputed - the MTF curves are different, could be a different sample but dont think so... I know I'm a bad person but it is most likely they had to redesign, either - for glass availability, - or ease of manufacture, I know it is more expensive, see 1st phrase of this sentence. Noel Link to post Share on other sites More sharing options...
jaapv Posted January 22, 2011 Share #68 Posted January 22, 2011 Well, I would call a lens without a floating element and one with a floating element fundamentally different designs. Link to post Share on other sites More sharing options...
ho_co Posted January 22, 2011 Share #69 Posted January 22, 2011 Jaap, I totally agree. Logically, I would expect a new design. (IIRC, Mr Puts also initially said it was a totally new computation.) But remember the LFI comment on the lens (in the "What an exacting tool the M8 is because it shows up lens errors we didn't know we had" article), reporting that Leica had said, "If we were designing it today, we'd have given it a floating element." Maybe this is simply an improvement in an otherwise excellent design, though I can't imagine that 'simply' locking down the rear group would overcome the focus shift problem. I mention it because I'm stuck between what I think Erwin first said and his later comment: First sentence under "Performance in the close range" at SX35FLE, part1:Leica states that the SX35 FLE is optically identical to the previous version. Link to post Share on other sites More sharing options...
lct Posted January 22, 2011 Share #70 Posted January 22, 2011 Erwin's sources are Leica, Solms. 2 different Leicas then i guess. Link to post Share on other sites More sharing options...
jaapv Posted January 23, 2011 Share #71 Posted January 23, 2011 2 different Leicas then i guess. :confused:Erwin has very direct contacts in Solms, even got lens-design tuition from them. I suppose that answers your question from post #65 Link to post Share on other sites More sharing options...
lars_bergquist Posted January 23, 2011 Share #72 Posted January 23, 2011 Now look here. Terminology amongst photographers and optical fanciers – and self-proclaimed experts – is very fuzzy and messy. But there are general optical layouts or "designs" within which different actual lens designs are possible. Take the classical double-Gauss "design": six elements in four groups. Leica 40mm Summilux, Zeiss 50mm Planar ZM, Leica 50mm Summarit, and untold other lenses, answer to that description. Does that mean that they are all "the same lens"? No. What is the difference? It is that within that general layout, the glasses have been specified, the curvatures and element thicknesses have been computed, and also the airspaces. All those computations have different numbers in them. That means that they are different lenses, performing differently. All those computations have been performed anew for the v.2 35 'lux ASPH. Ask Herr Daniel. The statement that v.1 and v.2 is "the same lens", they have "just" broken out the rear of the lens as a floating element, reveals an utter incomprehension of the realities of lens design. It's not something that you do on the kitchen table over a cup of coffee. Any such operation does absolutely require that the whole set of computations must be done all over again. This is beyond me, its beyond you, and we all better understand this. This is not a facile trick, fit for facile comment. Also, if e.g. a lens element has to be manufactured from a different glass, this means that the whole lens has to be re-computed, even if the general layout is preserved, and even if the object just was to preserve the performance, not to change it. In that case, we are as a rule not even told about it. The lens also keeps its name and catalogue number. In this case, we were told, because anyone could see that the mount had changed, and Leica wanted to tell us (in a whisper) that the focus shift had been attended to. So yes, it is a new lens. Or if you will, "a new version", v.2. The old man from the Age of the Slipstick Link to post Share on other sites More sharing options...
roguewave Posted January 23, 2011 Share #73 Posted January 23, 2011 Hi Ben - I agree with Jaap. A lovely shot, but I'm not sure you can credit the lens (save with the fact that the focal point seems to be in front of the eyes) ... That's just not the case. The focus is dead on her eyes. I oversharpened the edge of her sweater to create an illusion. Her eyes are naturally sharp. In real life, when you look at woman, do the eyes need to be "sharp" like the new asph lenses? In a way, it's kind of creepy to me. Very unrealistic and has no mood or mystery. What's worse is that the new lens are too clean all the way to the corners. That spoils the images even more. The idea is to elicit an emotional response from the viewer, not be a copy machine. Link to post Share on other sites More sharing options...
Xmas Posted January 23, 2011 Share #74 Posted January 23, 2011 Err.. In general it appears very difficult to me to make a design change to a lens without recomputing it... True. One could change the mechanical parts of the lens to allow the rear part to move differentially when focusing. But that would not necessarily produce otimium optical performance except at the origonal position. If you are going to do a floating element the design needs to be optimised at least at several floating differentlial positions, ideally you need the design software to be aware of the floating requirement, this means you get a different design because of the new requriement, either the optical designer does it or the optimisation software does it... It is most likely Leica redesigned the lens cause they could not make the older version any more, e.g. just like the CV f/1.2 35mm, i.e. a glass type not longer available. Or they bought a new CNC machine and they can make to better tolerances, so they redesigned to allow them to make the lens cheaper - fewer rejects. The MTF of the non floating and the floating look different, since Leica only publish the MTF at infinity the type II looks like a new lens... Noel Link to post Share on other sites More sharing options...
IkarusJohn Posted January 23, 2011 Share #75 Posted January 23, 2011 That's just not the case. The focus is dead on her eyes. I oversharpened the edge of her sweater to create an illusion. Her eyes are naturally sharp. In real life, when you look at woman, do the eyes need to be "sharp" like the new asph lenses? In a way, it's kind of creepy to me. Very unrealistic and has no mood or mystery. What's worse is that the new lens are too clean all the way to the corners. That spoils the images even more. The idea is to elicit an emotional response from the viewer, not be a copy machine. Sorry Ben, that is a question of taste. I don't feel that a clean focus necessarily means clinical or sterile images. In the same way that blur gives atmosphere or a better image. Lack of clarity isn't fatal to a good picture, but I certainly don't see it as a virtue. Don't get me wrong -I'm not a pixel counter. I love the image you posted. But you posted it to illustrate the strengths of the lens. I don't see the blur on the eyes as a adding to the image at all - she is your subject. It also looked to me as if the front of the earring and the edge of her top (at neck line) are crisp. As you have the benefit of the RAW image, I accept the focal point is at her eyes. If that is true, the lens certainly isn't my cup of tea. Cheers John Link to post Share on other sites More sharing options...
ho_co Posted January 23, 2011 Share #76 Posted January 23, 2011 Lars, everything you said is clear to me and to many on the forum. A change of one part of a design (can't get the same glass, for example) requires a new computation. That's "Lens Design 101." There are at least nine of us on the forum who could have written the same explanation as you. But Puts is not sloppy about optical terms, and he says the optics are identical. Not only that, he says it's Leica who tells him so. Leica states that the SX35 FLE is optically identical to the previous version. It's unintuitive, but I think it's a bold enough statement to carry some weight. You mention Stefan Daniel. He is the best spokesman Leica has, and I have tremendous respect for him. I don't recall seeing his pronouncements on the lens, and would like to know more. But between Stefan and Erwin, I would expect a more accurate use of optical terms from the latter. Link to post Share on other sites More sharing options...
jaapv Posted January 23, 2011 Share #77 Posted January 23, 2011 I think Erwin is just a bit sloppy in his language, not unknown for him To "Break [it] out"? Using what? Hammer and chisel, crowbar? The terminology indicates the root of the misunderstanding:rolleyes: I guess he means that the basic design is the same, with a floating rear element incorporated. Link to post Share on other sites More sharing options...
ho_co Posted January 23, 2011 Share #78 Posted January 23, 2011 Sorry, Jaap, that's my term, not Erwin's, and chosen for its effrontery because I'm interested in a clarification. I agree that "simply" making the rear section of an earlier design into a fixed, floating portion of the lens without a complete recalculation sounds like pure heresy. If I said that was the case here, no one would accept it. But hearing that from Erwin Puts gives it some credibility IMHO. Link to post Share on other sites More sharing options...
ho_co Posted January 23, 2011 Share #79 Posted January 23, 2011 Jaap, Lars--you have a PM. Link to post Share on other sites More sharing options...
jaapv Posted January 24, 2011 Share #80 Posted January 24, 2011 And an interesting one too Link to post Share on other sites More sharing options...
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