Re: Who said Canon sensors suck?!?
Fishnose said:
jrista said:
In comparison to my 7D, the D800 is 2.3 stops better. Period. I don't downscale my photos...on the contrary, I tend to upscale them, so there is no benefit of any kind of the D800 above and beyond the hardware's native 2.3 stops. In comparison to the 1D IV, the difference is only 1.7 stops.
Uh, now I'm not with you. If you tend to upscale your 7D images, you REALLY need a D800. If 18MP doesn't do it then 36 is going to be a WHOLE lot better, because then you can generally gain IQ rather than lose it when downscaling a D800 image rather than upscaling a 7D image.
And DR will in fact be more than 2.3 stops better, since one gains DR with increasing resolution and vice versa. So yes, there IS a benefit of the D800.
Your missing my point. I'm not saying the 7D will produce better upscales. I'm saying that upscaling a D800 image will not magically fabricate another 2 stops or more dynamic range. Dynamic range is a HARDWARE TRAIT!! Why don't people get that? The friggin sensor has an average read noise level of around 3 electrons, and a maximum saturation point (at ISO 100) of 44972 electrons. Those FACTS about the D800 sensor DO NOT CHANGE, no matter what you do with software.
Lets just screw comparisons for a moment. Let me ask a simple question:
If you photograph a scene with 14.4 stops of dynamic range with a D800...can you capture every distinct level of luminance in that scene with the D800?
Most people would say YES. Simple fact of the matter is, your 1.2 stops short!! I don't really give a damn how software wizardry, with a bit of dithering in a clever scaling algorithm can mimic a higher dynamic range when scaling my beautiful 36.3mp images down to the native size of a late 1990's DSLR. What I care about is whether I can photograph a scene with 14.4 stops of real-world DR, and GET IT ALL. Simple fact of the matter is the D800 CAN NOT DO THAT. It could capture the entire dynamic range of a real-world scene that contained 13.2 stops between its brightest and darkest points, but not one that contained 14.4 stops. If I try to capture the 14.4 stop scene, I have to give up something. Either I give up 1.2 stops worth of shadow detail, or 1.2 stops of highlight detail...or perhaps 2/3rd of a stop of both shadow and highlight detail...but the damnable hardware aint gonna capture it all. If I
upscale in post, so I can print at say 40x30 or 60x40, I'm not doing a damn thing to minimize noise (on the contrary, I'm scaling noise up as well, so it's going to become more apparent...particularly on my computer screen), so the benefit of using the D800 over the 7D is...well,
still 2 stops.
BTW, FYI...upscaling does NOT normalize noise...it exacerbates it because you sample the same source pixel to generate multiple output pixels. You can only produce anemic output pixels (in the destination space) that are sourced from insufficient original information. You can't
average noise during upsampling (as a matter of fact, you actually
distribute it.) Only when downscaling can you normalize noise, because you reference many noisy input pixels to produce a less noisy single output pixel. You sample multiple inputs,
average their values, and produce a better output pixel (in the destination space) that contains rich information. Even with downscaling though, it doesn't take a particularl intelligent mind to realize you can't generate more than TWICE THE LUMINANCE RANGE (1.2 stops worth) in a downsampled image from a source image that only contains 13.2 stops to start with.