WARNING: Sony Alpha A700 & Sigma 70-300 APO DG

Pirate!!

Banned
HEADS UP:

Sony A700 will strip AF gears in Sigma 70-300mm APO DG Macro.

I had heard of this phenomenon, but was advised the latest firmware 'cured' it.

NOT TRUE. I have no idea if same applies to A200/300/350.

Be aware.

Will post images in a few days. The A700 is AWESOME though.
 

denno75uk

Well-known Member
Will you be able to claim from Sony for that? Do they warn of it in the literature?
 

senu

Distinguished Member
HEADS UP:

Sony A700 will strip AF gears in Sigma 70-300mm APO DG Macro.

I had heard of this phenomenon, but was advised the latest firmware 'cured' it.

NOT TRUE.
What is not true? the problem or the "cure"?

The A700 is AWESOME though
Absolutely..:).
 

Pirate!!

Banned
What is not true? the problem or the "cure"?


Absolutely..:).
A700 firmware update V3 doesn't 'cure or prevent' Sigma AF gear stripping in 70-300mm APO DG Macro lens. Haven't read 'literature' but heard via other forums. Anyway, lens has to go to Sigma for repair now. Maybe Sigma will talk to Sony and ask *** is going on.

Have too many images to sift through now. Some top totty @ Thruxton. Racing wasn't bad either. Some nice candids of a few of the drivers. Give me a few days to sort out 100 odd images all shot in RAW.
 

springtide

Distinguished Member
That is bad luck! Sorry to hear about that.

There is a camera setting for "Slow AF" that is supposed to help. The issue is related to poor (plastic) mechanics within the lens.
 

Pirate!!

Banned
That is bad luck! Sorry to hear about that.

There is a camera setting for "Slow AF" that is supposed to help. The issue is related to poor (plastic) mechanics within the lens.
I found that out after the fact. Maybe Sigma (UK) will have a permafix for this issue. Am awaiting an email for return details. My Siggy 24-70mm seems unaffected. I got some right 'stotters' today too . . . am well peeved right now.
 

Pirate!!

Banned
Forgive my stupidity, but what does strip AF gears mean?
Knacker the AF motor??
Andy,

Basically what I believe is happening is the A700 sends an electronic signal to the lens in order for the AF motor to activate. It would seem the Sigma 70-300mm cannot deal with with the high torque signal from the A700 thus the gearing inside the lens (the teeth/cogs) basically wear themselves out so they do not engage one-another any more, or if they do . . just barely so you get the lens juddering away like crazy where the gearing teeth are trying to engage each-other.

So yes . . . knacker the AF motor in the lens.

Either way, it only took 2 hours after first use for my lens to become a victim of the phenomenon. I thought it worth posting a separate thread due to the nature of the problem.

Also, ADOBE are a bunch of ******. Why use a different RAW formula that requires the user to buy even more expensive software to open RAW files? Jeez, is buying a new camera wasn't expensive enough.
 

springtide

Distinguished Member
Andy,

Basically what I believe is happening is the A700 sends an electronic signal to the lens in order for the AF motor to activate. It would seem the Sigma 70-300mm cannot deal with with the high torque signal from the A700 thus the gearing inside the lens (the teeth/cogs) basically wear themselves out so they do not engage one-another any more, or if they do . . just barely so you get the lens juddering away like crazy where the gearing teeth are trying to engage each-other.

So yes . . . knacker the AF motor in the lens.

Either way, it only took 2 hours after first use for my lens to become a victim of the phenomenon. I thought it worth posting a separate thread due to the nature of the problem.


The A700 has a new high torque motor in the body for improved AF speed on all (excluding HSM) lenses.

The motor in the body uses a "screw drive" to the lens to focus the lens. It's the internal gearing on the lens that has been "striped".

The issue appears to be that the cheaper Sigma lenses seem to have used components that are not up to the torque generated by the A700, so the A700 AF motor strips the plastic gearing within the lens. Changing the AF speed to "Low" reduces the torque generated by the body.

This only seems to be an issue on the cheaper Sigma lenses, since I guess this is where Sigma have used lower quality components. I have also read that the issue also existed with the Film Dynax 9, which also had a fast AF.

I know it doesn't really help, but I would be interested to see Sigma's response. They basically need to upgrate these components to fix the issue once and for all. Repairing with the same components isn't really a fix.
 

Pirate!!

Banned
The A700 has a new high torque motor in the body for improved AF speed on all (excluding HSM) lenses.

The motor in the body uses a "screw drive" to the lens to focus the lens. It's the internal gearing on the lens that has been "striped".

The issue appears to be that the cheaper Sigma lenses seem to have used components that are not up to the torque generated by the A700, so the A700 AF motor strips the plastic gearing within the lens. Changing the AF speed to "Low" reduces the torque generated by the body.

This only seems to be an issue on the cheaper Sigma lenses, since I guess this is where Sigma have used lower quality components. I have also read that the issue also existed with the Film Dynax 9, which also had a fast AF.

I know it doesn't really help, but I would be interested to see Sigma's response. They basically need to upgrate these components to fix the issue once and for all. Repairing with the same components isn't really a fix.
I'll keep you posted. Sigma UK basically said 'send it' and provide a detailed explanation of the problem/fault and also send a copy of the purchase invoice.

Hopefully in two weeks . . . .

Sigma ought to have a chat with Sony. Too higher torque or naff components? Either way it really shouldn't be an issue. No point setting the camera to 'low' if you need high speed AF for action (as I did yesterday). Anyway, now you all know.
 

Ikki

Novice Member
It's very mixed on DPReview. A few report problems like this, the majority say that they have had no problems. However, that even a few fail is a cause for concern. If I make the jump to A700 or similar, the Sigma 70-300 will be going back on ebay first.
 

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