Interesting analysis by Thom Hogan

Started Sep 18, 2008 | Discussions thread
Thom Hogan Forum Pro • Posts: 13,660
Re: WEll, really? :-) But you can't have this both ways...

Raist3d wrote:

Yes, but then what's the point of spending $2700 USD on a full frame
camera with 21 not so hot megapixels clogging your workflow and
memory then? You can't have this both ways.

I need to be more specific.

Your E-420 has 3648 pixels to work with. At any size up to 10" wide, you can print at the highest dpi the Epson inkjets (or most other printers) can really handle effectively. Anything down at the pixel level is effectively buried. Print larger and at some point pixel level defects will have visual impacts. With the Canon you have 5616 pixels to work with. At any size up to 16" wide you can print at the highest dpi the Epson inkjets (or most other printers) can really handle effectively. Anything down at the pixel level is effectively buried.

Put another way, the Canon has a 1.6x advantage over your E-420 in terms of seeing pixel-level issues in print. That's enough to be visually significant (some people say that would occur at 1.15x, I tend to be more conservative and say it takes a 1.2x difference to be visually detectable).

But there's a bit more to it than that. The pixel density of the Canon is 2.4MP/cm, the Olympus 4.0. The net effect of higher pixel density numbers is less dynamic range (all else equal; it's never perfectly equal, as sensor makers have different photo diode designs, but it's typically close enough to make the generalization). Plus, of course, diffraction becomes more of an issue with higher pixel densities.

You ask what's the point about buying a 21mp full frame camera? More dynamic range, generally more acuity at the same print size, especially once you've gone past the optimal dpi.

I could get that very
shot and I will dare say- with even more visual impact- in a JPEG out
of the E-3 and comfortably print at 11x14'.

Actually, this is the same argument Nikon has been making, with only some success. When Nikon was at 4mp Canon was at 11mp. The argument didn't play at all then. When Nikon got to 12mp Canon was at 16mp. Then, the differences were small enough to be not worth spending too much energy arguing about. Now Canon is at 21mp and Nikon is still at 12mp. Because the sensor sizes are the same, there are pluses on both sides. The Canon bodies have the pixel count, the Nikon bodies have a dynamic range advantage. I'd also argue that Nikon has better wide lenses than Canon, which mitigates some of the pixel advantage. But I would not say "I could get more visual impact in a Nikon JPEG." At 11x14, I'd be pushing pretty equal images out of the Nikon and Canon, I think. I can't speak to the E-3 as I've not used it (and why did you suddenly switch from the E-420 to the E-3?).

Hell I would dare say I
can print that size this landscape -from my e-420- with better visual
impact than that. And yes I am talking about the color reproduction
Canon goes for vs the one Olympus goes for (particularly so, on the
E-3 which is simply superbly fantastic).

"Color reproduction" is an issue I've been harping on for a long time, actually. I think most people now finally realize that ACR/Lightroom had some severe weaknesses at color when they saw what the beta DNG Profile Editor was capable of doing. This started many into looking more closely at color. I've been trying to point this out for some time: most cameras and most converters were not necessarily giving accurate and optimal color. What I've been measuring is what I'd call major changes, yet most sources were accepting 7 and 8 value shifts (in 8 bit) as "accurate." And saturation values of 110% are not "accurate," though many find them pleasing. Everyone was providing what they thought was pleasing color in their cameras and converters. Indeed, this is one of my complaints about Nikon's camera defaults. But from the standpoint of getting the best image, you don't want any color shifts, saturation enhancement, or contrast build-up in your original data.

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Thom Hogan
author, Complete Guides to Nikon bodies (18 and counting)

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