Pentax K-r Review

Autofocus

AF Speed and Accuracy Testing

The following video clips demonstrate the new SAFOX IX Autofocus system with both a DA* lens that utilized the SDM AF motor, and a DA lens that utilizes the screw-driven motor. Focusing mode was AF-A, letting the camera choose between AF-S and AF-C. The camera was set on single point spot focusing, with the point set to the center of the frame. The subject matter being focused on was a an object with a decent amount of contrast, but in a indoor, not very bright, setting.

Neither style of lens caused the camera to hunt, however it did seem that the SDM lens would find the focus and lock on slightly faster than would the screw-drive lens.

The final AF video clip is shot through the viewfinder, to demonstrate the speed at which the image is brought into focus and the point on the image at which the focus is aimed. Single point focusing is used. Following the video is the resultant image. As can be seen, the spot at which the AF confirmation dot was located is the spot of the image that is in focus. Aperture for this image was f/4.

While a comprehensive test of accuracy and speed are difficult to undertake as to the tests easily being prone to user error, the K-r with a DA 55-300 lens mounted was used while shooting a youth (U-19 Boys) recreational soccer game, along side a K20D with a DA* 50-135/2.8 lens and a K-7 with a Sigma 70-200/2.8 HSM lens. An overall feel for the speed and accuracy of AF-C mode was obtained. The K-r outperformed the K20D easily, and seemed to yield a better rate of in-focus images than the K-7. This is difficult to quantify, however, as the nature of the subject being photographed is prone to user error and inaccuracies. These comments are based on the general impression of the performance of the camera based on field-use.