D300 autofocus problems

Ross

Ross

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Been a while since I have posted so hello all :wave:

I picked up a D300 around November time last year and haven't really had much time to use it for one reason or another. It had a few outings over xmas and I was pleased with the results on AF-S mode.

A few weeks ago I took it out and used AF-C for the first time. I had setup the autofocus menu as follows:

a1 - release & focus
a3 - 21 points
a4 - short
a5 - shutter/af-on
a6 - auto
a7 - no wrap
a8 - af11
a9 - on
a10 - af-on (i used an MB-10)

Camera was set to C mode, Continuous-High and the focus selector on the rear was set to the middle dynamic focus area. My Nikkor 70-200 f/2.8 was set to M/A as normal, VR off

The problem was that out of 200 + shots, not a single one of them was focussed correctly - all of them were blurred, and not just a little bit - by a fair margin.

Now this doesn't happen in AF-S mode - any of the focus points I select will give a nice crisp image.

The lens works fine on my D200, and again works fine in AF-S mode so it's not that. Again I have setup my D300 with very similar AF menu settings to my D200 and have taken in excess of 80,000 shots with that with virtually no problems (the majority being keepers so to speak) so I know it's not a problem with either my technique or the lens.

I have done an extensive search on google and have looked at similar D300 issues where the lens will focus from infinity to close and back again without obtaining a lock (mine doesn't do that), and also front/rear focus issues that can be partially eliminated with the lens fine tuning - but again the lens focuses fine when used in AF-S so I don't think it's that.

Unfortunately I have deleted those shots but here are another 2 using my Nikkor 17-55 - at both points the focus was right on her nose

http://www.itsnotarace.com/tpf/DSC_1328a.jpg
http://www.itsnotarace.com/tpf/DSC_1329a.jpg

Has anyone come across any issues like this?

I'm tempted to just take the camera back to the shop I bought it from and seeing if I can get an exchange - I have a paid sports event coming up in a couple of weeks and I have zero confidence in the autofocus abilities of my D300 so I'm going to have to turn back to my old D200 workhouse until this is resolved :shake:

Could anyone else that has known good autofocus settings for moving targets post theirs and I will try them out?

Thanks in advance
 
Sorry but RTFM my friend.
The D300 manual says against release+focus (page 267):
Photos can be taken even when the camera is not in focus. In continuous mode,frame rate slows for improved focus if the frame subject is dark or low contrast
Click to expand...

That implies to me that focus is never guaranteed in this mode.
 
Focus + release works fine on my D200 thanks. The odd shot might be out of focus but not ALL of them

Have you ever shot sports events? If you wait for focus lock on every single shot you would not take more than maybe 1 frame per second. Try getting 8fps on moving subjects with set to focus only and you'll see what I mean.
 
Were you in AV or TV mode for these images. For motorsport, especially if something is coming straight at me I use AV, i.e set an aperture and allow the camera to set the shutter speeds. If you used TV on a moving subject that is coming straight at you I've found that I don't get as sharper image as using AV. Not a nikon user so can comment on your setup, but when using * / and shutter button on my canon to set exposure lock and focus tracking, it's easy not to get the process right if you not use to this operation and completely fluff the shot, i.e image not in focus. From the 2 images you posted, it seems that the focus point is infront of the dog on the track not on the moving subject.

Peter
 
Should also mention I am on the latest firmware
 
pete.rush said:
Were you in AV or TV mode for these images. For motorsport, especially if something is coming straight at me I use AV, i.e set an aperture and allow the camera to set the shutter speeds. If you used TV on a moving subject that is coming straight at you I've found that I don't get as sharper image as using AV.
Click to expand...

Should make absolutely no difference which mode it's in, aside from the general rule of thumb of not shooting with a lower shutter speed than the effective focal length of your lens to avoid camera shake.

I am quite comfortable panning right down to 1/30th of a sec with a 200mm lens though.

The shots above are probably not a good example as Lily is very pale and I was shooting into the sunlight so it would have been more difficult to get focus lock on her nose/eyes and the camera not be fooled with her pale body and ears etc.

I will try and get some better examples of the problem over the weekend
 
Ross said:
Should make absolutely no difference which mode it's in, aside from the general rule of thumb of not shooting with a lower shutter speed than the effective focal length of your lens to avoid camera shake.
Click to expand...

In my experience it does, shooting Moving Tigers at the zoo or 200mph motorbikes at Brands, if there coming straight at me I always use AV to achieve the shot. For Panning shots, then I would use TV.
 
I guess the only explanation there could be if you were using a wide aperture and therefore have a narrow DOF on the moving subject, which would then move through the DOF as you were taking the shot
 
Here's the settings straight off the back of my D300. I use this week in week out for motorsport and it works for me. Note I use the AF-ON button for focussing.

a1 - release
a3 - 9 points
a4 - short
a5 - AF-ON only
a6 - auto on
a7 - no wrap
a8 - af51
a9 - on
a10 - af-on (i used an MB-10)

Not majorly different from yours. I would advocate using the AF-ON for focussing rather than the shutter release - but it takes a bit of getting used to.

My only other thought was VR, but you have that off already - as do I.

EDIT: one other thought - try also if possible to ensure you are using the cross AF sensors on the D300 - they form the central 3 columns in landscape mode. These are far more accurate than the outer sensors.
 
Bizarrely I had a try with AF-C today and also found the focus point switching all over the place but...and its a big but, I have only just got the camera so I set everything up as per the D300 settings spreadsheet available on the Nikonians website http://www.nikonians.org/dcfp/user_files/85767.zip and they are very different from you guys above?

These are mine from the sheet:

a1 - focus
a3 - 51 points 3d tracking
a4 - normal
a5 - Shutter/AF-ON
a6 - auto on
a7 - no wrap
a8 - af51
a9 - on
a10 - af-on

So I am very confused now, am I totally set up wrong or (unlikely I feel) are both of you set up wrongly?
 
nictry said:
So I am very confused now, am I totally set up wrong or (unlikely I feel) are both of you set up wrongly?
Click to expand...

I don't think there's a 100% right or wrong answer to this one. It's a matter of what works for you. No harm in using somebody else's settings as a base then fine tuning them. That's what I did.

The ones I posted work for me, but not everyone is happy using AF-ON. It confuses the hell out of people if you hand them the camera to take a shot. I don't like 3d tracking much either and would rather maintain control of the focus point.
 
3d tracking works ok sometimes.... but not others! I've seen it go bonkers on motorsport subjects!
 
I had a try with mine on some birds in flight yesterday and had changed the 3D back to normal 51 pts and got the following in focus shots (probably about 8 of the 10 shots in a row were in focus)

3339329504_2c15f6c85d.jpg


3339344646_cf0c5437c5.jpg


One thing did make me think though, as when moving the camera around to keep the animal/bird/cars etc. in focus surely your own movement could blur/oof the subject?
 
ive come from Canon and i shoot pro field sports, i use the d300 as a back up and i shoot like the canon "centre focus point only" and i nail focus every time, i also wait a fraction from focussing to firing the shutter so the tracking has time to start.

Forgive me if this hasnt come across as it should, in new to Nikon and still find myself using Canon terminology.

i did try the 3d tracking thingy but it was beserk.
 
Any chance it could just be motion blur? The ground at approximately the same distance from the lens as the dog's nose is nicely in focus.

Maybe 1/160 isn't quite quick enough for a moving subject coming towards the camera?:shrug:
 
There are a couple more things you might want to consider - when shooting a moving subject and you want to freeze the action, don't pussy foot around, get the highest shutter speed you can, take the ISO to the max you are happy with if the light is anything but full on. Remember you can use auto-ISO on your D300 - set it to say max 1600 and the minimum shutter speed to whatever you think you need (perhaps 1/500) and shoot away. Works a treat!

Also, the other thing is to do with the way AF systems work - the D300 is very fast (yes you can make it max speed btw by using just one cross focus point) but the closer you are to a subject, the more trouble it will have - too much rate of change. Try using a longer lens!
 
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