Schneider Xenotar 2.8/150mm rebuilding

[Jim Galli]

Some front elements use magnification to make a larger equivalent aperture than measured. 240/5.6=42.85 Where 150/2.8=53.57 Quite a difference in straight math. With the 150 front group in place, do you physically see the restriction in the shutter when aperture is wide open?

[MAubrey]

TTL measuring is really strange: it depends on the distance you look!

And that's exactly how it works!