[tjstimbo]

I have two K3 bodies and I know they are both almost 10 years old, but I have a curious problem with both. Using two different lens the Pentax 18-270 and the Pentax 55-300 PLM (latest version) both exhibit the problem of focussing from near to far which is most noticeable at the long end of the focal range. For example if I have the 18-270 at 270 and focus on something quite close it's OK, not quick but good enough. I then move the camera to focus on a far away say 70 yards and it will not focus, even if I press the shutter button again, it usually should automatically refocus in AF-C mode. OK so I tried it in AF-S mode and same happens, I have to press the shutter button several times and then it will refocus. Same happens on the 55-300 using both K3 bodies, although in live view mode it is much better on both. It's like the the focussing has lost its sensitivity.

To try and work out if it is the lens or camera I used my K3 III body with both lens and each works perfectly and quite quickly which I would expect. So it isn't the lens.

So I wonder if I have changed something in the settings for the K3's, although I don't remember this happening recently. Both cameras have fully charged batteries and the latest firmware, I also cleaned the contacts. Using the AF back button exhibits the same behaviour.

Any ideas esteemed forumites, as I would hate to think that both K3's have the exact same problem.

Thanks

Tim

[71sam64]

Have you checked the K 3 bodies for the latest firmware. Much of the latest updates have to do with focus issues with many lenes. My K 3 II had focus issues with my new HD FA 43 f1.9 Limited. After installing the most recent firmware, all is fine.

[AfterPentax Mark II]

As you said that you cleaned the contact points you included the power connections from camera to lens as well? Last resort maybe, but have you tried this with the old batteries or did you use new ones, perhaps from the K-3 Mark III? Might be that the power needed by the lensmotors demands too much from an old battery. Typical behaviour of old batteries that they need a quiet moment to get their strength again...

[mlag]

if it are both PLM SDM or HSM electronic focus motor lenses I would also suspect a weak, old battery, especially if you used same battery in both cameras....
an old screwdrive lens seems to suffer less from a weak , older battery..., so that's a first test possible.
test any another battery...(with 2 camera's you must have more...)
I would also check focus zone / points , especially if set earlier to off center area or point.
there is an option to take pictures after focus. conformation or just anytime , without focus confirmation (release priority)....
in general test/check autofocus/manual focus switches on both camera and lens, including focus limiters...

but it's weird that both cameras suffer, unless you used same older worn battery in both cameras..or you applied same settings in a previous shoot.

[tjstimbo]

Thanks for your suggestions so far. I have aa number of Pentax batteries that I rotate around the cameras, but I will try a nice fresh set. Options on AF-S and AF-C are both focus priority. Focus point is spot. I tried again late yesterday afternoon and it worked and then it didn't. The next stage will be to try some freshly charged batteries and maybe some different lens such as the 16-50 and the 50-135. Also I will try and reset one camera to factory settings to see if that makes a difference.

Cheers
Tim

Update: I think I may have discovered the problem insofar it is the batteries, or rather some of them. Both cameras were telling me that the batteries were good and as I don't often use my K3's I took it as gospel. Fresh set of recharged batteries and everything seems to be back to normal. I tried the batteries coming out of the K3 in another body and they registered as nearly depleted. So I suspect leaving the batteries in a camera for a long time doesn't mean they are not drained even if the battery monitor indicates they are good.