What the difference beetween camera sensor and camera focal length?

What the difference beetween camera sensor and camera focal length? To me it does the same - zoom in and zoom out

From the manual.

Sensor size
This setting is an alternative way to control the focal-length, it’s useful to match the camera in Blender to a physical camera & lens combination, e.g. for motion tracking

sensors determine numbers of pixels use on specific cameras !
The focal length select some standard lens for specific cameras!

happy bl

sensors determine numbers of pixels use on specific cameras !
The sensor size does not determine the number of pixels, it is the physical size of the sensor. You can have the same sensor size but with different numbers of pixels. The number of pixels of a sensor is not important, that info is set in the render settings

It’s there so you can basically put in real world camera data, it’s up to the user if this is necessary.

Thank you. “This setting is an alternative way to control the focal-length…” So its the same, as i expected.

Artisticly what you see is the field of view (fov), the focal length is distance from the focus point to the plane your scene is projected onto, so they both do kinda the same thing. In Photography and Videography people use common sensor sizes(i.e. APS-C, 35mm Full-Frame, etc.), so you need to change the focal length to change your field of view (i.e. “zooming”), because changing the sensor size in your camera is difficult…

http://i.stack.imgur.com/Z69Qc.png

In Blender the same units are used so people have a common idea of what field of view is achieved with what sensor size/focal length parameters. Also makes it easier if you are combining real footate and cg footate, so you can get the same perspective.

there are also some camera presets and not certain here what it changes

but first time you pick a camera it will change the viewport camera field of view
and also the ration X /Y
but not the render ratio !

after that if you select another camera it does not seems to re adjust the field of view in viewport !
is this a bug or what ?

thanks
happy bl

I’ve found both blender docs and this thread a bit light on precise details. Here’s how I understood this after probing about a bit:

Setting the Field of View controls a standard lens. This is the grey dotted line you see if your viewport is aligned to the camera perspective. This is probably some videography standard thing. I don’t know much about that one. Looks like a standard 4:3 ratio to me.

Then picking SensorFit “Vertical” will make the vertical field of view of the render viewport (in render settings) match that square. This means that the internal “angle_y” will be your fov (in radians).

If you pick SensorFit “Horizontal”, then the same will be true but horizontal, and for angle_x.

SensorFit “Auto” makes it pick the minimum of the two.

Now I wish i knew that "depth’ they are referring to when they talk about sensor sizes.

The aspect ratio of that rectangle is defined by your output resolution, which is by default a 1920x1080, so 16:9.

What depth are you referring to?