aperture sticking????

Bountyphotographer

My 24-70 2.8 Sigma lens for Canon is acting up.
I think the aperture is sticking because the blades are almost close by the time I take 3-4 pictures.
I take the lens off the body put it back on the body and voila the aperture is wild open.
I was told that most lenses these days will have a motor aperture problems sooner or later.

Do I have to send it to Sigma and pay >$200 or can I do it myself?

Thanks for any advice

Bounty

JimKarczewski

I'm assuming it doesn't happen with any other lenses?

Have you tried at least cleaning the contacts on the lens itself to see if that helps? Could just be a dirty contact...

But other than that, about the only kind of service I'd ever do to a lens is cosmetic.. too much crap in there for mere mortals to play with!

Bountyphotographer

JimKarczewski wrote: »

I'm assuming it doesn't happen with any other lenses?

Have you tried at least cleaning the contacts on the lens itself to see if that helps? Could just be a dirty contact...

But other than that, about the only kind of service I'd ever do to a lens is cosmetic.. too much crap in there for mere mortals to play with!

yes and yes it stick. My other lens is just fine. It's getting even worst than a month ago.
I used to stick after 20-30 pictures now after 2-3 it sticks.

ziggy53

Bountyphotographer wrote: »

yes and yes it stick. My other lens is just fine. It's getting even worst than a month ago.
I used to stick after 20-30 pictures now after 2-3 it sticks.

It definitely sounds like time to send the lens to Sigma for service.

If you are not familiar with working on lenses, and if you lack the necessary tools, you should not attempt to repair the lens yourself.

WilliamClark77

The aperture blades on my Canon 100/2.8 stuck wide open. They refused to do anything but 2.8 regardless of settings, cleaning, tapping, bodies, or begging. I THOUGHT I would attept it myself. Some internet searching later I found a video of disassembling a lens. About half way through the video I was hunting a box to ship it to Canon in. It has worked fine since.

Bountyphotographer

Thank you all, frustrating but it make sense.

Bounty

Bountyphotographer

Sticking Aperture issue
Finally, I had my lens looked by someone ( free estimate) who used to work for Canon and wanted $180 but said that it would take weeks because Sigma doesn t always have the part. He said that it was the ribbon cable, but Sigma sell it with the motor. He didn t think that I should have it fixed.
He kind of told me to buy a Canon lens instead. By the way he only does repair and doesn t sell any product at all.
I sent the lens to sigma (free estimate) and they just called my house and left a message saying that the lens is finedunnodunno
I triple check the lens before sending it to them and the aperture was sticking after firing 5-6 shots.
I also put another lens on my canon 30 D body and it was fine.
I'll call them back tomorrow but thought that I would share this on the DGRIN forum

To be continued.........................

KMpics

Have you tried the lens on another body? Sometimes there is a conflict between 3rd party lenses and camera (possibly why Sigma tested it and found no problem).

Bountyphotographer

sticking lens
No, I have not but I just called Sigma new York and they told me that they tried on a Canon 30 D and everything is just finedunno
This lens has been working great for the past 4 years with my Canon 30 D dunno
The lens usually is acting up while shooting indoordunno

Weird, isn t it?

Bounty

KMpics

What happens when you push the DOF preview button (set at more than f2.8)? Or... what happens when you just set the AV at 2.8? ...do the blades close past wide open anyway?

Not that this solves anything just curious. I had a Rebel that gave error codes with a sigma lens, the body would not function (remove replace and then it would work)...with Canon lenses it would happen less but still happened. Eventually the camera error coded out and would not function at all and I sent it in to Canon for repair.

Bountyphotographer

When pushing the DOF it get dark inside the lens.
I had no error at all.

Now Sigma wants $200 to change the pcb and diaphram???????????????????

ziggy53

In summation, you have an intermittent problem with the aperture, and 2 completely different potential solutions (at approximately the same cost each).

It does sound like, if you decide that the lens is worth keeping, you should attempt one or the other repair, keeping in mind that the other repair might be the actual repair needed.

You could also request that all of the potential components (ribbon cable and motor plus pcb and diaphragm) be replaced at the same time, probably at a cost of $400 or so. That should get you the best possible chance for success in a single repair ticket, i.e. the least amount of time without the lens (unless you get lucky with one of the other lesser repairs.)

Of course you could decide to give up on the lens, sell it on the open market with a truthful description, and purchase another copy, either another Sigma of the same make and model, or a different model altogether.

You could also try to find another source of repairs, hoping that they would corroborate one of your prior assessments, and then proceed on the consensus.

Those are, I think, your options. Nothing easy or cheap I'm afraid.

Bountyphotographer

OOOOOOOPS forgot to update.
Sigma from New York wanted $200 yet they couldn t find the problem. Better yet the lens was just fine up there.
I asked them to send it back to me and so far so good the lens is fine.
Not sure what happen? It didnt work now it works and nothing was done to the lens????????????????????