The electrical contacts between lenses and bodies are usually kept clean by the mounting and dismounting process. Each time you turn a lens towards the lock position, or away from it, it wipes clean the contacts by a very small amount. So, a seldomly mounted or changed lens only gets cleaned seldomly and can become 'iffy' in its connection. Sometimes I've had to hold in the lock button and work the mount to eliminate an intermittent electrical disconnection of a lens, which I've experienced in different mounts and their various sub-versions: Nikon, Pentax K, FourThirds and Micro FourThirds. They've all experienced this issue from time to time. Some people claim you should switch off a camera whenever you change lenses. I think that's being overly cautious, however if you're going to 'work the mount' like I suggested it'd be a good idea. Perhaps it's also a precaution to take with this lens in case it's getting premature and interrupted boot-ups during mounting to a powered camera. regards, Anthony
On 19 December 2017 at 07:10, Larry Colen <l...@red4est.com> wrote: > > > Anthony Farr wrote: >> >> First you need to isolate the fault to either the lens or the camera >> body. You have other camera bodies so start by determining if the >> Bigma behaves or misbehaves on those. >> regards, Anthony > > > I've had similar problems with the lens on other bodies. I don't tend to use > other lenses for birding. Cleaning contacts seems to be a good suggestion. > This was just the time it happened and I actually thought to mention it. > Since it's sporadic, that makes diagnosis a bit more challenging. > > > >> >> >> On 18 December 2017 at 17:49, Larry Colen<l...@red4est.com> wrote: >>> >>> This afternoon I was photographing a heron at the Waldport seawall with >>> my >>> K-1 and sigma 50-500 during low tide. It had flown from one spot to >>> another, I was walking back to the new spot, photographing as I went, and >>> at >>> one point the camera went completely out of focus, then wouldn't even >>> attempt to focus. I eventually got it back on track, got some more shots, >>> then the bird spooked, flew off (past me) I tried for some flight photos >>> but >>> the lens again went completely out of focus, then refused to do anything >>> to >>> get back into focus. With the bigma I couldn't (easily) manually focus >>> and I >>> completely lost my opportunity for those BiF photos. >>> >>> Does anyone know what causes the focus mechanism to freeze up like that, >>> or >>> any way to convince it to try to refocus? >>> >>> -- >>> Larry Colen l...@red4est.com (postbox on min4est) http://red4est.com/lrc >>> >>> >>> -- >>> PDML Pentax-Discuss Mail List >>> PDML@pdml.net >>> http://pdml.net/mailman/listinfo/pdml_pdml.net >>> to UNSUBSCRIBE from the PDML, please visit the link directly above and >>> follow the directions. >> >> > > -- > Larry Colen l...@red4est.com (postbox on min4est) http://red4est.com/lrc > > > -- > PDML Pentax-Discuss Mail List > PDML@pdml.net > http://pdml.net/mailman/listinfo/pdml_pdml.net > to UNSUBSCRIBE from the PDML, please visit the link directly above and > follow the directions. -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.