As I understand it, I can use the af-on button to focus with. How does it interact with the camera and lens when set to AF-C? Does it put my camera into AF-S while the button is depressed? Before I start experimenting I want to have a better understanding of how it works.
One of the main benefits of using the AF-ON button is that you never need to switch between AF-S and AF-C.
With the camera set to AF-C it will track focus as long as the button is pressed. If you want to lock focus just release the button.
You can focus then release the button and recompose and the camera will not attempt to refocus when you start to press the shutter release. Make sure that AF-C is set to release priority so the shutter will release if the AF sensor (after focus and recompose) is not over an in-focus area.
On the D300, if you use any VR lenses you will need to half press the shutter release to initiate VR.
Hi, got to know this feature only a few weeks ago. once you get used to it it will literally change the way you operate the camera. or, at least, that's what has happened to me. Couldn't go back. Takes a little in terms of getting into the habit and locate the proper button but it's extremely handy (especially when outdoor). AF-C, AF 51 points, matrix metering and 3d focusing.
The main idea of using AF-ON button is to decouple the focusing and the shutter release action, while still making easy to focus. It gives you more control over AF, mostly in deciding when NOT to refocus.
When can it be useful? In low light where focusing may be a challenge. You can focus once and avoid refocusing unless necessary. If you are waiting for something to happen and you don't want to/cannot hold the shutter release button. You can focus in advance lower the camera and when the time is right shoot without loosing time on focusing on the right place.
Personally speaking I have not seen any difference in terms of focusing speed switching between AF with shutter button and AF-ON mode. There is indeed a BIG difference (but in both cases) in low light if we talk lenses, at wide apertures a 2.8 will always focus faster than a say f4 or f5.6. Btw in these past few days got to play around with AF-ON a little deeper and definitely this is a saver in some cases. Again, have to get used to that but the results are excellent, also talking AF-C and kids moving fast
>Personally speaking I have not seen any difference in terms >of focusing speed switching between AF with shutter button and >AF-ON mode.
That's correct. Using the AF-ON button (or equivalent) doesn't alter the speed with which the camera acquires or tracks a subject - it's more about giving the photographer control over when and on what the camera focuses.
>>Personally speaking I have not seen any difference in >terms >>of focusing speed switching between AF with shutter button >and >>AF-ON mode. > >That's correct. Using the AF-ON button (or equivalent) >doesn't alter the speed with which the camera acquires >or tracks a subject - it's more about giving the photographer >control over when and on what the camera focuses.
thanks for your confirmation. The real difference is given by the lens, focusing at 2. is faster than at 5.6 or 4. This is something to bear in mind. Again, the "auto-switch" AF-ON option is something that can really change the way we take pictures, 3d matrix works very well so the only issue is playing around with exposure in case.
>My camera has. > >AF AE is the button for auto exposure and auto focus. And if >so how does the AE work with the AF?
It depends on how you have the button configured. By default the "ae-l/af-l" button will lock both the AE and AF systems when pressed. The manual will show you the multiple options available. Changing the button to be "af-on" will be one of the options.
---------+---------+---------+---------+---------+ Joseph K Seattle, WA, USA
It looks like you have two different body types being used (per your equipment list) - the D200 should have the AF-ON button I believe, so the D5100 must be the one you're talking about... But either way, your manual (or going on line) will help you set up the control fairly easily.
I switched one camera over and used it that way on one shoot (some architecture I was photographing, so easy ot try it out - nothing moved). I came home and set my other two cameras up that same way as I really liked it (didn't think I would, but it really is nice to not even think about switching the "S" to "C" at any time in the future - it's set and I'll leave it this way!).