lct Posted June 2, 2015 Share #41  Posted June 2, 2015 Advertisement (gone after registration) What "zone B dip" is if i may ask? Never got focus shift on my 35/2 asph BTW. Link to post Share on other sites More sharing options...
Advertisement Posted June 2, 2015 Posted June 2, 2015 Hi lct, Take a look here Leica / Zeiss: Who is better?. I'm sure you'll find what you were looking for!
algrove Posted June 2, 2015 Share #42 Â Posted June 2, 2015 Zeiss has the best 85mm and Leica has the best 90mm. You all know why. Link to post Share on other sites More sharing options...
edwardkaraa Posted June 2, 2015 Share #43 Â Posted June 2, 2015 What "zone B dip" is if i may ask? Never got focus shift on my 35/2 asph BTW. If you divide the image circle into 3 zones, A being the central one and C the peripheral one, you will notice that many M lenses have a drop in resolution in zone B. You can see it clearly in Leica 's published MTF and is often caused by field curvature. Link to post Share on other sites More sharing options...
lct Posted June 2, 2015 Share #44 Â Posted June 2, 2015 Always glad to learn new things thank you. Do you perceive that drop in practice really? Link to post Share on other sites More sharing options...
jaapv Posted June 2, 2015 Share #45 Â Posted June 2, 2015 It may well be caused by a wavy plane of focus. In that case it will have little impact on photographing most three-dimensional subjects. Link to post Share on other sites More sharing options...
edwardkaraa Posted June 2, 2015 Share #46  Posted June 2, 2015 It may well be caused by a wavy plane of focus. In that case it will have little impact on photographing most three-dimensional subjects.  AKA field curvature  The effect will be quite visible if you:  Focus and recompose as is usual with an M camera. Shoot more than 1 person standing side by side. (However if you let someone stand a bit behind he will be in focus ) Link to post Share on other sites More sharing options...
edwardkaraa Posted June 2, 2015 Share #47 Â Posted June 2, 2015 Advertisement (gone after registration) Always glad to learn new things thank you. Do you perceive that drop in practice really? Â It is most visible with Lux lenses due to the thin DOF. Forum fellows on FM have often mentioned they find it next to impossible to focus and recompose with the 50 lux for instance. I guess the effect is milder with the cron, or by stopping down (though some have reported with the 50 lux specifically the field curvature actually gets worse by stopping down to f/4-5.6). Link to post Share on other sites More sharing options...
hiepphotog Posted June 2, 2015 Share #48 Â Posted June 2, 2015 Despite what most would believe, field curvature can't be completely resolved by stopping down in some lenses. Wavy field curvature can create confusion to the viewers with sharp and un-sharp elements showing up on the same plane; a simple group picture would show. From my first hand experience, the 50 Lux ASPH still has noticeable field curvature even at f/8 and f/11. Once you notice it, it's hard to not seeing it. Definitely not good for landscape purpose. Now whether it's important for one's photographic vision is beside the point. Nonetheless, I think Karbe is moving toward a more even tempered design. The Lux 28 has the among the flattest MTF curves in all the Luxes, even more so than the Lux 35. The 50 APO is the epitome of this. It beats both the Otii in term of flatness of field in trade for the absolute sharpness. Link to post Share on other sites More sharing options...
lct Posted June 2, 2015 Share #49  Posted June 2, 2015 Forum fellows on FM have often mentioned they find it next to impossible to focus and recompose with the 50 lux for instance...  My requirement level must be lower than theirs then. Just shot this snap to make sure. Focus on "Michelin". M240, 50/1.4 asph, f/1.4, 0.7m, handheld. Good enough for me.  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!  Full size: http://tinyurl.com/npjf822 (12MB file) Link to post Share on other sites Simply register for free here – We are always happy to welcome new members!  Full size: http://tinyurl.com/npjf822 (12MB file) ' data-webShareUrl='https://www.l-camera-forum.com/topic/245753-leica-zeiss-who-is-better/?do=findComment&comment=2826411'>More sharing options...
edwardkaraa Posted June 2, 2015 Share #50  Posted June 2, 2015 My requirement level must be lower than theirs then. Just shot this snap to make sure. Focus on "Michelin". M240, 50/1.4 asph, f/1.4, 0.7m, handheld. Good enough for me.  M2409098_web.jpg  Full size: http://tinyurl.com/npjf822 (12MB file) Field curvature is not always bad. Sometimes it allows to get some elements in focus that otherwise would be oof with a more planar design. However unless you really know the lens behavior it will result in hit and miss shots. Link to post Share on other sites More sharing options...
lct Posted June 2, 2015 Share #51 Â Posted June 2, 2015 Could you show a pic with obvious field curvature out of the 50/1.4 asph? Just curious. Link to post Share on other sites More sharing options...
pgk Posted June 2, 2015 Share #52  Posted June 2, 2015 From my first hand experience, the 50 Lux ASPH still has noticeable field curvature even at f/8 and f/11. Once you notice it, it's hard to not seeing it. Definitely not good for landscape purpose. Well I've never noticed it. An mine is absolutely fine for landscapes. If you want real flat field lenses best buy copy lenses, but then again they are usually corrected for specific distances. In practice the 50 Lux aspheric is a fabulous lens and I have no complaints.  Funny the newbie who made the OP seems to have gone very quiet .....Hmmmm! Link to post Share on other sites More sharing options...
hiepphotog Posted June 2, 2015 Share #53 Â Posted June 2, 2015 Could you show a pic with obvious field curvature out of the 50/1.4 asph? Just curious. I guess I have too much free time . Here is the MTF of the Lux 50 ASPH (obviously for infinity focus): Â There is the mid-zone dip on the left and right of the 10mm mark. Here is the picture taken at infinity at f/1.4. I superimposed four different circles corresponding to the 5mm (red), 10mm (blue), 15mm (greem), and 18mm (yellow-edge) from the center. Â Here is the zoom crop of the zone of interest (left and right of the 10mm mark). I can clearly see the drop-off in resolution around the mark and the sharp areas left and right of that. The three trucks right at the 10mm mark experienced a severe drop-off and become a haze. Â Â This kind of behavior interferes with subject placement. In this case, the subject in the foreground would be sharper than the subject in the plane of focus. Link to post Share on other sites More sharing options...
hiepphotog Posted June 2, 2015 Share #54 Â Posted June 2, 2015 Well I've never noticed it. An mine is absolutely fine for landscapes. If you want real flat field lenses best buy copy lenses, but then again they are usually corrected for specific distances. In practice the 50 Lux aspheric is a fabulous lens and I have no complaints. Â Funny the newbie who made the OP seems to have gone very quiet .....Hmmmm! I admit I had to look for it and did a controlled comparison with a known flat field lens to see the drop-off. In my case, as shown in the picture above, the building with the four top vents can never get really sharp at any aperture. Stopping down does help flattening out the field curvature a bit but astigmatism comes into play. Test like this would clearly show how much better the 50 APO really is compared to the Lux 50, both WO and stopping down. Link to post Share on other sites More sharing options...
k-hawinkler Posted June 2, 2015 Share #55  Posted June 2, 2015 I can't help with the 50 mm lenses. But I vividly remember field curvature in this example of the WATE by http://www.3d-kraft.com/index.php?option=com_content&view=article&id=148:ultra-wide-angle-m-mount-lenses-on-sony-a7r&catid=40:camerasandlenses&Itemid=2 and this image. https://www.flickr.com/photos/hhackbarth/11036232333/sizes/o/  <script src="safari-extension://com.ebay.safari.myebaymanager-QYHMMGCMJR/2ddacf13/background/helpers/prefilterHelper.js" type="text/javascript"> </script> Link to post Share on other sites More sharing options...
pgk Posted June 2, 2015 Share #56 Â Posted June 2, 2015 I admit I had to look for it and did a controlled comparison with a known flat field lens to see the drop-off. In my case, as shown in the picture above, the building with the four top vents can never get really sharp at any aperture. Stopping down does help flattening out the field curvature a bit but astigmatism comes into play. Test like this would clearly show how much better the 50 APO really is compared to the Lux 50, both WO and stopping down. Well I've rarely shot real world images wide open at infinity (but as it happens I have) and on the rare occasions when I have, I've never noticed any curvature (and have had the images published so 'fit for purpose'). If you can't get the building sharp at any aperture then I'd say that your lens needs checking - of course it depend what you call sharp I suppose. And the APO really cannot be 'better' than the LUX simply because one has f/1.4 and one doesn't and I've never seen the point of compering different beasts as such comparisons are merely a simplification. Link to post Share on other sites More sharing options...
Peter Kilmister Posted June 2, 2015 Share #57 Â Posted June 2, 2015 Am I the only one who is completely baffled by all this? Link to post Share on other sites More sharing options...
hiepphotog Posted June 2, 2015 Share #58 Â Posted June 2, 2015 Well I've rarely shot real world images wide open at infinity (but as it happens I have) and on the rare occasions when I have, I've never noticed any curvature (and have had the images published so 'fit for purpose'). If you can't get the building sharp at any aperture then I'd say that your lens needs checking - of course it depend what you call sharp I suppose. And the APO really cannot be 'better' than the LUX simply because one has f/1.4 and one doesn't and I've never seen the point of compering different beasts as such comparisons are merely a simplification. Paul, I thought we were discussing about the technical aspect of this. The Lux 50 ASPH is more than capable to fulfill all of my artistic needs. Heck, before this lens, I was shooting with a vintage 55/1.2 that was nowhere as good as the Lux 50 ASPH at wide open and barely got ahead stopping down to f/8. But to base on this ground is often subjective. One can be contend with his Lux 50 Pre-ASPH without seeing the need for the ASPH version. Technically though, the ASPH should be head and shoulder above its predecessor. And so often time, people compare the Lux 50 ASPH against the Noctilux 0.95 or the Cron 50 APO, not because they share the same max aperture or even in signature draw. What I have seen is that most tend to believe that the 50 APO is not much sharper than the Lux 50, especially stopping down when everything becomes a wash. I do beg to differ. Even on an optical bench that spits out these MTF charts, the APO shows much flatter curves compared to the Lux 50. It's there if you look for it. As I focus mainly on landscape and I want to keep my kit at the minimum (i.e. one lens for one focal), the APO is clearly superior than the Lux 50 ASPH as an all around lens. Technically, it's definitely better than the Lux, even if it doesn't have that f/1.4. Link to post Share on other sites More sharing options...
pgk Posted June 2, 2015 Share #59 Â Posted June 2, 2015 But to base on this ground is often subjective. Actually the word I would use is not subjective but realistic, Enough said. Link to post Share on other sites More sharing options...
basse Posted June 2, 2015 Share #60  Posted June 2, 2015 Am I the only one who is completely baffled by all this? It´s cool, isn´t it?   Link to post Share on other sites More sharing options...
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