Pet peeve: This is a common misunderstanding. Focal length doesn’t cause the distortion. The distortion is caused by the distance between the camera and the subject. Think of longer focal length as an optical crop. A longer focal length allows you to be farther away from the subject while still filling the frame. If you took a photo from the same distance with a wider lens and simply cropped it afterwards to have the same composition there would be no difference in distortion.
In practice, people use the term “focal length” as field of view/zoom for the final image, especially when we start talking smartphones and full-frame “equivalent” focal lengths.
I don’t disagree, the article I got this image from explains exactly what you did, but… I think the semantic ambiguity is acceptable, in this case. The actual angular field of view in a shot isn’t advertised in specifications. Neither is the sensor crop factor in post processing. It’s all kind of impractical to calculate, so using FF equivalent focal length as a “zoominess” standard people can understand makes sense.
Sure, focal length as proxy for field of view makes sense, but that still doesn’t mean it’s helpful to incorrectly claim it distorts the image. Using a shorter focal length doesn’t mean you have to get closer to the subject.
So? There is no law saying your subject has to fill the frame.
It’s useful to know what affects what. That way you can make informed decisions. Distance affects the ‘distortion’, while zoom is more of a tool for composition.
Pet peeve: This is a common misunderstanding. Focal length doesn’t cause the distortion. The distortion is caused by the distance between the camera and the subject. Think of longer focal length as an optical crop. A longer focal length allows you to be farther away from the subject while still filling the frame. If you took a photo from the same distance with a wider lens and simply cropped it afterwards to have the same composition there would be no difference in distortion.
In practice, people use the term “focal length” as field of view/zoom for the final image, especially when we start talking smartphones and full-frame “equivalent” focal lengths.
I don’t disagree, the article I got this image from explains exactly what you did, but… I think the semantic ambiguity is acceptable, in this case. The actual angular field of view in a shot isn’t advertised in specifications. Neither is the sensor crop factor in post processing. It’s all kind of impractical to calculate, so using FF equivalent focal length as a “zoominess” standard people can understand makes sense.
Sure, focal length as proxy for field of view makes sense, but that still doesn’t mean it’s helpful to incorrectly claim it distorts the image. Using a shorter focal length doesn’t mean you have to get closer to the subject.
But if you don’t get close, it makes the subject smaller on the sensor, though.
So? There is no law saying your subject has to fill the frame.
It’s useful to know what affects what. That way you can make informed decisions. Distance affects the ‘distortion’, while zoom is more of a tool for composition.