Boone Loc: Groundhog Town USA

I have followed this lens since it first came out many years ago. So I do know a little about this. But...I can not get a firm answer to my question. (Maybe I asked it wrongly) I really don't "Need" this lens, but at my age of 70, I did order it because "I want It"!!!

That said...here is my question: I have also ordered the "Dock" to customize the lens for "Back Focus" or "Front Focus issues" etc...etc. (IF Needed)
I totally understand these issues, and this lens is "Tunable or Customizable as needed".

I have read (And watched on YouTube) about "HOW FAR THE FOCUS TARGET" should be set from the lens/camera for these tests. Some say that the target should be set at 12 feet for all testing. (ie: Focus issues and custom settings)
And some say that the target should be at 2 times the "Minimum Focus Distance". And...some say to set the target at "40 times the focal length you are working on. (150mm, 200mm, 300mm, 600mm etc...etc) I have done this with with several other lens, but...

"IF YOU HAVE THIS LENS...AND USE IT...WHAT ARE YOUR THOUGHTS ON THE DISTANCE BETWEEN THE CAMERAS SENSOR LINE AND THE TARGET" when making these adjustment.
Is one (1) distance good for all "Focal Points"???

Thank you in advance to all who "Own This Lens"!!!

I hope you understand my question.

Thanks,
Boone.

My Target

(Download)

Machinedoc Loc: Yorktown Heights, NY

Hi there - I have had this lens for about 5 years and first bought it to use with my Nikon D7200. I now use it with the Nikon FTZ adapter on my Nikon Z6ii. I get superb results with both bodies and also have the dock which I use to customize some of the shooting features. However, I do not use the dock to "fine tune" focussing. Rather I use Reikan FoCal software to accomplish this task. As I recall, Focal will "advise" the user what distance to place the target at. I does vary with the focal length the lens is set at. I usually fine tune at the min and max focal lengths.

Wallen Loc: Middle Earth

I have a Sigma 150-600 lens (sports) and have not found reason to micro adjust the focus.

For one, I or the Nikon I use it on would keep adjusting the focus till it is sharp on its sensor. It won't matter where the lens itself puts the focus, because me or the camera adapts to the what it see.

Second, at 30 meters and further, the depth of field is wide enough to accomodate subtle focus mistake.

Third, the camera itself has its own micro focus adjustment, and probably that is where it can be adjusted if required because it will adjust after finding the focus, negating point #1.

Or maybe I just got a good copy already adjusted to my camera. I dunno, never had a problem and I hope I never will.

A few images I used it on:

Focus DOF on this bird is more than adequate to have it sharp from wing tip to half the other wing.


For this one the sharp area is at least 5ft of DOF


This one is near full zoom, and focus is fine.

Revet Loc: Fairview Park, Ohio

I use this lens on my D500 and I did use the dock to calibrate the autofocus system. I used Michael Tapes Lens Align system which uses 25X the lens focal length. You either need the special long ruler or just use a yard stick with markings (what I used). I checked the lens it at all the focal length adjustment points using the dock (which I think I remember was 4 focal lengths). I only needed a very slight adjustment for back focusing at one of the focal lengths.

gmar3180 Loc: Waxahachie, TX

Sigma offers a one-time AF calibration for your new lens. Just send your lens and camera to them and they will calibrate the AF at four focal lengths at no charge. You only pay to send the camera and lens. I did this when I purchased my sigma 70-200mm Sport lens. I tried using the dock to do it myself but I just gave up. Give them a call to see if it's available for your new lens.

abc1234 Loc: Elk Grove Village, Illinois

I have this wonderful lens and use it on Canon bodies. I spent an extraordinary time checking the focus with several stationary targets including the original post shows. I tried the dock. I found these methods not worth the effort. And another lesson learned was that judging sharpness by looking at your photos does not tell you if the lens is focusing properly. That bird in flight could indicate the system is focusing short.

I bought the Reikan FoCal and found it was the way to go for me. Save your time and money and stick with FoCal.

tdozier3 Loc: Northern Illinois

I have the Nikon version and it has been flawless since day one. I haven’t even taken the dock out of the box. If it ain't broke, don't fix it.

TriX Loc: Raleigh, NC

Another vote for Focal. As has been mentioned, using the “slanted ruler method” is too subjective.

47greyfox Loc: on the edge of the Colorado front range

I owned both the Sigma 100-400 and 150-600 contemporary lenses. The dock was provided with both. I messed with focus on both lenses and also used the dock to update lens firmware. You can also use the dock to prioritize focus accuracy over shutter speed or vice versa. I sold the 100-400 when I found a reasonable price Canon version ii, but have kept and used it more now that I’ve gone mirrorless. I reset all the 150-600 settings back to baseline. The lens is a bit of a beast but I still enjoy using it. As for the focus tweaking, I found it to be an arduous task and for a zoom lens, a questionable use of time.

SuperflyTNT Loc: Manassas VA

I’m not sure about the Sigma but I’m assuming the adjustment is similar to adjusting a Tamron with the Tap-In Console. The problem with the in camera adjustment is that it only has one setting. You pick the focal length you want to adjust for and it applies that same adjustment throughout the range. With the lens adjustment you get a set of points that creates a curve that is applied within the lens itself, adjusting for every focal length in the range. Of course now I shoot mirrorless and it’s all moot.

TriX Loc: Raleigh, NC

Actually most cameras have two MFA settings for zoom lenses (not sure about his Nikon model), but regardless, he can use the data from Focal to set the tap in console correctly. Without an accurate tool to measure acutance, trying to judge sharpness from the slanted ruler is so subjective and has such a wide tolerance, that I found it unusable for accurate settings. Focal produces an accurate graph of calibration vs acuity for every zoom setting you care to measure.