I can't explain it, but it really bugs me. And even when the distance scale does not change at all, when switching between MF and PDAF, the resulting photo is completely blurry. This works well and is very quick.īut for infinity it never worked out. Then I did the fine calibration with actual photos. At 3m/4m I can use my SpyderLensCal tool, which is quite handy.įor all other distances I was successfull by monitoring the changes in the distance scale when switching between MF and PDAF. But of course, this was an error in reasoning. My first thought was that calibration can't be accurate if I calibrate Sigmas infinity-position with a measurement of 3m. Maybe 3-4m should work for me as well (indoor, low light, wide open).įor infinity mostly landscapes, I rarely shoot wide open. AF is like darts just as your graph above illustrates. Longer the subject distance, the more pronounced focus inconsistency will be. But no matter what distance you chose to calibrate at, the lens must focus accurately at ALL distances beyond 2m in the case of Sigma 18-35.Ĭalibrating infinity at closer distances is better because it is far easier to interpret results of whether something is within depth of field. In my case i calibrated infinity for distance of about 3 meters. Tip: Calibrate infinity for the distance you will using your lens the most at wide apertures. What is your subject distance at infinity? After calibration about the half is correct, the other half is off. Here is a graph: The red crosses show where the lens focuses at infinity. Calibration affects both, so whatever what values I dial in, the lens either front-focuses or back-focuses in about 50% of the cases. Repeated tests showed that the lens has two distinct distances, where it reapetedly focuses in in about 50% of the cases. It does not depend on where the focus search starts (MFD vs. No, I am not talking about speed, I am talking about accuracy and precision.īut I repeated my calibration today and it turned out that my first assumption was NOT correct. (BTW: I am using the new firmware version 2.0)Īre you talking about accuracy of AF speed?Ĭause there is a know issue of consistently different focusing speed from MFD to inf or vice versa. But infinity the 18-35 is quite important to me. Since I never use MFD on my 50-100 it does not bother me much. I had a similar issue with my 50-100mm 1.8 as well, just on the opposite MFD end. And this behavior is quite reliable: For a correct calibration I can either use the calibration value "0" (if the lens focus is coming from "past infinity") or calibration value "6" (if lens focus is coming from MFD or something in between). It makes a clear difference if the lens focus is starting at "past infinity" vs MFD. At most focal length it worked out quite well, but at 24mm I have a weird issue: Then follow the second link to make the booking.Today it was finally a clear day to finish the calibration of my new Sigma 18-35mm 1.8 at the infinity focus. To book a Sigma lens calibration service of 1 lens to 1 camera including the firmware upgrade (if applicable and configuration of User 1 and User 2 settings) please check if your lens is compatible. This would be of benefit to owners of these lenses who do not have a Sigma dock to perform these changes. The cost of this service is an additional £10.00 on top of our normal calibration prices. (Sigma 150-600mm range)Ĭonfiguring C1 - Changing the OS Setting - Part 2 - Dynamic View Mode Configure User 1 & User 2 settings (as in AF functionality and Optical Stabiliser settings) according to the user preferences be it Wildlife, Sport.Check and Update Lens Firmware (Depending of the age of the lens this can increase focusing speed by up to 50%).We intend to dedicate a further post on the pros and cons of using the dock as opposed to our preferred solution at a later date, so keep your eyes peeled.Īs such we have introduced a new Sigma lens calibration service to complement our existing calibration service with the addition of the following: For use with SIGMA Global Vision lenses UD-01 for DSLR lenses UD-11 for mirrorless (DN) lenses Update lens firmware on all compatible lenses Adjust focus position, AF parameters, OS settings, etc. But why not use this for calibrating the lenses themselves?Īlthough this is possible it is far more time consuming and ultimately not as accurate as the using the Reikan Focal software solution. You may be thinking we use the Sigma dock for updating lens firmware and configuring the AF speed and Optical Stabilizer settings. Many citing frustrations with the Sigma USB Hub. Here at Cameracal we have recently been inundated with requests for a Sigma lens calibration service for Sigma Contemporary, Sport and Art series lenses.
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