Optex Excellence Periscope Probe Boroscope - aka 'Abekus'
Optex spent 5 years developing the “world's first modular periscope/probe system for HD and film.” Built using telecentric optics (ideal for digital sensors), it is a multi-format lens system which can be configured for 2/3" HD, SD video or film. The main parts are: the periscope module which can be used at 90 degrees or extended straight in probe fashion; the main relay consisting of 0.8 Modulus gears for flawless integration with existing film accessories and Motion Control Rigs; and finally the Format Module for film or HD. The system includes four super-compact dedicated lenses offering 120°(10mm), 100°(14mm), 78°(20mm) and 60°(28mm) angles of view.
The entire system is color matched so whether it is used as a periscope or probe, and whichever lens is used, color remains constant. Hence, one can mix HD and film and retain the same depth-of-field at comparable apertures.
The system gives such high image quality you will think you are using a prime lens and as periscopes go, the Excellence is relatively fast having a minimum T stop of 5.6. There are no focus marks on the barrel, one eye focuses the lens, which is simple enough as the image is incredibly sharp.
As Phil Savoie of the BBC Natural History Unit says -
"The Optex scope is different from other periscopes and boroscope and an interesting one indeed.
Tony Scott the optical engineer who designed it spent five years to get it right, where as most scopes are hybrids from many bits the Optex Excellence is purpose built. It has its own lenses that are smaller than normal primes and very good optically; a 10, 14, 20, 28. They have no iris for stopping down; this is done with the body of the scope. The stop is also a function of the format; 2.8 for Super16, 5.6 for 35 & HD. Wide open it can render 150 line pairs on axis and 80ish edge to edge - the same sort of performance one would expect from primes. One stop in the edges are noticeable better, after that diffraction quickly takes over and the image starts to fall off. It was designed for shooting wide open or a stop in.
The feedback on the Excellence has been all very positive. More that one DP has mentioned it will cut with primes. The 90 degree prism may come in handy for your shoot to keep shadows out of frame."
For more comment, see here.