Sigma offers a USB dock and advertises that when used with its software on some Sigma lenses you can make adjustments to the focus point of the lens. I believe that some camera models allow this in their menus.
Are these adjustments necessary when the lens(Sigma 150-600 c lens) is used with either autofocus or manual. Doesn't the image shown on the lcd or in the viewfinder, when seen as sharp, show the image that the camera will capture?
My lens has a Canon mount and will be used with an MC 11 adapter on my Sony A 7 R 111 camera.
Any enlightenment will be appreciated.
TriX
Loc: Raleigh, NC
If you use the viewfinder (which uses phase detection auto focus), then there may be an error (front or back focusing). You can “tune” the camera to compensate for this error either by using the microfocus adjustment built into the body (assuming your body supports MFA) or the dock for the lens if available. You will get a difference of opinion as to whether this calibration is necessary. Some pros regularly calibrate every lens, and other successful pros never calibrate lenses and feel it is unnecessary. I calibrate all my lenses using the MFA in my camera using the FoCal system since my Canon lenses do not have a dock available.
Thanks for your response. After a long search of this topic on the internet, one suggestion was that focus adjustment is not necessary with a mirrorless camera. A DSLR sends a part of the image from the mirror to a focusing sensor which then transmits info to the lens for focusing. This split path could go out of alignment. T
Please accept the fact that I am not knowledgeable on this topic and am only seeking some answers.he mirrorless camera focuses from the image on the sensor, which is the same image scene in the viewfinder or LCD screen.
TriX
Loc: Raleigh, NC
grichie5 wrote:
Thanks for your response. After a long search of this topic on the internet, one suggestion was that focus adjustment is not necessary with a mirrorless camera. A DSLR sends a part of the image from the mirror to a focusing sensor which then transmits info to the lens for focusing. This split path could go out of alignment. T
Please accept the fact that I am not knowledgeable on this topic and am only seeking some answers.he mirrorless camera focuses from the image on the sensor, which is the same image scene in the viewfinder or LCD screen.
Thanks for your response. After a long search of t... (
show quote)
You are correct. Mirrorless cameras generally do not need microfocus adjustment to compensate for the errors of phase detection since they generally use AF contrast detection.
TriX wrote:
You are correct. Mirrorless cameras generally do not need microfocus adjustment to compensate for the errors of phase detection since they generally use AF contrast detection.
Which is the main reason they have not quite up with DSLR in focus speed for bif
Thanks to both for your replies.
It is interesting what situations demand exploration while we are generally confined to our homes.
Stay well!
NCMtnMan
Loc: N. Fork New River, Ashe Co., NC
Another purpose for the USB dock is that it allows you to update the firmware for the lens when they release updates. These are usually minor update to fix bugs in the software on the lens.
I got the doc with my 150 to 600 Sigma. Only used it for initial setup. It is supposed to be able to update your lens. So it is just something I will check once in awhile
You can auto fine tune the lens at all focal lengths (usually the camera has limitation to 1 or 2 focal length for auto fine tune), the hub also lets you do firmware updated on the lens, also you can customize some lens features using the hub.
The lens you have has had a couple of firmware updates since I got it a couple of years ago.
Leigh
There are other adjustments one can use the dock for - focus speed and custom settings for particular shooting scenarios - very handy to have. Consider getting one. I've had the 150-600 C for my Nkon for almost 2 years and really like the results. The dock has enhanced my experience.
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