focus problems? K10

Hi. I have uploaded a pic in the gallery. I spent a couple of hours taking pics of air cadets flying gliders. I am now viewing them and think they are all out of focus. Can someone confirm to me that I am seeing right? I changed to spot metering in the hope of getting a better response but I don't think this made a difference. The camera was set to AF.C to follow trhe movement of the gliders. Is it me, or the ca,mera? comments, please

it soft, what was your shutter speed, and was sr on or off,

From the EXIF, the shutter speed was 1/3000s at F8, so SR would be irrelevant.

It's just out of focus, I think. Aircraft in flight take practice.

Personally, I find the K10D's AF-C adequate for aircraft, especially when tracking left to right so that the distance from the camera isn't changing all that fast (at least compared with when they're heading directly for you).

It's the only situation in which I switch the AF-point selector to Auto, since if you use the centre point only, you have to be able to point the camera extremely accurately as you track the aircraft. Otherwise, it can lose focus very easily and hunt around dreadfully.

The other thing about AF-C is that, unlike AF-S, it will take the picture whether it has focus lock or not.

cheers chris, totaly agree, just keep at it, sound like you need to improve your panning skills,(practice practice)maybe try a slower shutter speeds and up the apature f16 shutters speed 1000/sec or 1500/sec

Is the original before you resized it to post it sharp?

I have problems with pictures which start off pin sharp and by the time they have been resized, hosted and posted, turn to mush.

Thanks, Guys. The pic is resized to load onto the gallery, but the original is just as out of focus. The settings are.. Point focus, panning, and the AF point setting at AUTO and as you know at F8 @3000s. I took about 100 shots. Maybe some could be down to my panning but ALL are out of focus. Surely, I should get some of these right. I suspect the autofocus system in the camera. Have since taken pics, at SRS suggestion, on green mode and these suggest the auto focus system is letting me down. Any further comments welcome.

How, specifically, do the green mode pictures you've taken suggest the AF isn't working?

I'd suggest the following things to try in the first instance:

First, check that AF-S works, using:

- the camera on a tripod,
- centre AF point selected
- pointing at something stationary, flat and contrasty.
- good light on the subject
- manual exposure, so you can be sure of consistent shutter speeds
- 2s delay mode, to eliminate shake

Ideally, use the chart from here, mounted flat, tilted at 45 degrees away from the camera, so that you can establish whether the picture is all out of focus, or if there is a part of it that's sharp.

Then, if the results are sharp, try switching to AF-C, again as above.

If it's still Ok, try AF-C with a very slowly moving target.

As I say, a properly functioning K10D's AF system should be perfectly capable of getting slowish moving gliders sharp. It's either technique, or it's not working properly.

This, for instance, was AF-C, probably going a bit faster than the glider.

If the AF system is at fault, it should be very easy to prove it, reliably and repeatably.

i would not use the af auto, use the centre af point and you will get better result as long as your panning good,

That can be quite an ask though, sometimes, especially with fast jets.

With something as slow as a glider, it should be reasonably easy to keep the centre AF point on the subject.

However, I'm not convinced that if the background is featureless, Auto-AF point selection is any worse than Centre-AF point. I've used both quite a lot, and not seen anything much between them.

Of course, if there are background features to confuse the situation, Auto-AF can indeed go horribly wrong, but I don't think this case is like that (edit: actually, it might be - see below).

Another thought:

How central are the gliders in your original frames? Is the one you posted to the gallery just resized, or is it cropped as well?

The reason I ask is that the glider is nowhere near the centre of the frame in the one you posted, and it may simply be that the camera was focusing on the clouds behind. The sky in the background is not featureless enough, as I mentioned above, to be confident that the camera won't pick it as the subject.

If that's the case, and you don't want to focus manually, you'll definitely need to force it to use the Centre AF point, and sort out your composition in the crop.

I'm sure you're aware, but just in case, the "half-press to lock focus, then reframe to compose" technique will not work at all with AF-C - because the focus will be changing all the time while the subject is moving and you have the button half-pressed.

I am getting a little confused. The glider is quite large at the distance I was focusing on it. The red focusing dot was on the glider. I took at least 6 or 7 shots of the glider landing. I should have been able to get one or two right. Getting them all wrong makes me ask questions. Had I mised the glider, then the clouds would surely be in focus, not as is, that all is out of focus. That is my reasoning, right or wrong. I have now used a focusing chart and most lens show no problem. Just wondering. I was using an F 70-210 backed by my Pentax 1.7 converter. Maybe this combination has let me down. Have tried the 70-210 on the chart and from a brief check it seems to be OK. Totally confused am I. I really am disappointed having sat on my bum for two hours without a decent result

The aperture of the lens needs to be F2.8 I think to use the 1.7x converter properly with AF. Especially at the longer end of the zoom, the AF system will not have been able to operate properly.

I think we have found the reason.

Try again with just the zoom and you should have no problems.

I never use AF-C with a converter as I think they slow the AF down ... I would have thought the lens wouldn't be able to keep up.

That is a relief...Knew there must be something I am doing wrong. Have checked the camera and lens against the focusing chart and all seems correct. Forgot my 70-300 tamron so decided to put the converter on the back of my 70-210. It seemed logical to me. Oh well. Maybe next summer when the cadets get another opportunity. Next question. Asked SRS for a split screen update. No Pentax split screen, so not interested. How can I proceed? I can get a split screen but beyond me to fit it. Who can I approach to do this with confidence?

Split screen is very very easy to do on a K10D, if you go to youtube there are videos on there showing how to do it step by step.

Are you going for a cheap Ebay screen or the Catzeye ?

If you fit it yourself I suggest finding somewhere as dust free as possible (bathroom after running a hot shower for a while, steam to settle any dust) is pretty good I found.