PopPhoto has completed testing a production unit (yes, they mention it is!) of the K20D and the full test report has been published:-
So, for such a formal test, of course our main concern is on the various measurement results which are obtained under their controlled lab environment, in their professionally set-up lab. Here is the direct link to the K20D lab test results page:-
In order to make the obtained results more meaningful, we need to interpret the results by comparing the results of other DSLRs in the "same class", i.e., the targeted market segment. As the K20D is priced somewhere near the Canon 40D, Nikon D300 and the Sony A700 (said also in the PopPhoto's article) and all are the latest offers from the four brands, it's just trivial and fair enough to compare them.
Specifications wise, putting aside the old 16-segment multi-pattern metering system in the K20D (which has the least number of segments in the industry) and that all other DSLRs has a more sophisticated AF system on paper, the K20D do have a similar specification close to the 40D and the D300.
In order to do a more systematic comparison, we need to have more controlled tested data of the other DSLRs above. Very fortunately, PopPhoto have already tested all of them in their previous issues, the direct links of the corresponding results pages are as follows:-
Now, we can go on to compare the results aspect by aspect. I summarise the key performance aspect results above in the following tables for easy reading and our quick comparison:-
Table 1:- Noise
|Pentax K20D||1.22 (Very Low)||1.49 (Very Low)||1.76 (Low)||1.64 (Low)||2.6 (Moderate)||3.8 (Unaccepatable)||6.04 (Unaccepatable)|
|Canon 40D||0.8 (Extremely Low)||0.95 (Extremely Low)||1.15 (Very Low)||1.49 (Very Low)||2.0 (Moderately Low)||2.9 (Moderate)||N/A|
|Nikon D300||N/A||1.1 (Extremely Low)||1.2 (Very Low)||1.1 (Extremely Low)||1.4 (Very Low)||1.95 (Low)||2.83 (Moderate)|
|Sony A700||1.25 (Very Low)||1.3 (Very Low)||1.6 (Low)||1.7 (Low)||2.5 (Moderate)||2.7 (Moderate)||3.1 (Unaccepatable)|
As we can see, noise wise the K20D is just loser here. At lower ISO speeds, it by no means can match the 40D and the D300 for their superior noise performance. At higher ISO speeds, it just always loses, even to the Sony A700 (which also loses to the Canon and Nikon).
Table 2:- AF Speed (in Second)
(at ISO 100)
* Update (Feb 23): The timing figures are actually K10D ones and I have also corrected the figures above as PopPhoto have already updated their chart in the K20D test report. In conjunction, I have also made two minor changes in the second paragraph below accordingly. For more about the story, see the post made by Jack (the PopPhoto forum adminstrator) in the thread below:-
Their main argument for using the K10D data is just that as far as they learnt from Pentax, the K10D and K20D share the same AF system and in order to avoid further "confusion", they opted to publish the K10D timing results after carried out some tests for verification. Anyway, I myself am not convinced with this "reasoning", though.
Well, as many of the Pentax DSLR users, especially for those who have compared their DSLRs of other brands side by side when they were using their Pentax DSLRs at lower light environments (including me), the lower light AF performance is just pathetic for *any* Pentax DSLRs, the K20D is of no exception, as it has been verified from the above same lab environment, again.
It should be noted that at EV -1, the K20D was simply nearly unable to focus at a rather lengthy time of 2.33s which is in fact impractical to use for the AF. Actually, no other DSLRs would ever require more than 1.37s to focus even at EV -2 and EV -3 where at such a dim lighting level there is simply no figure obtainable for the K20D as it is very probably that the K20D had given up already to do the AF job at EV -2.
Not even to say actually the AF systems of Canon, Nikon and Sony all are designed to have the f/2.8 AF sensors which cater for faster lenses for better AF accuracy when used with those lenses, mostly primes, which Pentax simply lacks such a design.
Table 3:- Other Measurements
|Camera||Resolution (lines)||Color Accuracy (Average Delta E)||Highlight/Shadow Details||Contrast|
|Pentax K20D||2350 at ISO 100-400||7.98 (Excellent)||High||Normal|
|Canon 40D||2100 at ISO 100-1600||7.7 (Excellent)||Very High||Slightly Low|
|Nikon D300||2350 at ISO 200-6400||7.19 (Excellent)||Extremely High||Slightly High|
|Sony A700||2280 at ISO 100||8.9 (Extremely High)||Very High||Slightly High|
The K20D seems to have high resolution on a par with the D300. However, at higher ISO, it fails to keep the high resolution figures which the D300 has been able to maintain. But since the K20D has more pixels than the D300, the results are somehow unexpected.
As for the color accuracy, the 40D and D300 both do better than the K20D whilst the A700 is worst.
However, for the preservation of highlight and shadows details (also commonly referred to the Dynamic Range or simply DR), the K20D comes last. The K20D has the most accurate contrast, though. Do note that normally a lower contrast would normally result for a wider DR. It is therefore the Nikon and the Sony should have the potential to yield an even wider DR range if the contrast is tuned down a bit.
Table 4:- Overall Image Quality (IQ) Grading
|Camera||IQ at ISO 100||IQ at ISO 200-800||IQ at 1600||IQ at 3200||IQ at 6400|
|Pentax K20D||Excellent||Excellent||Excellent||Extremely High||Not Rated|
|Canon 40D||Excellent||Excellent||Excellent||Extremely High||Not Applicable|
|Nikon D300||Not Applicable||Excellent||Excellent||Excellent||Extremely High|
|Sony A700||Excellent||Excellent||Extremely High||Extremely High||Not Applicable|
Well, I think the last grading is redundant, after we have gone through the results of all the above key performance aspects measured. :-)
Anyway, after reading all these, there is yet only one question comes into my mind: Could and should Pentax do better? Could they?? Actually, I really just start to puzzle.. ( but I still know that *Pentax* MZ cameras' AF are better - at least faster at low light! :-( )