Sigma 150-600 Sport - Some Thoughts (Images)

Started 5 months ago | Discussions thread
Bing Chow Senior Member • Posts: 1,799
Re: Sigma 150-600 Sport - Some Thoughts (Images)

mensch plus kamera wrote:


Might have to give Reikan a try then. I think doing it all manual will be too tedious and error prone.


I don't know how those commercially available targets work. My guess is that it's done at one distance so that the target occupies some significant area in the frame. The problem arises when either the FL is too wide, or distance becomes too great, that the (little) cardboard target is way too small. In my experience, in order to easily see the amount front or back-focus, the target has to take up a large enough part of the frame. So that when you view 1:1, there are enough pixels. One size target cannot fit all FL from 24 to 600mm or from minimum focus distance (MFD) to infinity.

To get around this problem, I've made my own high-contrast target with a slanted ruler for indoor distances. For longer distances, I use whatever buildings I can find and use adjacent structures (street signs, other buildings) to determine front/back-focus.

This is what I mean by tedious. Not difficult, just time consuming. But I've arrived at this method over couple years of owning Sigma Arts and it makes the most sense to me. Once I think I've got the lens calibrated, then I go shoot handheld at normal subjects and verify my result with what I get on the tripod and using live view.

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