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Archive 2013 · Sigma USB Dock in Stock for $59!
  
 
Photonic
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p.2 #1 · p.2 #1 · Sigma USB Dock in Stock for $59!


In a perfect world you would use a global MFA on each camera body you own to bring it to "dead center" and assuming all lenses had the MFA feature (like new Sigma) you would adjust all your lenses to dead center. Every lens would work perfectly on every body. Actually, if it were a perfect world these products would come from the factory with much tighter tolerances and users would not have to waste time doing any of this :-)

In the real world, bodies and lenses each have a focus accuracy margin which in some combinations produce sub-optimal outcomes. Most high end bodies now offer MFA (either global or per lens) allowing users to dial in the optimal settings (a time consuming and tedious process). To your point, the new Sigma MFA feature does offer value for bodies without MFA. I suspect, however, that the vast majority of folks with the means to buy a new 120-300mm will also be using it on a body with MFA. I think those folks will choose to MFA their bodies rather than their lenses so they can simply move a lens from body to body. Folks choosing to MFA their lenses will have to connect to the USB dock each time they want to switch bodies.

Listen, I am not trying to dissuade anyone from MFAing their new Sigma to their heart's content. I just see little value to this feature for folks who already own MFA bodies (me, for one). Furthermore, I am anticipating (perhaps prematurely) that the MFA process for a dismounted, USB dongled lens is going to be even more tedious than the already tedious process of in camera MFA adjustment with the lens always mounted to the body. I will retract this concern immediately if the new Sigma software allows you to mount the lens, run their application, dismount the lens, attach the USB and download the magic numbers (in fact I will cheer for them). If, however, you need to move the lens back and forth between body and dongle to make, test and then download refined adjustments, I think this "feature" will see very little use. I am very anxious to hear from anyone with the new dongle and software as to how hard or easy the process is.



Jun 05, 2013 at 07:45 PM
austin.grant
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p.2 #2 · p.2 #2 · Sigma USB Dock in Stock for $59!


Your concept of a global "number" is flawed because many/most lenses perform best with different MFA numbers at different focus distances. I keep saying it, you keep missing it. Have you watched the video for the Sigma USB dock? Check their website.

As for this whole mount lens to camera, remove, mount lens to dock, remove .... No, that's silly. You'll put the lens on be camera, find the MFA for each focus distance that's programmable in the software, remove the lens, attach the USB dock and apply the appropriate offsets.

I think you are just making it harder than needs to be. I also use MFA bodies, 2X5D3 and 1X1D4, and I can still clearly see the value in this tool.



Jun 05, 2013 at 07:54 PM
Photonic
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p.2 #3 · p.2 #3 · Sigma USB Dock in Stock for $59!


My concept of a global number was prefaced by "In a perfect world....." Trust me I understand your point. I was unaware of the video about the dock and appreciate your mentioning it. After reviewing it, I am afraid the screen shots of the MFA adjustment only confirm what I suspected. The video uses the 30mm f1.4 for the example. The application gives you the option to input MFA adjustments for four different focus distance ranges. Each entry is expressed as an offset from nominal (+2, -4) for example. For the 120-300 I am guessing they will allow you to do this for a couple of different focal lengths (minimum wide and tele, more likely a few in between, let's say 3). That's 12 parameters that the user must enter and then download to the USB docked lens. The question is where do these numbers come from. When the lens is on the camera it is not linked to the application. The user will have to set the focal length to 120mm and the focus distance to minimum and then take a picture. Next they will need to review the image at max magnification or on computer to determine if the focus could use a little front or back adjustment. Repeat nine times, write down all the numbers, dismount the lens, connect to dock, enter numbers into the Sigma application. Way too tedious for me and perhaps many others. I really hope you are right and that I am characterizing this process as harder than it needs to be. Its not worth debating at this point. Let's just wait a day or two until someone can report back on the actual mechanics.

I have a Sigma 35mm on the way, and already own their 50mm, 85mm, 120-300 OS and 300-800. I have as many Canon lenses. I am not a brand loyalist and judge any given product based on its merits or deficiencies. I am generally very happy with Sigma's new direction but still willing to call them on what I view as poor moves. I am hoping they will continue to focus on (pun intended) image quality, robust build quality and long term reliability, and NOT lose sight of their value proposition franchise.




Screen Capture Sigma Application



Edited on Jun 05, 2013 at 11:00 PM · View previous versions



Jun 05, 2013 at 10:36 PM
snapsy
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p.2 #4 · p.2 #4 · Sigma USB Dock in Stock for $59!


Considering how PDAF works, using multiple phase-sensing and motor movement cycles in a pseudo-closed loop, I'm not sure how a lens-based offset could actually work in practice. It might work for PDAF acquisitions where there is one final motor movement cycle to the distance-specific location that the lens has an offset for...but it's not clear what percentage of PDAF acquisitions that would account for.


Jun 05, 2013 at 10:40 PM
Photonic
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p.2 #5 · p.2 #5 · Sigma USB Dock in Stock for $59!


Snapsy,

You raise a very interesting question. I think the lens will have to wait for the PDAF cycle to complete (as far as the body is concerned) and add the offset as a final step. If so, this would suggest a slightly longer time to autofocus with lens MFA set to other than zero.



Jun 05, 2013 at 10:57 PM
austin.grant
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p.2 #6 · p.2 #6 · Sigma USB Dock in Stock for $59!


Focal or Dot Tune makes the process not that complicated. As for the 120-300, I think it's been confirmed to have 4 focal length ranges and four focal distance ranges, so 16 adjustments! It will take some work, that's for sure, but nothing that an hour, a nice tripod and good lighting can't handle. Like I said, if you want simple just stick with the old way.


Jun 05, 2013 at 11:17 PM
snapsy
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p.2 #7 · p.2 #7 · Sigma USB Dock in Stock for $59!


Photonic wrote:
Snapsy,

You raise a very interesting question. I think the lens will have to wait for the PDAF cycle to complete (as far as the body is concerned) and add the offset as a final step. If so, this would suggest a slightly longer time to autofocus with lens MFA set to other than zero.


I'm not sure if the EF interface delivers that "final movement" notification to the lens.



Jun 06, 2013 at 12:26 AM
Photonic
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p.2 #8 · p.2 #8 · Sigma USB Dock in Stock for $59!


Austin,

My hat is off to you for your willingness to go where no man has gone before. Please let us know how the AF tuning process goes when you get your new gear. I am truly hoping it is not as arduous as I am imagining.



Jun 06, 2013 at 12:58 AM
austin.grant
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p.2 #9 · p.2 #9 · Sigma USB Dock in Stock for $59!


Oh man, don't tip your hat my way just yet... I've only got the 35mm 1.4 coming in. While I have the time and patience to calibrate the 120-300, I don't have the cash to actually buy the lens!




Jun 06, 2013 at 01:09 AM
benee
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p.2 #10 · p.2 #10 · Sigma USB Dock in Stock for $59!


this may be a stupid question,but here goes. This works on bodies without MFA, right? I am hesitant to use sigmas on my 5d classic since the body doesnt have MFA, but if I could microadjust the lens directly, things would be peachy!


Jun 06, 2013 at 01:30 AM
 

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austin.grant
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p.2 #11 · p.2 #11 · Sigma USB Dock in Stock for $59!


Yes, it will give you that feature on lens. The 5Dc doesn't have live view though, so the method for MFA adjusting for other non-MFA cameras isnt possible. (For those, you could phase detect, switch to LV and using the Canon Utility software count the number of "bumps" it takes to get sharp focus. Average several shots, there's your MFA value.). Instead, you'll have to guess and check by the mounting / unmounting procedure mentioned above.


Jun 06, 2013 at 02:28 AM
Photonic
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Snapsy,

I am very grateful for having participated in this thread if only to learn about Dot Tune. Snapsy, YOU ARE THE MAN and have made a great time saving and hair preserving contribution to the photographic community. Thank you, thank you, thank you.

Austin,

Unless the Sigma MFA step values are identical to the Canon MFA step values (which I think is fairly unlikely), you will not be able to transfer the numbers you get from either Dot Tune or Focal into the Sigma lens.

With some experimentation, however, you might be able to determine a scaling factor between Canon MFA steps (for a given body) and Sigma MFA steps (for a given lens). One approach: Perform Dot Tune on Sigma with lens MFA set to zero. Next set the Sigma MFA to an arbitrary number of steps (let's say ten). Perform Dot Tune again. The difference between the two Dot Tune midpoints divided by ten will be a reasonable estimate of the relationship between Canon steps and Sigma steps. I would do this a few time to make sure the ratio is spot on and consistent. If this proves accurate enough you can then scale future Dot Tune results by this factor before plugging into your lens. You might have to do this again for each different body unless MFA steps across all Canon bodies are equal.



Jun 06, 2013 at 05:20 AM
myron lee
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p.2 #13 · p.2 #13 · Sigma USB Dock in Stock for $59!


Well I just got my sigma 35 this afternoon. Performs great . No adjustment required. Spot on in all light situations and no ma required. So now what am I to do with this USB dock. Return or save for future use?


Jun 06, 2013 at 07:44 AM
Lars Johnsson
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p.2 #14 · p.2 #14 · Sigma USB Dock in Stock for $59!


myron lee wrote:
Well I just got my sigma 35 this afternoon. Performs great . No adjustment required. Spot on in all light situations and no ma required. So now what am I to do with this USB dock. Return or save for future use?


Keep it of course I'm sure you like to buy new lenses and cameras in the future also or? And like to have the firmware upgrades for your lenses also? It's also more than just the MA you can do with the new USB Dock



Jun 06, 2013 at 08:04 AM
austin.grant
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p.2 #15 · p.2 #15 · Sigma USB Dock in Stock for $59!


Photonic wrote:
Austin,

Unless the Sigma MFA step values are identical to the Canon MFA step values (which I think is fairly unlikely), you will not be able to transfer the numbers you get from either Dot Tune or Focal into the Sigma lens.
.


Certainly a valid concern, but I'm gonna take the "why wouldn't they be" side. I don't claim to know as much of the software/hardware interface as you guys, but I know that Sigma reverse engineers the Canon AF system to get functionality. They likely know a bit more than you give them credit for. Either way, I'll wait until I've used mine a bit and then report back.



Jun 06, 2013 at 09:58 AM
Lars Johnsson
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p.2 #16 · p.2 #16 · Sigma USB Dock in Stock for $59!


austin.grant wrote:
Certainly a valid concern, but I'm gonna take the "why wouldn't they be" side. I don't claim to know as much of the software/hardware interface as you guys, but I know that Sigma reverse engineers the Canon AF system to get functionality. They likely know a bit more than you give them credit for. Either way, I'll wait until I've used mine a bit and then report back.


Why wouldn't a Sigma dock made for Canon EF mount lenses be compatible with Canon ? They have a different dock for each brand also. And why is it +, - 20 just like the Canon. Do you belive that's just a coincidence? I don't think we should assume the people at Sigma are that stupid Even then: the worst thing that could happen would be that you have to do the test a few times until the lens is sharp and good.
MFA is also only one of many things the dock can adjust. Look at their video when adjusting a lens like the 120-300. It's just incredible how much you can change in that lens if using the dock.
http://www.fredmiranda.com/forum/topic/1207711/0?keyword=sigma,dock#11507411



Jun 06, 2013 at 11:33 AM
SeverianTL
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p.2 #17 · p.2 #17 · Sigma USB Dock in Stock for $59!


Just got my dock yesterday afternoon. Haven't had much chance to experiment other than to briefly connect it to my 35/1.4. By the way, there is a firmware update available for the 35mm. I don't know what changes it makes and Sigma didn't say, but I updated anyway and thankfully my lens wasn't bricked ! I haven't noticed any significant changes but I haven't really put the lens through its paces yet. I plan extensive testing this weekend of both the lens and the dock.

Here are a few pictures:











This thing locks very firmly in place. Notice the locking pin and the prominent "lens release" tab.










Comes with a body cap and USB cable and the usual woeful instruction sheet.






A few screen grabs of the software:










Notice the new firmware version: FW.0.0.15.0224.












Jun 06, 2013 at 11:37 AM
Photonic
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p.2 #18 · p.2 #18 · Sigma USB Dock in Stock for $59!


Lars,

I am hoping you are right that MFA step size on lens and the body are the same. I certainly take your point that they could customize the step size for each mount type, hence dealing with difference between mount types (Canon, Nikon, et. al.) I am just not sure that MFA step size is the same even within a given brand across different bodies.

SeverianTL,

Thanks for sharing the images. You and Austin are charting new ground for the rest of us. A big question on all of our minds is how hard is it to determine the lens MFA numbers. Does Sigma outline a procedure in the documentation for the software? Even more importantly, are the Sigma lens/software MFA step sizes calibrated to the camera body MFA step sizes.

Also thanks for reporting on the software update for the 35mm. I was not aware one had been issued. The ability to upgrade the lens firmware without returning the lens to Sigma is for me the most compelling reason to own the dock. I wonder if Sigma will send notifications to registered owners on future updates or if we will have to wait for someone to notice one is available as you did?



Jun 06, 2013 at 12:09 PM
cmm0325
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p.2 #19 · p.2 #19 · Sigma USB Dock in Stock for $59!


@SeverianTL

That looks so cool! Me go get 35mm lens for new toy.



Jun 06, 2013 at 01:56 PM
badlydrawnboy
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p.2 #20 · p.2 #20 · Sigma USB Dock in Stock for $59!


I would also love to hear a "hands-on" report from anyone that uses the dock. I'm considering buying it along with a Sigma 35, but I have some concerns after reading through this thread.


Jun 06, 2013 at 04:57 PM
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