Peter L Posted February 24, 2016 Share #1 Posted February 24, 2016 Advertisement (gone after registration) Hello all, back on the forum after a while, Looking at some Leica Q raw images in Iridient developer and unchecking the lens correction check box, it appeared as though the lens uncorrected image is somewhat larger with vignetting and darker corners. Although not important : is the corrected image 28mm or the lens uncorrected, just curious . Link to post Share on other sites More sharing options...
Advertisement Posted February 24, 2016 Posted February 24, 2016 Hi Peter L, Take a look here Leica Q 28mm ?. I'm sure you'll find what you were looking for!
Herve5 Posted February 24, 2016 Share #2 Posted February 24, 2016 I believe the corrected is 28mm. All raw development programs that can open the Q DNG* do show much larger images (6120x4016 pixels instead of the 6000x4000 promised) but both the raws 'imported' by Lightroom (the version offered along with the Q, that does process the image silently, also correcting the barrel on-the-fly) and the jpegs produced by the camera are cut at 6000x4000. To me the extra 100+ pixels in the larger dimension may be used by the cam for image stabilisation, autofocus, whatever but they are away from the actual 28mm FoV. One clue to this ls the dark corners you see on some images: they are the corners of the lens hood, that are entering the FoV because the 'signature' Leica hood is oriented inwards rather than outwards (probably to allow the original lens cap to still be used over the hood). These corners are cut at 28mm, but clearly when you look further away, you simply see them, like on a zoom when you deployed the hood too far. Another clue is, you see really more things than expected in this larger FoV -indeed in some pics I discover big side details that normally should be out of the field, this sometimes is fun. To the extent that, not being a Lightroom lover, I sometimes delight myself correcting barrel and reframing the result, to non-standard image sizes... H. (*) among which the FOSS RawTherapee, DarkTable and LightZone, and GraphicConverter on MacOS Link to post Share on other sites More sharing options...
Peter L Posted February 24, 2016 Author Share #3 Posted February 24, 2016 I believe the corrected is 28mm. All raw development programs that can open the Q DNG* do show much larger images (6120x4016 pixels instead of the 6000x4000 promised) but both the raws 'imported' by Lightroom (the version offered along with the Q, that does process the image silently, also correcting the barrel on-the-fly) and the jpegs produced by the camera are cut at 6000x4000. To me the extra 100+ pixels in the larger dimension may be used by the cam for image stabilisation, autofocus, whatever but they are away from the actual 28mm FoV. One clue to this ls the dark corners you see on some images: they are the corners of the lens hood, that are entering the FoV because the 'signature' Leica hood is oriented inwards rather than outwards (probably to allow the original lens cap to still be used over the hood). These corners are cut at 28mm, but clearly when you look further away, you simply see them, like on a zoom when you deployed the hood too far. Another clue is, you see really more things than expected in this larger FoV -indeed in some pics I discover big side details that normally should be out of the field, this sometimes is fun. To the extent that, not being a Lightroom lover, I sometimes delight myself correcting barrel and reframing the result, to non-standard image sizes... H. (*) among which the FOSS RawTherapee, DarkTable and LightZone, and GraphicConverter on MacOS That makes perfect sense , Thanks for the explanation Peter Link to post Share on other sites More sharing options...
marchyman Posted February 25, 2016 Share #4 Posted February 25, 2016 I believe the corrected is 28mm. Some have compared the field of view between the Q and an M with a 28mm lens and have found the Q to be slightly wider. http://www.overgaard.dk/Leica-Q-Hemingway-digital-rangefinder-.html (about half way down the page) guestimated the Q at 24mm or 26mm Link to post Share on other sites More sharing options...
mgrayson3 Posted February 25, 2016 Share #5 Posted February 25, 2016 I just did a test, and can confirm that the 28 uncropped fills a larger frame (6452x4097 for 26.4 MP) with a FoV that almost exactly matches a Canon 24-105/4 at 24mm after the latter has had corrections applied (it is also wider uncorrected). Now I can't swear that the Canon is a true 24 at the wide end, but whatever it is, it matches the uncropped Q to within 1% across the horizon at mid frame. Best, Matt Link to post Share on other sites More sharing options...
mgrayson3 Posted February 25, 2016 Share #6 Posted February 25, 2016 I did some measurements with a pano head - so not tremendously accurate, say +/- 1mm. My calculations, again this is based on horizontal FoV, give an uncorrected focal length of 25mm and a corrected focal length of 26.5mm. At this point, I'm not sure it really matters. --Matt Link to post Share on other sites More sharing options...
Herve5 Posted February 25, 2016 Share #7 Posted February 25, 2016 Advertisement (gone after registration) I just did a test, and can confirm that the 28 uncropped fills a larger frame (6452x4097 for 26.4 MP)(...) Whoaa, you manage to extract 6450 pixels! I thought my 6120 was all there was to get :-) What software are you using? Link to post Share on other sites More sharing options...
mgrayson3 Posted February 25, 2016 Share #8 Posted February 25, 2016 I use Capture One v9.0 for everything (since I don't have a Leica S ... yet ... and even then I'd find a way - I *really* like C1v9). I wouldn't take the 6452 number that seriously. It comes from turning on distortion correction, but leaving the image as uncropped as possible. That's just what C1 does to the image. Now that I have experimented more, I can get other numbers from 6000 to 6458 by clicking the crop and correct flags in different orders. I really doubt that there are many more than 6000 "real" pixels across an image. --Matt Link to post Share on other sites More sharing options...
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