D9X

Started Dec 29, 2008 | Discussions thread
MirceaR
Regular MemberPosts: 234
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Re: Boomp...
In reply to bobn2, Jan 6, 2009

Almost any decent lens is (nearly if not perfectly) well corrected (i.e. the only limit in performance is the diffraction limit at that particular f/stop) at some f/stop, or at some combination(s) of f/stop and focal length(s) when we're dealing with zoom lenses.

While this is nice, only a few (dozens that is if we're talking about all the lens models ever manufactured for all the 135/APS (D)SLRs) 'select' lense models manage to be almost perfectly optically corrected at a broad range of f/stops. Some of those are/were moderately priced( below 500$), but most of them aren't (1k$+)

Of course, the lower count of megapixels, the larger that range is, if no other optical abberations start to show.

It takes excellent (read $) glass, serious QC (a little more $) and nearly perfect mechanics (more $) - more so when we're dealing with zoom lenses - to achieve that.

If one wants to wrap one's photo around the entire leaning tower of Pisa and have the tourists view it from 4 inches away and be amazed at the quality of the image, sure, 50-60-80+ megapixels on a 35mm FF would pro'lly do it - together with the > exquisite

bobn2 wrote:

MirceaR wrote:

Between the 'real image' and the sensor lies the lens.
Which in the (very very very expensive) end is diffraction limited.
Physics, eh...

Physics indeed, do you know how 'diffraction limiting' works?

Sure, any major manufacturer can cram 50-60-70 megapixels into a 35mm
FF sensor, but that doesn't mean squat.

Depends what 'not squat' means, but if it means 'could give you the
opportunity if used properly to significantly improve the quality of
your images' then your statement is broadly correct.

There won't be any photo lens to resolve them dozens of megapixels.
Yes, there are lenses (primes and zooms) used in cinematography that
can brilliantly resolve the 35mm FF equivalent of 24 megapixels and
even more, almost regardless of f/stops and focal length, but they're
priced into the tenths of thousands of $.

Interestingly, even some quite low cost lenses will outresolve todays
24MP FF cameras and 15MP 1.6x crop cameras (38MP FF equivalent)

Marketing doesn't care (or know) about physics, and at the same time
physics doesn't care about marketing or megapixels.

Yes, but physicists know their physics, and according to the physics,
there are some real benefits to be had from increasing pixel density.

-- hide signature --

Bob

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