Yeah. VERY VERY carefully, holding it over my head with the lens bayonet
facing down so nothing could fall inside.
I'm getting some kind of intermittent failure mode. I turn it on & it
prompts for a focal length. I select a focal length & press Ok and I get
the "F--" on the display.
I turn it off & wiggle the lens in the mount; turn it off & dismount &
remount the lens; turn it off & dismount the lens, clean the contacts on
the lens & body and remount the lens ...
When I turn it back on, maybe I'll get the focal length prompt again or
maybe I'll get the last aperture I selected.
If I *DO* get the aperture, it appears I'm going to get the "F--" again
after a few shots. It's definitely something going on with the lens.
I've tried it with a bunch of other lenses that have the aperture ring &
an 'A' detent. They all work just fine.
I've seen that "F--" before with several different lenses and it's
always been when I somehow got the lens unlocked from the 'A' detent. As
soon as I get the lens back in the 'A' position the problem goes away.
I think something inside this lens that has to do with whatever circuit
detects whether the lens is mechanically locked into the 'A' position or
not is wearing out.
On 7/15/2013 4:24 PM, Bob Sullivan wrote:
And John,
Did you clean the contacts on the camera as well?
Regards, Bob S.
On Mon, Jul 15, 2013 at 12:40 PM, John <[email protected]> wrote:
On 7/15/2013 1:03 PM, Zos Xavius wrote:
Did you try cleaning the contacts? There isn't an communication
between the lens and the camera for an A lens. It just reads the
contacts and determines aperture range. Try cleaning them.
Yup. That was something I learned from Army radios.
Don't know why it stopped working. Don't know why it started working
again once I got home. Don't know when it's going to decide to crap out
again.
But the contacts are clean.
I (gently) racked the aperture ring several times from 'A' to 2.8 & back
again to see if maybe some bit of grunge was keeping it from registering
the 'A' position internally.
I guess it's time to start looking for a backup/replacement before it
fails for good. Looks like the only thing available is going to be
either the 28-70 F2.8 SIGMA EX ASPHERICAL (77) or the 24-70 F2.8 SIGMA
DG EX ASPHERICAL (82).
Anyone have hands on experience comparing either of them with the Tokina
ATX-Pro?
On Mon, Jul 15, 2013 at 12:59 PM, John <[email protected]> wrote:
I finally dredge up enough motivation to actually go out and do some
photography. Got on site & my favorite lens takes a crap on me.
My workhorse has been a Tokina ATX-Pro 287 28-70mmf/2.8. I got two frames
&
camera won't fire the shutter. Aperture shows "F--". I do everything I
can
to make sure the lens is properly seated & that the aperture ring is
latched
into the 'A' position ... NO JOY! Nothing I can do will make it show the
aperture.
I have one other 'A' lens (SMC Pentax-A Macro 1:2.8 100mm) in my bag on
site, & when I switch to it the aperture works fine. I also try both
lenses
on my K10D (backup) and get the same results; Tokina "F--" & Pentax shows
the aperture selected with the thumb-wheel.
I'm back home & I've got a couple of other Pentax auto-focus 'A' lenses
to
test with. They all show the aperture & change with the thumb-wheel. And
just to add insult to injury, I give the Tokina one last try & now it's
showing the aperture again.
Meanwhile, every bit of motivation has drained away!
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