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12-02-2008, 04:54 PM   #1
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K10D and K20D - Best Approach to Comparing Performance

The K20D price drop, Amazon's Black Friday deal and a couple of hundred in Amazon gift coupons I'd forgotten about prompted me to finally pull the trigger on a K20D. Normally, I don't formally test a camera; I simply start using it and keep it if I'm happy with its output.

I would, however, like to compare the high iso (800-1600) performance of my K10D with that of the new camera - both in RAW.

What is the best approach for doing so without introducing variables unwittingly?

Thanks,

Jer

12-02-2008, 06:35 PM   #2
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Set up a shot in your home, where you can control the lighting and the objects. Set up a tripod. Once the tripod's position is set, don't move it. Mount the K10D, attach the lens you wish to use (more detailed the better) and take the picture at ISO 800, 1600. Then take it off the tripod, mount the K20D, attach the same lens (making sure you're at the same focal length if using a zoom) and take the same picture, at ISO 800, 1600, and just for the hell of it, 3200.

Don't change the aperture while you're shooting. Use the same aperture on both cameras with the same lens, and just up the shutter speed to keep the picture properly exposed when you up the ISO each time.

Good luck! Post the results.
12-02-2008, 06:55 PM   #3
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QuoteOriginally posted by drewdlephone Quote
Set up a shot in your home, where you can control the lighting and the objects. Set up a tripod. Once the tripod's position is set, don't move it. Mount the K10D, attach the lens you wish to use (more detailed the better) and take the picture at ISO 800, 1600. Then take it off the tripod, mount the K20D, attach the same lens (making sure you're at the same focal length if using a zoom) and take the same picture, at ISO 800, 1600, and just for the hell of it, 3200.

Don't change the aperture while you're shooting. Use the same aperture on both cameras with the same lens, and just up the shutter speed to keep the picture properly exposed when you up the ISO each time.

Good luck! Post the results.
Thanks Drew - excellent instructions. However - and I just realized how amorphous my original OP is - I'm really asking about how to avoid artifacts introduced by PP and how software treats files of different sizes coming from different sensors.

Again, thanks much for your suggestions - sorry all for my lack of specificity and clarity in my OP.

Jer
12-03-2008, 09:52 AM   #4
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There will alwys be variables, so mostly it's about controlling *which* variables you are allowing to vary.

For instance, one useful test would be to test in-camera JPEG from both. That's relevant in at least some way. So do that, although be sure to try a couple of different mdoes (Bright/Natural, high ISO NR off/weak/strong).

Another would be to test RAW, and you might *think* that's eliminating the variable of different in-camera processing. but in reality, it's simply replacing that variable with a different one: differences in how your RAW converter deals with one cameras versus another. Most RAW converters are tweaked to process each camera a little differently. And one converts might happen to favor one camera, while another converter might favor another.

Obviously, you'll want to test the defaults of whatever converters you have - you might find you get different imrpessions of the comaprison depending on which converter you use. At first, you'd want the default K10D conversion from a given processor against the default K20D conversion from the same processor. But if you are not tied to one particular converter, it would also make sense to compare the *best* converter for K10D against the *best* for the K20D (might be two different converters).

Also, it makes perfect sense to see if you can tweak the results from your favorite converter to imporve on the defaults. Who cares if the *default* settings are noisier in one camera than another, if a simple drag of a slider will turn that equation around? What I found comparing my K200D to my DS is that the defaults sometimes at first showed a slight edge to the DS, but a small amount of NR helped the K200D a lot without erasing detail much, while the same amount of NR on the DS would not help as much and would definitely start eating detail. That kind of stuff is worth knowing, too.

12-03-2008, 09:39 PM   #5
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QuoteOriginally posted by Marc Sabatella Quote
There will alwys be variables, so mostly it's about controlling *which* variables you are allowing to vary.

For instance, one useful test would be to test in-camera JPEG from both. That's relevant in at least some way. So do that, although be sure to try a couple of different mdoes (Bright/Natural, high ISO NR off/weak/strong).

Another would be to test RAW, and you might *think* that's eliminating the variable of different in-camera processing. but in reality, it's simply replacing that variable with a different one: differences in how your RAW converter deals with one cameras versus another. Most RAW converters are tweaked to process each camera a little differently. And one converts might happen to favor one camera, while another converter might favor another.

Obviously, you'll want to test the defaults of whatever converters you have - you might find you get different imrpessions of the comaprison depending on which converter you use. At first, you'd want the default K10D conversion from a given processor against the default K20D conversion from the same processor. But if you are not tied to one particular converter, it would also make sense to compare the *best* converter for K10D against the *best* for the K20D (might be two different converters).

Also, it makes perfect sense to see if you can tweak the results from your favorite converter to imporve on the defaults. Who cares if the *default* settings are noisier in one camera than another, if a simple drag of a slider will turn that equation around? What I found comparing my K200D to my DS is that the defaults sometimes at first showed a slight edge to the DS, but a small amount of NR helped the K200D a lot without erasing detail much, while the same amount of NR on the DS would not help as much and would definitely start eating detail. That kind of stuff is worth knowing, too.
Thanks, Marc - I was afraid such was the case. I think I'll look at some RAW examples from both cameras (taken in a way Drew would approve) converted without modification using Pentax software. I'll then experiment with optimizing images from both the K20D and K10D (I think I've got the K10D about pegged after a couple of years) and see how they compare.

I won't be too assiduous about this (I'm too busy) - from what I've read, the only significant advantage of a K20D over a K10D (unless you print posters the size of a barn wall) is better noise management at high ISO. Frankly, given the circumstances, the new camera is pretty cheap . . . . but money is money, and if I can't distinguish a difference in "image quality" (whatever that is) between a K10D and K20D, there'll be no use keeping it.

Thanks again,

Jer

Last edited by Sailor; 12-03-2008 at 09:40 PM. Reason: still can't spell
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