People are frequently confused by how much zoom scopes give you in tarkov, and this makes sense. I spent a few hours looking at pixel counts of screenshots of a reference object and now I can tell you exactly how they work, and give nice numbers for most of the scopes. These numbers agree with a previous guide available here (post), although I chose a different 1x zoom and included 1x modes on scopes.
Before you read that though, it might help if I explain what I found about how sights interact with your FOV. Normal sights (irons, red dots, etc.) all reduce your FOV by 15 degrees. That means that if you’re playing at the minimum of 50° FOV, when you ADS your FOV will be reduced to 35°, but if you are playing at the maximum of 75° FOV, when you ADS your FOV will be reduced to 60°. This means that you get a much larger zoom on lower FOV than high FOV. ADS at 50° FOV is equivalent to 1.4x zoom, while ADS at 75° is only 1.25x zoom.
Left side is ADS 50° FOV or magnified (35° effective), center left is 50° FOV, center right is 60°, right is 75°.
Oh, but all of that was only for non-magnified optics. Magnified optics, including the HHS-1’s 1x mode, reduce your FOV to 35° no matter what your general FOV is set to. The upside of this is that your sight picture will be the same no matter what your FOV is, but even 1x scopes will experience 2x zoom at max FOV.
35° FOV on the HHS
Finally, not all scopes are calibrated correctly. BSG appears to be drawing the view through the scope onto the scope without accounting for how far the scope is from the player’s face. The zoom levels are frequently quite close to what you’d expect after you know the rest of what the game does, but not always. Here’s that table again:
The worst offenders are the HAMR, which only gets 2.7x zoom despite being a 4x scope
and the VUDU, which gets nearly 2x at it’s 1x mode and 11x on it’s 6x mode.
Some notes about how I collected these numbers and potential sources of error: I was comparing the heights of the head of a metal target in the shooting range, with all scopes being mounted on identical M4s. I was always pressed up against the bench but I wasn’t particularly careful about where along the bench I stood. It was pretty close range, so if there was any differences in how close to the target the camera was, they might have shown up in the results slightly. Finally, I wasn’t careful about what part of a blurred edge I would use as a reference, so the results may have varied by as much as 1 or 2 pixels due to measurement inconsistency.