AE/AF-Lock mysteries solved with AF-S and AF-C

Started Dec 21, 2004 | Discussions
jfriend00 Forum Pro • Posts: 11,326
AE/AF-Lock mysteries solved with AF-S and AF-C

In a separate thread, there was a bunch of discussion of various focus and exposure modes on the D70. I was pretty confused about what the various options do and which I should use for the different types of shooting so I waded through the manual, through Thom's ebook and played with a bunch of settings on my camera to settle on two combinations I actually want to use for different types of shooting. These two combinations give me a great default behavior for a half press of the shutter and give me easy overrides using the AE-L/AF-L button. If you ever want to focus and meter on different parts of the frame or want to track a moving subject with AF-C focus, but not lock exposure at the half press, then you should definitely read this.

These are the three basic options that control when focus and exposure get locked into place:

CSM #2 controls AF-C vs. AF-S
===================
For AF-S, focus will lock once (typically on a half shutter press).

For AF-C, the camera will initiate focus tracking (typically on a half shutter press) and then continually refocus.

CSM #15 controls what happens when you press the AE-L/AF-L button
============================================

With one exception, this control has nothing to do with what happens on a half press of the shutter. Instead, it controls what locks when you press the AE-L/AF-L button on the back of the camera:

o Set to "AE/AF Lock" when you want both focus lock and exposure to lock on a press of the AE-L/AF-L button

o Set to "AE Lock only" to lock only exposure on a press of the AE-L/AF-L button
o Set to "AF Lock only" to lock only focus on a press of the AE-L/AF-L button

o Set to AF-ON to disable auto-focus on a half shutter press and ONLY focus on a press of the AE-L/AF-L button

There are more options in the manual than this, but there were the ones I found useful.

CSM #16 controls whether exposure locks on a half shutter press
========================================
o Set to "AE-L" button to make it so exposure does NOT lock upon a half press.
o Set it to "+ Release Btn" to make it so exposure does lock upon a half press.

So, after a bunch of reading and a bunch of experimentation, this is what I've found are the useful combinations for me:

Option 1) Lock everything on a half shutter press, but give you the ability to use the AE-L/AF-L button to lock exposure separately from focus:
o Set Focus to AF-S - (CSM #2 to AF-S)
o Set AE Lock for the half shutter - (CSM #16 to "+ Release Btn")
o Set AE-L/AF-L button to lock exposure only - (CSM #15 to "AE Lock only")

Option 1a) Lock everything on a half shutter press, but give you the ability to use the AE-L/AF-L button to lock focus separately from exposure:
o Set Focus to AF-S - (CSM #2 to AF-S)
o Set AE Lock for the half shutter - (CSM #16 to "+ Release Btn")
o Set AE-L/AF-L button to lock focus only - (CSM #15 to "AF Lock only")

Option 2) Lock only focus on a half shutter press, don't lock exposure until full shutter press or AE-L/AF-L button:
o Set Focus to AF-S - (CSM #2 to AF-S)
o Set AE to not lock on a half press - (CSM #16 to "AE-L button")
o Set AE-L/AF-L button to lock exposure only - (CSM #15 to "AE Lock only")

Option 3) Start focus tracking on half press, don't lock exposure until full shutter press or AE-L/AF-L button:
o Set Focus to AF-C - (CSM #2 to AF-C)
o Set AE to not lock on a half press - (CSM #16 to "AE-L button")
o Set AE-L/AF-L button to lock exposure only - (CSM #15 to "AE Lock only")

I'm basically going to mostly just use options 1) and 3) for most of my shooting.

Option 3) is for shooting sports or other moving subjects. It's AF-C for tracking focus. Press the shutter halfway to initiate AF-C focus tracking (and VR if you have it), but by default, exposure doesn't lock until you actually take the picture. This way if you track a subject with the half-press AF-C from one exposure area to another, the camera will adjust and not lock in the earlier exposure. If I want to lock in exposure at some point, I can just use the AE-L/AF-L button to lock the exposure at any time.

Option 1) is the way I take almost all my other non-sports photos. It's AF-S for single focus. By default, it locks both exposure and focus on a half press. For a portrait, I can pick which part of the face I want to be in best focus, point the center sensor at that, do a half press and that will lock both focus and exposure on that part of the face. I can then frame the picture and click. If, for some reason, I want to separately lock focus and exposure, I can just aim at what I want to meter off first, hit the AE-L/AF-L button to lock exposure, then point at what I want to focus on and press the shutter halfway. This gives me an easy dual lock on a half press with a single button override if I want different focus and exposure points.

Option 1a) is the same as option 1) with the focus override instead of the exposure override for the AE-L/AF-L button. It's your own personal preference which you'd rather have be the override on the button. For me, I like to keep the half press consistent to always drive focus and set the button for the exposure override (option 1).

You can build yourself many other combinations too, but these two got me pretty much everything I've wanted for the kinds of shooting I do.

This finally cleared it up for me and helped me solve two problems I'd had. First, how to focus and meter off different parts of the frame without changing a custom setting everytime? Second, how to NOT lock exposure when I initiated AF-C focus tracking for sports. Locking exposure when initiating AF-C focus tracking has cost me a number of sports shots with bad exposure.

So, I end up with a sports setting and a non-sports setting, each with an intelligent override. This should definitely increase my yield.

Does this make sense to folks? Any other combinations that people think they like to use?

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John

G70 Regular Member • Posts: 464
Re: AE/AF-Lock mysteries solved with AF-S and AF-C

hi, thanks a lot for the great explanations, now all these need to be test by me as well, but I'm sure you're 100% right on these settings, thanks for sharing and trying !
G

Global_m Regular Member • Posts: 382
Thanks a lot(NT)
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David Chin Forum Pro • Posts: 11,670
My version ...

... but essentially the same as yours, give or take a few points
http://www.pbase.com/dlcmh/af_ae_config

Thanks for a great write-up - I'll update my page with a link to your post.

jfriend00 wrote:

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John

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imokah Regular Member • Posts: 193
Re: AE/AF-Lock mysteries solved with AF-S and AF-C

John...thank you very much. One quick question. What is your CSM #04 setting?...ON? or OFF?

arek daniel Regular Member • Posts: 181
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imokah wrote:

John...thank you very much. One quick question. What is your CSM

  1. 04 setting?...ON? or OFF?

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MattLarson29 Regular Member • Posts: 185
Re: Bookmark(nt)

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JMJ575M
JMJ575M Contributing Member • Posts: 670
Re: Bookmark(nt)

Thanks!

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All the Best,

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Jeff Kohn Veteran Member • Posts: 4,855
Re: AE/AF-Lock mysteries solved with AF-S and AF-C

I mostly shoot with AE-L/AF-L set to "AF-ON" with continous focusing and I have half shutter press set to lock exposure. But I almost never bother with exposure lock because in situations where that would be use I just switch over to manual exposure.

The reason I use AF-ON instead of shutter-press for focusing is that I shoot a lot in continous drive mode, and if you focus and recompose while shooting continous you're in for a nasty surprise because the camera will re-focus after the first shot even if you're using AF-S. With AF-ON the camera only focuses when I want it to and I don't have to worry about this problem. I also find it easier to track focus this way because pressing AF-ON with my thumb is easier than half-shutter press for me.

I do wish that the D70 has separate AF-ON and AE-L buttons because there are times when I want to use AE-L/AF-L button for FV-Lock and having to go into the menu to remap the button and change focus modes is a PITA.

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Jeff Kohn
Houston, TX
http://www.pbase.com/jkohn

Bartman01 Contributing Member • Posts: 535
I also focus with AE-L/AF-L

Find it much more flexible, as it lets you precisely control when the camera focuses.

One caveat - if AF-S the camera will not fire if the image isn't in focus so I leave mine in AF-C most of the time. If I have prefocused, I don't want the camera to miss a shot just because my main subject isn't in center frame - and I don't want to hold down the AF-L button to tell the camera it is still in focus.

Jeff Kohn Veteran Member • Posts: 4,855
Re: I also focus with AE-L/AF-L

Bartman01 wrote:

Find it much more flexible, as it lets you precisely control when
the camera focuses.

One caveat - if AF-S the camera will not fire if the image isn't in
focus so I leave mine in AF-C most of the time. If I have
prefocused, I don't want the camera to miss a shot just because my
main subject isn't in center frame - and I don't want to hold down
the AF-L button to tell the camera it is still in focus.

Yeah, you pretty much have to use AF-C with AF-ON, since AF-S basically acts as a "trap focus" (which can also be useful in certain situations).

The way I look at it, AF-ON + AF-C basically lets me switch between continous and single focusing without having to go into a menu, since it's just a matter of whether I keep the AF-ON button pressed or not.

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Jeff Kohn
Houston, TX
http://www.pbase.com/jkohn

OP jfriend00 Forum Pro • Posts: 11,326
Re: AE/AF-Lock mysteries solved with AF-S and AF-C

I have auto-focus assist CSM #4 ON, but this only controls the auto-focus assist light that comes on when it's really dark. It really only gets used when it's so dark you have to be shooting with a flash.

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John

imokah wrote:

John...thank you very much. One quick question. What is your CSM

  1. 04 setting?...ON? or OFF?

OP jfriend00 Forum Pro • Posts: 11,326
Re: My version ...

Wow David. I wish I knew about your writeup before I set off to figure this out. Oh well, I probably learned it better by having to figure it out myself. Based on your notes and a couple of other posters, I'll have to experiment with the AF-ON mode, though I'm pretty satisfied with my two configuration setup now. I do wish I could reprogram one of the program modes on the A,P,S,M dial to make it really easy to switch between these, but oh well, it's not that hard to change two menu settings.

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John

David Chin wrote:
... but essentially the same as yours, give or take a few points
http://www.pbase.com/dlcmh/af_ae_config

Thanks for a great write-up - I'll update my page with a link to
your post.

jfriend00 wrote:

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John

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OP jfriend00 Forum Pro • Posts: 11,326
Re: AE/AF-Lock mysteries solved with AF-S and AF-C

Glad you found it useful. Let me know if you discover anything I got wrong or a different set of settings that work for you. Also check out David Chin's web page on the same subject (which I didn't know existed until today) http://www.pbase.com/dlcmh/af_ae_config .

-- hide signature --

John

G70 wrote:

hi, thanks a lot for the great explanations, now all these need to
be test by me as well, but I'm sure you're 100% right on these
settings, thanks for sharing and trying !
G

RonHrl Senior Member • Posts: 2,794
Thanks for the write-up, John...

For now I'm using CSM#15 set at "AE Lock Hold" so I don't have to keep the AE/AF lock button continuously pressed in while I'm taking the picture.

If I want to lock focus on one area but expose for another, I point the camera at the area to expose, press the AE/AF lock button once to lock that exposure, then point camera to the area of focus and lock that focus with a half-press of the shutter release.

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OP jfriend00 Forum Pro • Posts: 11,326
Re: Thanks for the write-up, John...

I'll have to try that. It sounds like it might be more convenient that way. If you don't take the picture, when does the "exposure lock/hold" expire?

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John

RonHrl wrote:

For now I'm using CSM#15 set at "AE Lock Hold" so I don't have to
keep the AE/AF lock button continuously pressed in while I'm taking
the picture.

If I want to lock focus on one area but expose for another, I point
the camera at the area to expose, press the AE/AF lock button once
to lock that exposure, then point camera to the area of focus and
lock that focus with a half-press of the shutter release.

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Jeff Kohn Veteran Member • Posts: 4,855
Re: Thanks for the write-up, John...

jfriend00 wrote:

I'll have to try that. It sounds like it might be more convenient
that way. If you don't take the picture, when does the "exposure
lock/hold" expire?

Actually the lock persists even after taking the picture, if memory serves. You have to hit the AE-L button again to un-lock exposure.

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Jeff Kohn
Houston, TX
http://www.pbase.com/jkohn

Cassandra Veteran Member • Posts: 9,301
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ivor monkey Forum Member • Posts: 55
Great.

Thanks

Skriver Regular Member • Posts: 172
Brillant Explantion (NT)
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