Essential viewing for all OM-1 owners.

[Dave in Wales]

https://www.youtube.com/watch?v=8uBowwXqlKw

[Miketoll]

Thanks for sharing Dave, clears up a few points I was confused over.

[Graham_of_Rainham]

Very useful information

[pdk42]

I've seen that video before. I don't believe many of the assertions he's making (e.g. "[in SAF] the chance of the camera making a false focus confirmation is very low" and "in low light scenarios, the accuracy of this method [SAF] is not impacted negatively". That is contrary to what I observed and also what Rob Trek has recently found.



Also, as per my previous comment, it's clear that SAF has at least two different modes depending on light level. The Thomas Eisl video doesn't mention this at all, even though he tries to present his video in a very authortative way.

I also doubt that SAF is only using CDAF (as he asserts). In fact, someone doubted just that in the YT comments and Eisl had to admit that he actually doesn't know:



Just what are Thomas Eisl's credentials? Does he have inside information? I doubt it.

Personally, I chalk this video up as yet another "this is what I think it's doing by a reverse engineering thought experiment from the results I'm seeing". If only OM could get one of their techs to write an article that explains what it actually does!!

[Ross the fiddler]

With respect, it is still useful for those using the OM-1 (not once used it). His credentials? Maybe you could ask him. In his latest video on Diffraction he discusses details I haven't seen before. I don't think he is guessing the information.
His web page https://www.thomaseisl.photography/

[pdk42]

I'm not saying that he isn't an intelligent, competent, and knowledgeable photographer - I'm only doubting his credentials to talk authoritatively on the internals of the OM AF system.

[bigsambwfc]

Good explanation of the focus systems,i especially agree on the TR issues being better depending on circumstances.Its not altered any of my set up though.

[Ross the fiddler]

Yes, well explained. Just to be clear though, I did ask him a question 3 months ago with his answer as follows.

Ross the fiddler

3 months ago
@ThomasEisl.Photography I was under impression that S-AF used "High-speed imager AF Imager phase detection AF and imager contrast AF used in combination", that is Phase Detect first followed by Contrast Detect. So that is not the case then?

Reply
ThomasEisl.Photography3 months ago (edited)
Ross, this is truly a complicated topic and it took a fair amount of testing. Here is what I found out: I am not sure whether the OM-1 uses PDAF first and then CDAF. One thing I'm 100% sure is that the "final" focusing is always done with CDAF in S-AF mode. In order to avoid confusion, I just mentioned CDAF in the video.

As part of that "complicated" S-AF process, I do see a few processes happening. If there is enough light it just quickly focusses & takes the shot, if in low light it produces quite an audible 'white noise' as it tries to focus & if it still doesn't lock focus it reverts to black & white, so it is true, "this is truly a complicated topic". And it is true, previous models with FAST DUAL IMAGER AF used PD-AF first but did finish with CD-AF.