Pentax K-x review
The metering system of the Pentax K-x is the same 16-segment system found in the Pentax K-m and the K20D, but is not as advanced as the 77-segment system of the K-7.The K-x’s evaluative metering produces good results in most situations. Like all such systems, there are times when a bright sky or very dark foreground can fool the camera. In such cases, I found that using the AE-L button and spot metering mode helped to get more accurate results.
Like other Pentax DSLR cameras I have tested, I found that the K-x had a tendency to underexpose slightly. Switching to spot metering mode and taking an image of a grey card confirmed this. The measured value of the midtone was around 118 rather than 128. This was easily resolved by setting the EV compensation to +0.3EV
Pentax K-x - Metering score: 7/10