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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