A New Canon Lens With A New Feature - In-Built
The lens is the new Canon EF 200- 400mm f:4L IS USM Extender 1.4x. It will replace the current 100-400 zoom lens. There are cosmetic differences to be seen in the illustration of the new lens - a deeper tripod foot for one and a circular zoom motion. There is a bulge on the left hand side of the lens just in front of the mount. Therein lies the real secret of the lens.
The bulge conceals an in-built 1.4x tele-extender element. If needed, it can be rotated into the light path, extending the focal length range to 280 to 560mm. It does cost one stop of light but remember that the subsequent downshift of the shutter speed can be adequately compensated for with the new IS mechanism in the lesn. You won't notice any inconvenience and you'll have a lot longer reach for animal shots.
They have reduced the weight of the lens through use of magnesium castings.
The convenience of this innovation will be at once evident to those people who have been faced in the past with demounting the old 100-400 and trying to prevent ingress of dust and moisture - not the thing does not have to be broken in the field and most of this dust will never get a chance to get in there.
This will be the lens for Africa and Alaska. And if they can get enough lions and rhinoceroses to emigrate to Anchorage, you can do it all in one trip...