AF frame coverage

I got an email saying it wasn't fair comparing the D3's AF frame coverage with only the D2X in my recent review, as the D2X is particularly impressive in this regard. Personally I am happy using the D2X/D2H as a benchmark as they were the previous pro-Nikon. But it is a fair point. So I thought I would try and find some AF patterns out there in internet land to compare them. Most hot-linked from DPReview.com

D3:

D300:

D2X:

D90:

D200:

5D Mk2:

1DSMk3:

50D:

40D:

5D:

Since I am not familiar with all these camera's please correct any errors.

Alex

Alex,

As one who has come quite late to this analysis of AF covergage, not thinkng too much of it before (as I was just happy to have any autofocus) is more coverage always better? It would seem that if the coverage is too extensive it could just as easily confuse the camera as to where you want the focal point to be?

Too much can certainly be confusing, but it's all in how the AF system is configured. With the different modes available, you should be able to use the one that's most suited to what you are shooting, as you're not required to have all AF points active all the time.

Too much can certainly be confusing, but it's all in how the AF system is configured. With the different modes available, you should be able to use the one that's most suited to what you are shooting, as you're not required to have all AF points active all the time.

Are the outermost points in a wide coverage setup like the D300 relatively less important. Put another way, when configuring your AF, how important are the widest points in most cases, at least underwater?

Hi Jeff,

It depends where you want your subject. If you always want it in the middle of your frame or the subject is big and fills most of the frame then most AF layouts are fine.

Particularly with macro I value the chance to place my point of focus away from the centre of the frame. The subject may fill the frame - but say you want the eye to be the point of focus and in some unusual place in the frame then having an AF sensor in that part of the frame is very useful. For me, the minimum is to have the AF points covering the centre and thirds (including intersections) of the frame. As these are places within the frame it is common to place a strong compositional element (where you have a desire to keep it sharp).

Many just use the central AF point, lock focus and then recompose and shoot. I don't favour this approach underwater where it is not possible to be completely still (in terms of macro depth of field), unless you like to lie across the scenery, but to do accept it is horses for courses. Many find AF-Lock and recompose (I think * button on Canon) works well.

To quote from my review:

"Of course the camera has an AF lock button, with a lever that falls right below your thumb on the Subal housing, but I do not favour such a solution. Particularly with macro shooting, I want to have my AF point right on a key feature, such as an eye, ensuring it is razor sharp in my preferred composition. Surely this is more desirable that focusing, locking focus and recomposing while all the time trusting that neither you nor the subject moves."

In every instance, having good frame coverage with AF points is advantageous, since all the cameras I have used allow you to select them singly or in groups and to turn others off. But you can select them or turn them on when needed.

Alex

Ive gotten so used to having an autofocus point on any of the 'thirds-rule' areas on my D2x, that I am completely baffled that the D3 wouldnt have AF points there. How insane is that.

d2x looks the best to me of the examples.

the rest seem far too centre weighted

the d300 is mind boggling with all those areas, but i see no point to them all so bunched together and leaving 40% or more of the frame uncovered?!?

my d70 has 5 points and i don't think then push far enough out to the edges, 12 would be great, 3 rows of 4. that would be about perfect

5dmark2 looks like it only covers 20% of the frame??! that seems a bit weird

another reason to buy a D300 for almost 1/3 the price of a D3! The D3's coverage makes me scared to use it. I agree with alex on composing subjects with continuous focus to the edge of the frame, do it all the time.

What about the D700, is it the same as the D3? Can any owners chime in.

another reason to buy a D300 for almost 1/3 the price of a D3! The D3's coverage makes me scared to use it. I agree with alex on composing subjects with continuous focus to the edge of the frame, do it all the time.

 

What about the D700, is it the same as the D3? Can any owners chime in.

D700 is the same as the D3

the cam 2000 (d2x/h) focus points are not on the classic rule of thirds points, they would be closer to a 4x4 pattern. the cam 3500 on the d300 has points closest with it's 100% view finder. the 1.6 crop canons and the cam 1000 (d200, d90) are on the thirds horizontally but well off vertically due to the 95% vf. a bit of product shooting on a cropped vf makes discrepancy's fairly obvious.

that being said the corner focus of the d2H,d2X points being cross type are just so bloody quick with a slight recompose it's a really great straight forward way for classic 4x3 or 5x4 shots.

on focus tracking, the cam 3500 also uses the 1005 point colour matrix meter. this can let a subject leave the focus points for example, on the left, go out of focus and go around the top or bottom of the focus points and so long as it remains with in the view finder, enter the focus points on the right, where it will be re focused upon. which is nice.

Particularly with macro I value the chance to place my point of focus away from the centre of the frame. The subject may fill the frame - but say you want the eye to be the point of focus and in some unusual place in the frame then having an AF sensor in that part of the frame is very useful. For me, the minimum is to have the AF points covering the centre and thirds (including intersections) of the frame. As these are places within the frame it is common to place a strong compositional element (where you have a desire to keep it sharp).

 

Many just use the central AF point, lock focus and then recompose and shoot. I don't favour this approach underwater where it is not possible to be completely still (in terms of macro depth of field), unless you like to lie across the scenery, but to do accept it is horses for courses. Many find AF-Lock and recompose (I think * button on Canon) works well.

I'm with you on this one Alex. As one of those D3 owners who hasn't gotten organized enough to share underwater shots and reviews yet (shame, shame), I'll at least mention that your criticism of the focus points seems very fair to me. When shooting macro with the D3, I found myself often having to recompose and shoot, when I wanted instead to use something other than the central AF point.

It would've been a bit more complicated for Nikon to design separate frame coverage patterns for the D3 and D300, as well as to disable the appropriate ones when a DX lens got slapped onto a D3 body, but I think it would have been well worth it.

Thanks a ton for posting that D3 field review too, by the way. That was incredibly useful and well put together.

Liz

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http://lizhanks.com/

Alex:

How do you do the "View finder" shots at the beginning of this thread?

They are stolen (sorry, hotlinked) from DP Review.com.

Alex