Archived posting to the Leica Users Group, 2013/11/08
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Microlenses came about since a digital sensor is not light sensitive over its whole surface. There is an insensitive wall around each pixel well. In order to avoid wasting light a layer of microlenses was added to the sensor such that most of the light impinging on the sensor was directed into the light sensitive pit of each pixel. This was a big step up for effective iso. Leica had always written that M lenses, particularly the WA lenses, were unsuited for use on digital sensors since the exit pupil of the lenses, even the retrofocus ones are nowhere near as retrofocus as SLR lenses, means that the edge rays from the lens would be shaded because of the acute angle at which the light hits the pixel well resulting in part of the pixel being shaded by the wall of the pixel well. I think if Epson hadn't come up with the RD-1 we may still never have seen a digital M. It showed that whilst not ideal, most of the lenses worked well enough to impress, even in a non-optimum situation. Leica came up with the idea of using a modified microlens layer on their version of the sensor with edge microlenses offset such that the edge rays of the WA lenses were better redirected into the pixel well. Two things seem evident to me here, please correct me if I have missed something. 1. The steep angle through the IR filter will always lead to colour shifts in some lenses which will always need to be software corrected. The microlenses don't fix that yet AFAIK. 2. These offset microlenses can only be optimum for one exit pupil distance, meaning that the sensor/microlens stack is slightly to greatly non-optimum for all other exit pupil distances. Now SLR lenses have exit pupils all over the place too, so it can't be that big a deal when the exit pupil is a long way from the sensor, but a -lot- of lenses for rangefinder cameras have their exit pupils very close to the sensor, but are not all the same. So I guess the light fall off and colour shift will always be there and will be different for each lens design (and only loosely related to focal length). The extent to which it can be software corrected will probably continue to be developed. Some lenses will probably never be all that good on a digital sensor. FD On 8 Nov, 2013, at 20:41, Richard Man <richard at richardmanphoto.com> wrote: > This indeed is the holy grail of all the M users - a simple, full frame, > digital M body. Heck, just put a tweaked A7r sensor with better microlens > for M lens in the lower cost ZM body and call it a day. > > > On Fri, Nov 8, 2013 at 12:38 PM, Scott Gregory <scottgregory at mac.com> > wrote: > >> Mark I hope that happens for you. M glass sitting around not being used is >> such a waste!! >> >> Scott >> >>> On Nov 8, 2013, at 3:06 PM, Mark Rabiner <mark at rabinergroup.com> >>> wrote: >>> >>> It turned out that layer of Microlenses was par for the course in sensor >>> design for many and most cameras way before even the M8.. The one's for >> the >>> Leica Ms were perhaps angled a bit more inward than the others but the >>> technology was there in the past and present. >>> It strikes me that other than the non micro 4/3's spec most present >> camera >>> systems have a wide in their systems that have a rear element which >> comes a >>> bit closer to the plane of focus. So its likely the edges of their micro >>> lens sensor layer have their angle turned in a bit. That's why the whole >>> layer is there. >>> I think there is hope for users such as myself looking for a simple not >>> super high end flat box (mirrorless) full frame camera for their/ my M >>> glass. >>> The idea being the bodies would not cost seven grand. >>> For sure the ideal M glass enabling solution would be a new M. but I >> think a >>> full frame mirrorless could get me out shooting with my M glass again >> with >>> results better not worse than what I'd been getting with my Nikon system. >>> And with a shooting solution which could take over my workflo. In other >>> words the camera I grab on the way out the door every day. >>> >>> >>>> On 11/7/13 10:14 AM, "Frank Filippone" <red735i at verizon.net> wrote: >>>> >>>> Bob Adler has stated that the dynamic range of the M far exceeds ( 2 >> stops?) >>>> the M9, and closely approaches his Phase 1 MF back. >>>> >>>> But back to the main discussion..... If the camera is applying >> corrections >>>> to the image, rather than a computer, aren't the same issues at play? >> To >>>> theory, yes. In practice, the microlenses take away part of the >> problem.... >>>> As Adler's shot of the Caf? shows, even at 21mm, there is some >> vignetting >>>> left, even on a M body. >>>> >>>> The sensor in the M9 ( and M8 and M) all have (M lens) tuned >> microlenses to >>>> help with the vignetting...... You will not get these in a non-Leica >> camera >>>> body. >>>> Of course, the amount of need of vignetting correction is dependent on >> your >>>> lenses... if you shoot a lot of 21mm, then it is handy that the >> microlenses >>>> are there. If you shoot at a minimum of 35mm, not so important..... >> and at >>>> 50mm and longer, not important. >>>> >>>> Personally, I do not find the vignetting issue a game killer. You can >>>> correct it. You can live with it, and for 150 years, it was not only >>>> uncorrectable, but desirable as part of the physical picture "frame". >> And >>>> again, it depends on your scene..... sometimes having the corners a bit >>>> darker is a real annoyance..... sometimes it makes not an iota of >> difference >>>> and adds to the ambience of the scene. >>>> >>>> The A7r is the camera Leica should be concerned with.... You may not >> call it >>>> a RF camera, but it represents the best of the RF camera genre..... >> Small, >>>> full featured, high resolution sensor (36MP), stealthy (? Not so sure >> yet, >>>> but the M9 is no Rollei TLR either in the noisy department), has real >>>> advantages in focus when in darkened lighting, reliable from the >> standpoint >>>> of small number of mechanical parts to go out of calibration, and best >> of >>>> all, it looks through the lens, and can use Leica (M or R) glass. If >> the >>>> focus peaking is good (jury is still out), it is a killer solution to >> the M >>>> and many DSLR cameras. >>>> >>>> Leica, if you are listening: The M Type 240 is going to have its lunch >>>> eaten because of this camera and others that will follow it. >>>> >>>> Go make an EVF only M camera. The competition is changing the >> market...... >>>> >>>> Frank Filippone >>>> Red735i at verizon.net >>>> >>>> >>>> If you needed to increase the exposure in the main part of the field by >> say >>>> two stops for every exposure and apply a colour correction you would >>>> appreciate that the correction comes at a cost of dynamic range, tonal >> depth >>>> and noise performance for example. It's happening in the corners for >> every >>>> frame with wides on the M9. Does it matter in practice??? yeah no maybe >>>> depends ;-) >>>> >>>> In the case of the M9, I can comment that the amount of correction with >>>> wider lenses is quite significant to achieve the desired result at all. >> I >>>> was a firmware tester for the system. >>>> >>>> The M is another discussion. I just recovered a few poor exposures that >> were >>>> two stops or more under (albeit minimum ISO) with excellent >>>> results...remarkable. >>>> http://www.pbase.com/hoppyman/image/153233601 >>>> >>>> >>>> >>>> >>>> >>>> >>>> _______________________________________________ >>>> Leica Users Group. >>>> See http://leica-users.org/mailman/listinfo/lug for more information >>> >>> >>> >>> >>> -- >>> Mark William Rabiner >>> Photographer >>> http://gallery.leica-users.org/v/lugalrabs/ >>> >>> >>> >>> _______________________________________________ >>> Leica Users Group. >>> See http://leica-users.org/mailman/listinfo/lug for more information >> >> _______________________________________________ >> Leica Users Group. >> See http://leica-users.org/mailman/listinfo/lug for more information >> > > > > -- > // richard <http://www.richardmanphoto.com> > // http://facebook.com/richardmanphoto > > _______________________________________________ > Leica Users Group. > See http://leica-users.org/mailman/listinfo/lug for more information