I did a REAL viewing angle measurement test:
http://videobam.com/VXDRM
or
Initial calculations or what it SHOULD have been (all references are linked to http://www.carbidedepot.com/formulas-trigright.asp):
b=30cm, A=70 degrees => a=82.4cm
What was measured:
a=31cm, b=30cm (as per initial setup) => A=45.9 degrees.
The whole viewing angle = A*2=45.9*2=91.8 degrees. Or, if we factor in a measurement error, it looks like the actual viewing angle is 90 degrees.
Any comments?
Then, someone on another forum suggested that the specs call for a "diagonal angle".
From the way it is printed on the box, it is clear to me that it is supposed to be horisontal angle.
Anyway, I've done the estimations for the "diagonal angle".
Given:
- resolution: 1080H x 720V
- distance from the camera: 30 cm
- horisontal field of view @ 30cm: 62 cm
Calculations:
In order to deal with right-angle triangulars, I split the image into four equal quadrants. So, each quadrant has 540H x 360V resolution. From my previous measurements, 540 pixels correspond to 31 cm, thus 360 pix=31cm/540*360=20.7 cm.
Using http://www.carbidedepot.com/formulas-trigright.asp , let's find "c" for "a"=31 and "b"=20.7; c=37.3cm.
Then, let's find A for a=30 and b=37.3; A=51.2 degrees. Thus, the "diagonal" angle is ~100 degrees.
Therefore, even the "diagonal" angle is far off the specs: ~100 degrees vs. 140 degrees claimed, i.e. they claimed 40% wider angle.
Note that in my estimations I assumed that the lenses are ideally linear (no barrel distortion), which, as we already know, is NOT the case. So, if I run another real test, the results will be much worse.
http://videobam.com/VXDRM
or
Initial calculations or what it SHOULD have been (all references are linked to http://www.carbidedepot.com/formulas-trigright.asp):
b=30cm, A=70 degrees => a=82.4cm
What was measured:
a=31cm, b=30cm (as per initial setup) => A=45.9 degrees.
The whole viewing angle = A*2=45.9*2=91.8 degrees. Or, if we factor in a measurement error, it looks like the actual viewing angle is 90 degrees.
Any comments?
![thread-wink-16.png](/forum/proxy.php?image=http%3A%2F%2Fforums.redflagdeals.com%2Fimages%2Ficons%2Fnew%2Fsmilies%2Fthread-wink-16.png&hash=5ed9cdabf59602557f6107319009297b)
Then, someone on another forum suggested that the specs call for a "diagonal angle".
From the way it is printed on the box, it is clear to me that it is supposed to be horisontal angle.
Anyway, I've done the estimations for the "diagonal angle".
Given:
- resolution: 1080H x 720V
- distance from the camera: 30 cm
- horisontal field of view @ 30cm: 62 cm
Calculations:
In order to deal with right-angle triangulars, I split the image into four equal quadrants. So, each quadrant has 540H x 360V resolution. From my previous measurements, 540 pixels correspond to 31 cm, thus 360 pix=31cm/540*360=20.7 cm.
Using http://www.carbidedepot.com/formulas-trigright.asp , let's find "c" for "a"=31 and "b"=20.7; c=37.3cm.
Then, let's find A for a=30 and b=37.3; A=51.2 degrees. Thus, the "diagonal" angle is ~100 degrees.
Therefore, even the "diagonal" angle is far off the specs: ~100 degrees vs. 140 degrees claimed, i.e. they claimed 40% wider angle.
Note that in my estimations I assumed that the lenses are ideally linear (no barrel distortion), which, as we already know, is NOT the case. So, if I run another real test, the results will be much worse.