Viewfiner AutoFocus Points (???)

[madFive]

So I was looking today at the D600, and trying to decide how many kidneys I’ll have to sell to get one. Decided to open up the user’s manual and peruse the specs to make sure I’m ok with it against the D800. Only feature I’ve found so far that the D600 is missing that I really want is the plug for an external flash, so it will work better with my pocket wizards. With the D600 I will have to keep using my adapter that goes on the hot-shoe on top – not too big a deal I guess. But I digress…

On to my main issue! Why do Nikon cameras always have all the auto-focus points crammed together in the center of the view-finder??? Here’s a few for example:

On my current D90, I feel a bit constrained by the fact that all the focus points are in the middle, so I can’t focus on objects that are closer to the edge of the frame. You never know when you might artistically decide that the focus-point might need to be out in one of the corners, so it’d be nice to have a camera that had, say, 39 or 51 focus points – that way they’d be spread out all over the frame, and I could focus wherever I want! Right?

Wrong. I see in the manuals for the current-gen full-frame cameras that even though they have tons and tons of focus-points, the points are all crammed together right in the center – almost even worse than my current crop camera.

So what gives?? I’m sure there’s a reasonable technical explanation for why they have to build them this way, but I’ve never heard it. Anyone know why this is? And how to you personally get around this issue? I guess I’ve lived with the current view-finder pretty well over the last few years, but I really wanted those points spread out for some additional capability. Discus!

 

[UnknownSouljer]

I am not an engineer, so this is just a theory, but I would assume that it has to do with the way light enters glass, and what sections therefore are the easiest to use to focus. The glass is designed to take all the light from in front of the lens and bring it directly to one area: the center. As you move farther from the center, there is light falloff. It may therefore have something to do then with optimization. Anyway, that's my best guess.

I've wanted points nearer to the edges of the frame as well, but I'm on a 5D2 where I don't really trust any of the points other than the center anyway. As a result, I am in the massive camp of "Focus, Recompose"rs.

 

[MN Scout]

I think it has something to do with the size of the focus module. I assume they are using the same size module for DX and FX. And I also assume that if they wanted to cover the entire frame the focus module would have to me even larger.

I love the coverage that I have on my D300S. Almost out to the very edge. The D600 looks very restricting, and the D800 a little restricting.

D300S coverage. (all three squares show the same thing... just ignore the duplication, and look at the coverage.)

 

[FLECOM]

...I'm on a 5D2 where I don't really trust any of the points other than the center anyway. As a result, I am in the massive camp of "Focus, Recompose"rs.

yep, I am on a 1D2 and have never used an AF point other than the center one

 

[Empty_Quarter]

Technicality aside, to get around the issue, you can always use the focus lock button (AF-L) to drag the focus point out of the "frame".