Camera/lens focus speed test (also about 20mm F1.7)

Started Mar 17, 2013 | Discussions thread
OP micksh6 Senior Member • Posts: 2,613
More videos

1. Pana 20mm lens with subject misplaced in AF focus box:

2. Pana 20mm lens with AF box not placed in frame center:

These two, in conjunction with previously uploaded video

3. Pana 20mm lens with AF box centered and target in the same position as with other lenses:
should show that:

a) the randomness of focus algorithm gives more AF speed variations than position of AF target
b) it looks like 20mm lens focuses a bit more consistent with AF box slightly off-center of the frame, but still results AF speed noticeably slower than other lenses.

4. Tough nut for 14-42 II kit zoom to focus in light as low as ISO1600, F2.0 and 1/15s. It just can't focus at close target with its F3.9 aperture at the same FOV as Pana 20mm.

But, with as little more light as 1/20s with the same ISO and F-number it focuses consistently faster than Pana 20mm at the farther target.

5. Oly 17mm F1.8. A speed demon, can't say much more than that. Very consistent and fast. There can't be significant errors in test setup relative to Pana 20mm. The FOVs of these lenses are very close for about 5 feet focus distance.

6. Oly 45mm. Very fast when focusing to farther focus target, but lags when switching focus to closer distance. The experiment wasn't fair for this lens in regards to close focus target. The light source was at the left and when moving closer, secondary AF target closer to camera to maintain similar focus distance ratio between main and secondary target, the secondary target got less light. I don't have perfectly even lit studio, sorry.


Different target. Flat photo of children, turned so it's angled a bit. This was an attempt to find how low contrast of human faces affects AF speed.

7. Looks like it doesn't reveal AF speed differences between lenses. 20mm doesn't hunt here, although it is measurably slower than 17mm F1.8. It seems that non-flat, curved AF targets present more chanllenges to Olympus cameras with Pana 20mm lens. 20mm:

8. Oly 17mm F1.8 lens. Same setup as the previous one (adjusted for the same FOV for both primary and secondary target). No need to do measurements, you can see how faster this lens is.

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