Pentax k r performing close to nikon d7000 at iso 6400.how is that possible?

Http://www.expertreviews.co.uk/gallery/reviews/1281262/pentax-k-r-with-dal-18-55mm/138262

http://www.expertreviews.co.uk/gallery/reviews/1281652/nikon-d7000-18-105-vr-kit/139879

Added (1). I would say pentax k r performing even better than d7000 at iso 6400

Added (2). Ethan don't believe in brand, trust your eye

I don't believe this. Nikon is renowned among camera brands, even surpassing canon, in having much much better iso performance. The d7000 is absolutely amazing. Really, try not to get too technical when it comes to camera stuff. The d7000 is an amazing camera. "Remember, the best camera is the one you have with you." -chase Jarvis

Here is what the tests show at high ISO setting performance of both cameras

http://front1.dxomark.com/index.php/Camera-Sensor/Compare/Compare-sensors/(appareil1)/672%7C0/(appareil2)/680%7C0/(onglet)/0/(brand)/Pentax/(brand2)/Nikon

As you can see, the Nikon D7000 out performs the Pentax Kr across the board

The Kr has no chance to outperform the D7000.It doesn't have to. Pentaxians don't mind the stats.

Apples and oranges!

Those are not in any way valid comparisons.
Different subjects (smooth baby skin compared to an adult woman with wrinkles, also hair - a totally different texture),
different lighting conditions (bounced flash or indirect ambient light compared to sidelight),
different focal length (60mm compared to 157mm),
different aperture (4.5 compared to 5.6),
different shutter speed (1/80s compared to 1/13s)

Possibly they also were shot with different noise reduction settings.

The K-r is a lovely camera and I'm a fan. I don't mind highlighting their capabilities amongst people who believe Canon an Nikon are the only two companies in the world who can make cameras.

I'm surprised it would match a D7000 though. From what I understand the D7000 and Pentax K5 share essentially the same sensor and some reviewers do put the K5 ahead (Amateur Photographer magazine for example). I would have expected the K-r to be a step behind the D7000 and K5.

I did notice the review is testing the D7000 with the 18-105 lens. I would suspect the camera to perform better with higher quality glass.

Nothing against the K-r though. It's definite competition for the D3100, D5000, 500D, etc if only people weren't so blinded by brand.

Using just those shots is a misleading comparison. While they may have both been shot at ISO 6400, it wasn't the same scene or the same exposure which is necessary for a true, "apples to apples" comparison. Random photos are subject to any number of factors that will impact final image quality. Those include the noise reduction settings or any other image processing done in camera or in post processing.

All that said, it wouldn't be a surprise to me at all to see a Pentax offering similar image quality to a DX format Nikon or even a Sony because Sony supplies sensors to both Pentax and Nikon. The image processors are proprieary to each manufacturer but, the imaging sensors are often identical depending on the model of camera. At the end of the day, the camera itself is not the primary factor in image quality. The photographer comes first followed closely by the lens and lighting. The camera, in reality, comes a little further down the list.

If you want a more practical comparions that border in being scientific, check out DPReview.com. I personally disregard DXO's testing because they claim to test the sensors themselves which would be fine if it weren't for the fact we don't generally buy DSLRs soley for the sensors. As even Fhotoace has said many times, a DSLR is part of a larger system and it this system that you are buying into. Pentax is a fine brand and they do make great cameras. That said, their lens system is limited in comparison to Nikon or Canon who each offer a wider selection of lenses that Pentax can't or won't offer anytime soon.