NX500 - Disappointed by AF performance

andre95 wrote:

Raw Jaw wrote:

Thank goodness it was the camera and not you.

No need to be offended?

I consider myself a beginner, and don't know the technical details. You suggested that using Continuous AF was the big mistake, and that I should read the handbook. The handbook did not clarify why Cont AF performs so much worse (this, BTW, is just speculation, we don't know whether single-AF would have been the solution, but of course I'll try).

So, all I did was ask, and I do it again: Can you explain to me why Cont AF performs so much worse?

I mean, some scenes didn't change much overall (like blowing out the candles), but still a lot happened. So I just took one picture after the other. Approx. 30% are utter rubbish, i.e. focussed on something completely different than the AF-square or is totally blurred (see the attached example, before releasing the shutter, there was a green square just covering the face of the central child). The next two images focussed on the red box in the background (at least something), and the next image was nicely focussed on the face of the girl (the way I wanted it, and the way I would have thought because indicated by the green square on the face).

Honestly, how can I avoid this? I take a series of pictures under virtually identical conditions, and some shots go wrong by so much?

If I can do better, then I really want to. But for this I need to understand what went wrong.

Best wishes,

Andre

You are shooting at F2 fairly close to the subject, which means your depth of field is pretty small. Also, the center of the image does not have much contrast, which is what the camera looks for. The subject is likely moving around, which makes it that much more difficult for the camera. All of those things combined spell trouble if you are shooting in low light with a lens that is a slow focuser.

Suggestions:

1) Choose something with high contrast to get the focus, then recompose and complete the shutter press.

2) Get in the habit of using DMF for those sorts of scenes. If I am shooting scenes with critical focus (I have an NX1, with the 16-50mm S and 50-150mm S lenses, so those might be quicker than your system) I use the autofocus to get the ball park range, then use DMF to adjust to get critical focus (you get focus magnification and peaking visible when you use DMF). Once you get used to doing it, you can do it in a fraction of a second, and it gives you much better focus consistency.

3) Use manual focus if the girls are sitting there for a while, and compose your field of focus beforehand. Again, once you get some practice doing this you can do it quite quickly.

That helps me. Never considered using AF to get into the ball park range before switching to manual. Is there a fast way to switch between manual and auto focus? The 45 has a switch but other lenses I own don't so I have to hunt for it in the settings.