Lens hunting

*sinus007* · 06-07-2009, 04:24 PM

Hi,
I've got da55-300 a few days ago. I did a few shots here and there. I'm satisfied with its iq. But what I'm really concerned about is that it hunts like crazy: it can take up to 2-3 sec to focus. The way around it is to 'prefocus', IOW turn the focusing ring to the aprox distance to the subject. Then the focusing time is on par with 50-135. Also, I didn't have this problem with da50-200. Oh, forgot to mentioned: the lighting is good, e.g. sunny afternoon.
My question is to people who have other '300mm' lenses: Sigma 100-300, da*300, da*60-250, fa300. Do they have the same "hunting" problem?
Thank you very much,

*Miguel* · 06-07-2009, 08:13 PM

You description of the problem is too vague for folks to be able to provide assistance. What AF setting are you using AF.S or AF.C ? And, what subject(s) are you shooting? Also, what focusing point(s) configuration are you using? How is your AF button configured?

M

*imtheguy* · 06-07-2009, 08:45 PM

Yes, tell us more. I have taken thousands of outdoor critter shots with my 55-300 during the last 3 months and can say I dont ever remember it taking 3 seconds to AF in decent light once i had the subject in the viewfinder and started to half-press the shutter. Now starting to focus and then accidently moving the viewfinder to the sky or something then back to the subject is a different matter.

*sinus007* · 06-08-2009, 09:07 AM

Hi,
Thanks for the replies.
I had the following settings:
I was using AF.S, central focusing point, objects were stationary, 30-50 ft away, camera was put on top of a solid fence ( I should've tried it on a tripod). I'm not sure what you meant by AF button configuration?
Thanks,

asdf · 06-08-2009, 09:44 AM

Originally Posted by sinus007

My question is to people who have other '300mm' lenses: Sigma 100-300, da*300, da*60-250, fa300. Do they have the same "hunting" problem?
Thank you very much,

DA 55-300 is slow F-stop-wise at the long end, which makes it prone to hunting. "Sunny" is a relative term. Sunny in Ohio is probably not as sunny as it is in California or Florida. So folks' mileage varies here.

The slow hunting time and noise makes it quite annoying to use:
YouTube - Pentax K20D + DA 55-300 Autofocus

DA* 300 f/4 was much more pleasant to use.

*imtheguy* · 06-08-2009, 11:02 PM

Originally Posted by sinus007

Hi,
Thanks for the replies.
I had the following settings:
I was using AF.S, central focusing point, objects were stationary, 30-50 ft away, camera was put on top of a solid fence ( I should've tried it on a tripod). I'm not sure what you meant by AF button configuration?
Thanks,

The only way I could possibly make my 55-300 take more than a second to home in on something at 30-50' when the lens is starting from a typical close focus position would be very low light (you said it was sunny) or missing a small target and aiming for a split-second into infinity, or having a target akin to a black cat against a black wall. If you cant home in on a contrasty, dog sized subject at that range with good light without hunting then IMO yes, there is a problem others of us dont have. I'll be happy to run some testing with you if you wish to state conditions.

*deadwolfbones* · 06-09-2009, 07:44 AM

Mine does this all the time as well. If you get focus, then re-half-tap the shutter to confirm focus it'll (about 50% of the time) swing from one end of the focus range to the other and back again. This is mostly when shooting distant objects like, say, the moon.

*imtheguy* · 06-09-2009, 07:49 AM

yeah, but the moon is not 30-50' from him. How about at that distance Bones?

*deadwolfbones* · 06-09-2009, 10:53 AM

Originally Posted by imtheguy

yeah, but the moon is not 30-50' from him. How about at that distance Bones?

Less often, but it does still happen.

*sinus007* · 06-09-2009, 05:46 PM

Thanks everybody for replies, suggestions, etc.
I'm getting used to the lens: hope I'll be able to get something decent out of it. If not - shame on me.