"Ken Hart" wrote in message
news
On 12/24/18 6:10 AM, nospam wrote:
In article , Sam Brown
wrote:

As I understand it, on a 35mm camera if 2 different lenses have the
same
focal length then the angle of view would be the same in each case.

only if the sensor size is the same.

a '35mm camera' can have at least five different sensor sizes.

A '35mm' _style_ _digital_ camera can have different sensor sizes.

An actual 35mm film camera has one sensor size, 24x36mm. (Unless, of
course, it is a half-frame 35mm camera, or one of the early 35mm cameras
made before the 24x36 standard, but that's a different animal.)


Is it the same on a smartphone (only focal length determines angle of
view) or does sensor size also affect the angle of view?

it does, the same as with any camera.


In theory, if the film/sensor size is increased, the angle of view from
a given focal length lens will increase, and the magnification of the
image will be less.

An 80mm lens on a medium format camera (60mm film size) is a 'normal'
lens. An 80mm lens on a large format camera (4"X5" film) is a wide angle
lens. An 80mm lens on a 35mm film camera (24mm X 36mm) is a long or
telephoto lens.

(In the real world, a lens is designed to cover a specific film/sensor
size. Putting a 35mm camera lens on a 4"x5" camera will most likely give
you a small image in the middle of the film.)

--
Ken Hart


I would agree with all that. A 35mm camera refers to one which uses 35mm
film and I would add the frame size implied is the standard one in such
cameras (24 x 36mm). Surely that is the reference being mentioned in
specs which state "35mm equivalent".

Of course you could have half frame 35mm cameras (or even some odd size)
but surely that's not what's being implied. If the frame size isn't
standardized then the focal length reference would become meaningless.