Originally posted by falconeye .......................
"equivalence" is no nonsense, just a way to understand things. Like if a larger format has more trouble being used handheld.
Equivalence is a way to understand things, but its usefulness is questionable. Every day there are people buying cameras that have never taken a single photo on 35mm film, so knowing the equivalent FL, or DOF, or anything else as it relates to that format is useless/meaningless to them. My Ram pickup has a cargo capacity of about 2,000lbs. How useful is it to know how many Ford Model A pickups would yield the equivalent carrying capacity? I know that if I hit my thumb with a hammer, it hurts. What's the benefit in calculating the equivalent force needed to yield the same amount of pain by hitting it with a rock?
Seriously, if I have an APS-c format camera and a 645Z and I decide that the 645Z is the best body to use for a particular subject or scene, (due to pixel count, DOF, whatever) I only need to know what lens to put on it to capture the scene as I wish to capture it. The comparative, or mathematical relationship between that and what I would need to do to get a similar result in the other format is completely superfluous.
As my sig line reads: Life gets easier once you forget the concept of "crop factor" and "full frame equivalent"
EDIT: Sometime between the time I quoted him, and the time I finished writing this response, Falconeye deleted his post. There is nothing wrong with that. I only mention it so nobody will wonder what I was quoting.