audio recordings to compare differences in focus speed between Panny 20 and Oly 17
Many people complain about the slow focusing of the Panny 20 and others insist it isn't slow to focus at all. I was intrigued by reports from people I generally trust that demonstrate it has fast focus, while so many people strongly believe that it is the slowest focus lens in the lineup.
So I tested my own copy of the Panny 20 (first version), using the Oly 17 f1.8 as the comparison lens and my EM5 as camera. Obviously this only relates to my own copies of these lenses, but I thought some might find it interesting nonetheless. I'm not trying to 'prove' one lens is 'better' than the other, but trying to figure out for myself why I've never really gotten on with my copy of the Panny 20. I know it is a sharp lens and has nice color and contrast, but I've just never enjoyed using it.
I'm not a scientist and haven't ever posted these sorts of comparisons because I know I'll get raked over the coals for not doing something right. Feel free to post comments and criticisms, but try not to assassinate me in the process!
First, I recorded each lens while I continually pressed the shutter button to AF while moving the camera from random subject to random subject around the room for about a minute each. This was done indoors during the day. The room has a full wall of windows with indirect light and there were no electric lights on. It was easily light enough to read comfortably (we never have lights on during the day), but there are definitely some shadow areas and contrast is variable about the room. Listen to the entire recording of each in order to hear the differences.
The next test was moving each camera/lens combination back and forth to focus on the same two subjects, one farther away and one closer.
The last test involved moving the camera back and forth to focus on the same two subjects (some distance between subjects but not as extreme as the previous test), while holding the camera very close to the microphone.
My conclusions are in next post.
Overall conclusions - with respect to my two copies only:
- under the right conditions (good light, good contrast, not moving from near subject to far subject), the Panasonic can be a fast focusing lens
- in real life, there is more variability to the Panasonic focus speed; it provides an overall slower experience with respect to focus, especially when moving from near subject to far subject
- conditions that make the Panasonic take a long time to achieve focus are less likely to impact the Olympus; when the Olympus slows down, it is not as slow as the Panasonic slowdown; don't know if difference in focal lengths accounts for any of that difference
- the noise and movement of the Panasonic lens while it is focusing makes the Panny seem slower than it is
- the Olympus visually appears to 'snap' into focus (i.e.., it does not show focusing behavior in viewfinder, or if it does, it is too fast to watch) while the Panasonic shows the focus behavior (moving into focus, overshooting and correcting while you watch); this behavior also makes the Panasonic seem slower
If you listen to the entire clips, you will hear more variability in focus speed with the Panny 20. At times, the focus speed is about as fast as the 17, but at other times the Panny takes much longer to focus (up to 4 or 5 seconds), although there was no real 'hunting' and it never failed to achieve focus.
The Panny takes a long time to focus when switching from a near subject to a far subject, not so much with the reverse.
Two points: First, all these audio clips were run through a basic noise filter because my recorder is cheap and has noisy preamps. Without using a noise filter, the preamp noise nearly obliterates the sound of the focus beeps. Unfortunately, the noise filter also erased much of the noise that the Panasonic makes while it focuses - in real life, the Olympus is nearly silent while the Panasonic is fairly loud throughout the focus process.
Second, here is a visual of the close up recordings, showing that the olympus is a bit faster across the clip:
For me, I think the visual cues that demonstrate the focus process, along with the noise cues and the feel of the focus mechanism at work, all combine to make the lens feel slower than it actually is.
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