Adding 1.4X teleconverter to a 300mm with 1.6X (10D) factor.

[Fuzzleak]

I'm kind of confused, is it 300mm * 1.4 = 420mm X 1.6 (10D)=672mm or is it 300mm * 1.4 + 1.6 = 900mm (doesn't seem right) Help us newbies, I'm sure others have this questions in mind. :?:

[eric1]

it's 672.

eric1

[ilya]

I'm kind of confused, is it 300mm * 1.4 = 420mm X 1.6 (10D)=672mm or is it 300mm * 1.4 + 1.6 = 900mm (doesn't seem right) Help us newbies, I'm sure others have this questions in mind. :?:

It is 672mm. A 300 mm lens with a x 1.6 crop factor = 480 mm. Add a 1.4 TC to that, you get 672 mm. There are a lot of old threads here about both the 1.6 crop factors, and teleconverters, if you're interested.

best