Archived posting to the Leica Users Group, 2002/08/27
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]All... Here is the Babel Fish translation of Nathan's letter. Regards, /Mitch _____________________________________ Mitch Zeissler E-mail: zeissler@directvinternet.com ++++++++++++++++++++++++++++++ Hello, I presuppose once that answers of the Leica are AG also for the peep de of interest. Therefore I take the liberty to give these here again. On my request, how now the technical connections are to be seen for the use of the Leica objectives by means of foreign adapters at digital housing (Canon D60 e.g.), I received the following Anwort: At the beginning of quotation: Dear Mr. Bindels, Zuallererst agree we you that digital M or R would make a camera sense, because you (the customer) could use your present objectives for the new system. On the other hand we (the manufacturer) could sell the new product to a group of consumers already existing. For these reasons this idea was examined intensively with Leica. Unfortunately we came to the result that a digital m-camera with the present conditions of the CCD or CMOS technology is not possible. For this some notes: A large advantage of the m-camera-system consists of the fact that the objectives possess a short cut width (no mirror between film/catch and the Hinterlinse). That makes the objectives very compact and bright. Due to these characteristics the rays of light meet the film in a flat angle. Mirror reflex objectives possess a larger cut width (larger distance between the rear lens and the film/catch to accommodate around the mirror). The rays of light meet therefore in a rectangular or nearly rectangular (telecentric) angle the film. If a film is exposed, the cut width is insignificant for the achievement. If a digital sensor is used instead of a film, there are one large-differentiated: 1. In order to protect the sensor, a protecting glass and a filter (anti aliasing, IR) before the sensor are arranged. These filters and protecting glasses would cause an additional and unwanted refraction, if the rays of light on the sensor in a not-rectangular angle fall. The optical achievement becomes so bad to the edge that the pictures would become useless. 2. In order to increase the luminous sensivity of the sensor, micro lenses are arranged, in order to collect more lights before the individual pixels. This causes vignettierung with objectives with short cut width (m-objectives) (darken corners). This are the main effects, which show that the whole system would bring only an unsatisfactory achievement. For these and other reasons we had to give this idea up at the current time. As soon as a new sensor technology is present, Leica will continue the efforts around a digital m-camera. The above-mentioned problems arise with SLR objectives less. The distance between film/catch and rear lens must be larger because of the mirror, which are rays of light nearly telecentrically and can therefore for digital applications are used. Possibilities for a digital r-camera are at present examined. Yours sincerely Attila of Gyimes end quotation Who has other and large knowledge in addition, I would be grateful to that for an addition. MfG Johannes johannes@bindels.de Well light! - -- To unsubscribe, see http://mejac.palo-alto.ca.us/leica-users/unsub.html