Iris at max opening = now I look very closely the iris opens up to maybe 30mm - it's in the centre of the lens half way down so hard to gauge with the optics
There is a mask near the rear element that is 25mm dia.
You can just see a glint of its edge above, its close to the rear element, but is NOT the iris.
Rear element is 50mm dia
Sheesh, plenty of crud in that lense!
34.6mm of shutter aperture. Plenty of holes for light to tumble in!
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