AF-S on K20D

<p>I have seen the AF_S on the side of my K20D along with the AF-C and wasn't sure on the AF-s what it was from what I have read on dpreview.com it has to do with a type of motor in the Nikon lenses. Why is it on the Pentax I thought that they weren't compatible. and what is the AF-C on the camera. I will read the manual guys but I just noticed it and got curious</p>

<p>oh, thats just the auto-focus dial for single (AF-S) and continous (AF-C), MF is for manual focus. the manual is great, it'll explain in more detail. plus you'll find the adavantages and disadvantages</p>

<p>Jordan,<br>

Both Nikon and Pentax use the same terminology roughly. But they should be treated as distinct systems. AF.C is for moving objects like sports and kids. AF.S is for more static objects. AF.S is also useful for activating a focus-assist beam from electronic flashes whose manufacturers support that function.</p>

<p>ME</p>

<p>AF-S is standard for most uses, and best for most purposes. It allows focus to be locked and held by the half press of the shutter release button, or the AF button. For fast-moving subjects, the AF-C, or continuous AF, continuously adjusts focus even as you press the shutter button. This continuously tracking predictive AF will provide a better chance of a clear shot of moving subjects, where the AF-S would instead lock focus at the half press, while the subject may have moved out of that focus range during the brief time of the actual shutter release. </p>

<p>I believe that in Nikon-speak, AF-S refers to lenses with integral autofocus motors. This would be analogous to Pentax SDM lenses...so we're talking about different things.</p>

<p>One use for APS setting:<br>

Tonight I'm going to do some strobe/umbrella shots outdoors, moonlight only, no modeling light. I'm after a softly lit foreground portrait, a little near-background detail (some pampas grass), and total black beyond that.<br>

With shutter button depressed fully, K20D focus spot beeps (if you want) and fires strobe when you move into focus with APS and M or green setting..in this situation, using an M 85/2 (manual focus) in a darkened room test, it fires on its own when I bring the lens into focus, even though I'm far from being able to evaluate focus, can barely frame the image ...doesn't need much light to focus..</p>

<p>can you give me some samples of your pics so I can see what it does</p>

<p>Jordan, what John is describing is the use of 'trap focus' with <strong><em>AF.S</em> </strong> (not <em>APS</em> ) when combined with manual focus lenses (has to be manual focus, won't work with autofocus. Not sure about the DA* lenses that have the on-lens AF/MF switch). If the setting to require focus confirmation is enabled (on by default), and you use a manual focus lens in AF.S, the shutter won't trip unless you have focus lock. What this means is that you can squeeze the shutter when the subject is NOT yet in focus, and the camera will wait to trip the shutter until the object <em>becomes</em> in-focus either because the subject-camera distance changed or because the focus was manually adjusted while holding the shutter release down.</p>