Field of View of lenses A , C2 , D

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Look at your diagram. What they call the "front principle plane" should be at the center of the protractor that I printed. It's somewhere between the front of the lens and the back of the lens, but we do not know where. No matter what, it's within a few millimeters of the front element
 
this reviewer uses a chart for measuring the viewing angle, in his test he came up with 110° Horizontal, the lens is 112° Horizontal which I would say is about as close as you could get using this method and near enough to say his method works, the review is in Russian but the pictures still work http://auto-dvrs.ru/review-street-guardian-sg9665gc/
 
I mentioned earlier in this thread that I tried the protractor technique several years ago. Basically, it sort of works for getting a rough idea of the FOV of a dash or action cam lens but it is only an approximation. The farther away from the camera and protractor you go in attempting to calculate the FOV, the less accurate the measurement seems to be because the minor errors compound themselves. On some occasions, like with @jackalopephoto's calculation for the Mobius D lens you can find yourself WAY off. I also seems dependent on the particular lens you are working with.
 
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I think the chart the guy uses is quite specific, camera has to be in a known position for the chart to work, I don't know who made the chart but his method seems to work
 
I think the chart the guy uses is quite specific, camera has to be in a known position for the chart to work, I don't know who made the chart but his method seems to work

Yeah, it looks interesting. When I get some time I'll run the link through Google translate.
 
I think the chart the guy uses is quite specific, camera has to be in a known position for the chart to work, I don't know who made the chart but his method seems to work

That's virtually exactly the same as what I did. It's super simple. This is the basis of all surveying. An angle at your optical device is the same as the angle a mile away
 
Surveyors use highly accurate precision theodolites for their work which these days employ computerized lasers for aiming and measuring. A dinky little camera sitting on a piece of paper with a crudely printed protractor on it is many, many, many magnitudes less accurate, especially as the distances increase. There is no equivalency.
 
Surveyors use highly accurate precision theodolites for their work which these days employ computerized lasers for aiming and measuring. A dinky little camera sitting on a piece of paper with a crudely printed protractor on it is many, many, many magnitudes less accurate, especially as the distances increase. There is no equivalency.

So what do you think the error is with a protractor printed by a laser printer?

1 degree?

Draw a 90 degree angle in a vector drawing program and print it. Measure it. I gaurantee it's exactly 90 degrees to within a tiny fraction of a degree. My laser printer prints at 600 dpi. Even the crappiest one does 300 dpi. Whatever math you used to come up with this idea about a "crudely printed protractor", go back and redo it.
 
So what do you think the error is with a protractor printed by a laser printer?

1 degree?

Draw a 90 degree angle in a vector drawing program and print it. Measure it. I gaurantee it's exactly 90 degrees to within a tiny fraction of a degree. My laser printer prints at 600 dpi. Even the crappiest one does 300 dpi. Whatever math you used to come up with this idea about a "crudely printed protractor", go back and redo it.

Still with the magical thinking despite the major error in calculating the D lens FOV. The whole scheme screams of inaccuracy at distance, But like I said before, have fun! ;)
 
D full sensor 1080p: 100 degrees horizontal

C2 full sensor 1080p: 130 degrees horizontal

ok question time, the numbers you got were only 5 degrees less for C2 but 30 degrees less for the D lens, they advertise them as 135 on the C2 and 130 on the D, 5 degrees is very minimal difference, how do the two lenses compare in actual results, is there an obvious difference when viewing video or not really?
 
So what do you think the error is with a protractor printed by a laser printer?

1 degree?

Draw a 90 degree angle in a vector drawing program and print it. Measure it. I gaurantee it's exactly 90 degrees to within a tiny fraction of a degree. My laser printer prints at 600 dpi. Even the crappiest one does 300 dpi. Whatever math you used to come up with this idea about a "crudely printed protractor", go back and redo it.

You know, as I've said, I've tried this, long before you ever did. Sometimes it sorta' works OK and sometimes it just doesn't. It's not a reliable, accurate methodology, it's a "ballpark" methodology. As for accuracy of 1 degree? The slightest imperceptible misalignment of the camera or the paper protractor will throw things off by WAY more than one degree. You can't "guarantee" anything. That's why you got "sort of" close with the C lens (5 degrees off) and WAY off with the D lens (30 degrees off). And it is also apparently influenced by the particular lens design and focal length from my experience.

But like I've said, have fun and believe what you wish to believe......
 
Is that flat field 'Field of View;
or
Constant radius, in Focus, 'Field of View' ?
:)
 
Still with the magical thinking despite the major error in calculating the D lens FOV. The whole scheme screams of inaccuracy at distance, But like I said before, have fun! ;)

I did not make an error in calculating anything. I didn't do any calculations. I measured.

You're assuming that Mobius's advertised numbers are correct, therefore anything that conflicts is automatically wrong. I have no idea how this possibly makes sense in your mind.
 
ok question time, the numbers you got were only 5 degrees less for C2 but 30 degrees less for the D lens, they advertise them as 135 on the C2 and 130 on the D, 5 degrees is very minimal difference, how do the two lenses compare in actual results, is there an obvious difference when viewing video or not really?

The D lens is closer to the A lens than it is to the C2. I just did some tests at a school by where I live, with buildings for easy reference. I'm going to post all my results but here is something that directly disproves Mobius's claims in their software. The PHOTO and the VIDEO have two DIFFERENT horizontal fields of view. That's something we have to keep in mind for all discussion of field of view. The whole width of the sensor is not used for video
 

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The D lens is closer to the A lens than it is to the C2

I thought when the D lens was introduced it was meant to be more like the A lens but their numbers are suggesting only 5 degrees less than the C2, I've never had a D lens myself to check so not really sure how it compares, the images achieved are generally a better indicator than the numbers
 
I did not make an error in calculating anything. I didn't do any calculations. I measured.

You're assuming that Mobius's advertised numbers are correct, therefore anything that conflicts is automatically wrong. I have no idea how this possibly makes sense in your mind.

I'm assuming you have no idea what you are talking about. I'll leave it at that.
 
Here are my comparison PHOTOS for the 3 lenses. I'm going to use these to calculate the geometry (to make Dashmellow happy). But keep in mind the video is a slightly narrower angle!
 

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I thought when the D lens was introduced it was meant to be more like the A lens but their numbers are suggesting only 5 degrees less than the C2, I've never had a D lens myself to check so not really sure how it compares, the images achieved are generally a better indicator than the numbers

No, they introduced the A2 lens to replace the A lens. The D lens was intended to be more like the C2 lens but with less barrel distortion.
 
Here are my comparison PHOTOS for the 3 lenses. I'm going to use these to calculate the geometry (to make Dashmellow happy). But keep in mind the video is a slightly narrower angle!

Wait! I thought you said "I didn't do any calculations. I measure.", so now your calculating? The more we get into this, the more silly and pointless the whole exercise becomes......but keep in mind!
 
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