Easy way to use Sigma Dock for microadjustment

Started Feb 18, 2016 | Discussions
Don_Campbell Senior Member • Posts: 2,790
Easy way to use Sigma Dock for microadjustment
14

Sorry for the length, but I hope it's sufficiently detailed to help someone.

I bought my Sigma 150-600 C last June along with the Sigma USB Dock. At the time I had just purchased a Canon 7DMkII body. The lens was pretty darned good straight out of the box and I had a busy summer of shooting a peculiar and interesting peregrine falcon saga so I delayed wrestling with 16 points of focus fine tuning with the dock.

Waiting for the gear to arrive, I had looked online at discussions of using the dock and I was certain that I had seen that the numeric value of the dock adjustment was 2X the numeric value of the in-camera AF microadjustment. However, when I got serious about doing the microadjustment I found that nearly every story of dock adjustment involved back and forth and back again between the lens+camera and the lens+dock+computer. Most of those stories also dealt with added complexity of many photos plus store-bought software and focus targets.

Then there were stories about using "dot-tune" methods for doing the offset detection without photos.

Finally, I read Lee Jay's method:http://www.dpreview.com/forums/post/56998000

He did initial focus using Live View AF to get the accurate focus on the sensor, then switched to viewfinder and watched the focus distance reading in its window on the lens while triggering AF using the phase detection system. Based on the direction the focus indication moved he could know which direction to change the microadjustment in the dock and iteration back and forth to the dock allowed him to find the adjustment where movement was zero during phase detect AF or it was equally likely to be + and - using phase detect. No photos but a lot of back and forth to the dock.

I tried to find the original story I had read giving the 2:1 ratio for the Sigma adjustment compared to the in-camera adjustments for both Canon and Nikon. Instead I found several vague statements--all about using a 2X ratio, including a discussion here:

http://www.dpreview.com/forums/post/56675910

and including use of the FoCal/Reikan system with the 2X ratio successfully here for Nikon:

http://www.dpreview.com/forums/post/55354553

Other forum posts here and at Fred Miranda also cited 2X as the ratio so I decided go with that for a first go.

I decided to incorporate Lee Jay's "which direction" Live View / optical view method with the idea of getting the estimate for the magnitude of the adjustment number using the in-camera Canon adjustment number. The process of course assumes you set up the phase detect AF and Live View to get optimal focus of the target at the various distances.

  • My process is to start with 0 for the in-camera microadjustment number for each of the 16 Sigma Dock points of distance/focal length.
  • Focus in Live View using contrast, switch to optical view and watch for movement of the focus distance in the focus window when triggering the phase detect AF.
  • If there is movement, indicating an offset of focus in the phase detect system, I adjust the in-camera MFA to get a "Canon number" for adjustment, write it down on paper, re-zero the in-camera adjustment value and repeat for the next Sigma Dock point.
  • Enter the numbers into the Sigma Dock software using 2X the "Canon number." Write them to the lens and check with the camera at the same distances and focal lengths.

Notes:

Along the way, I modified the above version slightly: I would confirm sharp focus in Live View at 10X magnfication. I also would manually move focus away from the AF position in both directions and re-trigger focus several times to pick the most consist result. I did this instead of "dot-tune" because I found the dot-tune values so far apart and not centered on the most frequently obtained AF focus position. Basically, I trusted my multiple focus to pick best, most consistent focus value (position of the focus indicator in the window) more than I trusted dot-tune's number.

After I entered my 16 microadjustment values into the Sigma Optimization Pro software and wrote them to the lens, I checked the values in the camera again and found all but two or three to be quite good. Good, meaning that the position of the contrast AF focus distance and the phase detect distance were equal within variations on both sides small and equivalent. In other words repeating phase detect AF (or even contrast in Live View AF) 10 times for the same target distance and focal length gives a small variation in focus chosen but that variation is distributed randomly around a "best focus" value that was the same for the Live View contrast AF and the optical view phase detect AF.

The 2-3 values (I forget already) that were still off might have been done when light was fading late in the afternoon when I first got the numbers--I redid the adjustment for them and all 16 distances/focal lengths were then properly adjusted. Weather has been terrible for photography so I haven't tried it on my favorite birds yet.

For a target I made a grid of horizontal and vertical lines of random width and spacings about 5x5 inches and printed it on card stock which I then taped to the side of a box so I could easily move it while keeping the camera stationary. For "infinity" I'm a bit challenged at my house since we're pretty much surrounded by NW forest of tall trees. The best I could find for infinity was an insulator at the top of lamp post which google earth tells me is ~125 yards away from my deck.

[Added in edit] I found an opening in the foliage of the trees through which I could spot the peak of a building that google earth says is 417 yards from my deck. That brings the focus mark at 600mm closer to the infinity symbol and the focus is still the same for the Live View contrast AF and for the optical viewfinder's phase detect AF. I guess that means that even though 125 yards isn't infinite distance for the lens at full telephoto it still is close enough for the microadjustment to be the same.

Don

Canon EOS 7D
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Vernon D Rainwater Forum Pro • Posts: 13,915
Re: Easy way to use Sigma Dock for microadjustment
1

Don_Campbell wrote:

Sorry for the length, but I hope it's sufficiently detailed to help someone.

I bought my Sigma 150-600 C last June along with the Sigma USB Dock. At the time I had just purchased a Canon 7DMkII body. The lens was pretty darned good straight out of the box and I had a busy summer of shooting a peculiar and interesting peregrine falcon saga so I delayed wrestling with 16 points of focus fine tuning with the dock.

Waiting for the gear to arrive, I had looked online at discussions of using the dock and I was certain that I had seen that the numeric value of the dock adjustment was 2X the numeric value of the in-camera AF microadjustment. However, when I got serious about doing the microadjustment I found that nearly every story of dock adjustment involved back and forth and back again between the lens+camera and the lens+dock+computer. Most of those stories also dealt with added complexity of many photos plus store-bought software and focus targets.

Then there were stories about using "dot-tune" methods for doing the offset detection without photos.

Finally, I read Lee Jay's method:http://www.dpreview.com/forums/post/56998000

He did initial focus using Live View AF to get the accurate focus on the sensor, then switched to viewfinder and watched the focus distance reading in its window on the lens while triggering AF using the phase detection system. Based on the direction the focus indication moved he could know which direction to change the microadjustment in the dock and iteration back and forth to the dock allowed him to find the adjustment where movement was zero during phase detect AF or it was equally likely to be + and - using phase detect. No photos but a lot of back and forth to the dock.

I tried to find the original story I had read giving the 2:1 ratio for the Sigma adjustment compared to the in-camera adjustments for both Canon and Nikon. Instead I found several vague statements--all about using a 2X ratio, including a discussion here:

http://www.dpreview.com/forums/post/56675910

and including use of the FoCal/Reikan system with the 2X ratio successfully here for Nikon:

http://www.dpreview.com/forums/post/55354553

Other forum posts here and at Fred Miranda also cited 2X as the ratio so I decided go with that for a first go.

I decided to incorporate Lee Jay's "which direction" Live View / optical view method with the idea of getting the estimate for the magnitude of the adjustment number using the in-camera Canon adjustment number. The process of course assumes you set up the phase detect AF and Live View to get optimal focus of the target at the various distances.

  • My process is to start with 0 for the in-camera microadjustment number for each of the 16 Sigma Dock points of distance/focal length.
  • Focus in Live View using contrast, switch to optical view and watch for movement of the focus distance in the focus window when triggering the phase detect AF.
  • If there is movement, indicating an offset of focus in the phase detect system, I adjust the in-camera MFA to get a "Canon number" for adjustment, write it down on paper, re-zero the in-camera adjustment value and repeat for the next Sigma Dock point.
  • Enter the numbers into the Sigma Dock software using 2X the "Canon number." Write them to the lens and check with the camera at the same distances and focal lengths.

Notes:

Along the way, I modified the above version slightly: I would confirm sharp focus in Live View at 10X magnfication. I also would manually move focus away from the AF position in both directions and re-trigger focus several times to pick the most consist result. I did this instead of "dot-tune" because I found the dot-tune values so far apart and not centered on the most frequently obtained AF focus position. Basically, I trusted my multiple focus to pick best, most consistent focus value (position of the focus indicator in the window) more than I trusted dot-tune's number.

After I entered my 16 microadjustment values into the Sigma Optimization Pro software and wrote them to the lens, I checked the values in the camera again and found all but two or three to be quite good. Good, meaning that the position of the contrast AF focus distance and the phase detect distance were equal within variations on both sides small and equivalent. In other words repeating phase detect AF (or even contrast in Live View AF) 10 times for the same target distance and focal length gives a small variation in focus chosen but that variation is distributed randomly around a "best focus" value that was the same for the Live View contrast AF and the optical view phase detect AF.

The 2-3 values (I forget already) that were still off might have been done when light was fading late in the afternoon when I first got the numbers--I redid the adjustment for them and all 16 distances/focal lengths were then properly adjusted. Weather has been terrible for photography so I haven't tried it on my favorite birds yet.

For a target I made a grid of horizontal and vertical lines of random width and spacings about 5x5 inches and printed it on card stock which I then taped to the side of a box so I could easily move it while keeping the camera stationary. For "infinity" I'm a bit challenged at my house since we're pretty much surrounded by NW forest of tall trees. The best I could find for infinity was an insulator at the top of lamp post which google earth tells me is ~125 yards away from my deck.

[Added in edit] I found an opening in the foliage of the trees through which I could spot the peak of a building that google earth says is 417 yards from my deck. That brings the focus mark at 600mm closer to the infinity symbol and the focus is still the same for the Live View contrast AF and for the optical viewfinder's phase detect AF. I guess that means that even though 125 yards isn't infinite distance for the lens at full telephoto it still is close enough for the microadjustment to be the same.

Don

Don, this appears to be a "time consuming" project.  How many Hours, Days, weeks, Months; etc (whichever is most relevant) did it take to complete the project.

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Vernon...

OP Don_Campbell Senior Member • Posts: 2,790
Re: Easy way to use Sigma Dock for microadjustment
3

Vernon D Rainwater wrote:

Don_Campbell wrote:

[snip]

Don

Don, this appears to be a "time consuming" project. How many Hours, Days, weeks, Months; etc (whichever is most relevant) did it take to complete the project.

The time-consuming version of dealing with the dock is starting at the camera, finding a disparity between the contrast AF in Live View, then moving the lens to the dock, setting a guessed value at that focal length and distance in the dock and checking it again in the camera. That's a lot of back and forth from lens on the camera and lens on the dock to do this for the 16 different focal length/focus distance combinations. Alternatively, taking many photos at each of the 16 points and running them through some software to get estimates of microadjustment values is also time consuming. I didn't do either because they seemed daunting.

The way I did it goes one at a time through the 16 combinations before ever going to the dock--finding an in-camera microadjust offset at each of the 16 and then entering them all at once into the lens via the dock. Each of the in-camera adjustments takes 3-5 minutes. That's way simpler than the alternatives. When I took the value of 2X the in-camera adjustment for the Sigma adjustment it worked for almost all the 16 FL/Focus Distance values. I tweaked the others and it was done.

Honestly, on the way to figuring it out it was a learning process that cost me quite a bit of time. I could do it all again in about an hour. I spent far more than an hour slogging through "dot-tune" processes to get the microadjustment number. I decided it was imprecise and far less useful than matching positions by eye of the focus distance in the focus window of the lens. I spent too much time getting variable numbers using a less than optimal target. I wrote this to save you and others the time it takes to figure the details out. Nonetheless, iterating back and forth from the camera to dock to camera to dock as implied in the Sigma documentation, the Sigma videos and most of what you find about this online would take several hours that I didn't spend.

It will take less time if you know in advance how to use Live View (I had never used it) and you set up AF by phase-detect properly from the start. If you have a good target to start with you won't waste as much time. I made a couple of targets before settling on a style. If you have good light instead of dark clouds all day you'll save time. Doing it for the very first time is a bit of a learning process for someone who didn't have a DSLR until buying the Sigma lens. Doing it if you already know your way around the menu choices in the camera will save time. I am hoping that my post will save people time that I spent less productively.

Your question implies you have similar prior experience or you might not understand what I wrote--either way you might spend more than an hour. Compared to shooting dozens or hundreds of photos of a store-bought target and running them through store-bought software, I think method I outlined will still save you hours. No photos, only a couple of trips back to the dock first to set and then to tweak--it's pretty fast if you do it this way.

Don

tektrader Senior Member • Posts: 1,694
Re: Easy way to use Sigma Dock for microadjustment

The first time I did it, it took 8 hours....

The results where very very good therefore well worth it..

 tektrader's gear list:tektrader's gear list
Nikon D800 Nikon AF-S Nikkor 70-200mm f/2.8G ED VR Nikon AF-S Nikkor 14-24mm f/2.8G ED Nikon AF-S Nikkor 200-400mm f/4G ED-IF VR Nikon AF-S Nikkor 24-120mm F4G ED VR +6 more
hikerdoc Senior Member • Posts: 2,267
Re: Easy way to use Sigma Dock for microadjustment
1

My problem with these extensive adjustments are that after completing them you go into different lighting (eg bright sun to inside) and the corrections are wrong, or you put the lens on another body and it is way off. Mine (35, 24-105) were pretty close in my typical usage that I just left them alone. I have not owned one the super telezooms.

I preferred Cicala's quick and good enough technique.

D

dmanthree
dmanthree Veteran Member • Posts: 7,715
No magic wand.

I use the dock as well, and when calibrating the 24-105 it required the same combination of 16 focal lengths and distances. I use a lensalign target, and start with a CDAF image, as well. After that it's not complicated, just a bit tedious. I'd shoot, copy the images to the PC, examine, mount the lens, adjust, and repeat. There is no other way to do this. But the results are excellent and the lens is nice and sharp at all focal lengths and distances.

You do need to get a feel for how the +- numbers on the dock software relate to your target, but that becomes pretty clear quickly. And I ignore any references to the camera's built in MFA adjustment since it's not relevant to this procedure. Shoot, examine, adjust, repeat until satisfactory. It's not complicated.

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OP Don_Campbell Senior Member • Posts: 2,790
Not magic, but logical and quicker

dmanthree wrote:

I use the dock as well, and when calibrating the 24-105 it required the same combination of 16 focal lengths and distances. I use a lensalign target, and start with a CDAF image, as well. After that it's not complicated, just a bit tedious. I'd shoot, copy the images to the PC, examine, mount the lens, adjust, and repeat. There is no other way to do this. But the results are excellent and the lens is nice and sharp at all focal lengths and distances.

You do need to get a feel for how the +- numbers on the dock software relate to your target, but that becomes pretty clear quickly. And I ignore any references to the camera's built in MFA adjustment since it's not relevant to this procedure. Shoot, examine, adjust, repeat until satisfactory. It's not complicated.

The method I used, derived from methods used successfully by others, bypasses store-bought software and bypasses multiple images processed in the computer. Using the in-camera MFA number to estimate the Sigma number to match the Live View AF focus to the phase-detect focus gives a very good first guess to enter into the dock. That first estimate is accurate enough to very much reduce the number if iterations from camera to dock to camera and overall I would guess that it saves tedium and a few hours.

It may be that other lenses are less well defined using this process but I doubt that for the 150-600 one does better with the 'take multiple images, feed them to the software and then guess the right Sigma number of microadjustment and repeat until satisfactory' method. Neither is complicated.

I have only tried this with the Sigma 150-600 C so I have no direct knowledge of its utility with any other lens.

Don

OP Don_Campbell Senior Member • Posts: 2,790
Re: Easy way to use Sigma Dock for microadjustment

tektrader wrote:

The first time I did it, it took 8 hours....

The results where very very good therefore well worth it..

Thanks for your original post a year ago:

http://www.dpreview.com/forums/post/55354553

That post and the discussion around it was the one that gave me confidence in the 2X ratio between the in-camera adjustment number and the Sigma Dock number.

In your post you said, "How did it go ?? FANTASTIC is how. I compiled the table using the Nikon Camera values, doubled them and wrote the table to the SIGMA dock."

I found a few references to the Canon ratio also being 2:1. I chose not to use the images/software approach because the Live View contrast AF vs optical view phase-detect AF seemed like the leverage for a faster and accurate method. An added advantage is the ability to check it in real-time without taking more images and going to the computer.

When I get a little longer rain break I plan to check other distances. The question in my mind is how well the lens interpolates between those setting distances. It is just a matter of curiosity since of course the dock doesn't give an option of intermediate settings.

Don

dmanthree
dmanthree Veteran Member • Posts: 7,715
Re: Not magic, but logical and quicker

Don_Campbell wrote:

The method I used, derived from methods used successfully by others, bypasses store-bought software and bypasses multiple images processed in the computer. Using the in-camera MFA number to estimate the Sigma number to match the Live View AF focus to the phase-detect focus gives a very good first guess to enter into the dock. That first estimate is accurate enough to very much reduce the number if iterations from camera to dock to camera and overall I would guess that it saves tedium and a few hours.

I read this, and it seems like you doing the calibration twice, and only to use the camera's value to give a starting point for the Sigma dock. I haven't done this, but wonder if it's just quicker to go right to the dock and skip the first camera-based calibration. Calibrating my zoom took about two hours, even shooting all those pix (16 per iteration).

Anyway, not trying to be argumentative, just thinking out loud.

It may be that other lenses are less well defined using this process but I doubt that for the 150-600 one does better with the 'take multiple images, feed them to the software and then guess the right Sigma number of microadjustment and repeat until satisfactory' method. Neither is complicated.

I have only tried this with the Sigma 150-600 C so I have no direct knowledge of its utility with any other lens.

Don

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OP Don_Campbell Senior Member • Posts: 2,790
Re: Not magic, but logical and quicker

dmanthree wrote:

Don_Campbell wrote:

The method I used, derived from methods used successfully by others, bypasses store-bought software and bypasses multiple images processed in the computer. Using the in-camera MFA number to estimate the Sigma number to match the Live View AF focus to the phase-detect focus gives a very good first guess to enter into the dock. That first estimate is accurate enough to very much reduce the number if iterations from camera to dock to camera and overall I would guess that it saves tedium and a few hours.

I read this, and it seems like you doing the calibration twice, and only to use the camera's value to give a starting point for the Sigma dock. I haven't done this, but wonder if it's just quicker to go right to the dock and skip the first camera-based calibration. Calibrating my zoom took about two hours, even shooting all those pix (16 per iteration).

Anyway, not trying to be argumentative, just thinking out loud.

Perhaps you found the process less tedious than seemed by your original response. If you prefer the Lens Align product and images and so on I have no argument. Whatever works.

The point of doing the in-camera determination of microadjustment number at each point is that the numbers are apparently quite accurate using the 2:1 ratio to get the Dock numbers. That's the key element here. If those numbers weren't pretty close to spot-on then the initial acquisition of the MFA adjustment number would not be particularly useful.

Tektrader (see above and the link in my response to him) used a multiple-image/computer system similar to yours if I understand correctly. I think that then his system gave him the MFA numbers and he entered those numbers, times 2, into the Dock and was done. I'm not certain of that but if so, it also seems easier than your iterative method.

The point was that the Nikon and Canon in-camera adjustment numbers are apparently a simple fraction of the Sigma Dock numbers for optimal correction. Each adjustment is just to acquire a number to use in the Sigma Dock--it isn't a total calibration of the lens--just a number at a focal length and a focus distance--and quite quick to obtain: dial in an estimate, check, refine estimate, write down the number when the phase-detect focus no longer differs from the Live View contrast focus. It is not iterating back and forth to the Dock numerous times to guess and check the corrections. It is written down and then the camera's microadjustment is returned to 0 for the next point--that takes a few seconds. Once the camera is on the tripod and pointed at the target at the correct distance it takes about 5 minutes or less to do 4 focal length numbers. Then you reset the target distance and do 4 more.

A lot of this was a learning process for me. I'd be surprised if that was not true for anyone doing this the first time using a store-bought system with target and computer program. Now, at this point, after making a good printed target, after finding a good alternative target 417 yards away for the 400mm and 600mm infinity adjustments, and refining my technique to get the most accurate Live View focus and the most reproducible optical view/phase-detect focus, I'm sure I could do 16 points in 20-30 minutes. That would be without any iteration to the Dock--all with the camera on the tripod and no computer yet involved--just a pen and paper to fill in the matrix.

I was doing this as it was getting dark in late afternoon. I entered my 16 point values into the Dock, wrote them to the lens and checked on it the next morning in better light. I found that 13 of the points gave me precise agreement between the focus of contrast-detect Live View and phase-detect optical view focus. At least 2 of the other points were the infinity distance at 400 and 600mm. With the fading light and trees blowing in the way it doesn't surprise me that I got less good numbers the first time through for those points. The 3rd point that was off might have been operator error.

So checking in better light I found 13 points worked first time and done. There was only one trip to the Dock at that point in the process. So I think it was 3 points that I had entered into the lens were not spot-on by testing in the camera. Not terribly off mind you but when you're screwing around you get fussy. I repeated them with the same process. Back to the Dock a second time--3 points reentered and written into the lens. Checked again on the tripod with the target. All were now good. Two trips to the Dock was all. All the points were obtained with the in-camera MFA adjustment method.

When I started I was uncertain how exact that ratio between the in-camera adjustment and the Sigma adjustment would be. I was also uncertain that the numbers themselves would not interact slightly. I'm still not precisely sure of either point using the Live View/optical view method to get the corrections worked remarkably well so I thought I'd share.

Don

tektrader Senior Member • Posts: 1,694
Re: Not magic, but logical and quicker

Don_Campbell wrote:

dmanthree wrote:

I read this, and it seems like you doing the calibration twice, and only to use the camera's value to give a starting point for the Sigma dock. I haven't done this, but wonder if it's just quicker to go right to the dock and skip the first camera-based calibration. Calibrating my zoom took about two hours, even shooting all those pix (16 per iteration).

Anyway, not trying to be argumentative, just thinking out loud.

Tektrader (see above and the link in my response to him) used a multiple-image/computer system similar to yours if I understand correctly. I think that then his system gave him the MFA numbers and he entered those numbers, times 2, into the Dock and was done. I'm not certain of that but if so, it also seems easier than your iterative method.

Don

Correct Don, The alternative of writing directly to the lens for each adjustment requires you to remove and refit the lens dozens of times. This is time consuming and wearing on the camera and lens.

Using the in Camera MFA to get the settings is far quicker and writing the lens table once is less wearing than using the dock multiple times...

 tektrader's gear list:tektrader's gear list
Nikon D800 Nikon AF-S Nikkor 70-200mm f/2.8G ED VR Nikon AF-S Nikkor 14-24mm f/2.8G ED Nikon AF-S Nikkor 200-400mm f/4G ED-IF VR Nikon AF-S Nikkor 24-120mm F4G ED VR +6 more
dmanthree
dmanthree Veteran Member • Posts: 7,715
Re: Not magic, but logical and quicker

tektrader wrote:

Don_Campbell wrote:

dmanthree wrote:

I read this, and it seems like you doing the calibration twice, and only to use the camera's value to give a starting point for the Sigma dock. I haven't done this, but wonder if it's just quicker to go right to the dock and skip the first camera-based calibration. Calibrating my zoom took about two hours, even shooting all those pix (16 per iteration).

Anyway, not trying to be argumentative, just thinking out loud.

Tektrader (see above and the link in my response to him) used a multiple-image/computer system similar to yours if I understand correctly. I think that then his system gave him the MFA numbers and he entered those numbers, times 2, into the Dock and was done. I'm not certain of that but if so, it also seems easier than your iterative method.

Don

Correct Don, The alternative of writing directly to the lens for each adjustment requires you to remove and refit the lens dozens of times. This is time consuming and wearing on the camera and lens.

Well, using the lens align tool I was able to achieve accuracy in 4 iterations, not dozens of iterations. After a few tries you can easily translate the scale on the lensalign to Sigma's software. I recently acquired Sigma's 20mm 1.4 and had that adjusted in 2 iterations.

Using the in Camera MFA to get the settings is far quicker and writing the lens table once is less wearing than using the dock multiple times...

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dmanthree
dmanthree Veteran Member • Posts: 7,715
Re: Not magic, but logical and quicker

Don_Campbell wrote:

dmanthree wrote:

Don_Campbell wrote:

The method I used, derived from methods used successfully by others, bypasses store-bought software and bypasses multiple images processed in the computer. Using the in-camera MFA number to estimate the Sigma number to match the Live View AF focus to the phase-detect focus gives a very good first guess to enter into the dock. That first estimate is accurate enough to very much reduce the number if iterations from camera to dock to camera and overall I would guess that it saves tedium and a few hours.

I read this, and it seems like you doing the calibration twice, and only to use the camera's value to give a starting point for the Sigma dock. I haven't done this, but wonder if it's just quicker to go right to the dock and skip the first camera-based calibration. Calibrating my zoom took about two hours, even shooting all those pix (16 per iteration).

Anyway, not trying to be argumentative, just thinking out loud.

Perhaps you found the process less tedious than seemed by your original response. If you prefer the Lens Align product and images and so on I have no argument. Whatever works.

I did, because I had no idea how long it was taking others to get it dialed in. Anyway, use whatever works for you. No big deal, really.

tektrader Senior Member • Posts: 1,694
Re: Not magic, but logical and quicker

dmanthree wrote:

Well, using the lens align tool I was able to achieve accuracy in 4 iterations, not dozens of iterations. After a few tries you can easily translate the scale on the lensalign to Sigma's software. I recently acquired Sigma's 20mm 1.4 and had that adjusted in 2 iterations.

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X 16 points, that means you removed and refitted the lens 64 times....... The values needed over the focus distances vary greatly, so you cannot just assume close by values are correct and write them.

The 20mm F1.4 has only 4 distance points to adjust, so sure its quicker.... You still have to remove and refit 8 times if you get your value quickly in 2 iterations.

Mate, use whatever method works for you......

 tektrader's gear list:tektrader's gear list
Nikon D800 Nikon AF-S Nikkor 70-200mm f/2.8G ED VR Nikon AF-S Nikkor 14-24mm f/2.8G ED Nikon AF-S Nikkor 200-400mm f/4G ED-IF VR Nikon AF-S Nikkor 24-120mm F4G ED VR +6 more
tektrader Senior Member • Posts: 1,694
Re: Not magic, but logical and quicker

BTW I have the lens align tool as well and use that for checking/QC after I have finished using FOCAL.

 tektrader's gear list:tektrader's gear list
Nikon D800 Nikon AF-S Nikkor 70-200mm f/2.8G ED VR Nikon AF-S Nikkor 14-24mm f/2.8G ED Nikon AF-S Nikkor 200-400mm f/4G ED-IF VR Nikon AF-S Nikkor 24-120mm F4G ED VR +6 more
dmanthree
dmanthree Veteran Member • Posts: 7,715
Re: Not magic, but logical and quicker
1

tektrader wrote:

dmanthree wrote:

Well, using the lens align tool I was able to achieve accuracy in 4 iterations, not dozens of iterations. After a few tries you can easily translate the scale on the lensalign to Sigma's software. I recently acquired Sigma's 20mm 1.4 and had that adjusted in 2 iterations.

X 16 points, that means you removed and refitted the lens 64 times....... The values needed over the focus distances vary greatly, so you cannot just assume close by values are correct and write them.

The 20mm F1.4 has only 4 distance points to adjust, so sure its quicker.... You still have to remove and refit 8 times if you get your value quickly in 2 iterations.

Mate, use whatever method works for you......

I think I used it differently than you. For the zoom, I removed it 4 times, not 64 times. My process: mount the lens on the dock and read the distances and focal lengths it expects to "see." Mount the lens on the camera and shoot all 16 pictures, 4 at each focal length and distance. Copy the pix to the PC, examine, remove the lens and mount, adjust, and repeat until it's dead on. So I shot four groups of pix per mount/unmount. I did not remove after each individual shot. Why would I do it that way?

I've done three lenses this way, all are dead on.

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tektrader Senior Member • Posts: 1,694
Re: Not magic, but logical and quicker

Now I see how you acheived your result. Its not too different.

I used FOCAL and tabulated the table using the MFA values that Focal recommended using the cameras MFA number. Did a spread sheet and wrote those values I arrived at into the lens in one go.

You did the same thing but a bit more manually using Lens align. As long as you are happy with the results all is good.....

 tektrader's gear list:tektrader's gear list
Nikon D800 Nikon AF-S Nikkor 70-200mm f/2.8G ED VR Nikon AF-S Nikkor 14-24mm f/2.8G ED Nikon AF-S Nikkor 200-400mm f/4G ED-IF VR Nikon AF-S Nikkor 24-120mm F4G ED VR +6 more
dmanthree
dmanthree Veteran Member • Posts: 7,715
Re: Not magic, but logical and quicker

tektrader wrote:

Now I see how you acheived your result. Its not too different.

I used FOCAL and tabulated the table using the MFA values that Focal recommended using the cameras MFA number. Did a spread sheet and wrote those values I arrived at into the lens in one go.

You did the same thing but a bit more manually using Lens align. As long as you are happy with the results all is good.....

I'm not familiar with FOCAL, so I'll look it up. And totally agree, if you're happy with the result, it is good. And the results with all three so far is excellent. In fact, the system (the dock and software) work so well Sigma is my first choice for primes. The 50 1.4 is just killer.

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pshummer Regular Member • Posts: 106
Re: Thank you,Don! :)
2

I calibrated my lens using the standard method and I got better results as compared to the one right out of the box. But I still didn't get a sharp image shooting @ wide open. Since I always shoot @ f/8, I didn't bother shooting wide open but when I saw your post,I decided to calibrate my lens again. Your method is quick and more accurate than the standard method and though my lens calibration may still not be 100% accurate, the results I got from your method is impressive. Finally I can get sharp images @ wide open. I may still have to do some minor calibration fixes, so far I'm pleased with the results. Thank you for your post and now I feel that I'm getting the real potential from my 150-600C. The first image is 100% crop.

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 pshummer's gear list:pshummer's gear list
Nikon D800 Nikon AF Nikkor 135mm f/2D DC Nikon AF-S Nikkor 50mm f/1.8G Nikon 85mm F1.8G Sigma 35mm F1.4 DG HSM Art +2 more
OP Don_Campbell Senior Member • Posts: 2,790
Re: Thank you,Don! :)

pshummer wrote:

I calibrated my lens using the standard method and I got better results as compared to the one right out of the box. But I still didn't get a sharp image shooting @ wide open. Since I always shoot @ f/8, I didn't bother shooting wide open but when I saw your post,I decided to calibrate my lens again. Your method is quick and more accurate than the standard method and though my lens calibration may still not be 100% accurate, the results I got from your method is impressive. Finally I can get sharp images @ wide open. I may still have to do some minor calibration fixes, so far I'm pleased with the results. Thank you for your post and now I feel that I'm getting the real potential from my 150-600C. The first image is 100% crop.

Thanks for your comment and feedback. I'm glad you found it useful.

I was deliberately staying away from claiming it to be more accurate since I did not do other methods and I hadn't yet tried it in the field. However, comparing the actual positions in the focus window of the Live View/contrast-detect focus to the optical view/phase detect focus does seem like it has not only the advantage of speed, but also the utility of being able to click the AF trigger multiple times in a very short time to see where focus is achieved most often. And, you can quickly determine that both focus methods give you the same focus position quite quickly.

This method seems intrinsically more direct to me by comparing where the camera actually chooses focus than to be dealing with analysis of multiple images with their own depth of field issues in addition. But I'm not willing to argue it with believers in the other methods and I'm quite happy with the focus I'm getting with this awesome lens.

Don

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