With the acquisition of my latest camera the Pentax K-3 and the fact that I pre-ordered it and ended up being among the first people to receive one I felt I needed to do some testing to determine how far I can push it in terms of ISO performance. This camera is an upgrade to my Pentax K-7 DSLR at 14.6Mpixel but in between I also have my mirrorless K-01 with its 16Mpixel sensor. I thought I would share my findings and hope that you find them useful.
I set up a simple scene of my Minolta Super A, a camera with a lot of details, against a black background with a constant fluorescent light. I used the Pentax SMC 100 Macro WR lens on all three cameras and set the aperture to f13 each time while allowing the camera to vary the exposure with a -1EV bias set to compensate for all the black. The images are all shot in DNG RAW and taken as screen captures from Lightroom where I have set all noise reduction, both chroma and luminance, to 0. A setting I would never use in normal operation but makes things equal and accentuates the differences
Here are crops from the two DSLRs set to ISO 100 a sensor level where they all perform well with the K-3 producing an image with more detail.
But it’s the higher ISO’s that are going to start to show the differences between the sensors and their noise performance. Next I jump to 1600ISO where the 4-year-old K-7 starts to struggle but the newer sensors produce images that can easily have evidence of noise removed.
In the above image comparing the K-01 and the K-3 at 1600 ISO you can see that the K-3 appears to have slightly more chroma noise however that is something that can be completely mitigated with very slight noise reduction.
Next I will jump to 6400 ISO a place the K-7 has no business going to but where the K-01 and K-3 still are producing files that would clean up with some noise reduction.
Despite both being shot in RAW it seems that the K-01 is using some noise reduction within the camera so while the K-01 image has less noise it also has less detail even more so than the difference in resolutions affords.
Here is the K-3 vs the K-3 at 12800 ISO with noise reduction in Lightroom 5. The K-01 file has less noise but also less detail I would choose the more detailed K-3 image if asked for a preference
Here is the K-3 at 6400ISO vs the K-7 at 800 ISO where the distance separating them is more than 3 stops. This is a major improvement for me as when I’ve shot performaces in the past I have needed to balance shutter speed aperture and ISO in a clumsy dance at the edge of the K-7′s performance envelope. Those extra stops can go into a faster shutter speed or smaller aperture or both. And the fact that the K-3 focuses in light the K-7 is blind in only adds more usability.
As for the K-3 vs the K-01 they have similar noise performance up to about 6400ISO after which point the K-3 starts to appear more noisy but the K-3 continues to retain more detail through out all ISO’s.
In conclusion the K-3 is a major ISO performance upgrade over the K-7 and therefore also the K-20d by default but is less so over the 16Mpixel sensor in the K-01. This is of course only one aspect of the camera and hardly begins to touch on what a fantastic camera the K-3 is. For instance I used manual focus for this test for the simple reason that I wasn’t able to set the focus exactly where I wanted with the K-7 or K-01 but with the K-3 I was able to easily select the active point from any of the 27 placing it where I needed. This is such a major upgrade for macro photography it can not be over stated.