Archived posting to the Leica Users Group, 2003/04/26
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]There's one huge problem with this new "standard," even if one assumes that it's a fabulous idea from an engineering standpoint - the partners are Kodak, Fuji and Olympus, and only one of them manufacturers lenses. AND, there are far too many pros heavily invested in Canon and Nikon to think that the pro world is going to dump all its gear to go for the "new standard." Now, if Olympus and its partners can figure out how, through the use of adapters, to allow Nikon and Canon lenses to be used with the new Olympus body and other 4/3 bodies, it could work - but otherwise...? - -----Original Message----- From: owner-leica-users@mejac.palo-alto.ca.us [mailto:owner-leica-users@mejac.palo-alto.ca.us] On Behalf Of Frank Dernie Sent: Saturday, April 26, 2003 7:11 AM To: leica-users@mejac.palo-alto.ca.us Subject: [Leica] Digital slightly OT If Olympus are right, and their statement in http://www.four-thirds.com/index_01.htm seems plausible to me, maximising the performance of a digital sensor may require hardware redesign. If the depth of the chip filter sandwich is significant rays impinging on the sensor at an angle will always have a different effect to those impinging normal to the sensor. This will obviously be most severe the nearer the rearmost lens element is to the sensor, making M lenses less suitable than R for digital work. At first I thought it would be worst in the corners and for lenses with small diameter rear elements because in this case none of the rays impinge normal to the sensor. In fact however large rear elements will suffer also because whilst some corner rays may impinge almost normally the diagonally opposite rays will come from the opposite side of a large rear element at a large angle of incidence. Erwin has lectured us on the incompatibility of the Hexar RF with Leica lenses due to a possible (depending on individual tolerance buildup) of the film to flange distance. The error he considers unacceptable is a max of 0,09mm (0.0035") in the worst case. His Leica acceptable error is 0,05mm (0.002). I hope I am not misinterpreting in assuming from this that unless the effective thickness of the sensor/filter sandwich is considerably less than this Leica M lenses can not achieve their potential. Clearly this problem is more significant the larger the sensor. Olympus propose their new E system standard with a smaller chip and bigger lens throat with lenses designed for parallel rays at the sensor (as they say they do in their E10 and E20 digital cameras). I have 2 questions. 1. If this is the case how can "parallel" rays ever be in focus at the sensor surface? 2. If not is there an optimum sensor size beyond which the reduction in performance in the corners due to optical and sensor thickness effects is more than the benefit of sensor size? I obviously have not got enough to occupy me this morning! frank - -- To unsubscribe, see http://mejac.palo-alto.ca.us/leica-users/unsub.html - -- To unsubscribe, see http://mejac.palo-alto.ca.us/leica-users/unsub.html