Hello Guest

Author Topic: Does getVerticalViewAngle() give actual Camera Angle Field Of View(CAFOV) value?  (Read 1331 times)

Offline Wm_Pooja

  • Newbie
  • *
  • Posts: 3
I am utilizing a built in function named "getVerticalViewAngle()" to get the Vertical View Angle of Android Device Camera. The above function returns "63.8146" degrees as the Vertical Angle.

Now if I use the tablet on a tripod so that tilt is eliminated (Keeping tablet camera lens height as 900mm) and capture a picture of a wall at a distance of 1500mm, then 1800mm of the wall(vertical) is included within the picture. Calculating the Vertical Angle based on above scenario yields 61.9275 degress which is not equivalent to 63.8146.



Can anyone please explain why there is difference between Angle values?

Offline LightWave

  • Administrator
  • Hero
  • *
  • Posts: 921
I doubt photographers would know tech details about Android functions but the answer I can think of is that some degree of cropping might be taking place in final image.

Offline Hankosaurus

  • Global Moderator
  • Hero
  • *
  • Posts: 586
Hello Wm_Pooja.

Welcome to PCI.

What are you working on wherein the difference in angle of view would matter?  Or is it a matter of academic curiosity?  I would tend to trust the trigonometry more than the product.  Like Doc, I suspect that your viewed image is cropped slightly.

Please make yourself at home.  What kind of imagemaking interests you?

:)
Henry
A Certified Dinosaur
D700, F, F2, M3

Some say that those of us who like to talk about cameras should instead go and take pictures. I say we should go and also take pictures.

Offline Wm_Pooja

  • Newbie
  • *
  • Posts: 3
Thank You Hankosaurus.

What do you mean by image is cropped slightly? Do you mean when the image is captured it is already cropped?

Offline LightWave

  • Administrator
  • Hero
  • *
  • Posts: 921
Yes. The image produced by lens is circular. Sensor is a rectangle. And diagonal of rectangle might be slightly smaller than diameter of circle.
« Last Edit: April 13, 2015, 01:06:53 PM by LightWave »

Offline Wm_Pooja

  • Newbie
  • *
  • Posts: 3
Are you talking about mobile and tablet cameras? We understood that the lens is rectilinear and hence the image is rectangular.

Offline Jasii

  • Trusted Member
  • Hero
  • *
  • Posts: 3203
The maths bit is kinda boggling!  ;)
Let us see some pics Pooja...........  :)
n
Welcome to PCI!
A Year young with my DSLR and loving it.........
Gear: Canon 600d + 18-55, +55-250

Offline LightWave

  • Administrator
  • Hero
  • *
  • Posts: 921
Rectilinear lens doesn't mean it produces rectangular image. It means it produces image with straight lens as opposed to fisheye lens. The image created will still be circle. This is true for DSLR and compact cameras and I assume also for mobiles.

Are you talking about mobile and tablet cameras? We understood that the lens is rectilinear and hence the image is rectangular.