I've recently seen the news about Canon's 5ds and 5dsr with their 50mp res sensors. Now I've read on some other forums that you would need some L lenses developed recently ( 5 years) or those woth mark ii versions to be able to fully resolve the full resolution.

My question is: does lens resolution really matter when it comes to real world results? (by 'real world results' I don't mean pixel peeping, but rather viewing photos at reasonable sizes maximum, like 30" enlargements) If lenses can resolve film with details, what makes it different in such a way that they cannot resolve sensors?

I've some L lenses myself, canon 135mm f2 and 35mm f1.4 but these were made in the 90s and they never had a -ii version replace them.

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    Yes. Lenses matter (you knew that). BUT decades old lenses MAY still be very good. And top new lenses are unlikely to match the 50mp body resolutions. A lens that exceeds 25mp effective performance is an exceptionally rare one indeed. Start here and work out look at various body and lens combinations. Body (sensor) can make an immense and unexpected difference. – Russell McMahon Jun 13 '15 at 8:39
  • The lens rather than the sensor seems liable to be the limiting factor here (5ds not available for comparison but 17mp max Canon EF 35mm f/1.4L ... – Russell McMahon Jun 13 '15 at 8:42
  • Liable to be of interest DxO 35mm f/1.4 multi brand comparison - do read discussion where tester interacts with users. – Russell McMahon Jun 13 '15 at 8:44

There's an obvious difference between "good" and "great" glass at 20mp, surely it's even more obvious at 50mp.

The problem is regarding resolution as some binary thing—it resolves or it doesn't.

The reality is that contrast at a given resolution is what really matters. The point at which it goes from 10% MTF* to 0% MTF—extinction resolution or maximum resolving power—is interesting if you're trying to read license plates from space.

The range at which MTF goes from 100% to 80% is a lot more interesting for "makes a damned crisp 8x10." And that range is generally at a shockingly low resolution.

Extreme resolving power seems like the less important quality of high-res sensors anyway. Avoiding aliasing/moire without degradation from low-pass filters seems far more real-world useful.

*MTF: Modulation Transfer Function... for a given frequency, how much contrast is preserved. So black bars/white space is recorded as 0%/100% at 100% MTF, but records as 10% gray/90% gray at 80% MTF.

A good discussion here: Is the camera sensor or the lens the limit to resolution?


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