AF not working...am I doing s'thing wrong?

[mdude85]

I just recently received a Sigma 70-210 UC II from a seller on Ebay ... seller ensured on auction page that the lens was new in box. In fact it IS new in box ... comes with warranty info, original manual, even says "sigma" on the plastic bags. Anyhow, lens is nice and clean except one major flaw ----- the focus ring doesn't seem to be catching onto the motor when the lens tries autofocusing. In other words, AF does not work at all!!! Did I get a dud, or am I doing something wrong? Thanks.

By the way the camera is a D30.

[CyberDyneSystems]

I've never heard of this particular lens .. ???

But does the focus ring move forward and backwards?

On some of the older lenses (and even new designs_ the focus ring needs to be moved back and forth (pulled front to back or vice cersa) to switch from Auto to manual focusing. Perhaps your focus ring is in the manual position.. or stuck in between?

[mdude85]

I've never heard of this particular lens .. ???

But does the focus ring move forward and backwards?

On some of the older lenses (and even new designs_ the focus ring needs to be moved back and forth (pulled front to back or vice cersa) to switch from Auto to manual focusing. Perhaps your focus ring is in the manual position.. or stuck in between?

Focus ring moves left to right to focus. Is there a manual "position" that I need to move my lens out of? I am afraid to move it with my hands when it is set on AF ....


http://www.jafaphotography.com/70210mm.htm#Sigma%2070-210mm%20f/4-5.6%20UC-II%20AF

[rsnadel]

Some of the Sigma lenses require a new chip to work with the Canon digital cameras. The process of "re-chipping" is fairly simple, but does require that the lens be sent to Sigma (if you're in the US, that means sending it to New York state). Here's a link to their website; you should contact them before sending it to make sure that's the problem:
http://www.sigma-photo.com/

[mdude85]

Some of the Sigma lenses require a new chip to work with the Canon digital cameras. The process of "re-chipping" is fairly simple, but does require that the lens be sent to Sigma (if you're in the US, that means sending it to New York state). Here's a link to their website; you should contact them before sending it to make sure that's the problem:
http://www.sigma-photo.com/

Question: the autofocus "works" per se, because the motor is moving...it's just that the focus ring is not catching onto the motor. Do you think this is a chip problem, or a mechanical problem? If I send it off, is there any charge, and how long will it take to get it back? Also, I don't know if they'd accept my warranty...I have a warranty card but I am technically not the original buyer.

[CyberDyneSystems]

I think you would need to contact Sigma for the answers to your latest questions?

[mdude85]

Yeah, I sent Sigma an email. The reason I don't really want to get my money back for the lens is that I got it at a really good price that I don't think I can replicate anywhere. plus, I really am tired of doing research on cheap zoom lenses!!! :(

I would much rather just have it fixed.

[CyberDyneSystems]

Oh.. was it new? If it's new can't you return it for a replacement? The shipped you a dud?

[mdude85]

Oh.. was it new? If it's new can't you return it for a replacement? The shipped you a dud?

It was new from a person who bought it from the inventory of a camera store that was closing. I can't return it to Sigma because I did not purchase it directly from Sigma, but maybe they will take it anyway because it is technically new and still has the warranty info.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&rd=1&item=3838185016&ssPage Name=STRK:MEWA:IT

[SnJPhoto]

It really sounds like it might be the slector for aut/manual focus. I didn't catch whether the fous ring had a forward and rearward position. The 24-70 I had was like taht, you slid the ring either forward or back to put it in manual or auto focus modes...


scott

[mdude85]

this is just a little button to switch from M to AF, at the bottom of the lens. http://www.cnphotos.net/image/syqc/sigma_70-210.jpg (except mine you cannot adjust the aperture on the lens)

[Jon]

The 15-30 has the AF/MF switch and the focussing ring slides forward ( marked AF) and back (MF) - both need to be set to change between AF & MF. Take a look-see if there are little AF & MF labels about the focussing ring. And does it focus manually OK?

[mdude85]

The 15-30 has the AF/MF switch and the focussing ring slides forward ( marked AF) and back (MF) - both need to be set to change between AF & MF. Take a look-see if there are little AF & MF labels about the focussing ring. And does it focus manually OK?

I don't think there are two places to change the focus mode but I will check when I get back to where the lens is. It focuses manually just fine, and photos are sharp even in manual focus w/o a tripod.

Here is a shot of the lens, except mine has automatic aperture not on lens.

http://www.chinaphotos.net/news/news/images/sigma_70-210f4-56uc.jpg

[rsnadel]

This lens does not show on the Sigma website as a current product. Do you have any idea how old it might be (separate question from whether it's "new" as in "never been used before"). I think the way you are most likely to find out whether Sigma will re-chip it for free is by calling and describing the problem..as well as explaining which camera you're using it with. That's most likely how they will determine if it's a communications problem (which is what the chip does). My concern (on your behalf) is that if this is an older lens that simply has never been used before, they may not be able to make it work with current camera technology.