CCTV Lens Guide

CCTV LENS GUIDE FOCAL LENGTH FOCAL LENGTH IS THE DISTANCE BETWEEN THE LENS TO THE POINT AT WHICH THE IMAGE IS FOCUSED LENS - GATHERS LIGHT REFLECTED FROM A SUBIECT FOCAL LENGTH IMAGE SENSOR - CONVERTS LIGHT IMAGE TO ELECTRONIC SIGNALS FOCAL LENGTH MEASUREMENT IS EXPRESSED IN MILLIMETERS (MM) 12MM THE SMALLER THE FOCAL LENGTH NUMBER ZOOM OF A LENS IS, THE WIDER ITS FIELD OF VIEW ZOOM LENSES CAN AUTOMATICALLY ADJUST FOCUS TO INCREASE THE DEFINITION ON A GIVEN OBJECT, BUT GENERALLY MORE EXPENSIVE THAN FIXED CAMERA LENSES FIELD OF VIEW FIELD OF VIEW IS THE AREA THAT THE LENS WILL LET YOU SEE THE FOV IS BASED ON THE CAMERA AND LENS. THE 2.8MM LENS ALLOWS BETTER WIDE-ANGLE VIEWING COVERAGE THAN THE 12MM LENS 20FT R VARIFOCAL VS MONOFOCAL 00 MONOFOCAL CAMERAS HAVE FIXED LENSES AND FOCUS AT A SPECIFIC DISTANCE, VARIFOCAL HAVE A RANGED FOCAL LENGTH APERTURE (F-STOPS) APERTURE IS THE SIZE OF THE OPENING IN THE IRIS. APERTURE OPENINGS ARE EXPRESSED IN F-STOPS. F/2.8 SMALLER THE F-STOP, LARGER THE OPENING. THIS ALLOWS A GREATER AMOUNT OF LIGHT PASSING THROUGH THE LENS TO THE IMAGE SENSOR. F8 C & CS MOUNTS BACK FOCAL LENGTH THE DIFFERENCE BETWEEN THE TWO TYPES "C" & "CS" MOUNTS ARE THE DISTANCE FROM THE BACK OF THE MOUNTING FLANGE TO THE FACE OF THE IMAGE SENSOR. CAMERAS AND LENSES NOWADAYS ARE GENERALLY CS MOUNT RATHER THAN C MOUNT. FLANGE BACK LENGTH REFERENCES http://reviews.ebay.com/CCTV-Complete-Guide?ugid=10000000002153882 INFOGRAPHIC BROUGHT TO YOU BY: INFOGRAPHIC CREATED BY: odesys W websquare webdesign Security Systems For The Future 2.8MM 2.8MM 8MM 12MM SENSOR IMAGE PLANE