Sigma 105mm F1.4 Art

[Peter Ward]

OK you can blame the rain on me....new toy arrived late last week,

A short review can be found here (http://www.atscope.com.au/BRO/TestReports/Sigma105.html)

[skysurfer]

105mm / 1.4 = 75mm aperture.

You can test it by flashlight test by shining through the viewfinder's eyepiece and measure the image circle coming from the lens (i.e. the reverse direction of the 'normal' light path).

[Peter Ward]

I ran a micrometer across the objective..

It measures 90mm in diameter..with a new picture now on the relevant web page.

Optical vs physical sizes can easily vary with multiple elements behind an objective.