Originally posted by clackers
If you think 4% of the noise pixels suddenly turn to 8%, or that stops of dynamic range are lost in the crop, I want some of what you're smoking!
I smoke the same stuff DXOMark smokes, or any sensor engineer who's ever written about the subject, or anyone who's ever bothered to crop and look at the results, FF or otherwise.
The resulting image noise is more obvious, and the image DR is reduced when the image is cropped and enlarged. That's just a fact, I'm afraid.
Nothing changes at the pixel level, which (I think) is what continues to confuse you.
I suggested before that you do the experiment yourself - crop an aps-c (or any) image at 1.5x, 2x, and 3x, look at the results on your display and in print at the same size. Is the noise more visible with each succeeding crop?
Look at the link Brianr provided. Here's
an interesting link where this is discussed, where the sensor engineer and creator of the sensorgen site tries to explain the effect, and here's another that talks about the effect on DOF:
here.
Here's Bill Claff's measured results based on raws from each sensor - the "DX" designations means 1.5x crops:
But really there are dozens or hundreds of links like that if you're interested in researching the subject.
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---------- Post added 02-10-15 at 04:14 PM ----------
Originally posted by traderdrew I've spoken to guys in a local FF Nikon click a bunch of times. One of them outright told me his D800 cropped to 1.5x has less noise than the D7000 with all factors being the same. I don't know how much less.
Not much less. You're actually hard-pressed to see any difference between a D7000 native and D800 cropped (I own D800 now and owned a D7000 for about a week.)
Quote:
What I really want to know is, since FF camera pixels are more efficient,
They're not
The pixel/sensor efficiency has everything to do with the level/age of the technology involved.
Quote: ...is is going to improve the autofocus with all other factors being equal? It seems to me all FF users prefer their FF autofocus to their crop cameras. I don't know if FF cameras simply have more expensive autofocus components or is is a litte bit of both.
There is theoretically going to be more margin for error with most FF combos lens/sensor because the act of enlargement is going to put the aps-c combo at a disadvantage, but personally I think the FF bodies tend to get better asics, more processing capability and the AF point tolerances lower and precision might be higher. The better AF system usually is folded ito the overhead and the customer pays for it happily
This is something IMO we should wish for with Pentax, BTW. Don't skimp on AF any longer, we'll gladly pay a small premium for the best AF. It's going to be a discerning factor from MILC for a while (PDAF,) lets take advantage of it.
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