Thanks Dom,
We ended up using the Optex as it had a slightly sharper image and a better light flaring quality - which is exactly what the DOP wanted. There was no need for the T-Rex's image rotation or other functions - although it was a marvelous lens system and tested really well on the Alexa. The Optex borescope was very simple to use and initially the DOP hoped that it would have a PL mount adapter for Master Primes, but the one we got could only use the Optex Field-of-view lenses. Apparently there is a PL mount available for the Optex.
The result was very impressive and I can recommend either lens systems to be used with the Alexa, depending on your need.
Reg Voges
Digital Imaging Technician
Cape Town
South Africa