Alan321
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 p.1 #4 · Nikon D700 Autofocus settings | |
svenjosh, thanks for that, and welcome to FM.
I have a few comments/queries regarding your blog for your consideration, presented here in no particular order:
1. Regarding AF tracking with lock on you wrote But for all other purposes where there is very little between you and the subject this setting will cause a delay in acquiring focus. So set this to OFF. (Remember default is normal so change this to OFF)
The focus delay in this mode only applies if there is a significant and fast change in detected focus distance. This can happen when something gets between camera and subject or when you decide to change subject, but if the camera does not already have focus locked onto a subject then there is no impact on the speed of focus acquisition for a new subject.
2. you wrote SHOOTING multiple FPS (ACTION)
If you are shooting multiple frames/sec. then you have to use AF ON to focus as this results in your camera continuously tracking and predicting the subjects movement and position and increases the focus accuracy in a series of shots. If you half press the shutter button for focusing then the first shot will be in focus but then the camera stops focusing till you half press again so if you do this you will only have a very few or at most one shot in focus.
I've seen no reference in the manual that using the shutter button for AF release will prevent refocusing during continuous shooting while the AF-On button will not. Unless of course you have AF in single shot mode while the shutter is in continuous mode, but then even the AF-On button would give you the same effect.
3. Why should using 51-point dynamic AF slow down the AF ? You still control which AF sensor is used for initial focus acquisition and so there should be no impact on AF speed. You just get a wider scope for lateral subject movement. Things might be different for the 51-point 3D mode in which the camera controls selection of AF point.
4. Regarding AF Activation you wrote But this setting (using only AF-ON to auto focus) will definitely improve the speed of auto focus.
I don't see why that should be the case. In spur of the moment shooting the shutter button is usually quicker unless you have trained yourself to pre-press the AF-On button, but that can also affect the choice of AF sensor - perhaps adversely. i.e. you might still have to release that button and press again to set a new subject for the dynamic area AF to track.
Also, if you rely on VR then it needs time to fire up and stabilise and that time doesn't start until you half press the shutter button, so you still need to wait to get a sharp image.
Also, if you use the shutter button then you can use your thumb to select different AF sensors with the multi-select wheel even while leaving the shutter button half-pressed. In that case AF is faster with the shutter button, or at least re-focusing is.
5. You wrote In the single servo mode, the AF tracks a subject till it achieves focus. It the locks (you get a green signal in the view finder) the focus as soon as focus is achieved, meaning the plane of focus is locked.
The word "tracks" is inappropriate in this context. There is neither lateral nor distance tracking while single-servo AF is happening. It just focuses on whatever it can see at the chosen AF sensor. The dynamic area AF expansion is ineffective in this mode. I agree that when the focus locks it stays on that one distance.
6. You wrote a2: AF-S Priority selection: Same as last but for single servo mode. Select focus priority.
I'm inclined to select release priority for this mode. The reasons are (a) you'll know whether or not you have focused on the static subject and you'll have time to adjust as required (unlike for moving subjects) and (b) you get the chance to adjust focus manually and shoot even if the AF has failed. Otherwise if AF fails then you get no shot at all.
The D700 needs to lock focus only once to allow shooting in focus priority mode, but it need not maintain that focus to let you shoot. You can focus, re-compose such that the AF sensor no longer has focus, and still shoot so long as you have not released the shutter or AF button. This behaviour may seem strange to the uninitiated but it mimics the Canon One-Shot AF mode. I don't know how it compares with other Nikon cameras.
cheers, and thanks again.
- Alan
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