At explainers.hdyar.com/perspective I have created an interactive tool to explore perspective distortion. Please go check it out.
Key takeaways:
- Zoom is just cropping
- Moving your feet is all that matters
- Everything is relative. Think in terms of camera-subject distances.
To practice, I recommend a counter-intuitive exercise: put some masking tape on your zoom lens to lock it from spinning. In other words, turn it into a prime lens, as wide as it will go, and go out shooting with that.
You'll be forced to move your feet instead of zooming, and when you look through the images later, you can explore their differences.
Evolution of the Dolly Zoom from Vashi Nedomansky ACE on Vimeo.