Canon has been experimenting with the 70-200mm L lenses and one of their best is the EF 70-200mm f/4.0 L IS USM Lens. Some would ask there were already the EF 70-200mm f/4 L USM Lens and the faster EF 70-200mm f/2.8 L USM and the EF 70-200mm f/2.8 L IS II USM Lenses, so why would Canon go for another lens in the same category? The answer is 70-200mm is a great range for medium telephoto and different photographers has different shooting needs even at this same focal range. Some need IS while others need FTM while still others need wider apertures for portrait shots using the medium reach. Apparently introduced at different price points, Canon seems to be trying to cater to each and every of its customer’s needs at this very popular focal range segment. But there is a bit more than just small refinements and marketing sense that prompted the launch of the EF 70-200mm f/4.0 L IS USM lens. The EF 70-200mm f/4.0 L IS USM is an improvement over its older sibling the EF 70-200mm f/4 L USM lens. Canon has introduced the IS feature in this focal range, giving the lens up to 4 stops of stabilization against camera shake. It also has FTM and additional elements and groups which makes the lens sharper and better than the older sibling.
Weight and convenience when using for handheld shots or carrying around
Weight is one of the strongest advantage of this lens over heavier f/2.8 version. Weight wise this lens is slightly on the heavier side at 760gms (when compared with the non-IS version). Again when compared with the f/2.8 lenses of the same focal range (from Canon), this one is a good 500gms lighter. Lighter weight is perfect for photographers who plan to shoot landscapes or any other subjects handheld at the maximum focal length. It is also ideal for carrying around for long periods of time mounted on a professional body.
Features & specs
Speaking of handheld shots, the IS feature with its up to 4 steps stabilization system makes it suitable for handheld shots at hitherto impossible slower shutter speeds. The EF 70-200mm f/2.8 L IS USM lens was ideally the best lens (not considering the price factor) at this range because of the IS. However not many photographers could afford the price tag of $2000. it is way too much for most photographers to invest on a single lens. Additionally, not all the time a photographer would be shooting at a faster aperture of f/2.8 which means the full capabilities of the lens would never really be required. Thus Canon’s decision to introduce IS to its slightly slower aperture of f/4 actually makes great sense. It is affordable, does everything that the more expensive lens does and at just one stop less speed, than the expensive sibling, makes perfect choice for most photographers.
A rock solid image stabilization system is perfect for handheld shooting. An example will make this point even easier to understand. Say you’re shooting in a tricky lighting condition and the available additional lighting options is not enough; you will need a faster aperture and a commensurate shutter speed to capture the moment. At f/4 this is certainly wide and in a non-IS lens one would have to use this together with a commensurate shutter speed to perfect the shot. However, without a built in IS it is not possible to use a slower shutter speed. This is where the IS lens is so handy as it allows slower shutter speeds without any image softening. Say earlier if one could shoot with a shutter speed of 1/250th of a second one can now use a 4 stop slower shutter speed and still get a sharp picture. The convenience of this is one can achieve much better results in low light and even when hand holding the camera.
Speaking of hand holding and IS, some photographers complain that when they mount the lens and the camera system on a tripod, with the IS on, the camera sometimes shoots soft images. The reason is modern lenses with built in IS often tries to correct camera shake even when there is none. In such circumstances one could try switching off the IS and then shoot the pictures to compare the results.
For any and every lens the biggest test of its quality is no doubt the images. At f/4 the lens is very sharp at the middle and at the corners. One does not need to stop down further to increase the sharpness (and there is no real improvement either at f/5.6 or smaller). Compared with the EF 70-200mm f/4 L USM lens (the non-IS version) this lens has 2 more elements and 4 groups. However the image quality for both the non-IS and the IS versions are more or less comparable. Performance of the IS version is slightly better though at the center and at the corners from 85mm up to its longest focal length. Canon has done a great job of suppressing chromatic aberrations which are present in most lenses when shooting at extreme focal lengths. At 200mm some amount of chromatic aberration is present, though overall performance is still great. Additionally there is less vignetting in the IS than in the non-IS version (when used with a crop body) making this a better choice for shooting at f/4 and 70mm. When used with a full frame body, some amount vignetting is unavoidable and is present in this lens as well. Flares are occasional hazards and the EF 70-200mm f/4.0 L IS USM performs really well. In fact it is better than the EF 70-200mm f/2.8 L IS USM lens making this a better choice for shooting in bright sunlight.
Almost all of Canon’s L series lenses are weather sealed. If one is using a professional body such as the 5D Mark II or the mark III or the flagship 1DX these lenses are perfect for an all round weather sealed system. Weather sealing in some lenses is complete only when a UV filter is screwed on. However this lens has no such requirement.
Is it a good buy?
The EF 70-200mm f/4.0 L IS USM lens retails at a price of $1099 which means it is a good $1000 less than the EF 70-200mm f/2.8 L IS II USM. For those who don’t need a very wide aperture this is probably the best buy given the remaining specifications are nearly the same.