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

A Canon EF 200-400mm f/4 L IS USM Lens has long been on my most-wanted Canon lens list, so I am excited to see this lens announced for delivery later in 2011 (Update: On Nov 15, 2011, Canon announced that this lens has been delayed until an unknown future date).
While many are asking me if the 200-400 is the upgrade for the Canon EF 100-400mm f/4.5-5.6 L IS USM Lens, and while I expect that the 200-400 L will be a significant upgrade from the 100-400 L in all ways, I do not see these two lenses being in the same class - in size, weight, image quality - or price.
Price first. Being a super-telephoto lens with high-grade specs, I fully expect the Canon EF 200-400mm f/4 L IS USM Ext 1.4x Lens to wear a super-high price tag. Hitting the buy button on the similarly-spec'd Nikon 200-400mm f/4G AF-S VR II Lens reveals the USA version currently selling for $6,800. With the built-in extender and more modern design, I would not be surprised to see the Canon 200-400 L selling for $11,000 - $13,000. And with the announced-at-the-same-time Canon EF 500mm f/4 IS L USM Lens arriving with a $9,500 price tag, I am perhaps being conservative with that estimate.
Size and weight next. With the built-in extender, I fully expect this lens to be at least as large as and even heavier than the Nikon 200-400. The Nikon lens is 4.88 x 14.37” (124 x 365mm) and weighs 7.4 lbs (3360g). While handholdable for very short periods of time, the Nikon 200-400 is more fun to use from a monopod or a tripod.
It is a super-telephoto Canon L Lens, so I fully expect extremely high image quality from this lens. The 100-400 has been quite good in this regard, but Canon's super-telephoto lenses have always been a class above even the other L lenses, so I expect we are going to see very impressive optical performance from this lens. Including impressive quality with the built-in 1.4x extender in use.
Let's take a closer look at the built-in extender. Since this lens is only a prototype as I write this, "look" is all we can do. And for now, looking is fun ...

The Canon EF 200-400mm f/4 L IS USM Ext 1.4x Lens has inherited the built-in 1.4x extender (in concept at least) from the rare Canon FD 1200mm f/5.6 L Lens (picture on PBase.com). The 200-400 L is the first EF lens to receive built-in, switch on/off extender.
I love the concept. A lockable lever is used to move lens elements into or out of the optical path. A unique bulge is present near the lens mount to house the extender when not being used.
The huge advantages of a built-in extender over a conventional 1.4x extender are improved image quality and convenience. A built-in extender will be tuned to the lens it resides in, and it should therefore deliver better image quality.
Swapping a conventional extender in and out of use on a super-telephoto lens takes far more time than throwing a switch. A subject can easily be gone in that time. Extender installing/removing can also allow dust and moisture into the camera and lens - and gives to opportunity for the lens or extender to be dropped.
With the Canon EF 200-400mm f/4 L IS USM Ext 1.4x Lens, the throw of a switch/lever instantly adds the 401-560mm f/5.6 range to the 200-400mm f/4 lens. The resulting 280-560mm f/5.6 IS Lens has a very useful focal range as well.
Hopefully Canon provides images of this lens with the bulge cover removed, because those cover screws are going to be very tempting to remove.
I was asked about the zoom ring being positioned in front of the ring as I've stated that I prefer rear-positioned zoom rings. I'm still trying to decide if the 200-400 L zoom ring positioning is going to be good or not. Since I don't expect to be handholding this lens a lot of the time, my left hand will often rest above the tripod ring area of the lens - and the 200-400 L design might work very well for this. When handholding the lens, my left hand is going to be directly under the lens far enough out to balance the setup. And I probably will not be rotating my support hand around the lens in this position as I will not have a solid-enough grip when doing so. So I guess I'm going to wait to form an opinion on this issue.
I was also asked if water and dirt were going to funnel into and pool in the extender switch area. My expectation is that the Canon engineers have thought of this issue and that we will not have problems in this regard.

Sports and wildlife photographers are going to represent the largest market for this lens. Having a zoom range to work with in a long focal length lens of this class will increase the variety of images able to be captured without a lens change - and without cropping.
My (complete) guess is that we will see this amazing lens formally announced (including a price) in August and available around the end of the year.

sourse : http://www.the-digital-picture.com/Reviews/Canon-EF-200-400mm-f-4-L-IS-USM-Extender-1.4x-Lens-Review.aspx