200 - 400mm zoom

[buffalobreath]

Does the built-in 1.4x extender make the lens 280 - 560mm or is the extender to get the 200-400?  Thanks.

[cicopo]

Your first set of numbers are what it becomes.

[ebiggs1 · Accepted solution]

"Does the built-in 1.4x extender make the lens 280 - 560mm or is the extender to get the 200-400?"

The lens is a 200-400 is a 200-400 is a 200-400 and will always be a 200-400.  It can not change its physical focal length after being made.  The 1.4x gives it the appearent AOV of a 280-560.

A 1.4x Extender simply multiplies the effective lens focal length by 1.4x.

[buffalobreath]

Thanks guys for the help.  I wasn't sure on that.  

[TTMartin]

The EF 200-400mm f/4L IS USM Extender 1.4X is a high-performance super telephoto zoom lens with an optically matched built-in 1.4x extender. With a flick of a switch, the zoom range can be quickly increased to 280-560mm (f/5.6).

EF 200-400mm f/4L IS USM Extender 1.4x

[RobertTheFat]

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@ebiggs1 wrote:

"Does the built-in 1.4x extender make the lens 280 - 560mm or is the extender to get the 200-400?"

The lens is a 200-400 is a 200-400 is a 200-400 and will always be a 200-400.  It can not change its physical focal length after being made.  The 1.4x gives it the appearent AOV of a 280-560.

A 1.4x Extender simply multiplies the effective lens focal length by 1.4x.

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Or to put it more familiar terms: The [effective] focal range of the lens/extender combination is 280-560 mm. (I say this with no intent to denigrate Ernie's often-expressed preference for AOV as the figure of measure. It just isn't the way most users are programmed to see it.)

[ebiggs1]

To get really technical the focal length does get a tad bit longer. It is just a small amount but is does happen. When you move the focus point farther from the focal plane something has to change.