I really like the 35 Art, but...

...something happened to me last wedding which I didn't like at all.

I really love this lens. It is sharp and it gives me wonderful results all the time. On a wedding, this lens is my most used lens.
I don't do much weddings so previous year I have had a wedding, I calibrated (with dock) the lens for one body (5DII) and everything came out perfectly,I used the other body for the longer shots. It was my best wedding I have shot.
One year later I had an other wedding (this year). I used this lens as well. The 35A on one body (6D), a longer lens on the other body. Everything should be fine... I thought.

But it wasn't. I now have lots of miss focussed shots. And the reason is that I didn't use the lens on the same body as the year before. The pictures made within 3meters are quite good, but everything behind 3m till infinity has a BIG back-focus problem. I didn't notice this till I came home . And I didn't know that the calibration only REALLY works for just one body. I thought that the settings would be the same besides some in-body MA. But it wasn't...

So be careful and DON'T use your dock-calibrated lens on multiple bodies. I am lucky enough to have enough photo's to successfully complete this wedding. But next time I will prepare my self better with this lens. This is not going to happen again for me.

This is true for any combination of lenses and bodies. The information about your focus adjustment settings are stored in the camera, and there is no way for the lens to communicate that information to another body. You must adjust every lens for every body on which is is to be used, whether you use the Sigma dock or not.

You can use the lens with multiple bodies, just calibrate it to each body.

Heya,

This applies to all lenses & bodies. Not just Sigma, nor that particular lens.

Same thing happens with L's.

Very best,

Yes I am aware of that! ^

But I thought that the adjustments made in the dock are corrections of the lens itself.
So I adjusted everything great on the 5DII but on the 6D the infinity is completely off while everything under 3m is fine.

I thought I could adjust the lens with the dock once. And correct the lens with MA in-body, but it wasn't good. I didn't know I had to use completely different dock settings for each body.

Bonbridge wrote in post #17702342
Yes I am aware of that! ^

But I thought that the adjustments made in the dock are corrections of the lens itself.
So I adjusted everything great on the 5DII but on the 6D the infinity is completely off while everything under 3m is fine.

I thought I could adjust the lens with the dock once. And correct the lens with MA in-body, but it wasn't good. I didn't know I had to use completely different dock settings for each body.

Gotcha,

Yea unfortunately some lenses and some bodies don't have their alignments within the acceptable thresholds to result in focus where you thought it would be (and it thought it would be). I've sold a 70-200 F4L because it refused not back-focus on any of my bodies, but was perfectly fine for someone else. I too had the Sigma ART (30 F1.4) and the dock. Truly wonderful to have the dock honestly. But I learned real fast, if I have to extensively adjust it's focus per body, I just didn't want the lens, so I returned it for another copy, but then ultimately just switched to the 35 F2 IS instead.

These days, if I get a lens and it's not already focusing where it should on my bodies, I return it. I just don't want to fool with focus alignment. Unless the camera body can do it, itself, like some of the more modern cameras (all of which I lack, I use old stuff).

Very best,

Can you save the settings for each camera in the Sigma software that you use with the dock, so that you can quickly reprogram the lens if you will be using it on a different body on different days? So for example supposing one day you know that you will be using it on the 5DII, you install that set of corrections before you go out. On another day it will be on the 6D, so you reprogram it from the stored data before you use it.

Actually if the lens could pull the body serial number, it would be real easy for Sigma to include enough storage for it to hold the MFA data for a half dozen bodies, even with all the different focus distances, and focal lengths for the zoom versions. I don't see Canon allowing this though. I wonder if someone like the ML team could fix it?

Alan

It doesn't matter if it's saved in the lens or the camera, the MFA adjustment needed for any lens is the lens tolerance plus the body mount tolerance. You must make MFA adjustments to a matched body and lens set. It doesn't matter which one you make the adjustment in, but you can't go swapping them afterwards without redoing the MFA.

I'm going to call BS on the comments about L lenses. you will not get major backfocus like the OP mentions from body to body with L lenses. in fact I have never seen any difference with my canon lenses from body to body. now, there may be a very slight difference in some cases but you'd have to be a pixel peeper to see it.

sigma sells the dock for a reason.

ed rader wrote in post #17705003
I'm going to call BS on the comments about L lenses. you will not get major backfocus like the OP mentions from body to body with L lenses. in fact I have never seen any difference with my canon lenses from body to body. now, there may be a very slight difference in some cases but you'd have to be a pixel peeper to see it.

sigma sells the dock for a reason.

Looking at your lens line up, you don't have anything that has fast enough aperture / thin enough DoF to notice it....

I notice BS when I read it, and that's what this is. sigma has a long history of focus issues. if not they would never sell a single dock.

I have to agree with Ed. I spent yesterday adjusting a major front focussing problem on the Sigma 35 Art. I've never had to do such a huge correction on any other lens. I made a minor adjustment for the 85 f/1.2 but it was pixel peeping in up close portraits at f/1.2 - but it is usable from body to body. The Sigma 35 Art is basically unusable without the adjustments.

The lens is amazing now it's calibrated (I think, more testing today) but pretty concerning and it will make me think twice before buying non-Canon glass.

I just did some further tests after adjusting the in-camera MA. Unfortunately it's works for up to 2-3 meters then the adjustment overcompensates. In the pictures (which are crops from the full images) I've focused on the front flower, which works up to about 2 meters, then at about 4 meters you can see the back focus. I wasn't focusing on the water bottle, but on the left-most flower.

It looks like I'll have to buy a Sigma dock to get this sorted out. BTW these are at f/1.4 - amazing sharpness and beautiful bokeh when it works, otherwise I would have returned it by now.

ed rader wrote in post #17705003
I'm going to call BS on the comments about L lenses. you will not get major backfocus like the OP mentions from body to body with L lenses. in fact I have never seen any difference with my canon lenses from body to body. now, there may be a very slight difference in some cases but you'd have to be a pixel peeper to see it.

sigma sells the dock for a reason.

ed rader wrote in post #17705276
I notice BS when I read it, and that's what this is. sigma has a long history of focus issues. if not they would never sell a single dock.

I have had zero issues with Sigma lenses from body to body on either Nikon or Canon systems and many of my Sigma lenses have been used on 3 or more bodies. None have needed MA on any of the bodies I've owned. And despite purchasing a Sigma Dock for my 35 and 50Art lenses I haven't needed to even open the box for it.

On the contrary, I have had to use MA on a number of pro grade Canon and Nikon lenses from body to body.

Your singular experience is valid for you (as is mine for me) but is completely invalid for the wider community, particularly when you attempt to make such absolute statements as those quoted here.

ed rader wrote in post #17705003
I'm going to call BS on the comments about L lenses. you will not get major backfocus like the OP mentions from body to body with L lenses. in fact I have never seen any difference with my canon lenses from body to body. now, there may be a very slight difference in some cases but you'd have to be a pixel peeper to see it.

sigma sells the dock for a reason.

ed rader wrote in post #17705276
I notice BS when I read it, and that's what this is. sigma has a long history of focus issues. if not they would never sell a single dock.

Oh Ed...

So before MFA was built into bodies, why were good folk sending their bodies and their big super telephotos in to Canon to do the calibration for them? And make money off of the service? Now that there is MFA, why are so many good folk using MFA on their lenses, especially the fast aperture, and super telephoto? These are all L's. Do you simply choose to ignore that this not just exists, but is prevalent? These are Canon lenses and Canon bodies.

By your logic, Canon's MFA addition to camera bodies, is the equivalent of Sigma's USB dock in terms of the meaning. Even though they are different.

So for "calling out BS" as you stated multiple times, you sir, are the one called out.

Very best,

smythie wrote in post #17705556
Your singular experience is valid for you (as is mine for me) but is completely invalid for the wider community, particularly when you attempt to make such absolute statements as those quoted here.

I assume you're referring to Ed's comments as I haven't made any absolute statements. I'm sure the 'wider community' is well practiced at collecting data points and forming an overall picture, so critiquing people from expressing their experience in a lens discussion forum is obtuse.

I've previously owned Sigma glass for my crop cameras and really enjoyed them, which is why I didn't hesitate to get the Sigma 35 art when I read the reviews. I would have been fine if the in camera MA could correct the lens but unfortunately not, so I've spent today doing calibration shots rather than taking pictures of stuff I planned to shoot...