http://www.imaging-resource.com/PRODS/KR/KRA6.HTM
We can see that the shortest possible shutter/system time lag is in 97 milliseconds for the K-r.
Now, let's check the K-5 figures here, for what IR measured before, the best figure is of 92 milliseconds.
Well, if you are to compare the best figures of K-7 and K-x, in 74 and 82 milliseconds only, it can be noted that the shutter/system lags of both the K-5 and K-r are prolonged. In fact, the K-5 is even a bit worse than the K-x, and is not faster than the K-r by that much.
So, what causes this? Is this a measure to eliminate some of the severe shutter vibration and blur that were found and have been infamous for the K-7 and K-x?
P.S. This is my first Blog article that is edited and published with the new Blogger interface and tool at their trial test site of draft.blogger.com. It is easier to use and is more intelligent. I like it! Great job, Google! My thanks! :-D There are still quite some bugs exist, though, e.g., all posts are not displayed after publish of this article and sometimes drafted articles could not be saved. I hope Google will debug those soon!
Update (7-10):-
As per the suggestion of Blog reader Alex, I have summarised and tabulated some results of the DSLR system shutter lags, as measured by the IR for many different popular newer DSLRs, as below, for the sake of easier comparison:-
| Rank | Make & Model | Shortest System Lag (in second) | Percentage Slower (against the fastest as the base) |
| Fastest | Nikon D3S | 0.043s | 0% |
| Nikon D3X | 0.045s | +4.7% (More Time) | |
| Canon 1DS3 | 0.045s | +4.7% | |
| Canon 1D4 | 0.049s | +14.0% | |
| Nikon D7000 | 0.053s | +23.3% | |
| Nikon D300s | 0.053s | +23.3% | |
| Canon 7D | 0.061s | +41.9% | |
| Canon 60D | 0.063s | +46.5% | |
| Nikon D90 | 0.067s | +55.8% | |
| Pentax K-7 | 0.074s | +71.1% | |
| Canon 5D2 | 0.082s | +90.7% | |
| Pentax K-x | 0.082s | +90.7% | |
| Pentax K-5 | 0.092s | +114.0% | |
| Canon 550D (T2i) | 0.096s | +123.3% | |
| Pentax K-r | 0.097s | +125.6% | |
| Slowest | Nikon D3100 | 0.117s | +172.1% |
So, do you have a better/clearer picture now? ;-D
Related:-
Is the K10D Really Sluggish in Shutter Lag?