M1 and 75/1.8, C-AF experience

Started May 18, 2014 | Discussions thread
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M1 and 75/1.8, C-AF experience
May 18, 2014

This is a long post and related to sport and CAF only.

Yesterday was my first outing with my new gear and luckily there was a marathon so I decided to try the CAF. This is the first time that I do CAF since I started taking pictures so the user error is the dominant factor in the keep rate.

My camera setting was Aperture priority, ISO 200, single frame continuous shoot, no preview, jpeg LS, NR on normal, natural colors and other parameters on default and IS on auto. I shot around 2025 pictures in 2:30 hour.

It took a while until I started to catch up with the speed of runners, keeping the subject in the focus frame, knowing when to hit the shutter, panning.

I tried CAF and CAF+tracking, single point focus and 3X3. I found CAFT works better with isolated and not very fast moving subjects. Having few people run close to each other the CAFT will jump on other subjects regardless how well you locked your middle focus frame on your subject. Unfortunately I do not know which pictures are taken with CAFT but I used it for 10-15% of the time (is there a way to tell since Olympus viewer doesn’t)?

Best AF setup that worked for me was CAF and single focus point. Did not try multi frame.

The 75/1.8 does not look very fast with CAF and can’t hold the subject in focus while the 12-40 is faster in focusing and keeping the subject in focus, and this is one of the problem that I suffered and was not sure if it was me, the camera or both. When using the 75mm I lock the middle focus frame on my subject and pan it but the camera/lens can’t keep the focus for over 1 second maybe 2, they either go out of focus or start hunting so I had to take the picture once I get focus confirmation without waiting for the perfect moment. The 12-40 was better in this regard. Not sure if this is a lens design related or focal length.

The other major problem with the 75/1.8 is purple fringing. See pictures below. I assumed the jpeg engine should fix that.

Look at the PF on the runners left shoulder and head

More PF

The biggest issue I had was the camera locked 6-7 times (FW 1.3, lens 1.1, card formatted). Lock up started happening when for some reason I went to the menu looking for CAF options and turned lens I.S. Priority on. I could solve the lock up by pressing lens release button, which is weird, this worked for the first 4 lock ups after that I had to turn it off and on and after that even turning it off and on did not work so I had to take out the battery then it worked. I read in other forums and this looks to be an ongoing problem.

Unfortunately, and this is my fault, after last couple of lock ups where I had I to take the battery out the focus went back to SAF without me paying attention to it so 99% of the pictures where out of focus until I changed it to CAF when I was trying CAF and CAFT

My results at the end were:

25% of the pictures could be viewed at 100% enlargement with acceptable sharpness

25% of the pictures could be viewed up to 50% enlargement with good sharpness

50% OOF or misfocused

(The first two were supposed to be around 40% each if I had the focus on CAF instead of SAF after the lock ups)


  • Is there any fix for the lock up?
  • Should I expect better result (in terms of sharpness with this kind of photography) with this setup?
  • How to improve focus, sharpness and keep rate
  • What do you consider keep rate, sharp at 100% enlargement or less 50% enlargement?


  • I am not sure if 75/1.8 is there right choice for this type of sport.
  • Shot wide open, I believe I needed to shot at least at f4. I shot 1.8-2.8 almost all the time.

I am kind of disappointed with the lock up issue and the lens performance in terms of PF and CAF focusing. For over $2000 I expected better results.

Below are few pictures which have acceptable sharpness when viewed at 100% enlargement (about 425 pictures has better or little bit worse sharpness)

Look at 100%

Below are few pictures which have acceptable sharpness when viewed at 50% enlargement (about 450 pictures has better or little bit worse sharpness)

The remaining of the photos are in the link below. Only photos posted on DPR are SOOC and zero adjustment has been made.


 shg's gear list:shg's gear list
Olympus E-M1 Olympus M.Zuiko Digital ED 40-150mm 1:4-5.6 R Olympus M.Zuiko Digital 45mm F1.8 Olympus M.Zuiko Digital ED 75mm F1.8 Olympus 12-40mm F2.8 +2 more
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