NEED HELP: Calibrating my S35 with the USB DOCK

As the title states, I need help with trying to calibrate my S35 using the USB dock. As I understand, you can calibrate it at FOUR different distances for the best results. My issue is, what, EXACTLY, are those 4 distances?

I had same issue. 3 of those 4 distances are very close, 1 feet as starting distance? Can we change the distances?

bobbyz wrote in post #16509548
I had same issue. 3 of those 4 distances are very close, 1 feet as starting distance? Can we change the distances?

No, we can't. That's why I'm so confused. This seems like a complete waste of time and money, yet everyone raves about it. 55 views; not a single answer. I'm calling Sigma directly tomorrow. This is ridiculous.

It's just means you have to figure out the MFA offset values you need at 0.3meters, 0.4meters, 0.6 meters, and "infinity', which I used 15 feet (feel free to use a further distance if you like).

I used the dot-tune method to find the MFA value that worked for each of those distance, and used the USB dock to write in those MFA offset value into the S35, and now it focuses pretty much spot on for near-field and far-field objects for me.

i didn't understand that either even trying to templates and other ways. i ended up just taking shots up close and varying distances and just trial and error. after 6 hours i think i got it right.

i'm not touching it anymore!

The distances are...

1) 12.25" (31.11cm)

2) 14.75" (37.46cm)

3) 26.24" (66.67cm)

4) infinity.

Hope this helps... It helped me though and a lot. Now the focus is spot on!!

Heya,

I did the same thing with my 30mm 1.4 ART.

When the lens itself, being so costly, doesn't focus, AND the USB dock is so hard to truly use, because it's not automatic, you have to do the calibration manually and you have to redo it over and over at each distance until you get it just right, I just can't imagine keeping it all after such a chore for such an expensive lens considering this kind of hassle. I sent my Sigma back and got a different lens alltogether. I'm done with Sigma until they license some Canon AF tech. It's silly to have to do this ourselves on so many lenses.

Anyhow, with the above posted distances, I suggest you work at ONE distance at a time. I tried over and over doing all of them and then calibrating each distance, and it was miserable going back and forth for hours. Do each distance separately until you are happy with the autofocus. Move on to the next distance once you feel like it's right. Always do this calibration at widest aperture.

Very best,

borg-1977 wrote in post #16510189
The distances are...

1) 12.25" (31.11cm)

2) 14.75" (37.46cm)

3) 26.24" (66.67cm)

4) infinity.

Hope this helps... It helped me though and a lot. Now the focus is spot on!!

How did you find this information? (BTW - thanks!)

ceriltheblade wrote in post #16510358
How did you find this information? (BTW - thanks!)

With lots of calculations (LOTS) and a properly calibrated laser distance meter. It all has to do with the throw of the lense, you are in a way calculating the lens trow in 4 equal distances. When you calibrate your lense in each of those distances you have to do it again and again in order to get the right pattern. It needs patience.... but believe me when you make it right it will be well worth it!

Well, I appreciate borg-1977's efforts here but in my opinion it's really not that difficult and are such specific distances necessary? Somehow I doubt it. Here is the way I did it:

Magic lantern + automatic DotTune method. Check each distance seperately (0.3, 0.4, 0.6 m & infinity). Sorry I used meters here since I live in Europe. I used measuring tape to get approximately correct distance. I really don't think it matters if its off by few centimeters. And works like a charm! Very easy and fast. Took me about 5-10 minutes!

Just remember:
1) First update the Sigma software to latest version
2) Update the firmware to latest one on the lens. Then perform the calibration (e.g. with Dot Tune method)
3) Just remember to check the MA values with good lighting. Sun light = the best. If you are doing it in poor light you are bound to get unreliable results

If you don't update the lens firmware first you might loose your previous settings. And the firmware update is really worth it with the Sigma 35

It's really not that difficult. And you also should make sure first that your lens autofocuses badly (note: after the firmware update). Regarding Sigma 35 and firmware update on the lens there definitely was a positive change for better. And I just want to remind folks that most Sigma lenses focus just fine but POTN has habit of blowing problems out of proportions regarding Sigma lenses...

P.S. And I use 5D II with ancient focusing system (married with center AF point). On 6D and 5D III it works much better.

MalVeauX wrote in post #16510340
AND the USB dock is so hard to truly use, because it's not automatic, you have to do the calibration manually and you have to redo it over and over at each distance until you get it just right, I just can't imagine keeping it all after such a chore for such an expensive lens considering this kind of hassle. I sent my Sigma back and got a different lens alltogether. I'm done with Sigma until they license some Canon AF tech. It's silly to have to do this ourselves on so many lenses.

It can't be automatic. That's the whole point of MA, you choose what you want the value to be. If it was automatic, there would have to be another manual override or method to correct any errors that system had, rendering it pointless. Its exactly the same with Canon's in-body MA.

The reason people rave about the USB dock is because it is exactly the same as Canon's in-body MA but gives you 3 more optional adjustments based on different distances. Meaning it is better than Canon's solution.

Why? Because if, for example, a Canon lens needs MA at 2 or more different distances which, surprise surprise does happen, you're screwed. If a new dock-compatible Sigma lens needs MA at 2 or more different distances, which also happens, you're good to go with the USB dock.

The only advantage Canon's method has is that you don't need to disconnect the lens to do it (which is a big advantage, but nothing anyone except Canon or magic lantern can do anything about since it is on Canon bodies and is independent of the lens, and I would think everyone can agree that the idea of having more distances for which MA is possible is far better than MA for a single distance but without having to disconnect the lens from the body).

Oh, and Sigma can't license Canon's AF tech because Canon won't license it out.

So I just opened up the box that the dock came in. There were 3 documents. Not ONE had a bloody phone number on it. I ended up finding it online and called. They're not open on the weekends. HOW CONVENIENT SIGMA> GAHHHH@#$

Aressem wrote in post #16510870
So I just opened up the box that the dock came in. There were 3 documents. Not ONE had a bloody phone number on it. I ended up finding it online and called. They're not open on the weekends. HOW CONVENIENT SIGMA> GAHHHH@#$

I would like to help you but I don't fully understand what is the problem here. What is wrong with those 4 distances for you? Why can't you just do what everyone else have done and use the distances indicated by the Sigma software? 4 distances, roughly 0.3, 0.4 and 0.7 meters, the last one is at infinity. Check the link above. That is also what Roger did in his review. And I really trust his opinion on these matters.

Works for me. Remember to update the lens firmware first, before you check the MA-values for each distance.

So yes, the dock works really well and I think Canon could also very much benefit from similar dock as well. And according to this link, the dock will later support older Sigma lenses as well. If it's true it's very good news for us Sigma owners

Relax a little bit... The distances don't have to be exact. If the MA changes 1 point every .25" then the lens would not be able to see straight. The MA is not expected to change a lot in the rough vicinity of the indicated spot

12" 15" 26" and 180" will do fine.

Aressem wrote in post #16510870
So I just opened up the box that the dock came in. There were 3 documents. Not ONE had a bloody phone number on it. I ended up finding it online and called. They're not open on the weekends. HOW CONVENIENT SIGMA> GAHHHH@#$

you are making a mountain out of a mole hill. In the software it tells you right there, there distances. Set camera said distance from the focal test chart (if you are using one) and test. Its very trial and error. If you use magic lantern, I have read its less trial and error. there is no short cut, its a pain in the rear, but its worth it.