Bigma or camera?

Hi Everyone,I have a K10D and a Sigma 50-500 which is used for bird/wildife photography.I was told about some Barn Owls in my area and went to see.Although it was 20.30 it was not really dark I just could not get one single shot(mainly bird in flight).The combo simply would not auto focus.I have mobilty/stability probs which doesn`t help.Would a 300 f4 lens enable me to get a decent photo although more distant or is the K10D autofocus not up to it.The Bigma is great on a beanbag/tripod.

Graham

Graham,
For all difficult AF situations I would suggest the following setup (if you haven't got it already!):

* Disable the AF-on-half-press in the custom options
* Use the "AF" button on the back to do a manually triggered AF

This helps in very low light and/or low contrast situations, as well as situations where timing is everything.

Simply estimate where the subject is going to be, find an item that's at the same distance (but has some decent contrast) - point the camera at that and hit the AF button to get a lock.

Now, when you hit the shutter (because the bird has just come into view) it will occur immediately without any focus-hunting.

Hope that helps!
Matt

Were you using a mono or tripod (I'm guessing not a tripod if they're moving around)? That may help the stability. If they are going in and out of the same place then a tripod would surely be best but you'd only get a few attempts.

If it's getting dark and the light is changing then autofocus would be a problem with fast moving subjects. I think you would struggle with any lens/camera in those conditions. I would have maybe tried manual focus (or catch in focus if the k10d does it).

edit:
Matt's suggestion seems to be a good one (more detailed than my "I would maybe have tried manual focus" comment)

Welcome to the forum Graham.

I have the same stability issues with my Bigma which spends most of its life attached to a monopod (with a ball head), this leaves the movement of the lens fairly flexible but eliminates the need to actually support it, a boon when the arthritis has flared up.

Yes, I've had problems with low light and focusing, the Bigma is a light hungry beast and doesn't perform very well if the light or the contrast is low, suggestions for other lenses have already been made so no need to repeat them.

Good Tip Matt. Thanks. I was out in dimmer light last night and focus hunting was annoying. cheers

Thanks everyone for the advice much appreciated will give Matt`s advice a go.Thanks again

Graham