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nickchew
03-16-2005, 11:09
Hi
I was wondering if you digital RD1 guys could help me with a nagging question I have.

With a CCD that is smaller than a 35mm film, the RD1 and most DSLRs have a 1.5x factor. While it is a pain for wide angle lenses, the plus side is that the pic excludes the periphery of the picture where optical resolutions are usually poorer.

Does it equate then, that digital cameras like the RD1 and DSLRs have a higher tolerance for poorer lenses than film cameras?

Since most modern lenses are very decent in the centre of the picture, does it follow that DSLRs / RD1 would do just as well with modern cheaper lenses 3rd party lenses like tamron/sigma?


:confused:

Thanks

Nick

Pherdinand
03-16-2005, 11:40
Nick... The idea is, IF there's a large difference between centre and edge quality, cropping digital sensors will help indeed. That's why manufacturers started to advertize lenses as "optimized for digital bodies" which is, in fact, saying that "at the edge it sucks but that you won't use anyway".
With old, full-frame-designed lenses, there's no real gain, since you could cut the middle of a negative and achieve the same effect...

As to the last paragraph, plenty of 3rd party lenses are good or better than the big ones, especially if you talk about the cheaper or middle category. Take as example, the tamron 90/2.8 SP macro lens. Reputedly better in resolution (and that's important at a macro lens!!!) than its expensive brother from canon. Or, the tokina at-x line, like the 17mm superwides and mid-range f/2.8 zooms - at least as good as the big name manufacturers' correspondents, at half price or less.

Sean Reid
03-16-2005, 14:35
Hi Nick,

I'm afraid there's no free lunch. Good digital cameras like the R-D1 can show the differences between various lenses quite clearly. Examples:
http://www.luminous-landscape.com/reviews/lenses/rd-1-lens.shtml

Lenses can indeed be optimized for digital capture. It isn't just *necessarily* a case of making a lens with strong center performance. A "designed for digital" lens will present the light to the sensor at less acute angles near the outside of the image circle. It can also address other issues (chrom. ab. included).

Cheers,

Sean

pfogle
03-17-2005, 02:12
Sean, 'there's no free lunch' reminds me of a quote by Allan Guth (inventor of the inflating universe version of big-bang theory) - "whaddya mean there's no free lunch? The whole universe is a free luch!" ;)