but when you use a long lens you also see a different amount of the background behind the subject and if looks as though there is less distance between them...
I remember the Hollywood Camera Work DVD set covers this.
I also have the Hollywood Camera Work DVDs, really a good series. You see a "different" amount of background behind the subject a because you usually move farther away (from the subject) with the camera when using a long focal length. In other words the perspective becomes flatter. With a shorter focal length you can move closer to the subject without changing the subjects size it occupies in the frame but you will get more of the background into the frame.
Aha! so it is simply the relationship between the size of the image to the distance to it is simply the distance to the subject that matters!
I thought it might be this but I was afraid of saying something stupid... it seemed too simple to be true... but heck, what makes most sense is usually the way it works...
Thanks CorVision, Barry, Herbal... I needed to put this one to rest in my head and now it is crystal clear.
:thumbsup: