Argh, my sigma's broke :(

dod

dod

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Ebenezer McScrooge III
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Was shooting in manual most of today and noticed something very unusual. With two shots taken back to back one would expose fine, the next was severely overexposed. Threw on another lens and couldn't replicate the fault at all. Any body else vote for a sticky diaphram??

Edit: these happen to be shutter priority when I was trying different combinations to rule things out :p

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i have the same problem with a sigma 18-125 i just got . first time anything like this has happened to me if you find a solution to this mate please let me know...
 
its possible its a sticky diaphragm, but try cleaning the contacts first, just in case ! i have a similar problem with my nifty, the first shot is always over exposed but is fine after that ! I haven't tried cleaning the contacts yet, but am going to ! :)
 
IanC_UK said:
its possible its a sticky diaphragm, but try cleaning the contacts first, just in case ! i have a similar problem with my nifty, the first shot is always over exposed but is fine after that ! I haven't tried cleaning the contacts yet, but am going to ! :)
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Tried that Ian, didn't make any difference. :(
 
A sticky diaphragm is quite likely and not at all uncommon. It's possible some dust/grit has got in there given the shooting you do Doddy. With the electronics in modern cameras though, it could be anything. Were the shots on continuous drive or single shot?
 
CT said:
A sticky diaphragm is quite likely and not at all uncommon. It's possible some dust/grit has got in there given the shooting you do Doddy. With the electronics in modern cameras though, it could be anything. Were the shots on continuous drive or single shot?
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The ones above were on continuous. It happened as well when taking single shots. I'm thinking a bit of dust as well to be honest although there's nothing obvious in the lens when you look through it.

Time to get it serviced I think. As luck would have it I picked up a 70-200 F4 last week cheap, looks like I'll have to keep it a while now :lol:
 
Snip,...

King.

ACTUALLY!

This just popped into my head,... do you think the diaphram is struggling to keep up with the burst rate? So when the sensor takes the shot the diaphram is still open?

Or doesnt it work like that...?
 
:thinking:


not sure whats gone on here but mine to is working ok now ..

very strange ..

hope your rights itself dod.
 
Weak battery not supplying power fast enough to close the diapgragm? :shrug:
 
monkeydave said:
i have the same problem with a sigma 18-125 i just got . first time anything like this has happened to me if you find a solution to this mate please let me know...
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I have that same lens but never had a problem. It´s for sale now as I need to fund the 10-20mm. Maybe I had a good one?!
 
RobertP said:
Weak battery not supplying power fast enough to close the diapgragm? :shrug:
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Don't think so Robert, freshly charged battery and worked fine with the next lens.

Spoke to Sigma, the guy refused to believe a DG model could be sticking but said to send it in anyway. Clean, service and repair for a total of £120, not too bad really.
 
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