Post by Deleted on Jun 2, 2014 13:01:53 GMT
For those new to this type of "C/CS" mount Surveillance Video camera's, here are some basic facts you need to know.
In the early days of this type of C mount video camera, 1/2" detectors were superior to 1/3" detectors. Over time this has changed with 1/3" detectors being equal to or superior in some cases, so slowly many 1/2" detectors are used in top end spec scientific/medical cameras because 1/3" detectors and lenses are so much cheaper to manufacture. This has resulted in many excellent 1/2" lenses no longer being made, such as some of the very fast F/0.8 Computar's that I have in a wide range of focal lengths, bought many years ago and prefer over the cheaper 1/3" lenses.
The distance from the front flange on the camera with a 1/2" detector is 17.5mm, so lenses called "C" mount are designed with a back focal length to suit this distance of 17.5mm.
The distance from the front camera flange with a 1/3" detector is 12.5mm and lenses designated "CS" have this back focal distance 12.5mm.
My professional quality C/CS mount video Camera's (Sony, Panasonic) etc.have adjustable detectors to allow the detector to be moved forward or backwards to use either type of lens, depending on the FOV required
This means in reality that a 1/3" CS lens will not come to focus on a 1/2" "C" CCD-not enough back focal distance.
However, a 1/2" lens with a 17.5mm back focus distance will work on a 1/3" CD camera 12.5mm by the addition of the 5mm spacer (making up the 17.5mm distance) often supplied with C/CS mount video cameras.
The C/CS thread is the same on all such cameras and lenses 1" x 32 TPI.
The "C" designation comes from Cine camera days and the lens threads are the same.
Hope this answers a few questions and helps prevent folks from buying mis-matching camera/lens combination.
This link will show you some of what I have talked about:
picasaweb.google.com/lh/photo/-qpoDMQ1EA7cJRK7xokPt9MTjNZETYmyPJy0liipFm0?feat=directlink
Clear skies,
Shevill
In the early days of this type of C mount video camera, 1/2" detectors were superior to 1/3" detectors. Over time this has changed with 1/3" detectors being equal to or superior in some cases, so slowly many 1/2" detectors are used in top end spec scientific/medical cameras because 1/3" detectors and lenses are so much cheaper to manufacture. This has resulted in many excellent 1/2" lenses no longer being made, such as some of the very fast F/0.8 Computar's that I have in a wide range of focal lengths, bought many years ago and prefer over the cheaper 1/3" lenses.
The distance from the front flange on the camera with a 1/2" detector is 17.5mm, so lenses called "C" mount are designed with a back focal length to suit this distance of 17.5mm.
The distance from the front camera flange with a 1/3" detector is 12.5mm and lenses designated "CS" have this back focal distance 12.5mm.
My professional quality C/CS mount video Camera's (Sony, Panasonic) etc.have adjustable detectors to allow the detector to be moved forward or backwards to use either type of lens, depending on the FOV required
This means in reality that a 1/3" CS lens will not come to focus on a 1/2" "C" CCD-not enough back focal distance.
However, a 1/2" lens with a 17.5mm back focus distance will work on a 1/3" CD camera 12.5mm by the addition of the 5mm spacer (making up the 17.5mm distance) often supplied with C/CS mount video cameras.
The C/CS thread is the same on all such cameras and lenses 1" x 32 TPI.
The "C" designation comes from Cine camera days and the lens threads are the same.
Hope this answers a few questions and helps prevent folks from buying mis-matching camera/lens combination.
This link will show you some of what I have talked about:
picasaweb.google.com/lh/photo/-qpoDMQ1EA7cJRK7xokPt9MTjNZETYmyPJy0liipFm0?feat=directlink
Clear skies,
Shevill