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Thanks useful information: 2
I'm using a D300s. I use AF-ON and AF-C. When I shoot people walking, it's generally fine. But for a baby, very slow and uneven movement, the failure rate is around 99%. No matter what settings, number of AF points, I can't do it. The focused part is always a little behind.
What is going on?
Other settings? In particular shutter speed?
Maybe try a flash at very low power. That may help to freeze movement.
I have the same issue with my cats. They seem slow and deliberate but the camera sees them as making rapid movements. Maybe to your eye the child is moving slowly - to the child it is moving as fast as it can!!!! perhaps the camera is picking up on that emotion
Last edited by fess67; 20-07-2012 at 8:46pm.
Threadstarter
Flash is not the problem, AF is missing either front or back. I can see where the ground is sharp. I'm wondering if a non-tracking mode would work, but I couldn't see any way to 'dumb' it down. I got it on single AF point now.
Of course could be that it's always night indoors and my house lights are dim. They don't seem so, at 1/250 f2.8 ISO400 I still get ambient showing up.
What focal length?
Are you at 200? is your body a crop sensor? If that is the case it could put your effective focal length out over 300, making 1/250 possibly a bit slow and maybe susceptible to movement. Just trying to think of possible issues.
What lens? Some lenses are slower to focus than others and thus also have trouble keeping up when in AF-C mode. Try a different lens
Last edited by ricktas; 21-07-2012 at 7:53am.
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You Haven't mentioned which lens you were using. Obviously it must be reasonable, to be able to use f/2.8. And with a D300 there shouldn't be any dramas.
I would say at a guess it would have to be the distance between the camera and the subject. Did you use "Spot focusing"???
I'd also try to use a higher f/ stop. Around f/8, and maybe bump up the ISO to compensate.
Just a thought.
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It is the Nikon 24-70G 2.8
I'm using single spot AF, but it's doing both 'predicting' forward too much and also being left behind other times.
Shooting distance is about 2-6m.
Since I'm moving and using on camera flash I want to avoid a much higher f/ stop. Also my place is quite cluttered so another reason for shallow DOF.
I've been trying f3.5 for a bit which gives me one baby thick (15cm) DOF from review. AF is off by one baby step. ie I can see his front foot is in 1/3 into the focused area which extends further forward.
Even at f/3.5 it doesn't leave much room for error.Originally Posted by reaction
I've been looking through the formal and posed section of the forum, and going through the exif data on images similar to the ones you are trying to take. Most are f/5.6 or higher.
I've also checked out the reviews on the lens. And they mostly say that the lens is one of the best you can get.
I think if you are unsure, do a AF test on the lens and camera combination. Get a bit of white board, mark out lines a cm apart, number the lines from the centre (0 +1 +2 -1 -2) and try the AF at different zoom positions (24mm - 70mm) Make sure when you do it that the board is at a 45 degree angle.
This will give you a good idea whether it's you, or the gear.
You have turned the focus mode in the menu to "focus tracking with lock on"? Check your camera manual.
The other thing to consider is that in the AF-C mode, your camera/lens combination is front focusing. Try another lens and see what happens.
Threadstarter
The lens is properly calibated, so it's definitely me not the gear.
I have "focus tracking with lock on" set to 'normal'. Maybe I'll try it 'off'.
I have also tried a 50mm f1.4 and it's worse, but the 50mm is known for slow AF.
Perhaps it's just too dark indoors to grab focus quickly, even at f/2.8. Have you tried shooting with the little light thingy turned on? ("Focus Assist Light" ?)
Phil.
Some Nikon stuff. I shoot Mirrorless and Mirrorlessless.
Maybe post some examples. I have had no issues with my little one who is two years old. (or for the last 6 months where I've been using the 24-70) That said, I'm also using the D700 which probably has a better focus engine but the lens would make the major difference and its the same in this case.
The 3D/tracking works well but only in certain environments otherwise I generally switch to single point focus and select my focus point manually and then run with AF-C
Auto Focus works by using contrast to lock onto. If the child is wearing a plain coloured top and you are trying to get the camera to lock onto that ( or any other plain coloured area) and stay focused, under dim light, that could well be the issue.
Threadstarter
"Focus Assist Light" doesn't turn on in AF-C. That's why I also tried AF-S a bit but he moves too fast for me. I'm trying to lock onto his face, maybe it is just to dark for the speed.
We're all sick atm, will try again when we're better. Maybe i'll try outdoors in the sun too.
OK, now I am confused. In your first post you said "But for a baby, very slow and uneven movement" and ^ you state "but he moves too fast for me."
i think you probably need to post a photo or two in here so we can see examples of what you are getting and thus assist further.
Threadstarter
I use AF-ON. In AF-S the time to press AF-ON, let go, press the shutter, he's moved his half a step. Esp since I'm used to holding the AF-ON button down.
Well, I'm not really comfortable posting my son here... ok not that I'd post other people's babies here either...
Last edited by reaction; 22-07-2012 at 7:46pm.
Fair enough, but I think you have exhausted any help we can offer without seeing the issue in photos.
Have you tried using just holding the half press of the shutter for focus. The lag between the AF-ON and the shutter seems to be the problem.
Last edited by MissionMan; 22-07-2012 at 8:18pm.
You could try rolling a ball slowly and try taking pics of the ball in the same lighting. If its a focusing/lighting issue more experienced people in this forum might be able to help you
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