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-   -   Focusing, for over 50 years I've been getting it wrong. (http://e-group.uk.net/forum/showthread.php?t=48014)

Dave in Wales 1st June 2018 10:06 AM

Focusing, for over 50 years I've been getting it wrong.
 
In all that time I've been using the Focus-Recompose Method, sounds like a form of contraception.

Sorry I digress, on another forum it was stated that the FRM does not work....https://www.mu-43.com/threads/sharper-af-tips.98592/

Well it has worked for me for 50 years I thought and read on. The very reason I read the thread was because that in all the previous OMD cameras I've owned, 3 x E-M1, 1 x E-M5.2 the method (FRM) seemed to work fine, or I thought it did.

https://digital-photography-school.c...ompose-method/

The focus recompose method seemed to fall down when I acquired a new E-M1.2 with 12-40 a month or so ago.

If I position the focus box where I want it then things are fine, but using the FRM I have definitely had the subject OOF.

Anyone else noticed anything funny with the E-M1.2, is the focusing different from it's predecessors?

Graham_of_Rainham 1st June 2018 11:01 AM

Re: Focusing, for over 50 years I've been getting it wrong.
 
I have used FRM from virtually the first time I had a range finder and SLR as the image overlay & split image were all we had.

But we were taught about the distance error (aka Pythagoras) at close range and large angles, but in the real world with mostly f/2.8 lenses and working distances of 6ft minimum, with f/5.6 to f/8 this was hardly ever an issue.

When things got seriously critical, in the studio, we reverted to the tape measure and the distance scale on the lens, having checked the focus with the split image looking at a B&W "4 checker board".

With the current love affair some have with using f/0.9 - f/1.2 at close distances, the article has some merit, however like most things, it's useful info to keep in mind should the case or need arise, in which the situation could be relevant.

RobEW 1st June 2018 11:10 AM

Re: Focusing, for over 50 years I've been getting it wrong.
 
I don't have E-M1 II but I have a couple of thoughts occur to me which might be relevant to someone if not to you.

Focus/Recompose was standard practice on film cameras so it can't be that bad. An article linked from the other site ( https://digital-photography-school.c...ompose-method/ ) makes a big drama about the difference in length of a hypotenuse compared to the adjacent of a right angled triangle. However a bit more geometrical knowledge than the author's will show that if your subject is at a distance and the angle of recomposing is small, the two lengths are near-identical.

The other thing (well known to those street photographers who rely on zone focusing) is that if you have adequate depth of field then any difference in these lengths will be even less important. (So wide angle lenses, distant subjects, small sensors and narrow apertures all help, but if using telephoto macro with f/1.4 then even slight inaccuracies in focusing are critical).

As for why it may not be working well on E-M1 II, I can only guess based on E-M1 Classic. A couple of settings to check. (Cog - C) Rls Priority - setting this to Off will allow photos to be taken before AF has happened. (Cog A) AEL/AFL - gives you the ability to specify whether AF actually happens when the shutter button is half pressed. (If you select Mode 3, then AF won't happen unless you use a different button to invoke it). these options may be in different places on the Mark II. As these are body settings, not lens, then it would affect any lens you attach. Oh - also I once had a problem with AF when the lens I had attached had a "clutch" which I had inadvertently moved and which made it MF. I think some lenses have a an extra button to do this too.

Sorry if most of that is stating the obvious. (At least in a mainly male forum, I might not get accused of "mansplaining"! :-) )

(Edited to add - I see Graham of R has posted some similar points while I was writing this)

drmarkf 1st June 2018 11:14 AM

Re: Focusing, for over 50 years I've been getting it wrong.
 
I use FRC at times, but I'm doing more movement of the focus point/area nowadays, for several reasons.

That Digital Photography School article more or less explains the principle of how it can fail, but I reckon there are some other tweaks:

4/3 sensors have got more depth of field than full frame or crop, so our latitude is greater so it's less of an issue for us.

As sensors get higher resolution, minor focus misses will become more obvious, especially if we're printing large.

Modern Oly Pro lenses are mostly fantastically sharp even towards the edges of the frame, so again this may now reveal problems. We (I, anyway) now very often tend to use them at or near full aperture, especially for wildlife shooting, so that is also more likely to show problems because of the narrow dof.

Some otherwise brilliant lenses have got marked warps in their zone of focus - especially for example the Oly Pro 7-14 f2.8 at full aperture - and that can certainly cause issues.

Moving the focus point/area has now just got a lot easier and faster with today's responsive touch rear screens, so that's another reason I'm doing more of it.

How did I do?

[Looks like 3 of us have now done this, but actually we've all covered at least some different issues!]

Dave in Wales 1st June 2018 02:27 PM

Re: Focusing, for over 50 years I've been getting it wrong.
 
Quote:

Originally Posted by RobEW (Post 448226)
I don't have E-M1 II but I have a couple of thoughts occur to me which might be relevant to someone if not to you............

As for why it may not be working well on E-M1 II, I can only guess based on E-M1 Classic. A couple of settings to check. (Cog - C) Rls Priority - setting this to Off will allow photos to be taken before AF has happened. (Cog A) AEL/AFL - gives you the ability to specify whether AF actually happens when the shutter button is half pressed. (If you select Mode 3, then AF won't happen unless you use a different button to invoke it). these options may be in different places on the Mark II.

Thanks Rob, but I think you have the highlighted sentence the wrong way around.
The 'Info' displayed by the camera says, verbatim....'If ON is selected the shutter can be released even when the camera is not in focus in S-AF'

RobEW 1st June 2018 03:56 PM

Re: Focusing, for over 50 years I've been getting it wrong.
 
You're correct. well spotted.

MJ224 1st June 2018 05:20 PM

Re: Focusing, for over 50 years I've been getting it wrong.
 
I think close up shots deserve some thought about DOF etc, but in general the focus on any / most camera's works well.

Pixel Peeping is a disease, IMHO the photo should tell a story, despite technical issues. Those afflicted should really get very strong glasses...………...*chr

RobEW 1st June 2018 06:23 PM

Re: Focusing, for over 50 years I've been getting it wrong.
 
:d

:d

:d

:d

:d

(think maybe I'm too old to attempt smileys / emoticons)

MJ224 1st June 2018 08:34 PM

Re: Focusing, for over 50 years I've been getting it wrong.
 
Out of focus I think................*chr

Ross the fiddler 2nd June 2018 04:14 AM

Re: Focusing, for over 50 years I've been getting it wrong.
 
Quote:

Originally Posted by RobEW (Post 448252)
:d

:d

:d

:d

:d

(think maybe I'm too old to attempt smileys / emoticons)

Let me help you (use a 'p' instead of a 'd'). ;)

:p

:p

:p

:p

:D *chr

OM USer 3rd June 2018 03:39 PM

Re: Focusing, for over 50 years I've been getting it wrong.
 
If you are talking about the minutiae of focussing then its not just pythagorous that matters but field curvature of the lens as the plane of focus is not quite a flat plane.

MJ224 3rd June 2018 04:16 PM

Re: Focusing, for over 50 years I've been getting it wrong.
 
And perhaps air density and humidity.................

Shall we just get on with it...........*chr

Harold Gough 10th June 2018 06:38 AM

Re: Focusing, for over 50 years I've been getting it wrong.
 
In macro, I focus, recompose and refocus manually to my judgement. Failure to check that it looks in focus after I reframe would lead to most of my images being OOF.

Harold


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