Pentax-DA 10-17mm F3.5-4.5 Fish-eye
Autofocus Performance
The SMC Pentax-DA 10-17mm F3.5-4.5 Fish-Eye ED [IF] uses the screw drive autofocus mechanism. This is compatible with all Pentax DSLRs (and with the K-01 as well). Because of the short focus throw, we would expect this lens to autofocus fast.
In this test we measure the time that it takes for the body to displace the focus from the closest focus distance (0.46' or 0.14m) to the farthest focus distance (infinity) and vice versa. We performed each test 5 times and then averaged the resulting time values to provide a more representative number.
We used a Pentax K-5 body with 1.14 firmware, using it's phase-detect auto focus method. The test scene had a luminance equivalent to 6.4 EV. The average autofocus times in such conditions are the following:
AF locked after | |
| From infinity to 0.46m | 0.356s |
| From 0.46m to infinity | 0.392s |
Verdict
We were extremely pleased to discover that the DA 10-17mm Fish-eye boasts very fast autofocus. We did not notice any significant latency between half pressing the shutter button and the actual autofocus action. Because of its wide depth of field this lens will often be used with its focus near infinity, which will further increase apparent autofocus speed: we noticed that in practical use the DA 10-17mm Fish-eye will autofocus almost instantly. Overall, we consider that the autofocus performance of the DA 10-17mm Fish-eye to be excellent. For convenient manual focusing this lens also offers "quick-shift" full-time manual override.
Note that because this lens uses the traditional screw drive AF system the autofocus movement is quite audible when in use.
