Sigma 24-135 compatible with Ist DL?

Just received the Sigma 24-135 lens Pentax mount today. It will not work on my

Ist DL digital SLR. I also tried it on my daughter's Ist (same DL). AV flashes

in the info panel. Lens does not operate. Has anyone used this lens on the

Pentax Ist Dl. Is it compatible? Do I have a faulty copy of this lens? Thanks

for your help.

Is the lens set to A on the aperture ring? If so, you've got a classic case of Sigma Firmware Malfunction. Sigma's notorious for firmware issues causing problems with cameras newer than the lens.

Otherwise set the aperture ring to A.

Thanks

It was the A setting. Did not have the lens adjusted properly. I like this lens when I pack only 1 lens. I picked it up new for $100. Paid over $350. for my Canon version that I traded in last year.

Thanks again