A difference between the Pentax K-x and the Pentax K-7 is that the K-x can take 3 auto-bracketted exposures and the K-7 can take up to 5. When I decided to buy a K-7 also, this was a great feature that I was excited about. But recently I have been taking HDR photos with both my K-x and my K-7, and honestly, I think the K-x performs better in this category. Or maybe using 3 exposures instead of 5 performs better.
HDR with the Pentax K-x (3 exposures)
HDR with the K-7 (5 exposures)
It is difficult to tell the differences by just looking at the photographs, but I found that I was getting consistently better results when I was using my K-x. But then, upon closer inspection I think that it is really a factor of how I have the exposures set.
On the K-x I typically do a normal (0 ev) an under (-3 ev) and an over (+3 ev) exposed photograph. Getting this sort of result.
On the K-7 I was typically doing a (0 ev), (-2 ev) (+2 ev) (-4 ev) and a (+4 ev). But getting strange artifacts, like this. Notice the clouds on the left side.
So really, it comes down to how you have your auto bracketing set. Here is what I do now.
On the K-x for auto-bracketting I use
- +/- 3 for extreme lighting conditions (conditions with very bright/dark areas)
- +/- 2.5 for normal conditions (no extreme bright/dark areas)
- +/- 2 for mild lighting conditions (not much variation between brights/darks)
On the K-7 for auto-bracketting I use
- +/- 1.3 & +/- 2.7 for extreme lighting conditions
- +/- 1 & +/- 2 for most lighting conditions
Really, I would just experiment with the different auto-bracketted settings. When you take your 3 (or 5) exposures just look at the top over and under exposed photographs. If the bright is almost ALL washed out (or the dark is almost ALL dark) I would turn down your ev steps and take the shot over again.
Finally, here is a comparison
Let me know what you think, or your own experiences with this.