Lens Calibration Sigma 18-35mm - changing distances

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ja-ki New Member • Posts: 2
Lens Calibration Sigma 18-35mm - changing distances

Hi,

I'm currently trying to calibrate my Sigma 18-35mm for my Fuji XT4 (Fringer Adapter in between).

What I'm really struggling with is finding a definitive answer to which distances to choose. For this attempt (it's not my first) I wanted to set the scale according to the Sigma Calibration Software that comes with the Dock and focusing manually e.g. moving the camera until it's in focus then switching to autofocus and let the camera focus again.

When doing this, I have to change distance for every focal lenght as fokus shifts towards the back when zooming in (longer focal lenghts) before activating AF. You can clearly see that focus shifts about 1cm at the minimum focusing distance which in this case is a lot at f1.8

What should I do? Focus at 18mm and keep it there or adjust focus everytime I change focal length? I'm confused as there is no definite answer to this.

Thanks!

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