EDIT: Thread moved from members' articles to Pentax DSLR Discussion per Adam's advice, for greater visibility...
Despite having been released in 2006, the Pentax K10D and its cousin, the Samsung GX-10, remain popular cameras even now in 2019. A major reason for this popularity is the claim by fans that the CCD sensor produces more pleasing colour and tones when compared to later CMOS sensor Pentax models.
I decided to perform a quick test to demonstrate the difference in colour and tone rendering between my Samsung GX-10 and Pentax K-3, as I felt it may be of interest to other members.
This was not a scientifically-controlled test, though I did attempt to make the conditions close to identical for both cameras.
I placed my X-Rite ColorChecker chart on my dining room table. Facing towards the window. It was a dull and very cloudy afternoon (the sky was completely greyish-white). I also had the overhead room light turned on, but this was not shining directly onto the target, being some way behind and above it.
Both GX-10 and K-3 were set to their sRGB colour space, "Natural" profiles, with DNG selected as the file format, ISO set to 100, and AWB white balance.
Using the same SMC Pentax-DA 35mm f/2.4 lens, I took almost identical shots of the ColorChecker chart with each camera, differing only slightly in angle and distance since these were taken hand-held.
I imported the resulting files into Darktable 2.4.4. For each photo, I:
- disabled all default processing options (base curve etc.) that might affect colour, shadows and highlights, black and white points, contrast, tone curve and so on
- set input color profile to "embedded matrix"
- set demosaic to AMaZE
- cropped and rotated to select the same area of the chart
- set white balance by spot selecting the same mid grey tone on the chart
Both shots were slightly under-exposed, so I adjusted them such that the luminosity of the mid-grey tones matched. (using the color picker tool for measurement). I then re-performed white balance adjustment, just in case.
Both shots were exported with output color profile set to sRGB (web-safe).
See below the results of the test, displayed as an animated GIF...
please excuse the compression artefacts :
The difference in colour and tone is clear, with the GX-10 photo looking brighter, warmer and richer. Indeed, the GX-10 photo requires little further processing. The K-3 photo, by comparison, looks flatter... lacking in saturation; almost pastel-like. It requires more post-processing to achieve a pleasing result.
Some believe that the GX-10 / K10D sensor has a yellow cast, but it's not that simple. White balance has been normalised for both shots, and we can see that the white-grey-black squares match very closely, with no obvious colour tint. It's true that most of the colours have a warmer hue, but saturation and luminosity are also quite different. For example, the GX-10's reds are warmer, brighter and more saturated, while the blues are more saturated yet darker. Clearly there's a lot more to the differences than a simple colour tint.
Is the CCD sensor responsible for this difference in colour and tone? In the past, I've said that I prefer the "look" of photos from cameras with CCD sensors, but it's difficult to say conclusively whether the sensor alone should be credited for the rendering. I believe the sensor is partly responsible, but feel the camera's colour matrix is also a significant factor.
Whatever the reasons, I continue to prefer the colours and tones from my GX-10 raw files. I'm in no way unhappy with the K-3's files, though. Quite the contrary... They respond well to post-processing, and it's possible to achieve similarly appealing results. It just takes a little more work
As a final note, I'm unaware if the color matrices for the GX-10 and and K10D are the same, or tweaked slightly by each manufacturer. I don't own a K10D, so can't compare. However, it seems reasonable to assume they are the same, or at least quite similar.
I hope this is of interest to some of you
Last edited by BigMackCam; 02-07-2019 at 01:35 AM.