Tuesday, September 26, 2006

Comparing 10.2MP to 6MP

(Updated 3pm EST) Unless you've been playing with a similar 10.2MP camera to the Pentax K10D, like the Sony Alpha which has the same 10.2MP dimensions per photo, you may not yet know what kind of new cropping you can do with all those extra pixels you get from jumping up from a 6MP camera. If you consider keeping things around 250ppi (pixels per inch), you have a much wider area from which to choose your crop. Consider that with a 6MP camera, a typical 8" x 10" print can be almost 250ppi, but with a 10.2MP camera, it can be over 325ppi without upsampling any pixels. So if you choose to print with the higher ppi, you'll find the cropping ratios to be nearly identical.

I've set up a simple 1:1 scale image of how the new dimensions compare to 6MP Pentax DSLR photos, including some standard croppings (roughly overlaid), to give you an idea of how much extra play you're getting. As you can see, the aspect ratios are quite nearly the same (roughly 1:1.5, or what almost gets fully printed in a standard 4" x 6" snapshot).

Click image for full resolution 1MB jpeg

To be more specific, the new resolution, 3872 x 2592 (10.2MP) or 1.493:1, compares well to 3008 x 2008 (6MP) or a 1.498:1 ratio. If you scale up a 3008 x 2008 6MP image to 10MP keeping the same ratio of 1.498:1, you get 3882 x 2592, which is 10 pixels wider than what Pentax is offering in the K10D. So, the new pictures will have just a little bit narrower ratio, but more leg room and higher ppi for your cropping.

As it was pointed out to me at DP Review Forums, "everyone will take [this comparison] according to their prejudices."

I agree, the prospect of upgrading your 6MP camera just for increased resolution when you only print average sized pieces is a canard. The K10D has other benefits that should be more appealing, such as the 22-bit AD conversion, shake reduction and the weather proofing. But the industry's toil will probably continue beyond surpassing the average drum scan resolution of 35mm film (36mm x 24mm or 1.4174" x 0.9448"), then 4x5, and on... until every average digital camera outperforms film, including the dynamic range of captured light and the speed efficacy of doing so. Let me clarify why I think this is happening.

Maybe this race is because society perpetually wants to see things better than the average human eye can, especially anything far away, small, huge, worth sharing, or too complex to remember adequately. And maybe it's because we want to trust that we're getting as much uncorrupted information as we can. Which is partly why a whole society of astronomers stitch together Hubble Telescope pictures to get the most resolution they can muster. Eventually, it's always more than the average person needs, but then most of us like to think that we should prepare for the opportunity to be extraodinary if we ever bump into that moment. And, of course, there's consumerism and industry winding the spring tighter and tighter because most of us picture taking folk aren't agrarians.

In traditional 35mm conversion to digital, if you want to just make it to the level of the grain, you need to scan at about 2500ppi, which is a 35mm film image digitized to 3543 x 2362 pixels.

But then if you want the grain really clearly defined, to see the whole contour of the grain, you need to scan at about 4000ppi (about 5670 x 3780 pixels, or 21MP), or even higher for fine grain film.

So when will we all be satisfied? I tend to think it's a generational thing. Some people who grew up with 35mm will finally be satisfied when digital can claim to be equal or better to 35mm slide film, not just in terms of convenience, but with color, resolution, and exposure latitude. Some people already feel satisfied. The IMAX generation who've known digital since they were young probably won't be satisfied until the average camera is better than IMAX (the 4000ppi scan of 2.692" x 2.056" equivalent: 10768 x 8224 or 88MP). And once we've caught up to film and we have the technology to process it all very quickly and do anything with it, our eyes will already be dreaming about something bigger and better, like projecting images into the air with a tangible density that you'd swear you were looking at the Grand Canyon and not a rush of generated photons hiding your lousy backyard in the suburbs.

4 comments:

okto said...

The native resolution of the K100's imager is 3008x2008, not 3008x2000. For some reason when you shoot JPEG you lose those eight rows of pixels. The real aspect ratio of the imager is 1.498:1, almost exactly the 1.5:1 of the 35mm film frame.

I know it's super nitpicky. I just like accuracy. ^_^

OK-1K said...

Ahh, I wondered if my brain was misfiring a little. I've gone back and fixed the post and images to say 2008 (which I should know, seeing as all my RAW shots are in that size)... thanks for the correction.

Jens said...

The resolution of the CCD is even higher. Convert a RAW file with RawShooter Essential and be amazed...

Cheers
Jens

Geraldo Moochie said...

The dreamer that I am, I dream of being able to drill down into any sized digital photo into infinity, to see beyond the next hill, to look into the eyes of the bald eagle from 20 miles, to peer into the structure of his feathers, to see the mites as they thrive on their host. Digital technology will greatly exceed optics technology within the next year.

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