Lens Focal Length (mm)		Distance From Camera to Object (Ft.)
		10	20	30	40	50	60	70	80	90	100	120	140
Fixed Focal	Viewing Width Covered by Lens (Ft.)
	2.2l	22	44	66	88	110	132	154	176	198	220	264	308
	2.9	17	34	51	68	86	103	120	137	154	171	205	240
	3.6	13	26	40	53	66	80	93	106	120	133	160	186
	4	12	24	36	48	60	72	84	96	108	120	144	168
	4.3	11	22	33	44	55	67	78	89	100	111	134	156
	6	8	16	24	32	40	48	56	64	72	80	96	112
Variable Focal	2.8-10	5-17	10-34	15-51	20-68	25-86	30-103	35-120	40-137	45-154	50-171	60-205	70-240
	2.8-12	4-17	8-34	12-51	16-68	20-86	24-103	28-120	32-137	36-154	40-171	48-205	56-240
	3.5-8	6-14	12-27	18-41	24-55	30-69	36-82	42-96	48-110	54-123	60-137	72-164	84-194
	4-9	5-12	10-24	16-36	21-48	26-60	32-72	37-84	42-96	48-108	53-120	64-144	74-168
	4-12	4-12	8-24	12-36	16-48	20-60	24-72	28-84	32-96	36-108	40-120	48-144	56-168
	5-50	1-9	2-19	3-28	4-38	4-48	5-57	6-67	7-77	8-86	9-96	11-115	13-134
	6-60	1-8	1-16	2-24	2-32	3-40	4-48	4-56	5-64	5-72	6-80	7-96	8-112
Note: Viewing height is calculated by multiplying viewing width by 0.75.

The lens dictates the field of view that the camera provides. Lenses range from 2.2mm to 60mm. The larger the lens size, the farther it will view. Fixed.A camera lens that is a specific focal length. Variable.A camera lens in which the focus is not fixed, and can be adjusted manually or automatically. Steps: • Determine the desired field of view in feet horizontally • Determine how far away the camera is to be mounted in feet • Consult chart below to choose the approximate focal length needed