Optics thoughts
Hello, fellow M43 friends!
Since I got into photography about a year ago, I’ve been trying to do two things: 1. Take good pictures, and 2. Understand the physics of focal length, depth of field, etc.
Speaking of focal length, something has been scratching my brain for a while now. A phrase that always comes up is: "In M43, you simply multiply the focal length by 2 to get its Full Frame equivalent."
Is this entirely true? I think it’s true in terms of framing (how much of the subject fills the sensor), but not when it comes to how much of the background is visible. I tried sketching what I recall from grad school. If our subject is "A" and the background is an arrow, it seems like the background is much more compressed on the FF sensor (meaning more of the background appears), even though "A" takes up roughly 25% of the height in both images.
So is that all garbage because I am missing a lot of what is a camera lens and I just can't summarize it to a simple lens or is there something true about it ?
Thanks for the physics help y'all !