Archived posting to the Leica Users Group, 2000/02/11
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]At 11:12 PM +0100 2/10/00, Stephen Holloway wrote: >Mark Rutledge wrote: >> >> >>N**** and C**** use lens elements in their digital bodies to correct the >> field of view so that the smaller format area of the CCD sensor shows the >> same field of view as what a photograpgher is used to with their 35mm SLRs. >> In other words without the corrective lens elements a normal 50mm lens would >> turn into a small telephoto. << >> >> John, >> Is this a new thing for the digital SLR? I seem to remember the N90/Kodak >> digital camera didn't compensate for the CCD/Film size discrepancy,. There >> was actually a rectangle inscribed on the screen that showed the "new" image >> area of the CCD. >> Is this what you mean, or have I been out of the digital loop too long? >> Thanks, >> Mark Rutledge > >None of the current 35mm-bodied digitals (such as the D1) use corrective >elements. Nikon did make such a camera, but it wasn't so hot. The frame >size is effectively a crop from the center of the 35mm frame. So >effective focal length is changed (something like x1.5 for the current >generation). The D1 viewfinder just shows this smaller area. > >I've no idea whether film lenses aren't suitable for CCDs (but I'm a bit >of a skeptic) but the D1 gives pretty nice images. A CCD with the same >pixel density and 35mm size would be very welcome (especially in an >M6!). Lenses for high performance digital cameras _NEED_ chromatically highly corrected lenses. The problem is one of color fringing. On analog material (film) the color fringing spreads softly from the principal element. With a digital sensor, the one color can be on one pixel, and another color on a different pixel. Truly ugly. Therefore the high end digital cameras, such as those from Sinar, use APO lenses even for relatively short focal lengths, and are horrendously expensive. A strange thing to say on a Leica list, but true. Another thing to remember is that today's high end camera/sensor array will be tomorrow's point and shoot. Lens design will have to hit new heights, at affordable prices. Some of Leica's recent lenses will be fine with tomorrow's sensors, but not many of the older ones. The Nikon D1 is quite decent, and the new Fuji Pro camera seems like it will be even better (as far as picture quality/price is concerned). As these cameras generally have a sensor size which is equivalent to 1/2 frame or so, they only use the center of the lens' imaging ability, which is usually better. As the sensors reach into the corners, and the pixel density goes up, more problems will crop up. Jim Brick is the guy on the list who would probably know this stuff the best (but I, of course, don't hesitate to jump in even at the partial information level ;-)) * Henning J. Wulff /|\ Wulff Photography & Design /###\ mailto:henningw@archiphoto.com |[ ]| http://www.archiphoto.com