Angle of View makes sense out of millimeters. It tells you the actual angle (in degrees) that your lens gives you.

This app lets you compare five sensor sizes simultaneously on one display, showing what the millimeters are equivalent to on four other formats relative to your currently selected format. You can swap out other sensor formats from a list of sensor sizes that you can modify. You can see the "magnification factors" for your sensor size relative to those four other formats.

But there's much more. This app appeals to beginners and pros alike.

This is also a powerful and advanced FoV calculator / Field of View calculator / AoV calculator for advanced and professional photographers, directors of photography, photo industry professionals, etc. Beginners can use this to make sense out of sensor sizes and see what millimeters actually mean on their lens.

Plus, free upgrades for life, including the upcoming universal iPhone/iPad version.

Advanced Features:
** full CoreData database for sensor formats
** all data and settings are persistent and stored
** full multi-level undo/redo support in editor mode
** supports multi-aspect ratio sensors (GH2, LX5,
etc.)
** supports cropping sensors for 16:9 mode (5D
Mk II, 7D, D7000, etc.)
** customize/create sensor formats
** tells you the "Absolute Zoom" of any lens on
any format
** add a sensor format three different ways:
- knowing X by Y in mm
- knowing just the diagonal and aspect ratio
- knowing just the horizontal and aspect ratio
** Full-color, four-page PDF user manual is built
right into the app, always available.
** lifetime free updates, including free update to
iPad-compatible version (coming soon)
** even more cool stuff coming soon

One-handed operation with multi-touch gestural support:
** pinch the angle to set a "measuring tape"
distance for a to-scale reference
** move the slider to set distance-to-subject
** spin the numbers to set lens focal length
** switch between feet or meters with just one
touch
** all controls respond instantly
** quickly change between sensor formats
** customizable dashboard for your top five
formats

Complex trigonometric equations computed in real-time:
** angle of view in degrees for horizontal, vertical,
and diagonal dimensions across the field of
view (FoV)
** horizontal & vertical distances across the focal
plane update smoothly in real-time as you
move the slider
** you select a format to serve as the base format,
then the app computes the equivalent focal
lengths and relative magnification factors ("crop
factors") for the other four sensor sizes, relative
to the base format size
** ever wondered what the crop factor is from
35mm to 120? Now you can make snobby,
well-informed comments to your "full-frame"
friends about their crop-sensors...
** you set the measuring tape length, and the app
shows you how big that size would be, relative
to the total horizontal distance across the image
frame, also updated smoothly in real-time as
you move the slider (useful for planning shots)
** (height of the image frame is displayed
numerically only at this time, additional views
planned for future)

Fully customizable via settings screen:
** add new focal lengths to the spinning selector
** customize the min/max distance range for the
slider
** add a new sensor format to any of the five slots
** edit an existing format and save as new, or
modify existing
** browse your library of sensor formats,
alphabetically
** choose a format to work with, or delete the
ones you hate