I decided to do a cunning test to find out which is faster: Pentax traditional screwdrive AF, or the new SDM AF motor.
SDM
[YT]http://www.youtube.com/watch?v=CjL1QNR9TmU[/YT]
Screwdrive
[YT]http://www.youtube.com/watch?v=8ZCw83BqFYw[/YT]
AF speed findings (EV 14, daylight) using the DA* 50-135mm:
AF Type | Time to focus from infinity | Time to focus from min |
SDM | 6/30s (0.2000s) | 20/30s (0.6667s) |
Screwdrive | 4/30s (0.1333s) | 18/30s (0.6000s) |
Conclusion: Pentax SDM is unfortunately not faster than screwdrive AF, although it is much quieter.
I guess this simply says that Pentax should really work on either noticeably increasing SDM speed, to make it worthwhile for us, or simply continue using screwdrive AF with potentially quieter or more powerful motors.
Several tests were done for each category, and the most frequently-occurring result was selected to estimate the true speed. Results varied from 18-19/30s for the screwdrive measurement, and from 20-21/30s for the SDM measurement. Times were found by analyzing each video frame-by-frame.
Adam
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