D800 AF-ON focussing technique

[anuragagnihotri]

Jacques,

Thanks a ton for the

explaination...and the

patience.

[apple-and-eve]

<p>"<em>Jacques, Thanks a ton for the explaination...and the patience.</em>"<br>

You're most welcome Anurag !<br>

I hope you have the technique now sorted out and that it will work for you - have fun !</p>

[brian_mchattie]

<p>excellent information that works for me.. Thanks a bunch</p>

[anuragagnihotri]

<p>Jacques, <br>

Was reading your article again, found an update:<br>

[<em>Updated 30/1/2013</em>] In the Autofocus custom setting menu, set AF-C priority selection (a1) to Release priority. This will allow the camera to fire with no hesitation regardless whether AF-ON is depressed or released, or whether the subject is in focus.<br>

Here, If you set the AFC on release priority, then doesn't it start behaving like default (focus with shutter button) mode...(camera keeps clicking whether in focus or not)? Also the focus recompose goes for a toss....<br>

Why do you recommend release priority over focus priority?</p>

 

[apple-and-eve]

<p>Hi Anurag,<br>

Setting AF-C to release-priority is actually a spill-over from the previous generation cameras (D300/D700/D3) where if set to focus-priority you cannot focus/recompose because those cameras behave differently from the new generation bodies, such as the D800. With the D700 (and AF-C set to focus priority) if you focus, release the AF-ON to lock, and recompose on an out-of-focus subject, the camera <strong>do not</strong> fire. This is now different with the D800 - it <strong>will</strong> fire under these conditions. This change in behaviour has upset a number of folks who used focus-trapping, which now does not work anymore with the newer bodies.<br>

So strictly speaking, with the D800 you can leave AF-C set to focus-priority and it will work fine, only firing when the subject under the selected focus point is in focus while AF-ON is pressed, and firing regardless if AF-ON is released AFTER focus has been acquired.<br>

I hope this has answered your question ?</p>

[anuragagnihotri]

<p>Jacques, thanks.<br>

One more thing: <br>

Why did you update this point in your write up? Shouldn't the recommended setting be 'focus priority' instead of 'release priority'?<br>

Because, as you said, with FP you will get focussed shots as against RP where the camera will fire irrespective of finding focus...<br>

Thanks for your answers :)</p>

[apple-and-eve]

<p>Hi again Anurag,<br>

Thanks for raising this point - I've added this update to my write-up:<br>

"[<em>Updated 25/02/2013</em>] Although Focus-Priority will work just fine in most situations with the D800 it might still be preferably to use Release-Priority, especially if you are using previous generation bodies (D700, D3, D300) in addition to the D800. This way you will ensure that all your bodies behave in a similar manner. "<br>

Anurag, in my experience I found <em>very</em> few images to be OOF when using RP, unless there is very rapid and significant movement of the subject. FP will guarantee every shot to be in focus whereas with RP you will get some images out of focus. However I will rather have the odd slightly OOF images (which might still be perfectly useable) than no image at all - I can always decide afterwards to keep or delete it. With the huge images produced by the D800 even slightly OOF images can still be useful at normal viewing size!<br>

Regards,<br>

Jacques</p>

[marcus_miller3]

<p>Dear Jacques,<br>

when you use this technique for focus and recompose, what about the exposure meter? I mean, if I focus on the face of my subject then also the exposure must be taken from his face. But with AF-ON button to hold the exposure I must press also the shutter button.<br />Do you have any suggestion to hold focus and take the correct exposure?<br>

I noticed also some interesting behaviour:<br /> - When I press and keep AF-ON pressed, also the exposure seems to be locked. I wrote seems because the exposure reading value has a strange reading. Try to acquire focus with AF-ON, keep AF-ON pressed, and then move completely the camera to a different light source and intensity. The exposure meter reads a certain value. Now release the AF-ON button. The exposure meter reads a totally different value.<br>

I believe that the AF-ON must lock only the autofocus and not the exposure.<br>

Thanks for your comments.<br>

P.S. I'm using Nikon D800 with latest firmware.</p>

[apple-and-eve]

<p>Hi Marcus,<br>

Normally exposure is locked only when you fully depress the shutter-release (you can change that) so when you move the camera around the meter will show you the reading at that point in time. A shutter-release half-press will NOT lock the exposure, unless you set custom setting c1 to "ON", which will then lock exposure with a half-press of the release button.<br>

I prefer to use the AE-L/AF-L button to lock exposure when recomposing, even though it means I need to move my thumb from the AF-On button. It really boils down to your own preferences whether you want to lock exposure with the AE-L/AF-L button, with a half-press of the shutter-release, or at full shutter-release.<br>

Once exposure is locked you will notice that when moving the camera around the meter will not change it's reading.<br>

I hope this helped!</p>

[marcus_miller3]

<p><br>

</p>

<p >Dear Jacques,</p>

<p >many thanks for your reply.</p>

<p >Now I use the shutter-release half-press technique to lock focus and exposure and then I recompose. With just the forefinger I can control two parameters.</p>

<p >But also the AF-ON button could help me when I use the AF-C capability and I don’t want to switch from AF-C to AF-S all the time. </p>

<p >But as I’ve already mentioned in my previous post, I noticed that holding the AF-ON button and point the camera toward different light source, the light meter change exposure value. This is normal because as you reported the AF-ON only lock the focus. </p>

<p >The strange thing is that when you release the AF-ON button the exposure reading show now a totally different value.</p>

<p >If you own a D800 try and verify this issue.</p>

<p >I noticed this behaviour also with D600.</p>

<p >In my previous D300 everything was working as expected. The AF-ON locks the focus and the light meter always reads a correct value.</p>

<p > </p>

<p >Do you have any explanation or I’m doing something wrong?</p>

<p >Thanks.</p>

[marcus_miller3]

Sera Jacques,

Yesterday I've tried again to test the AF-ON button and the problem with exposure meter accours only in AF-S mode.

In AF-S mode the exposure meter report bad reading value when I move the camera.

In AF-C mode the reading is perfect.

Please if someone here is usino Nikon D800 try to test it.

Probably it is a firmware bug.

[apple-and-eve]

<p>Marcus,<br>

I checked on my D800 and both AF-C and AF-S behaves the same - when I move the camera around the exposure meter changes value as I would expect, regardless of whether AF-ON is pressed or not. My firmware version is: A=1.01, and B=1.02.<br>

If you are at the same firmware level then the only reason that I can think why yours behaves differently is that you might have some other setting on your camera that is different from mine, but I have no idea what.<br>

Perhaps there is someone here that can check how their D800 is behaving and let us know?</p>

[marcus_miller3]

<p>Hi,<br>

actually the exposure meter change the value when I move the camera AF-ON is pressed. But the reading value is wrong because when I release the AF-ON button the reading value change dramatically.<br>

Try to do this:<br>

Use the AF-S mode<br>

Use Aperture priority exposure mode<br>

Set the aperture lens<br>

Set the camera to focus only with AF-ON button<br>

Use a fixed ISO (for instance ISO 400) and NOT auto.<br>

Point the camera toward a subject and focus with AF-ON<br>

Hold the AF-ON pressed and move the camera toward the window where there is a big difference in brightness. Now the reading value is for instance 1/250s.<br>

Then release the AF-ON button. Now Does the reading exposure value change? When I release the button in my D800 the value change from 1/250s to 1/4000s for instance.<br>

Try to do something like that and tell me if you observe the same issue.</p>

[apple-and-eve]

<p>Marcus, I tested with the settings exactly as you suggested but my D800 changes exposure as it should and the reading does not change when I release AF-ON. In other words - if the reading changes from 1/60 to let's say 1/1000 when moving the camera to a brighter scene while keeping AF-ON pressed, it remains at 1/1000 after I release the AF-ON button. That is what I would expect.<br>

It works like this with both AF-S and AF-C.<br>

It sounds like your D800 does something differently which I don't understand either.<br>

I even tried changing some other settings to see if it makes a difference, but it still works correctly.<br>

I have NO idea what causes the strange behaviour and hope that you can find the problem. Perhaps try this on someone else's D800 ?</p>

[marcus_miller3]

<p>Hi,<br>

thanks a lot for your support. I observed the same behaviour on my previous D600. In my old D300 everything worked fine as expected.<br>

I forgot to tell you that I set also shutter release button to lock the exposure (anyhow I don’t press this button during this test).<br>

I tried to assign the focus lock only to the AE/AF button and it has the issue of the AF-ON.<br>

I’m sorry for that but it sounds quite strange that in my D600 and D800 I observe the same issue.<br>

I don’t think that my D800 has some faulty condition but I have some setting that cause this trouble. These particular settings probably cause this issue and in my opinion this is firmware bug.<br>

I hope someone else will reply to my post and see what happen.<br>

I can try also to re-install the firmware (if the camera will let me do that since the new one is already installed).<br>

Thanks.</p>