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GRAHAMJ
6th July 2012, 06:41 AM
Good morming people, I have a question about the Focus point on the OMD. In fact 2! Is it possible to change the size to smaller and how do you stop it from moving around the grid when ever it wants to?
I, being a sad person with loads of spare paper and too much time on my hands, have download the manual to read but I must be missing were it is in it.

Many thanks.

Graham

Loup Garou
6th July 2012, 11:36 AM
I know what you mean. In the Auto mode it reads the full frame but in P, A, S and M modes you can set it manually to what you wish. Go to the Super menu by pressing the button to the right of the hotshoe, choose the focus grid and the central rectangle (if that is what you prefer) by moving the arrow buttons. You'll quickly find out how it works.

StephenL
6th July 2012, 12:26 PM
Unfortunately, you can't reduce the size of the focus point, except in manual focus magnified view. However, a crumb of comfort is that it seems to be pretty precise on the focus point being the dead centre of the square.

Loup Garou
6th July 2012, 01:23 PM
I can understand that the focal 'point' grid is a bit big in the auto but why would anyone want to change it in the other modes? I thought the smaller rectangle is quite narrow and you can alter its position in the focus grid to suit your choice.

peak4
6th July 2012, 05:09 PM
Unfortunately, you can't reduce the size of the focus point, except in manual focus magnified view. However, a crumb of comfort is that it seems to be pretty precise on the focus point being the dead centre of the square.

Oh yes you can, I hadn't realised until it was pointed out to me by Zuiko *chr

If you set Fn2 to multi-use Magnify; press Info and or Fn2 until the green square appears, then hit Info, and you can zoom the green square to different sizes. press info or Fn2 again and it remembers the size even when you change modes.

StephenL
6th July 2012, 06:02 PM
Unfortunately this doesn't work if you have the histogram or highlight/shadow clippings display, which is how I work.

peak4
6th July 2012, 06:15 PM
Unfortunately this doesn't work if you have the histogram or highlight/shadow clippings display, which is how I work.

So do I broadly, If I can stand the larger focus area then I just carry on as normal.

If on the other hand I want something more precise, I leave the camera set to histogram for general framing, zooming exposure control etc. but just before firing the shutter, a short press of Fn2 displays the smaller focus area and after release a longer press resumes the histogram display ready for the next shot.

Not ideal perhaps, but the best I've found so far.

PeterBirder
6th July 2012, 10:18 PM
So do I broadly, If I can stand the larger focus area then I just carry on as normal.

If on the other hand I want something more precise, I leave the camera set to histogram for general framing, zooming exposure control etc. but just before firing the shutter, a short press of Fn2 displays the smaller focus area and after release a longer press resumes the histogram display ready for the next shot.

Not ideal perhaps, but the best I've found so far.

Yes that's what I do. Works OK for me.

Regards

Ross the fiddler
7th July 2012, 08:30 AM
The other way I get the focus point & size is when I use the touch to focus setting to give me the focus point exactly where I want it & the size can be adjusted at the right hand side slider. After that, I can still use the EVF if I want. The smallest setting (at 14 X) is ideal for photographing birds in trees & concentrating on their eyes.

GRAHAMJ
9th July 2012, 07:09 AM
Thanks for the help I will try all your ideas out to see which one I prefer.

Many thanks

Graham

ayewing
9th July 2012, 10:52 AM
Thanks to all who contributed to this most useful thread. This is just the sort of information I am struggling to find in the manual. I am most impressed that it is possible to adjust the size of the focus point - a most useful feature when trying to focus on a small bird and not on a leaf in front or behind it.

Having taken delivery of my OMD a week ago I have sorted out most of the "standard" settings but I think the learning curve will continue for some time as I explore the more subtle capabilities of this remarkable camera.

Archie

StephenL
9th July 2012, 11:44 AM
To be picky, I'm not sure that this alters the size of the "focus point" at all. After all, the focus point is just that - a point. It will always be in the centre of the box, no matter what size the box is. You cannot adjust the position of that point within the constraints of any of the fixed-size 35 squares, or AF Targets as Olympus calls them (p44/45 of the manual).

What it does do is allows you to aim with more accuracy.

andym
9th July 2012, 11:53 AM
To be picky, I'm not sure that this alters the size of the "focus point" at all. After all, the focus point is just that - a point. It will always be in the centre of the box, no matter what size the box is. You cannot adjust the position of that point within the constraints of any of the fixed-size 35 squares, or AF Targets as Olympus calls them (p44/45 of the manual).

What it does do is allows you to aim with more accuracy.

Tend to agree with you Stephen.In my mind the focus box is square ,the box you see after magnifying and setting to x14 is oblong which I think is just showing the magnified size.

Ross the fiddler
9th July 2012, 02:21 PM
To be picky, I'm not sure that this alters the size of the "focus point" at all. After all, the focus point is just that - a point. It will always be in the centre of the box, no matter what size the box is. You cannot adjust the position of that point within the constraints of any of the fixed-size 35 squares, or AF Targets as Olympus calls them (p44/45 of the manual).

What it does do is allows you to aim with more accuracy.

Tend to agree with you Stephen.In my mind the focus box is square ,the box you see after magnifying and setting to x14 is oblong which I think is just showing the magnified size.

Thanks, I'll have to investigate that further, but it seems to select the birds in the branches better. :confused:

StephenL
9th July 2012, 02:35 PM
Thanks, I'll have to investigate that further, but it seems to select the birds in the branches better. :confused:

Perhaps because, by using a smaller box, there's less room for error when aiming. But if you could accurately estimate where the exact centre of any box were, you'd achieve more accurate focussing?

The other possibility, which I've just thought about, is that within any box the camera focusses on the closest object. So by using a smaller box, there's less room for the focus point to wander around.

PeterBirder
9th July 2012, 05:41 PM
To be picky, I'm not sure that this alters the size of the "focus point" at all. After all, the focus point is just that - a point. It will always be in the centre of the box, no matter what size the box is. You cannot adjust the position of that point within the constraints of any of the fixed-size 35 squares, or AF Targets as Olympus calls them (p44/45 of the manual).

What it does do is allows you to aim with more accuracy.

I'm not sure this is right but stand to be corrected.

With phase detect there is a separate pair (or two pairs for cross point) of physical sensors for each "focus point".
With contrast detect the data from the main (only) sensor is subjected to mathematical analysis, by firmware ,of the relative amplitude of the signal from adjacent pixels. A large difference will indicate high contrast which is interpreted as "in focus" and a small difference as low contrast/out of focus. No doubt some form of average (possibly "centre weighted") over the whole box is computed. The size and shape of the box should not be too critical and in fact a smaller box should make focus more precise.

If my hypothesis is correct it explains all of the following.
1/. If you use the default matrix of all boxes the camera often picks an area of the scene which is not where your subject is. This is because your subject may not be the highest contrast part of the scene.

2/.Face Detection works. Faces are actually low contrast so the processor first looks for areas of low contrast and then defines them as focus boxes on which it performs its focus operation.

3/.Eye Detection. This is the clincher for me. To focus on an eye (and allow you to dictate left or right) the processor must create a focus box that matches the size of the eye within the overall image and then perform the focus operation.

Trust me, I used to be an electonics engineer.:eek:

On second thoughts ask Snaarman, he is an electronics designer.*yes

Regards.*chr

StephenL
9th July 2012, 05:51 PM
As my father used to say, I'll retire with my neck in a knot! :D

PeterBirder
9th July 2012, 06:36 PM
As my father used to say, I'll retire with my neck in a knot! :D
Hehe, not heard that one before, I think I know what you mean.:)

Regards.*chr

dko22
9th July 2012, 09:17 PM
However, a crumb of comfort is that it seems to be pretty precise on the focus point being the dead centre of the square.

Now that's useful, Stephen. However, such is my lack of trust in AF systems, I prefer to do a MF in anything with a layered texture, above all for flowers. If you can avoid touching the focus ring when you don't want to, AF + MF can work well in magnification. If you want to focus on something really small in a different plane from anything thing else then AF often seems to fail wherever you try. But, if it ever dries out sufficiently to take any photos at all, I'll experiment a bit with exact centre of spot.

David

Ross the fiddler
9th July 2012, 11:24 PM
To quote the manual on page 45,
"Zoom frame AF/zoom AF
You can also zoom in on an area of the image in the monitor and adjust focus. Choosing a high zoom ratio allows you to use autofocus to focus on a smaller area than is normally covered by the AF target. You can also position the focus target more precisely."

I believe this is telling me that I can adjust the actually AF area & when I use the smallest size (largest magnification), it allows a more precise focussing area, but for general use it doesn't cover enough area for a quick, reliable focus unless there is a concentration of contrasting detail.

It is interesting how it is activated on this page & a little clumsy, where-as the "touch to focus" method I described, makes it quick & easy. I'm not sure, but I think it is available from the "info" selection because I last used the F2 button in "magnification mode" (of the multifunction set). That's something else I have to verify.