Pentax K-3 Mark III Review

ISO Comparison: Colors

High ISO performances will likely be the most interesting comparison point for many users. We will thus look at the new camera's results in detail, using a method comparable to our K-3 II review.

This first page looks at both sharpness and colors. The following page will consider low-light performances.

All images were shot in RAW+ mode and developed in Lightroom. Default development settings were used in both cases. We used auto white balance, "bright" custom image with default settings, no in-camera noise reduction, and no lens corrections. The lens used was the D FA 28-105mm. Natural light was used.

In-camera JPEGs

We will first look at how the camera performs when generating JPEGs in-camera.

ISO 100

ISO 200

ISO 400

ISO 800

ISO 1600

ISO 3200

ISO 6400

ISO 12800

ISO 25600

ISO 51200

ISO 102400

ISO 204800

ISO 409600

ISO 819200

ISO 1600000

Surprisingly, the camera overexposed at base ISO values. We elected to use these results since they highlight how the camera actually metered.

At ISO 1600 and below, images are essentially interchangeable. Noise isn't apparent, and color reproduction is repeatable and accurate. Starting at ISO 3200, luminance noise becomes visible, but without any true negative effect on details. ISO 12800 shows a significant drop in perceived sharpness, which further degrades as the ISO value increases.

ISO 51200 is the limit of what could realistic be considered usable; images beyond are muddled by noise. Still colors remain accurate until ISO 409600. Beyond that, colors are all over the place, and their accuracy is low.

The following table offers full-resolution links to the files.

Lightroom-processed RAW

We now look at how the camera delivers when generating RAW files processed in Lightroom.

ISO 100

ISO 200

ISO 400

ISO 800

ISO 1600

ISO 3200

ISO 6400

ISO 12800

ISO 25600

ISO 51200

ISO 102400

ISO 204800

ISO 409600

ISO 819200

ISO 1600000

Using the RAW files deliver about two stops of advantage over in-camera JPEGs. Images up to ISO 12800 are mostly comparable (even though there is an increase in noise, of course, it is not detrimental to the end result).

At ISO 204800, there is no true details left to see. Before that, details are partially gone but still visible, but at this value, there is nothing left truly.

Again, the good news is that color accuracy remains constant until and including ISO 409600. Beyond that, colors become inaccurate.

The following table offers full-resolution links to the files.

Comparison with the original K-3

The following slider presents a simple comparison of what to expect when going from the origonal K-3 to the new K-3 III regarding noise. We used the DA* 16-50mm PLM at F8 and 50mm, and set the ISO at 6400 on both cameras, then cropped the center section. We used the JPEG output from both cameras for this comparison. The images are downscaled, originals can be found here for the K-3, and here for the K-3 III.

The difference is significant, especially the level of detail on the lettering at the bottom, the colored flowers and the definition of the details on the moon and banner (look to the left in particular).

This simple comparison illustrates how much the K-3 III's noise handling has improved when compared to the original K-3.

Verdict

The K-3 III is able to deliver accurate colors until ISO 409600. Using in-camera JPEGs, users can reliably use ISO 1600 and below without any worry, as noises levels are low and very well controlled. Above ISO 1600 but below 12800, details are still adequately preserved.

Using RAW and developping in post-processing, even with default settings, delivers 2 stops of benefits regarding noise management.

What noise there is manifests almost exclusively in luminance, with little chroma effect. This kind of noise is, in general, easier to manage.