Question about 200-400

[Pinchers of Peril]

So I was daydreaming about the 200-400 lens today and something occurred to me. Without the built in 1.4 extender "activated" the focal length is 200-400 and with the extender activated the focal length is 280- 560. So does that mean that since there is an overlap from 280-400 that you can get to that range of focal length two ways: one way with the extender activated and the other way without? If this is true is there any difference in the image depending on how you get to that overlapping focal length? For example I know that with regular (not built in) extenders like you 2x, you lose a stop of light when you attach it to your lens. Does activating the built in extender affect your maximum aperture? Although the answers to these questions will never affect me in real life (as my wife would kill me if I spent this much on a lens), I was curious to know.
Thanks

 

[Loswr]

Without the extender engaged, it's 200-400mm f /4. With the extender engaged, it's 280-560mm f/5.6.

 

[Mt Spokane Photography]

So I was daydreaming about the 200-400 lens today and something occurred to me. Without the built in 1.4 extender "activated" the focal length is 200-400 and with the extender activated the focal length is 280- 560. So does that mean that since there is an overlap from 280-400 that you can get to that range of focal length two ways: one way with the extender activated and the other way without? If this is true is there any difference in the image depending on how you get to that overlapping focal length? For example I know that with regular (not built in) extenders like you 2x, you lose a stop of light when you attach it to your lens. Does activating the built in extender affect your maximum aperture? Although the answers to these questions will never affect me in real life (as my wife would kill me if I spent this much on a lens), I was curious to know.
Thanks

If you want to shoot a image in the 280-400mm range, don't use the extender. See the post of the lens Rental review. they tested the lens at 400mm with the extender in. It does lose a little IQ, as you would expect. If you are shooting at 580mm and must zoom out to 280-400mm, to quickly get the shot, it will still be plenty sharp, just as sharp as a 70-200mm f/2.8 MK II is at 200mm, but it will be better yet without the extender.

 

[Pinchers of Peril]

Thanks for the info. If I ever get a chance to use this lens I will be sure to keep the tips in mind.