>>2602064Certainly.
A lens designed for a 35mm sized negative will project its image over a certain footprint. Let's say that it's 1 inch, just to make it easy. (It's actually more than that, but for the sake of explanation, we're keeping it simple)
Digital sensors come in multiple sizes, and smaller sensors are cheaper to produce, and therefore cheaper to buy. They also allow for smaller cameras, smaller cheaper lenses, etc. So most mirrorless cameras use a sensor that is smaller than a 35mm negative (These smaller sizes are usually APS-C, or Micro 4/3)
So your lens is projecting the entire image across a 1 inch space for the large film, but the sensor of your mirrorless camera doesn't fill that whole inch. So the outside edges of the image are being projected, but it's not hitting the sensor, because the sensor is only half an inch across (for example). So on either side of the sensor, you have a quarter inch of light that's being wasted. You're "cropping" the center of the image, which gives the same effect as "zooming in"
So in the real world, if you put a 50mm lens on an APS-C camera, there is a 1.5 (or 1.6 on Canon) magnification factor, and your effective focal length is now 75mm.
pic related is a visual representation of the effect.
If I've explained it poorly, ask questions and I'll try my best to answer.
