D800 AF-ON focussing technique

Discussion in 'Nikon' started by apple-and-eve, Jan 29, 2013.

  1. Very well written, Jacques.
    You mentioned that you may add or amend; what are your thoughts about the oft-repeated lament (Thom Hogan, etc.) about the D800 and the changes making trap-focus unattainable? Many thanks!
    (P.S., Shun, I hope I'm not being repetitive with this request; I know there are some threads specifically addressing it, so I'm asking Jacques to add it to his linked post. --Bill)
     
  2. Bill,
    Thanks for your response. To my knowledge focus-trap is not supported anymore, I suspect the reason for that might be the fact that continuous focus (AF-C) kind of caters for the situations where focus trapping would've been used previously. The last time where I myself used trapping was when I was shooting with an old manual film SLR and no such thing as AF existed !
    Okay, I suppose that also tells you something about my age :)
     
  3. Jacques,
    I understand that AF on decouples the focus from shutter button. So one can do shooting and focussing separately and doesn't need to initiate focus each time the shutter button is pressed.
    Well, that much i understood, but beyond this, i couldn't. The settings argument...that one doesn't have to change settings with AF on....isn't that true with normal shooting also..? Maybe there's something i'm missing...? You write, "Notice that you can switch between shooting any of the example scenes above withouthaving to change any focus settings? That’s the beauty of using this technique – no more fumbling with focus settings when you can least afford to!.." But i just can't seem to notice or get it...
    Focus recompose: this also is same in both techniques. In normal shooting, you focus lock and recompose. In AF on shooting, you do the same...
     
  4. Anurag,
    You are correct in what you're saying that focus/recompose can be achieved in normal shooting equally well.
    The point I'm trying to bring across is this:
    If you're using the normal (default is perhaps a better term) way of shooting (AF-S, no AF-ON button) and you suddenly or unexpectedly want to shoot a moving subject, then you need to switch to AF-C to enable tracking a moving subject before you can shoot, else you might loose focus. When you want to revert back to the default way of shooting, you once again need to change settings (AF-C to AF-S) before continuing.
    Using the AF-ON technique frees you from having to change settings in between, you can accomplish everything for shooting both stationary and moving subjects without making any changes in between. This is really the benefit of using this technique.
    I agree if that you always shoot either stationary or always shoot moving subjects only, then you do not benefit much from this technique. However, if you switch between shooting stationary and moving subjects regularly (like wedding photographers do) then there is huge benefit in using this method.
    I hope this has cleared it up for you?
    Regards,
    Jacques
     
  5. the reason for that might be the fact that continuous focus (AF-C) kind of caters for the situations where focus trapping would've been used previously.​
    Not so, focus trapping also allow you to set up your camera near a spot where you expect in a certain point in time that there will be someting "in Focus", by setting up a "focus trap" combined with a repeatedly triggering the shutter ( like by using a MC-36 remote with timer ), you are able to just fire the shutter when there is actually something to frame upon. This is a technique that i suse sometimes to shoot a bird on a spot where i expect it to be in a near future whithout me having to be close to operate the shutter while still having a picture with the bird in focus.. ( srry if this sounds fuzzy, but English is not my mother tongue..) .
     
  6. Jacques,
    Well written explanation of the advantages of using the AF-ON technique with AF-C. It is particularly pertinent to the D800 where one needs to use two hands to switch between AF-S and AF-C.
    I have always used this technique with Nikon DSLRs since it is suitable for moving as well as stationary subjects (allowing focus/lock/recompose, without requiring another button to lock focus).
    In short, using this method there was never any need to switch the camera to AF-S, EXCEPT when one wanted to use trap focus (on a D700 or any earlier model). And therein lies the nexus of my discontent. By crippling the use of the AF-ON button in AF-S mode (in the D800) and offering no advantage in return, Nikon has made a serious error.
     
  7. Jacques,
    Well written explanation of the advantages of using the AF-ON technique with AF-C. It is particularly pertinent to the D800 where one needs to use two hands to switch between AF-S and AF-C.
    I have always used this technique with Nikon DSLRs since it is suitable for moving as well as stationary subjects (allowing focus/lock/recompose, without requiring another button to lock focus).
    In short, using this method there was never any need to switch the camera to AF-S, EXCEPT when one wanted to use trap focus (on a D700 or any earlier model). And therein lies the nexus of my discontent. By crippling the use of the AF-ON button in AF-S mode (in the D800) and offering no advantage in return, Nikon has made a serious error.
     
  8. Jacques,
    Why would i change to AFS when shooting normal?
    I can keep it to AFC no matter what i'm shooting, stationery or moving objects...right? Because everything moves anyway, if not the subject, then the photographer...so its a good idea to be on AFC anyway with this kind of camera...
    So this is the part i get and agree:
    Decoupling the AF so one doesn't have to refocus each time a picture is clicked.
    Sorry, i am trying to understand the damn thing...:)
     
  9. Jacques,
    As I have stated (inadvertently twice above) your description of the technique is well done. However there is one point that I must question:
    In the Autofocus custom setting menu, set AF-C priority selection (a1) to Release priority. Even though the D800 will fire (if AF-C priority is set to Focus priority) when recomposing to an out of focus area after the AF-ON button has been released (once focus was achieved), you might encounter some hesitation to fire if there was the slightest shift in focus distance.​
    Once the AF-ON button has been released all autofocus operation ceases and focus remains unchanged (effectively locked). Thus even when AF-C Priority (a1) is set to Focus, the shutter will release instantly even when the recomposition causes a major shift in the focus distance of the object under the active focus point. This is the behavior I have observed with my D800.
     
  10. Decoupling the AF so one doesn't have to refocus each time a picture is clicked.
    Sorry, i am trying to understand the damn thing...:)
    Anurag,
    The reason to decouple the AF (from the shutter release) is to ensure that one (the camera) is not forced to refocus each time a picture is clicked. This allows one to focus (using the AF-ON button and then release the button) then recompose the shot while having the focus remain unchanged from the initially chosen subject.
     
  11. Normally on Nikon if you use the shutter to autofocus and have the camera in AF-C you can't focus and recompose. As you recompose you move the camera and it will then focus on something else.
    And focus points never cover the entire frame, especially on full frame cameras, so focus and recompose is often needed when you shoot something where you don't fill the entire frame with the subject.
     
  12. @Mike - Thanks Mike for pointing out my mistake, I have now updated the blog and hope it now explains point 3 correctly.
    The loss of focus-trap in the newer bodies appears to upset a lot of photographers, it's a pity that Nikon did not leave that as an option in the custom setting menu.
    @C.P.M. - you are quite correct in you explanation. My version of focus-trap is actually more a case of pre-focussing at some point, and then releasing the shutter once the subject has reached that point.
    @Anurag - You are starting to understand the concept and you are correct in saying that using this technique you don't have to alternate between AF-S and AF-C - just stick with AF-C. I think Mike has also answered your question about decoupling the AF better than I could.
    @Pete S - you are 100% correct !
     
  13. "Normally on Nikon if you use the shutter to autofocus and have the camera in AF-C you can't focus and recompose" Of course you can... IF you use the focus lock button.
     
  14. "Of course you can... IF you use the focus lock button."

    Elliot is correct, the AE-L/AF-L can lock focus (and exposure unless the button has been reconfigured to only lock focus), or some of the other buttons can be configured to lock focus in AF-C mode.
     
  15. Mike,
    The reason to decouple the AF (from the shutter release) is to ensure that one (the camera) is not forced to refocus each time a picture is clicked. This allows one to focus (using the AF-ON button and then release the button) then recompose the shot while having the focus remain unchanged from the initially chosen subject.
    But this can be done by half pressing the shutter and locking the focus also...
     
  16. "But this can be done by half pressing the shutter and locking the focus also..."
    Yes, in AF-S mode. In AF-C half pressing the shutter will not result in focus-lock, the camera will focus continuously. You can in fact perform focus-lock in AF-C mode by assigning the AE-L/AF-L button to "AF-lock" and pressing it once you want to lock focus while keeping the shutter-release half pressed.
    Anurag I suggest you set up your camera as I described and then play around with it, you will soon see how it all fits together and works. It does take some time to get one's head around this but once you get the hang of it you will most probably not want to shoot any other way.
    Keep asking questions if you get stuck !
     
  17. "Of course you can... IF you use the focus lock button."

    Elliot is correct, the AE-L/AF-L can lock focus (and exposure unless the button has been reconfigured to only lock focus), or some of the other buttons can be configured to lock focus in AF-C mode.​
    Well, but then you are using two buttons again :) But instead of telling when you WANT to focus you're telling when you NOT WANT to focus. Might as well program af-on to af-lock to make the confusion complete.
     
  18. "Well, but then you are using two buttons again :)"
    Yes, and that is what I'm trying to avoid as much as possible. During a busy shoot there is enough going on to keep me very busy so I don't want anything extra to distract me. It is for this reason that I find the AF-ON technique so useful - it leaves me free to concentrate on the shoot instead of having to deal with camera settings in between.
     
  19. Thanks for the great discussion.
    On my D700, I commonly set it to AF-C (Release/AF-ON) and then the AF-C Priority to focus and was always happy with the results.
    Using similar settings on the D800, I feel that the AF-C results are not quite as sharp as the AF-S settings. Just an impression. This is true with stationary objects. Wonder if other people feel the same way?
     
  20. Thanks for posting this, Jacques. I played around with this technique this afternoon on my D800 and it works great. What a breakthrough!
    --Greg Embree
     
  21. Thanks Steve & Greg.
    Steven, generally I get sharper images more consistently with AF-C on both D700 and D800. However with the D800 you need to be very careful using dynamic 9/21/51 points when shooting stationary subjects, it is far more eager than the D700 to switch focus to the neighbouring focus points without you realising it and that might result in softer images, whereas with the D700 that seldom happens.
    My suggestion is that you try single-point only focus with AF-C and see how that works for you, in my experience it works extremely well and I seldom get soft images this way.
     
  22. Mike said:
    Once the AF-ON button has been released all autofocus operation ceases and focus remains unchanged (effectively locked). Thus even when AF-C Priority (a1) is set to Focus, the shutter will release instantly even when the recomposition causes a major shift in the focus distance of the object under the active focus point.​
    And explained why:
    The reason to decouple the AF (from the shutter release) is to ensure that one (the camera) is not forced to refocus each time a picture is clicked. This allows one to focus (using the AF-ON button and then release the button) then recompose the shot while having the focus remain unchanged from the initially chosen subject.​
    Anurag responded:
    But this can be done by half pressing the shutter and locking the focus also...​
    I used the AF-ON button on my D200 for the same reason Mike described. However, there is another very important reason not mentioned.
    I want to decouple the focusing point from the exposure metering point, like I do with my film bodies. It took me some time to figure out how to do this on the D200, and I know of no other way. Pressing and releasing the AF-ON button once allows me to focus at a point and lock it, WITHOUT locking the exposure. After locking the focus, I then turn the camera and recompose. Releasing the shutter will then meter the exposure for this composition and capture the image.
    If instead of using the AF-ON button, I half press the shutter to lock focus as suggested by Anurag, I would lock the exposure metering as well. When I turn the camera, recompose and release the shutter, I may end up with an erroneous locked exposure metered from a different composition.
    The reason and practice of decoupling focusing from metering is an important topic that is seldom discussed. Even Thom's guides don't touch upon it. On film bodies, that is easy. But with the dslrs, it can be a challenge to figure out all the settings correctly in order to accomplish this simple goal. (And can't be done at all on most p&s?) Every time I ask a sales staff at a camera store to demonstrate how to do this on a new body I'm interested in, he/she won't have a clue.
     
  23. Robert K,
    Thanks for pointing out this additional advantage of using only the AF-ON button for focus. (It's sometimes referred to as "back button focus".) Those of us who have been using this method for a long while are so accustomed to this advantage that we don't give it a second thought. So even though Thom's guides do mention this method (I think he calls it the pro's approach to autofocus) he also fails to point out this benefit.
    Thanks again.
     
  24. Jacques,
    Thanks a ton for the
    explaination...and the
    patience.
     
  25. "Jacques, Thanks a ton for the explaination...and the patience."
    You're most welcome Anurag !
    I hope you have the technique now sorted out and that it will work for you - have fun !
     
  26. excellent information that works for me.. Thanks a bunch
     
  27. Jacques,
    Was reading your article again, found an update:
    [Updated 30/1/2013] 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.
    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....
    Why do you recommend release priority over focus priority?
     
  28. Hi Anurag,
    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 do not fire. This is now different with the D800 - it will 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.
    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.
    I hope this has answered your question ?
     
  29. Jacques, thanks.
    One more thing:
    Why did you update this point in your write up? Shouldn't the recommended setting be 'focus priority' instead of 'release priority'?
    Because, as you said, with FP you will get focussed shots as against RP where the camera will fire irrespective of finding focus...
    Thanks for your answers :)
     
  30. Hi again Anurag,
    Thanks for raising this point - I've added this update to my write-up:
    "[Updated 25/02/2013] 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. "
    Anurag, in my experience I found very 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!
    Regards,
    Jacques
     
  31. Dear Jacques,
    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.
    Do you have any suggestion to hold focus and take the correct exposure?
    I noticed also some interesting behaviour:
    - 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.
    I believe that the AF-ON must lock only the autofocus and not the exposure.
    Thanks for your comments.
    P.S. I'm using Nikon D800 with latest firmware.
     
  32. Hi Marcus,
    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.
    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.
    Once exposure is locked you will notice that when moving the camera around the meter will not change it's reading.
    I hope this helped!
     
  33. Dear Jacques,
    many thanks for your reply.
    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.
    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.
    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.
    The strange thing is that when you release the AF-ON button the exposure reading show now a totally different value.
    If you own a D800 try and verify this issue.
    I noticed this behaviour also with D600.
    In my previous D300 everything was working as expected. The AF-ON locks the focus and the light meter always reads a correct value.
    Do you have any explanation or I’m doing something wrong?
    Thanks.
     
  34. 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.
     
  35. Marcus,
    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.
    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.
    Perhaps there is someone here that can check how their D800 is behaving and let us know?
     
  36. Hi,
    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.
    Try to do this:
    Use the AF-S mode
    Use Aperture priority exposure mode
    Set the aperture lens
    Set the camera to focus only with AF-ON button
    Use a fixed ISO (for instance ISO 400) and NOT auto.
    Point the camera toward a subject and focus with AF-ON
    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.
    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.
    Try to do something like that and tell me if you observe the same issue.
     
  37. 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.
    It works like this with both AF-S and AF-C.
    It sounds like your D800 does something differently which I don't understand either.
    I even tried changing some other settings to see if it makes a difference, but it still works correctly.
    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 ?
     
  38. Hi,
    thanks a lot for your support. I observed the same behaviour on my previous D600. In my old D300 everything worked fine as expected.
    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).
    I tried to assign the focus lock only to the AE/AF button and it has the issue of the AF-ON.
    I’m sorry for that but it sounds quite strange that in my D600 and D800 I observe the same issue.
    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.
    I hope someone else will reply to my post and see what happen.
    I can try also to re-install the firmware (if the camera will let me do that since the new one is already installed).
    Thanks.
     

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