Sending in Sigma 30mm 1.4 for adjustment

Has anyone done this before? I find the focus inconsistent on my copy.
(and I've have a couple copies... I kept the best one)

I expect focusing at 1.4 to be always problematic, but I find even stopped down, I have inconsistent focusing.. (both front and back)

It's going to be about 100$ to have Sigma do this... I'd love any input!

Your lens should come with a 4-year warranty from the date of purchase if you registered it. I sent in a 50mm awhile back to one of their authorized service centers awhile back (C.R.I.S. in Chandler, AZ) and they calibrated it no charge. Your T4i does not have micro adjustment so you may want to send in the body along with the lens. Hope this helps.

Thanks. I bought this used.. so no warranty.

Also, ya... I expected to send body in.

That was the most frustrating lens I've ever owned. Went through 3 copies and multiple shipments to/from Sigma for service...I eventually exchanged for a 4th copy and sold it without ever taking it out of the box.

Good luck

Dan Kearley wrote in post #16353800
Has anyone done this before? I find the focus inconsistent on my copy.
(and I've have a couple copies... I kept the best one)

I expect focusing at 1.4 to be always problematic, but I find even stopped down, I have inconsistent focusing.. (both front and back)

It's going to be about 100$ to have Sigma do this... I'd love any input!

My price quote for this was only $60. How did you contact them? I have a 50D which I bought for the AF Microadjust and a -8 setting fixed everything but it would be nice to use it on my other bodies w/o AF microadjust.

I emailed them thru the Canadian distributor I guess...Gentec.

Dan Kearley wrote in post #16356215
I emailed them thru the Canadian distributor I guess...Gentec.

If you bought the lens outside of Canada (i.e. no Canadian warranty) then you'll need to pay Gentec to service it. It was $50 when I did it. Did they raise the fee to $100? In most cases, it's still worth it as Canadian prices are much higher.

One thing that I would suggest is that you thoroughly test and document the issue(s) that the lens has. I had sent it and just told them that it had focus issues. It came back exactly as it was with no explanation. It was really my fault for not being specific.

Good luck with the repair.

Ok, my $60 fee was for Sigma USA

I also had two copies of this lens at the same time. One focused perfectly on my 7D, and the other required an adjustment of +11. With the adjustment, it was fine. I sold that one, and warned the buyer. He didn't seem to care.

So it's actually 120$, plus my initial shipping charges.
Now... the issues with the lens have been the same across a couple copies for me. I'm starting to think this isn't an uncommon issue. (it's not front or rear focusing.. it's just not 100% consistent)

I wonder if a used 30mm ART model would be a better long term solution. Reviews of them have been great.

Dan Kearley wrote in post #16353800
Has anyone done this before? I find the focus inconsistent on my copy.
(and I've have a couple copies... I kept the best one)

I expect focusing at 1.4 to be always problematic, but I find even stopped down, I have inconsistent focusing.. (both front and back)

It's going to be about 100$ to have Sigma do this... I'd love any input!

Many of us have a love/hate relationship with this lens. I assume you have the EX DC HSM version, not the newer version without the EX in the name. There were a number of QC issues with this lens related to focus. Many seem to back or front focus. My first copy was decentered and sent back to B&H. The second copy back focused a bit so I brought my lens and camera, a 60D, to Sigma's US headquarters in Ronkonkama, NY an hours drive from my home. They fixed it for me while I waited. However, the focus algorithms Sigma uses are still problematic. Sometimes the lens focuses dead on, sometimes not. I have discovered after a significant amount of testing and pixel peeping that getting accurate focus on very small targets can be difficult, especially in low light. The more contrast the subject has, the more accurate the AF. The more edges and texture the subject has, the more accurate the AF. I find this problem to be at its worse at f/1.4, and as you stop down the problem gets less frequent. The lens also tends to be softer at the edges the wider you open the aperture. These are some of the reasons this lens was just replaced by Sigma. However, to paraphrase the nursery rhyme, "When it's good, its very very good, and when it bad it horrid" For me, it is more often very good than horrid. Here are a few good examples, IMHO.


Northern Vermont

IMAGE LINK: http://www.flickr.com …/75627613@N05/9​229017002/

IMAGE LINK: http://www.flickr.com …/75627613@N05/8​498960263/

IMAGE LINK: http://www.flickr.com …/75627613@N05/8​498958839/

IMAGE LINK: http://www.flickr.com …/75627613@N05/8​505040248/

IMAGE LINK: http://www.flickr.com …/75627613@N05/8​503932341/

IMAGE LINK: http://www.flickr.com …/75627613@N05/9​474381206/

Thanks. Those ARE good. I'm going to look at an ART model this afternoon. We'll see.

And thanks for your info! Very helpful.

Dan Kearley wrote in post #16363787
Thanks. Those ARE good. I'm going to look at an ART model this afternoon. We'll see.

And thanks for your info! Very helpful.

In case I confused you, these shots were taken with the older EX version, not the newer ART lens. I got my copy just before the ART version was released at an excellent $289 USD new. I probably would have preferred the ART version in retrospect, but at the price I paid I think it was a bargain. And I wasn't in a position to spend $500 for the ART at that time anyway.

Ya, I understand that mwsilver... I'm checking out an ART model regardless.

Dan Kearley wrote in post #16363859
Ya, I understand that mwsilver... I'm checking out an ART model regardless.

Its supposed to be quite an improvement over the older model. Good luck.