Focus and Recompose or AF point?

[SuzukiGS750EZ]

Which is better to do, not for composition but for metering and such. I use back button focus so my shutter button does the metering. Does it not matter with back button focus in a static image?

 

[photo1x1.com]

For me that depends on the camera and it´s focussing system. On my Canon bodies, I do focus and recompose. When I shoot fast moving subjects in AF-C, unfortunately I can´t do that and therefore have to crop afterwards.
My Sony mirrorless bodies have focus points all over the place and I can easily pick one that fits. Also it has face (and eye) recognition which helps a lot when taking pictures of people when they move. However, I still find myself focussing and recomposing at times - it has become a habit that is burned deep in my brain.
But for me it is mainly a question of focus than anything else because another habit I have adopted is manual exposure since all my Canon bodies before my latest were never able to expose accordingly. It must be me though, not the camera .

 

[Derrel]

At CLOSE distances and at wider f/stop settings (f/1.8, f/2, f/2.8, f/4), the distance to the edges of a frame can be significantly longer than the distance to the center of what is within the frame. With a wide-angle lens for example, the outer periphery of the frame can be significantly farther than the center of the framed area; with a telephoto lens, the edges and the center would tend to be less-far-separated in actual distance.

The issue may also be complicated by field curvature of the specific lens; some lenses have a lot of field curvature, so the edges and the center might very well be pulled to different focus points. Nikon 35mm f/1.4 is a great example of this, a lens with very strong field curvature; Zeiss also makes a wide-angle that also has tremendous field curvature.

The problem with focus and recompose can easily appear at close distances, and wide apertures, when the actual,measured distance an object is located at, exceeds the depth of field of the shot. At close ranges, it is possible that the depth of field band is a mere one, two,three, or four inches. At 10 feet, measured, with a 30mm E-quivalent lens on a Canon APS-C camera, the EDGES of the frame will exceed the physical distances of the objects in the center of the frame by some five inches....at wide f/stops, this will cause a focusing error that you could probably see, unless the shooting aperture is small, like f/8 or smaller, like say f/10 or f/11.

Using lenses like FAST primes, say 85mm f/1.8 at 10 feet at f/2.0 or f/2.5 or even f/2.8, you'd most likely want to focus using a focus square as close to the final positioning as is practical.

At longer distances, there will be more depth of field, which can make such issues as above nothing to worry about.

 

[dennybeall]

No.

 

[weepete]

For metering it depends on the mode unless you have focus point linked to metering. For spot, partial and CWA as far as I'm aware they are all linked to the centre of the frame in most Canons. So if lighting is dynamic and a good exposure is needed most of the time I just use a central focal point and shoot wide, crop later. If the lighting is pretty static I tend to spot meter and move my focal point. Sometimes I just ballpark the hyperfocal distance, so I focus 1/3rd into the scene so I guess that could be considered focus-recompose.

 

[beagle100]

I agree - no

 

[SuzukiGS750EZ]

Maybe I need to shoot conservatively more often. I do for photos in taking for others but an in the moment shot I try to get it "right" in the camera.

 

[Braineack]

I focus and recompose often, no issues. The D610 has a very small focus area, so even at the edge points, it doesn't allow for a good composition. I also like to use spot meter, so ill often meter, lock exposure settings, find my focus, then compose and shoot.

sill nailing it at f/1.8:


Momo by The Braineack, on Flickr