Thinking of something narrower: Panasonic 42.5 F/1.7, Olympus 45mm F/1.8 or Sigma 30mm F/2.8

neil holmes wrote:

Jacques Cornell wrote:

neil holmes wrote:

Hithertoo wrote:

If I got an EF adapter I have a bunch of lenses that I can borrow. I would suspect the issue with the EF adapter is the slow AF speed. People say the Panasonic 20mm F/1.7 is slow because of its focus motor, and it is to a point, but on top of the fact that EF lenses generally require a PDAF sensor (excepting the EOS M), most Canon lenses have the same sort of focus motor as the Panasonic 20mm F/1.7. That is slow and noisy screw drive lenses.

It's an interesting prospect but I would have to at least own an E-M1 first and then I may think twice about it. Adapted lenses no matter on the format including Sony E mount (where there are numerous AF adapters) or Canon EF mount, are always slower than what they would be on a native camera.

The Canon 40 2.8 STM at least is NOT slow to focus....not on my CDAF GX7 anyway.....it is pretty much native in focus speed.

It did have a lot of distortion before the firmware update but is fine now.

How does firmware affect distortion? Which firmware are you talking about - camera, lens, adapter? MFT bodies correct distortion with MFT lenses, but I'd be very surprised if Pan/Oly were building in corrections for something as alien as a Canon 40 on Kipon.

There was hideous distortion with most lenses at first but particularly evident with the 40 2.8 it was only really a problem with straight lines close in but when something (like a chair for instance) with a straight top was close in it would be clearly bowed........not anymore and distortion is one of the things that Kipon said they corrected with firmware ...may have been an earlier version firmware I didn't bother with.

I'm puzzled how Kipon firmware could affect distortion. Does the Kipon have any optical glass elements? If not, the only thing firmware could change would be focus... Wait, maybe the Kipon's firmware is writing lens corrections into the camera's image processing engine. Any info on this?

In low light it is a bit slower but not really any more than many native lens.

What lenses are you thinking of? There are a few f2.8 native MFT primes, but not many. The only ones I can think of are the Pan/Leica 45, which is a macro, and the Sigma 19/30/60, which are all APS lenses with MFT mounts.

Well the 40 2.8 is about the same speed to focus as my Olympus 14-42 ii kit lens in my bedroom at night with light off but a light on in the next room (top window and door but not direct) and TV on.....so quite low light without being really low.

EDIT just trying various points around my room to focus and the kit lens is SLOWER to focus for most than the 40 2.8 (when set to the same focal length)......probably to be expected given the kit lens is slower in aperture.

Not an absolute speed demon but fast enough and very good in good light.

Ah, I see. By "slower" you meant AF speed. I was thinking of max aperture, in which respect f2.8 is 1.5 stops "slower" (less bright) than many MFT primes.

Still works fairly well in low light with a GX7 (EV -4 AF is ok).....which is also much better I think since the firmware update.

One thing that is still a small issue is it keeps trying to focus when not being used so will drain the battery if not turned off when not using it.

Do you have Quick AF turned on?

Yes.

Well, that'll kill the battery. Quick AF forces the camera to constantly AF on whatever's in front of it, even when the camera's just dangling from a strap. S-AF on the GX7 is so quick I never bother with Quick AF. You'll get better battery life if you turn Quick AF off. You might also want to make sure the camera's set to go to sleep after a few minutes idle.