Guest EarlBurrellPhoto Posted October 9, 2009 Share #21 Posted October 9, 2009 Advertisement (gone after registration) I haven't tested it on film but I've been told there's quite a bit of luminance vignetting. Are you sure you haven't seen that? Cheers, Sean Oh, sure there is some on film. Not as much as someone close to me said there is on his M9 though. Link to post Share on other sites More sharing options...
Advertisement Posted October 9, 2009 Posted October 9, 2009 Hi Guest EarlBurrellPhoto, Take a look here Cv 15mm Versus Leica 18mm. I'm sure you'll find what you were looking for!
tashley Posted October 9, 2009 Author Share #22 Posted October 9, 2009 I will shoot with Dietmar's elegant and simple solution over the next day or so. I will also shoot through a Lens Cast Calibration perspex sheet directly into a well diffused flash source, which will eliminate the need for white wall shots. I am directly in touch with the Leica engineers and will let them have my results, as well as posting them here. T Link to post Share on other sites More sharing options...
sandymc Posted October 9, 2009 Share #23 Posted October 9, 2009 Tim, If you could shoot the sheet both coded and uncoded it would allow us to distinguish between what the lens is doing and what the correction is doing. Regards, Sandy Link to post Share on other sites More sharing options...
tashley Posted October 9, 2009 Author Share #24 Posted October 9, 2009 Tim, If you could shoot the sheet both coded and uncoded it would allow us to distinguish between what the lens is doing and what the correction is doing. Regards, Sandy Will do! Link to post Share on other sites More sharing options...
sean_reid Posted October 9, 2009 Share #25 Posted October 9, 2009 Or simply by turning the camera for 180 degrees - and you will find the red-drift again on the left side (camerawise); but now on the right side of the scene. Cheers, Dietmar That's a good idea if one has the right tripod to do it. Cheers, Sean Link to post Share on other sites More sharing options...
dietmarpaul Posted October 9, 2009 Share #26 Posted October 9, 2009 ... if one has the right tripod to do it. You're right, that may be a problem. On the other hand, the asymmetric red-drift with the CV12/CV15 - and even with Leica wides, in the cases it occurs - is enough pronounced, that with every handheld test one will confirm the issue. Cheers, Dietmar Link to post Share on other sites More sharing options...
tashley Posted October 10, 2009 Author Share #27 Posted October 10, 2009 Advertisement (gone after registration) These were all shot using at close range through a thick, pure white perspex diffusing sheet (usually used for LCC corrections with Medium Format digi backs when mounted on technical cameras) pointed at a 2 metre wide Bowens Wafer light box powered by a Bowens flash. The camera was about two feet from the front of the softbox and was focussed at infinity throughout. Shutter speed was 1/180th throughout on the M9 and a Gitzo CF tripod with Arca cube were used, along with a cable release and a remote flash trigger. The file names tell the story of what aperture and orientations were used for each shot, as well as how each lens was identified to the camera body. The final two shots were underexposed by one and then two stops so as to see if that had any real impact, though that was only at F11 so there may be other effects at other F stops. NOTE: the files are reduced to 80% quality JPEGS and 2000 pixels on the long side. They are in the ProPhoto (rather than SRGB) colour space so they might look odd on your monitor - in other words they are intended to be downloaded and looked at in the software of your choice so you can check colour casts with an eye dropper. Right-click on any file to download the 2000 pixel wide version to play with. All files were developed from RAW in LR using defaults and with WB set to Flash. It is pretty clear to me that the Auto setting gives the cleanest file with very few colour shifts, mostly subtly in the blue, green and cyan parts of the spectrum rather than the 'red on the left hand side' type. What do other people think? Zenfolio | Tim Ashley | Leica 18mm Super Elmar ps the one shot I forgot to do was Uncoded. Sorry! Will try to run one off soon. Link to post Share on other sites More sharing options...
hoppyman Posted October 10, 2009 Share #28 Posted October 10, 2009 I think this is a very informative discussion. May I suggest a control series if possible to distinguish between what are lens characterictics and those from the M9 itself? Specifically can a film M be shot iunder the same conditions for comparison? Link to post Share on other sites More sharing options...
chrism Posted October 11, 2009 Share #29 Posted October 11, 2009 I'mm seeing the left side colour cast with the CV15 as well. Could examples of this lens have their optical axis slightly canted to the right due to an eccentricity in the manufacturing/polishing process? Cornerfix doesn't seem to be able to do much with it. Chris Link to post Share on other sites More sharing options...
sean_reid Posted October 11, 2009 Share #30 Posted October 11, 2009 I'mm seeing the left side colour cast with the CV15 as well. Could examples of this lens have their optical axis slightly canted to the right due to an eccentricity in the manufacturing/polishing process? Cornerfix doesn't seem to be able to do much with it. Chris Hi Chris, People seem to be reporting this behavior with various lenses. Cheers, Sean Link to post Share on other sites More sharing options...
sandymc Posted October 11, 2009 Share #31 Posted October 11, 2009 I'mm seeing the left side colour cast with the CV15 as well. Could examples of this lens have their optical axis slightly canted to the right due to an eccentricity in the manufacturing/polishing process? Cornerfix doesn't seem to be able to do much with it. Chris Chris, Is the CV15 coded or uncoded, and if so, as what? Sandy Link to post Share on other sites More sharing options...
dspeltz Posted October 11, 2009 Share #32 Posted October 11, 2009 Which viewfinder are you using for the 18? I have the WAT as well and the 18 is tiny and a terrific lens. I like them both but when I go ultralight the 18 is the choice. But the large WAT viewfinder needs a small brother at this point. Link to post Share on other sites More sharing options...
tashley Posted October 11, 2009 Author Share #33 Posted October 11, 2009 Which viewfinder are you using for the 18? I have the WAT as well and the 18 is tiny and a terrific lens. I like them both but when I go ultralight the 18 is the choice. But the large WAT viewfinder needs a small brother at this point. I use a CV 15 viewfinder - or, more often, I just use my eye and guess! Link to post Share on other sites More sharing options...
Shootist Posted October 11, 2009 Share #34 Posted October 11, 2009 Thanks for this thread. I have been considering the CV 15 M-mount for use on my M8 and for a ultra wide on my future, very future, M9 but after reading this thread, and the one about the Zeiss 21/25 f/2.8, I think I'll skip this lens altogether and when and if I ever can afford a M9 I'll try my CV 21 f/4 M-mount lens on it and then make the decision whether to sell or keep it and or get the Zeiss 21 f/2.8 or the 25 f/2.8. Link to post Share on other sites More sharing options...
chrism Posted October 11, 2009 Share #35 Posted October 11, 2009 Chris, Is the CV15 coded or uncoded, and if so, as what? Sandy Coded (via Millich adaptor) as a WATE 16mm. Chris Link to post Share on other sites More sharing options...
dspeltz Posted October 11, 2009 Share #36 Posted October 11, 2009 I use a CV 15 viewfinder - or, more often, I just use my eye and guess! I use the 15 cv viewfinder as well, and sometimes the 21. But you are right, it is a guess, but does not matter much since the lens gulps in so much real estate and chimping can tell us immediately if we need adjustments (landscape). With people, guesses are usually just fine. Link to post Share on other sites More sharing options...
sandymc Posted October 12, 2009 Share #37 Posted October 12, 2009 Coded (via Millich adaptor) as a WATE 16mm. Chris Chris, It is starting to look as if coding the CV's may cause more problems than it solves. Can you try the lens uncoded with CornerFix? If you can, I'd like to see the two reference images - the coded one and the uncoded one. Sandy Link to post Share on other sites More sharing options...
reven Posted October 12, 2009 Share #38 Posted October 12, 2009 I'm little surprised that it took so long for people to notice. I have seen it in quite a few 18mm, wate and 21 images that the M9 is not doing a great job correcting the cyan drift. Or should I say to good. I mean WHAT did Leica expect, that there one lenses are all the same and that a generic correction will work ? Certainly not. There is a reason you shoot ColorCast files on MFDB on a Large format camera. There is also a reason you can't use one LLC profile for different 35 Schneider lenses. The only real solution I see, is something like a LLC profile generation for DNG files. However, I fear Phase won't open that up and Leica perhaps if we are lucky will be able to supply something like that with a M10. A different solution is to buy a lens, try it and bring it back to your dealer. Do this until you find one that works well with the M9. The dealer won't be happy, but I wouldn't care about it. Link to post Share on other sites More sharing options...
sandymc Posted October 12, 2009 Share #39 Posted October 12, 2009 IThe only real solution I see, is something like a LLC profile generation for DNG files. However, I fear Phase won't open that up and Leica perhaps if we are lucky will be able to supply something like that with a M10. An LLC profile is technically no different to what CornerFix does, so I don't think what we have here is a lack of tools for post processing, although CornerFix might need further tweaking for the M9. E.g., it might be necessary to add compensation for optical de-centering. However, the problem right now is that we don't fully understand what the M9 is doing. Most of the issues right now appear to be related to the M9's internal corrections - we just don't understand (yet) why we get overcompensation (the red corners/edges) in some cases. But various people are working on it; if Tim is able to do an uncoded test with his rig that should tell us a lot. Sandy Link to post Share on other sites More sharing options...
UliWer Posted October 12, 2009 Share #40 Posted October 12, 2009 Please take into account, that the "red shift" is not an issue of the M9 alone! It is as well visible - perhaps even more - with the 3.8/18 Super-Elmar on the M8. I think Leica has to tweak the in camera correction for this lens - perhaps for the WATE as well - in both cameras to avoid overcorrection of cyan shift. Link to post Share on other sites More sharing options...
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