Please forgive me for asking such a basic question, new to the game and trying to educate myself a bit as I prepare to begin filming using my FS100.

I understand the 1.45 or 1.5 crop factor when we talk about using a "still photography" Full Frame lens on an s35 mm sized sensor such as the one found on an FS100 or 700. My question is, the s35 mm sensor sized cameras that are used for mainstream commercial features (such as Arri or Panavision film cameras, and digital ones like an Alexa or a Sony F65, etc), do these cameras have the same crop factor when the high end primes (Cooke, etc) are used on these cameras?

In other words, aside from the glass, build quality, rendition attributes, etc., does a 50 mm "still photography" Full Frame lens (say a Canon) have the same DOF and FOV as a 50 mm motion picture film lens (say a Cooke or Arri-Zeiss) if both lenses are used on the same s35 mm motion picture camera? If set to the same f-Stop, say f4, will both lenses produce the same FOV and DOF if used on the same camera?

Many thanks.

It would be best to say lenses of the same focal length will have similar characteristics.

Yes. It's the sensor size that creates the crop factor. A 50mm lens is a 50mm lens no matter what you put it on. The size of the sensor will make a lesser field of view if it's smaller than "full frame."

Thanks Chris and Bill, much appreciated.

Yes this was bugging me for the longest time, I guess the whole Canon still photography "Full Frame" thing (Full frame only in the still photography world) thru a wrench in the mix for me, fun.

Or was it clever marketing on Canon' part, to make the industry standard s35 mm motion picture film frame come across as some how inferior to the still "Full frame" size, it sure has worked fine for them :)

I guess since still photography lenses have to cover larger area of Full Frame still sensor, when used on s35 mm sensor we are taking advantage of the sharpest portion of the lens (center of the glass), correct?

I am using an Sony Zeiss alpha mount zoom lens (24-70mm/f2.8), if it was designed for full frame then the above maybe true for this lens as well.