Autofocus
The SAFOX IX+ is Pentax’s latest AF system and it graces both the new flagship K-5 DSLR and the 645D. It features an 11-point selection, nine of which are cross-type sensors for increased sensitivity. The nine points are placed fairly centrally in the viewfinder, with only the two non-cross-type points edging out to the left and right for any real off-centre focusing.
For ease, this can be switched to just five points, three points, one point or even set to auto selection. This arrangement may not seem that impressive in DSLR terms, and is certainly no match for cameras such as the Nikon D3X, but as most medium-format models use only a central AF point, it is way ahead of the game.
It even allows continuous AF and, although not the quickest, will capably allow you to remain fixed to a moving subject. There is a dedicated AF button on the rear of the camera for those who prefer not to use the half-press method – again, handy for outdoor use with numb or gloved hands.
In poor lighting or low-contrast scenes, the camera struggles to find focus and there is no AF illumination to aid it. In these cases, for speed, it is often best to switch to manual. In regular light, however, it performs without a quibble, locking onto the subject with ease and, using the new SDM lens, zips into focus. Focusing is noticeably speedier when keeping to the nine cross-type sensor points, however. Some photographers are likely to want to keep the camera in manual focus for control and simply use the AF confirmation light in the viewfinder, which flashes red when focus is achieved.
