Olympus OM-D E-M1 low light auto focus performance

Started Jan 16, 2014 | Questions thread
alcelc Veteran Member • Posts: 9,940
Re: Olympus OM-D E-M1 low light auto focus performance

photofan1986 wrote:

msnremea1 wrote:

Looks like I found a "solution" for the focus problem. I have been googling and reading white papers and forums many hours last night and found some interesting stuff.

At the E-M1: Menu -> Cutom Menu -> D (Disp/Tone/PC) -> Frame Rate
This setting significantly affects AF performance in low light. When setting this to "High" the E-M1 is getting nearly as fast at low light as the GH2 and in some cases it matches the GH2 speed. This setting affects EVF and LV the same way.

But there is a drawback. The manual says "Select [High] to reduce frame lag. However, the image quality may drop." I don't see any differences in the pictures taken but the image quality of the EVF and LV gets worse the darker it gets. Worse means: It is loosing more and more colour (I don't care) but at some point with very low ambient light there is nearly no picture visible anymore.

I was wondering how Panasonic can do so much better with 3 year older hardware on the GH2. From what I learned reading all the stuff last night is that it is not the hardware. Panasonic does something similar but it basically always leaves the frame rate low enough to show a proper picture in the EVF and LV but as soon as you start focussing in low light it changes the frame rate to a high level to allow fast focussing and then it switches the frame rate to normal after the focus is locked.

You can see that in the video that I posted. With a fast lens (first try with 45mm / 1:1.8) the GH2 has the same picture colour and brightness during focussing. Using a slow lens (second try with 140mm / 1:5.8) the image in the EVF of the GH2 changes during focussing. It's getting dark and loosing some colour.

This is basically close to what my E-M1 looks with "frame rate" set to "high".
Looks like the E-M1 hardware would be good enough for fast focussing at dim light. It's just the software of the GH2 that is working better. I would be happy to see a firmware update for the E-M1 that changes the frame rate to high only during focussing (like Panasonic does) and then switches back to normal but my guess would be that Panasonic is holding some patents for this because what I saw in forums that E-M5 users are suffering from basically the same low-light problem and it is still not fixed so I don't expect a fast fix for the E-M1.
At least the possibility to set this "Frame Rate" function on the "Fn1" button would be great but that is not possible either right now.

I'm pretty new to Olympus. Are they interested in customer concerns (being on this planet for several years I know only very few companies are)? Is there a good point of contact where you can suggest improvements?

This, sir, was extremely useful to me! Having an E-M5 and GX7, I found disappointing that in low light, the E-M1 was slower to focus than both (the GX7 is by far the quickest). I really considered sending the E-M1 back for this reason (among others). Now I will give it a second chance. Many thanks!

You are correct. At the present moment, just a few bodies could reach -4ev AF detection range. They are GH4, GX7 and GM1 plus A7s.

EM1 could be as low as -2ev whereas the older EM5 was -0ev (as most M43s are) as below:


Indeed, all others pro dslrs like D750, 7D II, 5D MIII, 6D, K3 etc would be similar to G6's -3ev.....

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