smkoush Posted March 1, 2011 Share #1 Posted March 1, 2011 Advertisement (gone after registration) Hi all, I'm contemplating the purchase of a 50mm Summilux ASPH. I've been browsing at images on this side as well as other photo sides, and noticed one particular feature that stands out (to my eyes, perhaps not to others). If you look at images taken with this lens at apertures 2.8 or 4 (or thereabouts, i.e., to a lesser extent at 2 and 5.6) you notice that the aperture blades do not form a nice circle like the latest pre-ASPH one (E46). Instead, the aperture blades form a strange object that on average resembles a circle. As a result, at roughly 2.8 to 4, this shape manifests itself in the presence of background out of focus bright sources (not visible unless there is a bright source). I find the rendering of this lens very pleasing in all other aspects. This is a very subjective observation of mine, and I was wondering if other people have noticed this, and for those who use this particular lens, how often do they actually encounter it? Best regards, Savvas Link to post Share on other sites More sharing options...
Advertisement Posted March 1, 2011 Posted March 1, 2011 Hi smkoush, Take a look here 50mm Summilux ASPH aperture blades. I'm sure you'll find what you were looking for!
lct Posted March 1, 2011 Share #2 Posted March 1, 2011 Yes compared to the pre-asph 50/1.4 (2nd crop) the asph's bokeh (first crop) is generally harsher. Here at f/2.8. Doesn't make a huge difference in day to day use though. The asph remains probably the best 50 ever made. I still prefer the pre-asph for portrait though. Welcome, dear visitor! As registered member you'd see an image here… Simply register for free here – We are always happy to welcome new members! Link to post Share on other sites Simply register for free here – We are always happy to welcome new members! ' data-webShareUrl='https://www.l-camera-forum.com/topic/145320-50mm-summilux-asph-aperture-blades/?do=findComment&comment=1603051'>More sharing options...
jaapv Posted March 1, 2011 Share #3 Posted March 1, 2011 Interesting. Thanks for posting. Another thing I notice is that the better differentiation of contrast steps (more defined on the asph) contributes to the difference in bokeh. Link to post Share on other sites More sharing options...
marknorton Posted March 1, 2011 Share #4 Posted March 1, 2011 As always, excellent demonstration images from LCT. I don't much care for the shape of the aperture when the lens is moderately stopped down. I think this is further evidence that the barrel diameter of the lens is less than it ideally should have been. We know that the focussing action can be far from perfect with the need for complex close focus correction. Real-world experience is that there is significant sample variation with stiffness and backlash in the focussing action which may improve with time. It may be too that the constrained barrel diameter compared to the speed of the lens forced a compromised aperture blade design which had to provide the correct action within the limited space available - those blades have got to go somewhere when the lens is wide open. It would have been preferable to have a perfectly circular aperture, such as exists in the new Noctilux but interestingly not the older lens. Nikon know this too; during the life of the Noct Nikkor, they changed from 7 to 9 blades to improve the shape of the aperture and the bokeh in consequence. Their current f1.4 AF-S lens has a perfectly round aperture. Perhaps the next revision of the lens should be a few mm greater diameter to allow a better and more consistent (both over the life of the lens and between samples) focussing action and a perfectly round aperture. Link to post Share on other sites More sharing options...
01af Posted March 1, 2011 Share #5 Posted March 1, 2011 Instead, the aperture blades form a strange object that on average resembles a circle. As a result, at roughly 2.8 to 4, this shape manifests itself in the presence of background out of focus bright sources (not visible unless there is a bright source). [...] This is a very subjective observation of mine ... This is in no way a subjective observation of yours but a very objective fact. The "strange object" resembles a star. And it's found not only in the Summilux-M 50 Asph but in nearly all current Leica lenses—the exceptions I encountered so far include the Elmar-M 24 Asph and the Summarit-M line of lenses. I have no idea what the purpose of the star-shaped apertures is. Does anyone know? I feel they're rather ugly, and furthermore I am afraid they might increase the unwanted effects of diffraction. I like straight polygons better, and circular-shaped apertures even better still. EDIT: Mark might be right assuming it's a consequence of spatial constraints inside the lens barrel. Sounds plausible to me ... Link to post Share on other sites More sharing options...
wattsy Posted March 1, 2011 Share #6 Posted March 1, 2011 Interesting illustration from LCT. Also shows how sharpness in the close focus range is not a particular 50 ASPH strength. This accords with my experience in that the lens is bitingly sharp (almost too much so) when the subject is a few metres away or at distance, but less impressively sharp (albeit perfectly decent) up close. I guess floating elements only take you so far and that lens design is always a compromise of sorts. Link to post Share on other sites More sharing options...
lct Posted March 1, 2011 Share #7 Posted March 1, 2011 Advertisement (gone after registration) The asph (first crop) remains sharper than the pre-asph (2nd crop) at f/1.4, even at short distance (0.7m here); and the asph's bokeh is less questionable at full aperture imho. Welcome, dear visitor! As registered member you'd see an image here… Simply register for free here – We are always happy to welcome new members! Link to post Share on other sites Simply register for free here – We are always happy to welcome new members! ' data-webShareUrl='https://www.l-camera-forum.com/topic/145320-50mm-summilux-asph-aperture-blades/?do=findComment&comment=1603138'>More sharing options...
jaapv Posted March 1, 2011 Share #8 Posted March 1, 2011 So here we see what a floating element does - interesting And here contrast works to the advantage of the asph. And how DOF shrinks with magnification - at 100% it is limited by the diffraction of the sensor, not the aperture. Link to post Share on other sites More sharing options...
wattsy Posted March 1, 2011 Share #9 Posted March 1, 2011 The asph (first crop) remains sharper than the pre-asph (2nd crop) at f/1.4, even at short distance (0.7m here). Yes, that seems clear although the sharpness advantage seems to go with the non-ASPH at F2.8 (in your crops above). I guess you would need to focus bracket these shots to be sure the comparison is meaningful (at which point life seems too short). Link to post Share on other sites More sharing options...
farnz Posted March 1, 2011 Share #10 Posted March 1, 2011 The asph (first crop) remains sharper than the pre-asph (2nd crop) at f/1.4, even at short distance (0.7m here); and the asph's bokeh is less questionable at full aperture imho. LCT, With the greatest respect, I'm not sure that I agree with you. It seems to me that the pre-asph is clearly sharper at the bottom of the medallion, ie on "1935" but the asph is clearly sharper towards the top of the medallion ie on the "79280". Since the medallion is at an angle to the film/sensor plane could these differences merely be differing planes of focus? Pete. Link to post Share on other sites More sharing options...
lct Posted March 1, 2011 Share #11 Posted March 1, 2011 Both focused on "Normandie". Link to post Share on other sites More sharing options...
wattsy Posted March 1, 2011 Share #12 Posted March 1, 2011 Both focused on "Normandie". Yes, but that doesn't rule out minor differences in how each lens is calibrated for the RF. Is "Normandie" in the sharpest plane of focus for each lens. I think the only way to make sharpness comparisons is to do some tedious focus bracketing. Link to post Share on other sites More sharing options...
lct Posted March 1, 2011 Share #13 Posted March 1, 2011 Just showing those pics as representative of my modest experience with both lenses. In day to day use the asph is evidently sharper at f/1.4 at all subject distances, to me at least. Link to post Share on other sites More sharing options...
Xmas Posted March 1, 2011 Share #14 Posted March 1, 2011 Hi The aperture blades are probably for production cost, lenses are built down to a cost. And it is big enough already, I suggest get a ZM lens if you want it big. The pre-asph was designed with optical glass from the 60-61 glass catalogue the asph 04-05. The refractive index and dispersions available allow a different level of performance even without the floating elements, the aspheric surface, and a more deliberate hill climb for cost optimization. You would not expect a mini from 60 to take on a new BMW today, or Sonny Liston to take on ... The preasph has a lot more aberration including more curvature of field, so comparing off axis is apples and oranges, and the asph floating cell optimizes it for close up where the pre asph performance is a compromise. You can look at MTF diagrams, but they are typically only published at infinity. The only fair comparison for the ASPH is the Nikkon 2000 S3 f/1.4 lens in a M adapter, and it has not been designed for digital. Noel Link to post Share on other sites More sharing options...
smkoush Posted March 1, 2011 Author Share #15 Posted March 1, 2011 JCT: Thank you for the images, the crop shows exactly the shape I was referring to. If the background contained a bright source of light (e.g., Christmas lights, or something like that), then the weird shape stands out. But I agree that at 1.4, the rendering is second to none. I can see how the design of the aperture blades and mechanism can be directed by cost, but I find it surprising that they had it done fairly well before (e.g., the pre-ASPH one), so I would think it made sense to incorporate the aperture design in the new lens. But I'm sure things are much more complicated than that. Thank you for the responses. Just for fun, here are 5 scans (PanF+, scanned at 3200 dpi jpeg'ed to fit the forum's attachment constraint). They are taken with the latest pre-ASPH E46, at 1.4, 2, 2.8, 4 & 5.6. The upper right corner is where I suspect the ASPH would render those reflections with that weird shape. Best regards, Savvas Welcome, dear visitor! As registered member you'd see an image here… Simply register for free here – We are always happy to welcome new members! Link to post Share on other sites Simply register for free here – We are always happy to welcome new members! ' data-webShareUrl='https://www.l-camera-forum.com/topic/145320-50mm-summilux-asph-aperture-blades/?do=findComment&comment=1603454'>More sharing options...
Nicoleica Posted March 1, 2011 Share #16 Posted March 1, 2011 Since the medallion is at an angle to the film/sensor plane could these differences merely be differing planes of focus? I thought that the angled image was an attempt at realism, as most images that I've seen of the Normandie show it laying to one side. (Please don't take offence LCT, I believe that was a very sad ending for such a fine ship.) Link to post Share on other sites More sharing options...
Xmas Posted March 1, 2011 Share #17 Posted March 1, 2011 JCT: Thank you for the images, the crop shows exactly the shape I was referring to. If the background contained a bright source of light (e.g., Christmas lights, or something like that), then the weird shape stands out. But I agree that at 1.4, the rendering is second to none. I can see how the design of the aperture blades and mechanism can be directed by cost, but I find it surprising that they had it done fairly well before (e.g., the pre-ASPH one), so I would think it made sense to incorporate the aperture design in the new lens. But I'm sure things are much more complicated than that. Thank you for the responses. Just for fun, here are 5 scans (PanF+, scanned at 3200 dpi jpeg'ed to fit the forum's attachment constraint). They are taken with the latest pre-ASPH E46, at 1.4, 2, 2.8, 4 & 5.6. The upper right corner is where I suspect the ASPH would render those reflections with that weird shape. Best regards, Savvas They dont copy current designs if there is a saving e.g. they went to Zinc top plates & black chrome to shave a few pennies from production costs, only CNC milling has allowed them to go back to brass tops again. If they did not do value engineering the camera & lenses would be more expensive. Think the ZM lenses have more uniform iris, but they may have other problems you cannot stand. Noel Link to post Share on other sites More sharing options...
lct Posted March 1, 2011 Share #18 Posted March 1, 2011 ...Please don't take offence LCT, I believe that was a very sad ending for such a fine ship.... Yes it was indeed. Link to post Share on other sites More sharing options...
Guest #12 Posted March 2, 2011 Share #19 Posted March 2, 2011 I got both of the lenses three years ago (asph and pre-) and have posted on this several times. I should say--I actually use the 50A as main lens. But I don't find the kind of sample posted even usable. I was also disappointed by the shape in the 90 summicron. The stop is supposed to be circular--in the really old days you slid it in yourself. To me the polygons are a step backwards and the stars are just plain odd. There is the same kind of issue with square catchlights from softboxes. If the art directors don't like the squares, you know they are going to pass on the stars, too. Link to post Share on other sites More sharing options...
Guest #12 Posted March 2, 2011 Share #20 Posted March 2, 2011 To the OP--I think the last time this topic came up I asked about the 50 summicron...I think this has the circles, but I don't have the lens. The 1.4 pre has the circles and is just as sharp I think as the asph. ...maybe a little difference wide open, maybe not. If you are already bothered by the stars, it is not going to get any better after you get the lens. On the other hand, all I do is shoot around lights, and I don't get the effect very often. Link to post Share on other sites More sharing options...
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