Focus-Recompose is fundamentally unsound...?

[StewartR]

This cropped up in another thread but to my mind it's so important that it needs airing with a catchy thread title.

This article Why Focus-Recompose Sucks (http://visual-vacations.com/Photography/focus-recompose_sucks.htm) says that focussing on the centre of the frame and then recomposing is fundamentally unsound and guaranteed to cause focus errors.

Is it really true? Can any knowledgeable POTN members confirm or deny?

<edit>
Credit to cosworth for finding the article in the first place.

[Curtis N]

As stated in the article, it depends on certain factors related to geometry and depth-of-field. Understanding those factors help in determining when to use this technique and when it might cause a problem.

[tweatherred]

At some point during the next few days I may test this out, if I get the time.

[SonyaL]

Sorry I misunderstood.
Sonya

[Longwatcher]

I can verify this quite easily as I experienced it this past weekend.

Especially when shooting at f1.2 on a 85/1.2. I even used one of the outer focus points and it didn't always make it so I had to focus and recompose and although not as bad as if I had used the center focus point, it will still back focus frequently (although just a little - but just a little at f1.2 is enough to notice it).

At F8 I usually didn't bother recomposing as I could get close enough.

[Curtis N]

when you are shooting in the shade but the background is brightly lit if you dont do this then what you will get is a blown out background. With Center focusing its possible to expose both background and subject both in some situations.Sonya,

Focusing and metering are different things. While proper metering is especially important when the background is considerably lighter or darker than your subject, it's unrelated to the focus-recompose technique.

However, if your camera is set to lock the metering at the same time it locks focus (by pressing the shutter half-way), then the focus-recompose technique opens up a whole new can of worms, especially with evaluative metering (which concentrates on the active focus point) or partial metering.

The ability to focus-recompose without screwing up the metering is one of many reasons to use custom function 4-1 and focus with the * button.

[StewartR]

The ability to focus-recompose without screwing up the metering is one of many reasons to use custom function 4-1 and focus with the * button.Indeed. Now if only we could be confident that we had the ability to focus-recompose without screwing up the focussing!

[Mark_Cohran]

With shallow dof, focus-recompose is definitely an issue, however, for smaller apertures and deep dof, this is much less of an issue.

Mark

[CyberDyneSystems]

It has it's downsides,. learn to use focus points other than the center point to overcome this.

[Bodog]

Unfortunately the focus points don't always line up with how I want to frame the shot...

[SonyaL]

I edited my post I didnt I thought yall were talking about something else.


Sonya

[SkipD]

Indeed. Now if only we could be confident that we had the ability to focus-recompose without screwing up the focussing!I use focus-recompose quite frequently. I just make sure that the distance between the camera and the point on the subject that I do my focussing is the same as the distance between the camera and point (plane) on the subject where I want the final shot focussed.

I always use the Custom Function 4 = 1 and always use the center focussing point only whenever using autofocus.

At times, I will tweak my focussing manually and not push the * button (thus not activating autofocus at all). All of my lenses allow full-time manual focussing.

[Longwatcher]

It has it's downsides,. learn to use focus points other than the center point to overcome this.

45 focus points and not one of them close enough to make it :)

I did have focus points on my "yeah, that would be nice to have" list, but since Sunday, I have moved it to the "I definately would appreciate it if Canon would give me at least a couple more focus points farther out (say another 10 points - 2 each end, one each tob/bottom, and one each half way to corner (at least 1 each at the 1/3 point)" list.

Even if they only work with say an 85/1.2, 50/1.4, and 200/1.8, thats when I need them (not that I have a 200/1.8 but I can dream) at F2.8 they are good enough.