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andym
9th December 2007, 11:53 AM
Just a copy of a post I made on 4/3 user this morning in answer to Ian's question about focus points.

Just a few observations from playing around this morning.

1 However I set release priority either on or off I the shutter will still release if its focused or not.With the release set to off the focus seems to stutter a bit more.
I thought the shutter should not fire if the priority was set to on(or is it off??).

2 If you review the images on the camera on the viewing screen on the info page that shows the 4 coloured histograms and shooting information it also shows a red square on the image as to which focus point the camera has chosen.This focus point does not appear on every image so I assumed this does not appear if the camera is not focused.I dont think this is the case as when I look at the images on my PC some where the square is not present are in focus.
I assume somewhere in the EXIF data the used focus point is shown.

3 When I set the camera to single auto focus and with all 11 focus points and plug away with the shutter the results seem much better and also the red focus point square is show on every shot!!!

4 I'm not sure if there is any difference between the five point diamond focus configuration and single large,is this just a diferent term for the same thing.
I have been using single small for most of my images as this seems best form my style of image.

Just a few thing to mull over.

Hope this makes sence

All the best

Andy

Ps I'll post this over on 4/3 user also.

emirpprime
9th December 2007, 06:48 PM
Numbered replies below.

1 - I think, from what I have found without testing, is that it will realease when it gives up trying to focus. However is set to release proprity S, it will release as soon as you press the shutter.

4 - The point of the diamond mode is to set 'back up' sensors to use for focussing, ie, it will try and focus with the set point (usually the centre of the diamond), but if it cannot it will use the other points in the diamond. Single point however if better for really precise focussing, eg on the eyelashes not eyeball. The differences between single point small and large is smaller, but makes it even more precise, but in this mode it won't use another point if it cannot focus using the selected point.

I don't have anything to say about the other points i'm afraid.

Hope that helps a bit.
Phil

R MacE
10th December 2007, 10:43 PM
You may have already seen this, if not then it attempts to explain how the 11 point AF works.

http://www.olympusamerica.com/e3/speed.asp

Ian
10th December 2007, 11:07 PM
You may have already seen this, if not then it attempts to explain how the 11 point AF works.

http://www.olympusamerica.com/e3/speed.asp

I had a look there but didn't really find anything that explained how the 11 point mode makes its initial focus selection.

Ian

R MacE
11th December 2007, 01:38 AM
You're right, it doesn't fully explain how it works. My guess is that it picks the closest subject initially, probably weighted to the 6 center points of the frame and then uses the distance information to continue tracking the subject.

Nick Temple-Fry
11th December 2007, 02:39 AM
My experience would suggest that it is not necessarily the nearest - contrast plays some role in the selection - so if you shoot a bird amongst branches and one branch is highlighted against a bright background then that will be the chosen focus point, whether or not it is closer.

I think the E3 requires you to think far more beforehand about how you want focussing to work, there are a plethora of options (mayhaps an opportunity for Olympus to record a 'masterclass')

Nick