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Post by Eric Patdu on Apr 1, 2009 19:09:53 GMT
While reading about how the APS-C sensors can "extend" the lens' effective zoom range by cropping the image thrown by the lenses, a question popped in my mind. To clarify, I've created the image below similar to what I saw on the site explaining the sensor sizes.  From the image, I am assuming that APS-C cameras can take a sharper "full-frame" photo than a full-frame camera. Of course, the full-frame camera can take a bigger slice of the entire scene but my point is, it is a given fact that lenses are usually "soft" at the edges and sharp at the center. So, if the APS-C crops the edges, then does it mean that the "full-frame" shot of an APS-C is sharp to the edges as compared to a "full-frame" shot of a full-frame sensor? I hope my question is clear.  |
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Post by ppaaoolloo on Apr 1, 2009 19:33:11 GMT
You are right about the corner sharpness/resolution. Your assumption is also supported by most lens MTF charts.
Corner sharpness/resolution suffers more often with zooms and less noticeable on primes.
IMO corner sharpness/resolution is not as important as most people would think as subjects are framed a good distance away from the frame edge. ALso with the trend towards OOF/bokeh it doesnt really become such an issue unless you stop down to take a group or landscape shot.
The thing with smaller sensors is that they do not produce as good IQ as larger sensors.
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Post by Teddy Regpala on Apr 4, 2009 6:34:07 GMT
Assuming:
- same lens is used. A lens sharp in the middle, but soft outside
- sensors have the same pixel density
Comparison of full image:
- APS-C sensor produces a sharper image from edge-to-edge, only because it cropped the edges, as compared to the full-frames image
But:
- the middle portion of the full frame image is sharp as well, exactly the same as the APS-C sensor image
Therefore:
- APS-C cameras doesn't really take sharper image.
From the assumption above, change the lens that's super sharp to the edge. Both sensors will produce an image that's sharp corner-to-corner. It's not the sensor, it's the lens.
Agree with Paolo. For birding and portraits (among other things), corner sharpness is not that critical. It's important for landscapes and other applications that needs the whole frame to be sharp.
My two sentimos. ;D
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Post by Ronnie Dominguez on Apr 4, 2009 9:15:29 GMT
In my non-expert opinion:
given the same MP rating say 8MP rating and sensor type and design (structural,gaps and all): means that pixel density for full frame and APS-C are not the same. The smaller sensor size is cramming more pixels to a smaller rectangle size making its light and detail gathering a little poorer, so details are not so much captured compared with the larger full frame.
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Post by ppaaoolloo on Apr 4, 2009 9:32:55 GMT
You'd be surprised that some people would say P&S photos are as sharp as DSLR photos. This is due to the DOF of P&S cameras.
Given time and the natural progress of technology IQ of current pixel densities of P&S applied to full frame sensors in say 5-10 years time will look a leagues better than today's 1-Series or 5D2's.
Some even say today's $100 P&S take better photos than the most expensive film SLRs two or three decades ago.
To give an non-camera analogy it is like comparing the fuel economy & performance ratings of a Ferrari two or three decades back to your current V8 Camry. The Camry would post better race circuit lap times and sip fuel instead of chugging it down.
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, AFS 18-135mm f/3.5-5.6G , TC 1.4EII, TC 1.7EII, SB-800, Manfrotto 190CXPro3/393(3421), RRS BH-55, Kirk NC300 lens collar