I dont mean when for example 35mm on a crop sensor “equals” a 50mm on a full frame camera. My question is a bit weird, here we go.
So i have a 18-55mm lens (on a crop camera) and people say that 50-55mm is the focal length of the human eye. Here, my experiment comes into the play:
My camera has a 1.5x crop factor so 35mm looks like 50 mm on a full frame because of narrower field of view right? So when people say field of view of a 50mm on a full frame is the same as your eye, my first thought is 50mm on a full frame = 35mm on my camera. Then what i do is i take my camera put it on 35mm and then look at the vizor. What i expect is no zoom at all but the objects look smaller in the vizor (so fov is higher). When i put my camera at 55mm, the objects size match up with exactly what i see. But from what i learned 35mms should be like a 50mm on a full frame therefore it should match my eye.
So here comes my question:
Are the numbers of focal lengths on my lens already multiplier by 1.5x ? So do i have to subdivide the numbers to get the full frame equivalent ?
Sorry for spelling mistakes.
Where your equation goes wrong is here “35mm looks like 50mm on a FF because the narrower FOV”
Just no.
Optically 35mm = 35mm and 50mm = 50mm on both Crop and FF. It will look the same regardless of your sensor size.
A crop will give you the idea of a narrower FOV because your image is cropped, aka the outer edge of your image is cut off.
The focal length, and thus how “large” objects look through the viewfinder is the same on both systems.