D800 AF points

[marcmccalmont]

How do I set up the D800E to illuminate all 51 AF points?
Been trying all morning w/o luck?
Marc

[langier]

Even if the AF is set to 51 points (a click of the sub-command dial away from 3D AF), it will only show the one AF spot, I believe. Illumination of the AF point is set with custom setting A5.

One thing I've found is that if you want the AF to illuminate red in the dark, you only get a frame on all the crop modes. If you want the crop mode settings to gray-out the frame, you loose the AF spot illumination.

Just another idiosyncrasy of the D800 to learn to accept until/if they ever get the menus organized and updated.

HTH,

[marcmccalmont]

Thanks, I thought I was doing something wrong? But it is still Autofocusing using the 51 points right?
Marc

[Stephen Starkman]

Yes. It will first try to focus using the focus point you've chosen (lock on) and will then utilize the other points if the subject moves from the initial point.

If you set AF-C and 3D, you can actually observe this behaviour in the viewfinder (3D adds colour info to the subject tracking, as well, I believe, using 51 points).

S.

[Ray]

Marc,

With +51 dynamic area AF the autofocus system will predict focus using the AF point chosen - could be any of the 51 points. If the subject moves across the frame or finds an area of better contrast it will use one of the surrounding (50) AF points which are on call if needed.

On the D4 and D800; +9 dynamic area AF, +21 and +51 also utilises the colour meter (emphasis, secondary to contrast) - D3 series +dynamic 9/21/51 didn't (other than 51 3D focus tracking).

Auto area AF predominantly use colour information and face recognition technology to try and point the AF system (contrast) in the right direction.

The more tasks you give the cameras AF brain the slower the response - depends on the type of action. From experience, less is more - provided user has good hand eye coordination, one or +9 dynamic area AF is the most responsive.

One or +9 dynamic area AF works very well for fast moving sport (occasionally +21 dynamic area AF), +51 dynamic area AF, 51 3D focus tracking (colour + distance) and auto area or okay for less demanding movements.

It is also important to set the correct focus tracking with lock-on settings to cater for abrupt changes in focus distance - e.g. subject being tracked when another person or object comes between you and the main subject. Longer tracking timings ignore the abrupt focus change (obstruction) and tell the AF to keep tracking as if the obstruction didn't exist - shorter timings instruct the AF system to quickly drive the lens to the new focus distance measured - it's all about mathematics.

Nick,
Thanks for this description of focussing options. I have just two Nikkor lenses, the 14-24/2.8 and 24-120/F4. Since receiving my D800E a few days ago, I've experienced a few puzzling results with the 14-24 at 14mm.

My first option was to set the camera to 11 autofocus points. I'd prefer just the one autofocus point, but this doesn't appear to be an option, although I see only the one focus point in the viewfinder, which can be moved around using the multi-selector wheel on the back of the camera.

The first few test results at 14mm, of a rural scene with very slow-moving river, using a range of apertures, produced a few images which weren't sharp at any point in the scene, despite the fact that the shutter speed was clearly adequate. It's as though the lens was sometimes focussing beyond infinity. Other times, when focussing on the foreground at F2.8, to check focussing accuracy, I was surprised that the foreground wasn't sharp, but some other significantly more distant part of the scene was sharp instead, as though the focus point had shifted on its own accord.

I'm wondering if the cause could be that the selection of 11 autofocus points, instead of 51, resulted in the focussing being more responsive to movement in the scene away from the point I was focussed on. For example, I'm focussed on a tree trunk about 10 metres away, at F2.8, and on the other side of the river bank, about 50metres, away there's a tall tree swaying in the breeze which the camera automatically locks onto, despite my wishing to focus on the nearer point.

Perhaps this is just a characteristic of a very wide-angle lens. At 21mm and 24mm I didn't notice such issues, or at least the focussing wasn't so so far out.

Looks like I'll have to do some more tests using the various focussing options. Perhaps either the lens or camera is faulty.Today is ideal because it's windy and there are lots of trees swaying around.

[marcmccalmont]

Nick,
Thanks for this description of focussing options. I have just two Nikkor lenses, the 14-24/2.8 and 24-120/F4. Since receiving my D800E a few days ago, I've experienced a few puzzling results with the 14-24 at 14mm.

My first option was to set the camera to 11 autofocus points. I'd prefer just the one autofocus point, but this doesn't appear to be an option, although I see only the one focus point in the viewfinder, which can be moved around using the multi-selector wheel on the back of the camera.

The first few test results at 14mm, of a rural scene with very slow-moving river, using a range of apertures, produced a few images which weren't sharp at any point in the scene, despite the fact that the shutter speed was clearly adequate. It's as though the lens was sometimes focussing beyond infinity. Other times, when focussing on the foreground at F2.8, to check focussing accuracy, I was surprised that the foreground wasn't sharp, but some other significantly more distant part of the scene was sharp instead, as though the focus point had shifted on its own accord.

I'm wondering if the cause could be that the selection of 11 autofocus points, instead of 51, resulted in the focussing being more responsive to movement in the scene away from the point I was focussed on. For example, I'm focussed on a tree trunk about 10 metres away, at F2.8, and on the other side of the river bank, about 50metres, away there's a tall tree swaying in the breeze which the camera automatically locks onto, despite my wishing to focus on the nearer point.

Perhaps this is just a characteristic of a very wide-angle lens. At 21mm and 24mm I didn't notice such issues, or at least the focussing wasn't so so far out.

Looks like I'll have to do some more tests using the various focussing options. Perhaps either the lens or camera is faulty.Today is ideal because it's windy and there are lots of trees swaying around.

Ray
I think single shot forces single point focus and continuous enables multipoint focus
Marc

[Ellis Vener]

My first option was to set the camera to 11 autofocus points. I'd prefer just the one autofocus point, but this doesn't appear to be an option, although I see only the one focus point in the viewfinder, which can be moved around using the multi-selector wheel on the back of the camera.

You should be able to select a single point while holding down using the button in the AF  and using the main control wheel.

The first few test results at 14mm, of a rural scene with very slow-moving river, using a range of apertures, produced a few images which weren't sharp at any point in the scene, despite the fact that the shutter speed was clearly adequate. It's as though the lens was sometimes focussing beyond infinity. Other times, when focussing on the foreground at F2.8, to check focussing accuracy, I was surprised that the foreground wasn't sharp, but some other significantly more distant part of the scene was sharp instead, as though the focus point had shifted on its own accord.

If you have not already done so use the AF micro-adjustment to tune your individual body's AF system to your lens.
if your camera is mounted on a tripod, use the camera's Live view AF system. pick the point where you want focus to be and tap the "+" sign a couple of times to get to a 100% (1:1 sensor pixel to display pixel mapping) view. For landscape and architectural work, once i see that prime spot is definitely in focus I switch either the lens or body to manual focus mode. I do this for Canon's, Nikons and Phase One cameras.

I'm wondering if the cause could be that the selection of 11 autofocus points, instead of 51, resulted in the focussing being more responsive to movement in the scene away from the point I was focussed on. For example, I'm focussed on a tree trunk about 10 metres away, at F2.8, and on the other side of the river bank, about 50metres, away there's a tall tree swaying in the breeze which the camera automatically locks onto, despite my wishing to focus on the nearer point.

That sounds like you have the camera's AF system  set to look for motion tracking.

Perhaps this is just a characteristic of a very wide-angle lens. At 21mm and 24mm I didn't notice such issues, or at least the focussing wasn't so so far out.

it isn't a characteristic of the 14-24mm. I'd look at how you have set up the camera.

Looks like I'll have to do some more tests using the various focussing options. Perhaps either the lens or camera is faulty.Today is ideal because it's windy and there are lots of trees swaying around.

Sure the lens could be at fault  and so could the camera's AF system  but I'm inclined to look for simpler more basic explanations first. Are you new to Nikon?

[Ray]

That sounds like you have the camera's AF system  set to look for motion tracking.

Hi Ellis,
You're right. Focus tracking with lock-on was enabled by default when I received the camera. Problem solved, for the time being. However, it's still a mystery how I could have got some shots which were not in focus at all in any part of the scene, and at F8 too.

Could it be that the focus tracking latched on to some movement in the corner of the frame where image quality is so degraded on full-frame that I couldn't discern that it was the real focus point when examining the processed image?

[Ray]

Ray
I think single shot forces single point focus and continuous enables multipoint focus
Marc

Thanks. That could be part of the problem too, although I've never seen multiple focus points through the viewfinder yet. I'm really not enthralled by 400 page manuals, but I guess I'll have to force myself to read this 447 page D800 manual. 

[Ray]

I would strongly recommend deactivating the shutter button AF and operate the AF via the AF-ON back button - custom function a4 - AF-ON only. It allows greater flexibility - the moment you release your finger from the AF-ON button the AF is locked. The AF-ON button also saves accidentally tripping the shutter button at the wrong moment whilst half depressing the shutter button to activate the AF - sporting disciplines such as golf.

In AF-S I also prefer 'release' priority over focus priority. The most accurate method with AF systems is to compose the subject and move the AF point to coincide with the area to be focused without moving the camera. If the key area of interest to focus on is outside the AF points you will have to swing the camera until one of the outer AF points covers the subject and recompose. After recomposing if you are using focus priority the camera will refocus using the current AF point which may not be where you want critical focus (background instead of foreground). With release priority using the back button, after you have focused and released the AF-ON button, the focus stays locked and you can trip the shutter at will, knowing the camera will not refocus.

Thanks, Nick. That's a good tip. I've taken your advice and find I can now use those two buttons, AE-L and AF-ON to great effect in aperture priority mode. The way I've got it set up for the moment is, pressing the AF-ON button does all the focussing rather than the shutter release button. Having focussed, after moving the focus square with the multi-selector wheel as close as possible to the object I want to be in sharp focus, I then have the option of keeping my thumb on the button or removing it. Keeping the button depressed locks both focussing and exposure. Removing one's thumb allows the autoexposure to readjust to changing lighting conditions as one recomposes the image, but keeps the original focussing locked. In fact, with focussing locked, one can then swing the camera around in the opposite direction in order to get an autoexposure for, say, a bright sky which one doesn't want to be blown. Having achieved what appears to be a good exposure for the sky, one can then lock that exposure by pressing the AE-L button, recompose the image again, and with thumb still on AE-L button, press the shutter-release button with forefinger.

Of course one might not find this approach ideal with a Canon 5D3, for example. One might lock focussing on a subject in the shade, near the bottom corner of the image, then swing the camera around to get an exposure for the sky which one also locks, then find later during processing that the main interest which has the best focus is spoiled as a result of being too noisy because of the camera's limited dynamic range.  (Sorry, Canon guys. Couldn't resist  ).