Most helpful critical review
7 of 11 people found the following review helpful
Wonderful at low resolutions; problems at high resolutions
on September 6, 2011
I received and subsequently returned three consecutive copies of this lens from Amazon.com. Every copy had a very significant "back-focus" problem at f/4. When focusing on an object at f/4, the object in question will be slightly out of focus, while objects behind it will be in focus. For example, when focusing on a person's face, their eyes will be somewhat blurry and their ears will be in focus. This is not a problem with my camera, since the back-focus problem disappears at other f-stops. It's worst at f/4, perceptible but acceptable at f/2.8 and f/5.6, and nonexistent at other f-stops.
I verified this problem using a tripod and a cable release at ISO 100 and manually focusing on the subject (manual and auto focusing are both implicitly done at the lens' lowest f-stop, f/1.4). The subject was in focus at f/1.4, blurry at f/4, and in focus at smaller apertures.
However, it's worth saying that the "real world" pictures that I took with the lens looked AMAZING when viewing them at less than 100%; wonderful colors and bokeh. I just couldn't stand looking at them at 100%. I returned my final copy of the lens and got the SAL35F18 instead (the 35mm length is a better all-around lens on APS-C sensors), and I love it.