Originally posted by PentaxPoke So I'm feeling a lot better about my k10d. ... I was really surprised that the k10d was better at all iso levels except 800. Same with k10d vs C 40D. Better at all iso levels. If I had anything older than my k10d, I would go for the k20d in a heartbeat, but I now feel comfortable waiting for the next generation (or later) Pentax.
Hey, Pokey! These are numbers from Popular Photography, right? I have the March 2008 issue in front of me with the review of the K20D, but I don't have the issue with the numbers for the K10D to compare. I'm surprised to see it being claimed that the K10D outperforms the K20D at ISO 1600. My impression is that most who have the K20D feel this is not the case.
I'm afraid I do not understand how they do these tests. One of the things I really don't understand is, what difference does the greater resolution of the K20D make to these tests--and to the way that things look in the end? I mean, I gather that, other things being equal, more pixels generally = more noise
per pixel. But if you get more data to start with, and then reduce the size of the image, say, for printing or display on the Web, it seems to be the case that res trumps noise and you might get less noise. In other words, the K20D might actually be noisier than the K10D, but its images clean up better. Am I making any sense?
I happen to have the December 2007 issue of Pop Photo here, too, and it pains me to read the numbers for the Canon 40D.
.ISO . Canon 40D vs Pentax K20D
.100 . 0.8 .xlow .. 1.22 vlow
.200 . 0.95 xlow .. 1.49 vlow
.400 . 1.15 vlow .. 1.75 .low
.800 . 1.49 vlow .. 1.64 .low
1600 . 2.0 .mlow .. 2.6 . mod
3200 . 2.9 ..mod .. 3.8 . bad
The 40D also has dramatically better numbers relating to auto-focus speed (not a big issue for me, but it is for some), and it looks like the 40D does better in the area of highlight and shadow detail, too.
On the other hand, both cameras get "excellent" ratings in the image quality department, and "extremely high" image quality at iso 3200--which I find frankly incomprehensible, since they claim that the K20D's noise at 3200 is bad (their word is "unacceptable").
Pop Photo concludes that the K20D can indeed challenge the Canon 40D, although I don't see what in their tests gives them the right to say this, and they do qualify their praise by adding that the K20D challenges the 40D "except at the upper ISO limits and in extremely low-light AF challenges." Since the 40D costs $100 LESS than the K20D at the moment (Amazon.com prices: $1150 vs $1250), in what was does the K20D compete?
So I'm stumped. I need to sort this out before hit the "buy" button on a K20D....
Will
P.S. Using your numbers, the K10D is NOT better than the Canon 40D at all ISOs, as you say. K10D seems to be better at 1600 and 800, a little worse elsewhere.