D800 AF-S priority selection, a rant

<p>I have just received my new D800 and, much to my distress, I have discovered a bug/feature which has been previously discussed in <a href="../nikon-camera-forum/00aZ5a">this </a>forum.<br>

<br /> I refer to the fact that CSM a2 (AF-S priority selection), when set to <strong>focus</strong> priority, has <strong>no effect</strong> on limiting the shutter release only to situations where the subject is <strong>in focus</strong>. In particular in the case where the AF-Activation (a4) has been set to AF-ON only.<br>

<br /> What surprises me is the fact that several knowledgable contributors to Pnet have seen fit to defend this change in behavior as a feature which, in some (undefined) circumstances, is desirable. I suppose I am posting this rant in the hope that some defender of this change can precisely describe a situation where the change solves a problem that could not otherwise have been handled (with equal ease) by the earlier functionality as found in my D700. Perhaps then I will feel better and be less aggrevated by Nikon's blunder.</p>

<p>In my case, since I do not use the AF-ON button, there is no change to me. However, if you have been a regular user of AF-ON, this change can be very annoying.</p>

<p>There is little doubt that Nikon made this change on purpose. Whether that is a welcome improvement or it is a blunder is a matter of opinions. I am sure that every time you change something, there are people who are pro and are against it.</p>

<p>If you use the AF-ON button as intended, won't your images always be in focus before you press the shutter?</p>

<p>If indeed Nikon made this change on purpose, I still fail to see what the purpose is. The change consists (IMHO) solely of removing a function without replacing that function with another (perhaps to some preferrable) alternative behavior. I cannot conceive that this results from anything less than careless oversight.</p>

<blockquote>

<p>If you use the AF-ON button as intended, won't your images always be in focus before you press the shutter?</p>

</blockquote>

<p>Yes & No. With the CSM settings as I specified; i.e. autofocus implemented only by the AF-ON button. Once pressed the object under the active focus point is in focus. If the button <strong>is then released</strong> and you reframe, such that the object under the active focus point is no longer in focus, it is now possible to release the shutter, while with the earlier implementation, the shutter would not fire.</p>

<p>Now it could be argued that the new behavior allows one to focus (using a <strong>press and release</strong> of the AF-ON button) and then reframe and shoot while keeping focus locked on the originally focused point. The earlier (D700) implementation accomplishes the same end, requiring only that the AF-ON button remain depressed while reframing.</p>

<p> </p>

<p>I had filed a bug report with Nikon Canada about this.</p>

<p>After a number of weeks they closed the report ... when I complained that they had not communicated anything to me ... they sent a message indicating that this behaviour is "as designed" in other words, if you have release priority set to "Focus" and you program focus acquisition to the AF-ON button only (no half press of the shutter release), the shutter will fire regardless of whether or not anything is in focus.</p>

<p>Complain to Nikon, maybe they will reconsider if there are enough complaints.</p>

<p>The same situation holds true for the D4</p>

<p>Lorne-<br>

I have filed a bug report/complaint with Nikon. I have very little hope for a positive response. I have been using Nikon DSLRs since the D200 and have kept myself informed on the subject. To my knowledge Nikon has never once published a firmware update in response to consumer complaints and requests to change camera operating parameters. The only firmware updates issued have been to correct gross camera malfunctions.</p>

<p><em>"If the button <strong>is then released</strong> and you reframe, such that the object under the active focus point is no longer in focus, it is now possible to release the shutter..."</em><br>

<br>

That is exactly what I would expect and want to happen. Isn't that the point of prefocusing? When you reframe, the object under the active focus point would likely/typically <strong>not</strong> be in focus <strong>intentionally</strong>. When I prefocus, I would be highly irritated if I<strong> could not release</strong> the shutter exactly when I wanted to after prefocusing regardless of what is in or out of focus in the frame.<br>

<br>

</p>

The purpose of the modification is so

that you can use focus and recompose

with AF-ON and have the camera

interrupt focusing when it considers

focus accurate, rather have the user

guess. Previously when using AF-ON to

focus, you could not do this. In release

or focus+release mode, it is the user

who must decide when to stop

depressing AF-ON and there is no

guarantee of the outcome. The only

way to use AF-ON and be sure it had

reached focus was to use focus priority

and not recompose at all, which limits

compositional options. I use AF-ON with

release+focus priority and accept some

uncertainty because I can do all my shot

without having to change any focus

setting, ever, using this combination of

settings, as long as an AF-S or manual

focus lens is used. Lack of modality

helps achieve results since the camera

is always set up the same way, ready for

any situation. I do switch exposure

modes from time to time though.

Mike, I understand that the real issue is that the camera is doing something other than is expected and what you think you are telling it to

do when you set up the priority selection. It does not make any sense. In the D800/e case you are stuck with using only the shutter

release in focus priority and once you isolate the focus from the shutter release focus priority is turned off. This seems to be true for both

AF-C and AF-S. Given the cost of this camera you would think Nikon would have gotten it right. Sorry I missed out on the D700 though

my D3s works correctly the same way as the D700. I wonder if this is a change that has to do with live view or video? The owners

manual was not helpful. I think you will otherwise love this camera and Nikon has come a long way from when you had own a Fuji S2 to

get the most out of your Nikon lenses. Good ranting:) Andy

Ilkka: I'm confused - I didn't know release/focus/release+focus had any effect on when focussing stops (AF-S vs AF-C). Can you elaborate?

 

Elliot: You could always focus and recompose with release priority (though I don't entirely understand, Ilkka seems to say not perfectly).

Focus priority and separating the focus from the shutter release button gave you the ability go trigger the shutter when something moved

into focus (compose, then shoot when something moves to the right place - a bird flying through the air in front of a nest is a typical

example). It's annoying that it doesn't work with manual focus (unchipped) lenses, but more annoying that it doesn't work at all on the D800.

Canon dropped trap focus a few generations ago too - it was one thing that made me switch to Nikon.

 

You can still get the effect by using a manual focus lens chipped with an autofocus chip, so the camera thinks it's trying to focus the lens

while it's checking for focus. Having to switch lenses is a bit annoying, though.

<blockquote>

<p><em>"If the button <strong>is then released</strong> and you reframe, such that the object under the active focus point is no longer in focus, it is now possible to release the shutter..."</em><br>

That is exactly what I would expect and want to happen. Isn't that the point of prefocusing?</p>

</blockquote>

<p>Elliot, you are quite right; (if you are familiar with the modified behavior of the D800) that is what you would expect to happen when you wish to prefocus (using the AF-ON button) and then reframe, while retaining the originally prefocused point in focus.</p>

<p>However, as I mentioned above, one can achieve the same result with the earlier (D700) implementation by a simple change in technique. Press the AF-ON button to focus and then <strong>maintain this button depressed </strong>while reframing and shooting. In this case having AF-S Priority set to FOCUS does not prevent the shutter from firing. While the D800 implementation may make it easier (for some) to prefocus and reframe, the change comes at the cost of completely eliminating the possibility of trap focus.</p>

<p>Ilkka makes a similar point, however I am not familiar with the use of RELEASE or FOCUS+RELEASE mode when using the AF-ON button in <strong>AF-C mode</strong>.<br>

In the earlier (D700) implementation it is clear that, when in<strong> AF-C mode</strong>, the use of the AF-ON button to achieve focus makes it impossible to prefocus and recompose. Thus the modification allows one to leave the camera set to <strong>AF-C mode</strong> and still prefocus and recompose. Previously the solution was to switch to <strong>AF-S</strong> mode when one wishes to prefocus and recompose. An inconvenience perhaps to some, but the change comes at the cost mentioned above.</p>

<p>On re-reading Ilkka's response I do not understand the following:</p>

<blockquote>

<p>"The purpose of the modification is so that you can use focus and recompose with AF-ON and have the camera interrupt focusing when it considers focus accurate, rather have the user guess. Previously when using AF-ON to focus, you could not do this. In release or focus+release mode, it is the user who must decide when to stop depressing AF-ON and there is no guarantee of the outcome."</p>

</blockquote>

<p>I particularly don't understand the part about the user needing to decide when to stop pressing the AF-ON button, and this being guesswork.</p>

<p>I have just performed the following test with my D700. Camera set to <strong>AF-C mode</strong>. Area mode: <strong>Single Point</strong>. AF-C Priority Selection (CSM-a1) set to <strong>Release</strong>. AF Activation (CSM-a5) set to <strong>AF-ON only</strong>.</p>

<p>I position the center focus point on a nearby object and a single short press of the AF-ON button brings the object into exact focus. I now recompose the frame such that the center focus point is over a rather distant object, but the original object is still within the frame. A press of the shutter release takes a photo. Thus I have prefocused and reframed and the initially prefocused object remains in focus.</p>

<p>So I have to retract my earlier statement to the effect that when in <strong>AF-C mode</strong>, the use of the AF-ON button to achieve focus makes it impossible to prefocus and recompose. And that makes the rationale for the change even less comprehensible.</p>

<p>Please forgive my behaving a bit like a dog with a bone. I really have become rather fond of the bone and reluctant to relinquish it.</p>

<p> </p>

At the risk of chewing on my own bone (which is one of those statements I may regret being attributable to me when someone does a web

search), if the reasoning is that focus and recompose works whether you're in AF-C or AF-S, Nikon could have fixed that problem better by

making it easier to switch. By, for example, allowing the AF mode button's functionality to be mapped to something I can actually reach (i.e. a

programmable button near my right hand). Much like my rant about ISO.

 

My feeling is that this behaviour was a bug, and Nikon have decided to call it a feature rather than fix it - if it was REALLY deliberate the

documentation wouldn't still describe the old behaviour.

 

But if Ilkka is sure there's a good reason and doesn't mind another go at explaining, I'd be much less frustrated if I thought someone was

gaining in return for my pain.

<p>I too would be less frustrated if Ilkka (or anyone) could describe a situation where the new behaviour provides some functionality not easily available in the earlier version. For a moment I thought he had done so; but I seem to have proved myself wrong.</p>

<p>Mike, are you happy with the camera otherwise?</p>

<p>Elliot-<br>

Have had the camera for only 1 week and so far no chance for a real photo outing and no images printed yet.. But just using it a bit around the house, I am fully satsified with performance and ergonomics.</p>

<p>Does the AF-ON button works as desired in AF-C mode?</p>

<blockquote>

<p>Does the AF-ON button works as desired in AF-C mode?</p>

</blockquote>

<p>Elliot, not sure what you are asking. If by "desired" you mean allows trap focus then, on D800: NO.</p>

<p>Mike, I'm sorry but I was wondering if you could explain exactly how you shoot?</p>

<p>I've tried but I just can't wrap my head around what it is you are trying to accomplish with your settings therefor don't understand what it is that doesn't work the way you want.</p>

<p>Just to provide some background I use AF-ON with AF-C and release priority and select which focus points to use. With those settings I can prefocus, I can zone focus by prefocusing on a certain distance, I can focus and recompose, I can track moving subjects while shooting, I can shoot stationary subjects and I can manually focus and shoot regardless if the subject happens to be under my selected focus point or not. And I can do it without changing any settings which in my mind means that I'm ready for any type of situation without fiddling with the camera. I've shot like that for many years but perhaps there is some other way that is better, I don't know.</p>

 

<p>I have elaborated on this subject but (unfortunately) placed my response in <a href="/nikon-camera-forum/00bEUi?start=10">another thread</a> which deals with much the same subject. Please see my latest response there.<br>

Sorry for the inconvenience.</p>

<p>Pete S.<br>

This whole rant was initiated by the inability of the D800 to perform trap focus. I will not take the space here to describe exactly how this was done on the D700 and other earlier DSLRs. However the method relies on setting the AF-S (or AF-C) <strong>priority to FOCUS</strong> and setting the <strong>AF activation to the AF-ON button only</strong>. Thus ensuring that the shutter will fire <strong>only</strong> <strong>when</strong> the object under the selected focus point was <strong>in focus</strong>. Using these settings on the D800 one finds that the shutter will fire regardless of whether or not the object under the selected focus point is in focus. This may make it more convenient (for some) to prefocus and reframe with the D800, however it comes at the cost of making trap focus impossible to implement.</p>

<p>Thanks Mike, I understand. </p>

<p>With my limited imagination I can only see one application for trap focus and that is to prefocus somewhere in anticipation of a moving subject. When the subject is in focus the shutter fires.</p>

<p>One problem with this technique is that the shutter fires when the subject is in focus but as the subject is moving it will not be in the right position when the actual exposure takes place due to shutter lag. If that is a problem or not depends on the subject speed and DOF.</p>

<p>Without having made an actual experiment I would assume that prefocus and then tracking the subject with af-c would yield better results as the AF now can anticipate focus and subject speed.</p>

<p>But perhaps you are using trap focus in another way or perhaps with a locked camera on a tripod so you can't track or won't due to changing compositions between shots?</p>

 

<p>BTW, I tested a D600 and it behaves just as the D800. It will happily shoot OOF images in af-s when set to focus priority.</p>

<p>It's only after you press af-on and then the shutter that it will wait for the first focus acquisition before releasing the shutter. After that you can shoot as many oof images as you want. And if you don't press af-on it doesn't require focus confirmation at all.</p>

<p>Pete: Yes, you're right. However, the camera's autofocus has very good reactions (though, I've discovered, not perfect). This means that, for example, you can focus on the air in front of a bird box, hold down the shutter release, and the camera will take a shot when a bird leaves the bird box and passes through the focus point. Doing this with human reactions isn't feasible. The better solution is to set up an infrared remote trigger, so the shutter is released (with the camera in pure manual focus) when the beam is broken, but that's an expensive and inconvenient solution when the camera already contains a perfectly good mechanism for telling when something is there.<br />

<br />

Canon users found the same problem when trap focus was removed (or on systems without trap focus). The workaround was to put the camera in AF-C, the hold you hard in front of the lens. The camera hunts and gives up with the lens at infinity; keeping the shutter release depressed (preferably by remote release) you can then use USM (or in Nikon terms AF-S/SWM) manual override to focus where you want, so long as you're careful that nothing triggers an autofocus sensor (so you effectively have to focus by eye in the viewfinder, using the edge of the frame). The camera would then "notice" it had suddenly achieved autofocus when something passes the sensor, and release the shutter. Of course, you then have to go through the same process again in order to take the next shot.<br />

<br />

I've not tried this yet with an AF-S lens on my D800. (Actually, I never tried it on Canon, since I never owned a lens with manual focus override.) I'd be interested to know whether it works, though the "chipped manual lens" solution is probably more practical.</p>