Discussion in 'Olympus Cameras' started by Jonathan F/2, Apr 22, 2012.
Has anyone tried this combination yet? And if so, how is the performance? Thanks!
Well, there's a short video on youtube that gives some sense of the speed. [ame="https://www.youtube.com/watch?v=ICfJNokJhMo"]E-M5 AF test[/ame]
same question ..anyone with OMD+ Oly 14-54 mm MrkII Lens?
Have been using it regularly. AF speed is pretty similar to the EM5 + 20mm, or the EPL1 + 14-42 I. Reasonably prompt, but clearly not fast action. Very occasionally (less than 1 in 50 times) it will fail to focus entirely for no apparent reason. Once it does focus, optical performance shames most if not all m43 lenses, and we're not even in the SHG series.
We've this discussion in several other threads, and unlike the issue that Promit has in terms of missing focus entirely, my lens tends to miss focus when in low light just by a tiny bit, and it happens quite often. The missed focus is not enough to show up on the camera display, but becomes quite noticeable on my desktop display, which is rather annoying, and it happened like 1 out of ten shots one time I was using it at a dinner party. I think reducing the focus box to the smallest size available helps, but I haven't done extensive testing with the small focus box set-up...
Otherwise, I agree that when it nails focus, the optical performance it superb!
I've been idly thinking about this and I do have a theory.
Contrast detect fundamentally works by conducting hundreds of micro-adjustments of the focus point, and checking the resulting image. CDAF systems are optimized to adjust the lens very quickly in this way. PDAF, on the other hand, involves select a focus distance and sending the lens there in a single shot. So even on a "CDAF-optimized" lens like the 14-54 II, that's the primary mode of operation.
What if the steps on the 4/3 lenses aren't quite small enough? It's possible that the lens skips right past the focus point in a single step, making it impossible to lock onto even an easy focus target. The lens would hunt back and forth, never seeing a focused image. It's also possible that the camera is forced to settle for the closest step under some threshold even though it doesn't quite match. This would explain what you and I are both seeing from our individual lenses, and it's possible that sample variation and tolerances affect the exact behavior too.
I wouldn't doubt it. That seems to me what happens with the 70-300mm, too. Manually adjusting is always more effective...which is a pain with focus by wire.
I think you might be onto something! When I have the time, I will try to use the 14-54MkII extensively on my E-M5 using the smallest focus box to see if it makes a difference.
Anyway, I sure hope Olympus develops a long-term solution in the m4/3 system to maximize the focus performance of 4/3 lenses. It would be a boost to the 4/3 lenses sale...
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