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New Olympus 17mm 1.8

Started Mar 7, 2014 | Discussions thread
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Anders W
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Re: New Olympus 17mm 1.8
In reply to Mark Chan, Mar 13, 2014

Mark Chan wrote:

Never tested it? hmmm; he did; here:


Others have tested the difference between the two versions:


I saw no real tests in either of those links. Just a report of impressions. Let me know if I have missed something.

But I am certainly not arguing that anything has changed with regard to AF when going from version I to version II of the 20/1.7.

and I quote:

"But over time, more lenses have appeared and all recent lenses used faster auto-focus motors. Out of all M43 lenses currently available, the PANASONIC 20MM f/1.7 is now considered one of the slowest when it comes to auto focus speed. So despite having multiple positive traits, some consider this lens unacceptable, which is really unfortunate."

This video for your 'visual study': And yes the initial try was with f5.6 for the pana; since changed to f1.7 later on


Yes I saw that. He makes the same mistake (from a practical-relevance point of view) as I have seen others make. He sets the lens to the minimum focus distance (0.2 m) and then focuses out to a distance of a meter or so. What that means is that the AF mechanism has to travel a very long way. While the distance between 0.2 m and 1 meter is short as measured in meters, it is very long in terms of "focus throw" (how far the AF mechanism has to travel), much much longer than the distance between 1 meter and infinity.

As recognized in this thread here


and further explained here


and in many threads before the present one, the 20 will indeed be significantly slower than other lenses when you rack focus between something extremely close and infinity (or the reverse) as well as when it hunts. The reason is that in these cases the main bottleneck is the focus mechanism of the lens, which does have a lower max speed for the 20 than for other lenses.

But when you AF between more normal distances (as in the test of mine that I linked to in this thread, where I go between infinity and 0.75 m), the main bottleneck is body processing time, which means that you will get roughly the same result as with other lenses (just as my test shows).

In short: If your need for fast AF includes the range of 0.2 to 0.5 meters (or so), then the test you linked to is relevant. If your need for fast AF doesn't include that range, its results do not apply.



Which quotes:

"There is no draw here, the Olympus 17mm simply crushes the Panasonic 20mm when it comes to autofocus speed. In terms of autofocus, I think this may be the fastest lens in the M43 lineup. If autofocus speed is critical to you, then there is no doubt that the 17mm is the way to go for you."

So yeah, I'd say that the 17mm f1.8 actual exceeds the focus speed of the 12mm and 45mm. I will have to stand 'corrected' of my previous claim that the 17mm f1.8 is on par with the 45mm. Its better.

Now of course given that these are ALL secondary sources, you are free to view otherwise.

I have absolutely no problem with the fact that you refer to the tests of others. All I care about is whether they are good and relevant tests.

1. we can agree that IQ wise the PANA wins

We certainly can.

2. I disagree that the Pana has fast AF speed. It doesn't, especially in comparison with the 17mm.

I am not claiming that the 20/1.7 has fast AF. Rather, what I am saying is that its slow AF mechanism is only a problem under certain specific conditions, like those described above.

So I revise my understanding of your view now:

The 20mm f1.7 has 'fast enough' AF under 'normal' conditions. I would say 'specific'.

You may call it what you want. What I mean by "normal" conditions is AF within the focus range from 0.75 m to infinity on a target and under light conditions such that the lens won't hunt. Even if you extend that range to the one from 0.5 m to infinity, the difference in AF speed is likely to be small (about 0.1 s with my E-M5).

In your words: 20 will indeed be significantly slower than other lenses when you rack focus between something extremely close and infinity (or the reverse) as well as when it hunts.

its slow AF mechanism is only a problem under certain specific conditions, like those described above."

So we agree! The 20mm f1.7 is INDEED slower when used in a variety of conditions. Such as when a photographer wants to take a pic of a landscape; then turns to focus on his kid running to him at close quarters. The 17mm f1.8 INDEED does better in such scenarios.

No. Unless you try catching the kid at a focus distance of less than 0.75 m, in which case the difference would be uninteresting since you'd miss the shot with any lens.

And maybe less so in a museum where all objects are of a particular focus range.

In any condition meeting the requirements already stated above.

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