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The new Canon EF 400mm f/2.8L IS III and 600mm f/4L IS III Super-tele Lenses

The new Canon EF 400mm f/2.8L IS III and 600mm f/4L IS III Super-tele Lenses

What’s New: Canon EF 400mm f/2.8L IS III and 600mm f/4L IS III Super-tele Lenses

By: Rudy Winston

October 11, 2018

EF 400mm f/2.8L IS III and EF 600mm f/4L IS III

The new EF 400mm f/2.8L IS III and EF 600mm f/4L IS III are a clear statement of Canon’s commitment to the EF lens series, and this article discusses their innovative features in detail.


The Canon EF 400mm f/2.8L and 600mm f/4L lenses have been mainstays among high-end users for sports, action, wildlife, commercial shooting, and so on for decades.  For 2018, Canon has totally redesigned both, making them by far the lightest Canon lenses ever in these important focal length and speed categories.  And, these lenses bring other new features to telephoto users, broadening their potential reach beyond just major sports and photojournalism users.


A Commitment to Weight Reduction

While a super-telephoto lens providing full-frame coverage with apertures as wide as these will never be tiny, given the general laws of optics, what Canon engineers have done in these Version III lenses is nothing short of remarkable.  Without reducing image quality, these new lenses have managed to lose substantial weight, transforming the ways they can be used and opening them up to areas where previous versions were simply regarded as too heavy to be considered.

EF 400mm f/2.8L IS III:  6.3 lbs. (2840g) — approx. 2.2 lbs. (1 kg) lighter than Version II

EF 600mm f/4L IS III:  6.7 lbs. (3050g) — approx. 1.9 lbs. (850g) lighter than Version II

A total optical redesign, along with a brand-new mechanical structure and barrel design, have teamed up to trim the weight of these two lenses significantly.  At the time of their announcement (September 5, 2018) these are the world’s lightest autofocus 400mm f/2.8 and 600mm f/4 super-telephoto lenses for full-frame cameras in the industry, according to Canon Inc. research.  We’ll detail some of these changes shortly.

EF 400mm f/2.8L IS III and EF 600mm f/4L IS III

A host of innovative design changes, from optics to electronics, have resulted in the world’s lightest-weight 400mm f/2.8 and 600mm f/4 AF lenses for full-frame cameras, as of the time of their announcement (September 5, 2018). Most important to demanding Canon customers, the outstanding optical performance of their predecessors is preserved in both Version III lenses.


What This Means to Canon Photographers

But the net result is something beyond mere weight specifications.  Until now, lenses like the EF 500mm f/4L series, and recently the EF 200–400mm f/4L IS 1.4x, were considered the way to go by advanced photographers who needed to combine telephoto power with portability and ease of operation (especially for monopod use).  Motorsports, action-type wildlife imagery, birds in flight, and similar subjects were historically often considered areas where the 400mm f/2.8 and 600mm f/4 designs were simply too bulky or difficult to handle to be widely used. 

Now, with weights under 7 pounds (3.2 kg), the latest Version III 400mm f/2.8 and 600mm f/4 lenses rival — and actually in some cases undercut — the weight of what had been industry standards for portability and telephoto power.  While we’re certainly not saying the traditional 500mm f/4 and 200-400mm f/4 designs don’t merit strong consideration from users who need mobility, consider the following:

Canon EF 400mm f/2.8L IS III — 6.3 lbs. (2840g)

Canon EF 500mm f/4L IS II (current version) — 7.03 lbs. (3190g)

Canon EF 600mm f/4L IS III — 6.7 lbs. (3050g)

Canon EF 200–400mm f/4L IS 1.4x — 7.9 lbs. (3620g)

Remarkably, these two long, fast lenses, often previously considered too heavy for easy following of fast-moving subjects (or too bulky and heavy to be carried into the field for wildlife and nature work) are now lighter than the 500mm f/4 and 200–400mm Canon designs.  Canon professional and high-level enthusiast users now can utilize the added f/2.8 speed of the 400mm Version III lens, or the combination of added reach and f/4 max. aperture of the 600mm Version III, to exceed the capabilities of lenses previously considered standards for high-end users in the above-mentioned fields.


A Totally New Optical Approach

In previous EF super-tele lenses, Canon’s design was based on several large-diameter lens elements being positioned toward the front of the lens — including two extremely important Fluorite elements.  While this isn’t the forum to detail the benefits of Fluorite and Canon’s long-term, industry-leading use of this outstanding optical material, rest assured its presence has been a key factor in the tremendous optical performance of previous generation Canon super-telephoto lenses.

However, putting large diameter optical elements at the front of the lens meant two by-products:  more overall weight, and the weight tended to be toward the front of the lens.

For the 400mm and 600mm Version III lenses, Canon has taken a radically different approach, but one that preserves the optical benefits of Fluorite.  Now, two smaller, lighter weight Fluorite elements are placed much farther back, in the narrower mid-section of the lens.  Combined with a Super-UD (Ultra-low Dispersion) glass element farther back in the optical system, the result is superb correction of chromatic aberrations, but in a significantly lighter design.  The optical changes alone result in approximately a 1.5 lb. (700g) weight loss for the Version III 400mm f/2.8 lens, and about 1.3 lb. (600g) reduction for the Version III 600mm design.

EF 400mm f/2.8L IS III and EF 600mm f/4L IS III

Highlighted here are the vital pair of fluorite lens elements (in a single optical group, along with one optical glass element), which are key to the spectacular image quality in Canon super-telephoto lenses like the 400mm f/2.8L and 600mm f/4L designs. In this pair of cutaway images, the reduction in size and weight of this three-element group (highlighted in red) in the new Version III design is obvious, as well as their relocation much farther into the middle of the lens. The 600mm design is nearly identical.


And, by moving the heaviest optical elements further toward the rear of the lens, the balance is much better as well.  In fact, the heaviest optics are now positioned directly above the lens’ tripod mount.  This is something that will be especially valuable to users who need to move the lens to follow moving subjects — motorsports is one obvious example.  Simply stated, the Version III lenses are noticeably less front-heavy, and along with significant weight reduction, means handling is far superior.  Photographers who work with gimbal-type tripod heads, and particularly monopods, are in for a treat with these two new Version III lenses.


Air Sphere Coating (ASC)

In addition to Canon’s extensive multi-coating of lens elements throughout the optical design (Super Spectra Coating, or SSC), Canon engineers have added Air Sphere Coating to the front surface of the 13th optical element.  This addition applies to both the 400mm f/2.8L IS III and 600mm f/4L IS III lenses.

Flare in back-lit situations was never a problem with previous versions of the EF 400mm f/2.8L IS and 600mm f/4L IS lenses, but the addition of ASC now provides an additional measure of protection for photographers who shoot in heavily backlit conditions, or with bright specular light sources in the frame.  ASC is particularly effective at reducing internal reflections for light rays striking directly into the lens, at an angle parallel or near-parallel to the optical axis (an imaginary line drawn through the center of the lens, directly to the imaging sensor).


New, Lightweight and Heat-resistant Lens Barrel

Canon engineers didn’t stop at a redesigned optical system.  The entire mechanical design of these new 400mm and 600mm super-teles has been restructured as well.

The outer barrel is a completely new, lighter design — but one created with two goals in mind:

•     Lighter weight
The barrel is thinner, but a new carbon-reinforced magnesium alloy provides a very high-strength design

•     Improved heat resistance
A two-layer barrel design (think of a “double wall” construction, with air space between the two layers) minimizes the transfer of external heat from prolonged exposure to sunlight and other potential heat sources.  And, a new type of white paint with increased infrared reflection properties is used, further minimizing heat build-up during long outdoor shooting sessions in sunlight.  This same heat-shielding coating is used on the lens hoods for the Version III lenses as well.

EF 400mm f/2.8L IS III and EF 600mm f/4L IS III

This cutaway graphic highlights the new barrel design of the EF 400mm f/2.8L IS III and 600mm f/4L IS III. Its thinner, double-layer construction is clearly visible, and points of contact between the outer and inner barrels — where heat from sunlight can directly transfer into the lens — are intentionally limited (two are highlighted here in red). For added strength, the barrel is now composed of carbon-reinforced magnesium.


New Image Stabilization

Yet another area where Canon lens designers have enhanced the shooting experience for photographers with these new Version III super-tele lenses is their optical Image Stabilization.  Both lenses have a redesigned IS mechanism, which is lighter than the one used in the previous-generation lenses — contributing to the overall reduction in total lens weight.  And, combined with a new lens electronic system and central processing unit, both lenses now offer up to 5 stops of shake-correction for still-image shooting (based on CIPA-standard industry test procedures, using an EOS-1D X Mark II camera).

Photographers who want to see the continuous effect of stabilization will notice even greater steadiness with the 5-stop shake correction active, when looking through the viewfinder.  And for photographers who want the effect of stabilization in their still images, but who prefer not to have a constant stabilization effect be visible in the viewfinder, IS Mode 3 will provide exactly that.  Actual stabilization only kicks in when the shutter button is fully depressed, but the lens is actively detecting shake and processing the stabilization needed continuously, so it’s ready to instantly apply stabilization during shutter operation.  The operation and effects of IS Mode 3 are not new or unique to the Version III super-tele lenses, but it’s a setting some users aren’t completely familiar with, so we’re repeating it here.


Lighter-weight, Electronic Manual Focusing

Here’s yet another change from the previous Version II 400mm f/2.8L IS and 600mm f/4L IS designs — manual focusing is performed electronically, rather than via a direct-coupled, mechanical design.

First of all, this change to electronic manual focus is yet another area where weight is saved — fewer mechanical components are required, and the existing AF drive system can be leveraged to move the focusing optical group when the photographer manually turns the lens’ focus ring.

The entire lens electronic system, including the central processing unit, is redesigned in the Version III lenses as well.  One by-product is the way manual focus is performed.  As the lens’ manual focus ring is rotated, a detection system very finely assesses the rotation direction and rate. It converts that into electronic signals which then cause the Ultrasonic Motor (same motor used for autofocus) to move the single lens element that varies focus in both the 400mm and 600mm designs.

A further result is that users can now vary the manual focus rotation “speed,” or sensitivity, using a 3-position switch on the side of the lens barrel.  A given amount of rotation of the manual focus ring can result in a small change in actual focus (think of it as a “fine” focus adjustment), a standard rate of change at the #2 setting, or a “fast” setting with significant change as the focus ring is rotated.  Users are free to adjust this according to personal preference, or depending on the types of scenes or subjects they’re photographing.

EF 400mm f/2.8L IS III and EF 600mm f/4L IS III

The primary switch panel on the side of the two Version III super-tele lenses is shown here. At the bottom is the Manual Focus Speed switch, with three positions to vary the sensitivity of rotation of the manual focus ring — a direct benefit of the change to electronic manual focusing. The Focus Preset feature, described below, uses its own controls on this same switch panel.


Sharp-eyed users who know Canon’s EOS history will recall that Canon’s first-generation EF super-tele lenses, without Image Stabilization, used a similar electronic manual focus design (and had a similar 3-position “focus speed” switch on the side of the lens).  While the new lenses use a totally different internal system to detect focus ring rotation, and there are no mechanical “brushes” to wear or accumulate dirt or dust, the overall concept is somewhat similar — albeit much more refined on the Version III Image Stabilized lenses.

Just to be clear, the 3-position “focus speed” switch has absolutely no impact on autofocus performance, and you most assuredly will not get “faster” AF performance by changing the position of this switch!


A Canon First:  TWO Focus Presets can be Memorized

Focus preset is another feature Canon users have seen since the first-generation EF super-tele lenses, without Image Stabilization, appeared in the late 1980s and very early 1990s as the EOS system was initially launched.  Focus preset basically lets the user focus upon a pre-determined subject or distance, memorize that distance with the push of a button, and then the user can immediately return to that memorized setting by turning a thin, spring-loaded metal ring on the lens.  This can be done whether the lens had been in AF or manual focus.

An obvious example is something like pre-focusing on 2nd base or home plate in a baseball game.  The photographer can then either manually or autofocus upon any other parts of the field, but if something happens at the place he or she memorized, a quick and very slight turn of the thin metal Playback Ring on the lens immediately jumps focus to that memorized distance.

With the Version III 400mm f/2.8L IS  and 600mm f/4L IS lenses, Canon has responded to user requests and now two different distances can be memorized.  Each is set independently, and each is applied to one specific rotation direction of the spring-loaded Playback Ring.  To repeat the example given above, a photographer shooting baseball could pre-focus and memorize 2nd base from his or her shooting position, press the Focus Preset button, and then immediately turn the Playback ring in a clockwise direction until a beep is heard (meaning the preset distance has been memorized by the lens).  Then, they could repeat the procedure, now focusing on home plate (or any other position on the field), and turn the Playback ring counter-clockwise until a beep is heard.  Once that’s been set, the user can quickly return to the latter position by a slight turn counter-clockwise, and to the first position with a clockwise turn of the Playback Ring.

Of course, the applications of this can extend beyond a baseball field.  Wildlife photographers can pre-focus upon a spot where animals or birds might be expected to appear.  Birds-in-flight shooters could pre-focus on a nest, anticipating a mature bird returning there from flight.  Another effective use of focus preset is to set a distance where a photographer could quickly return if his or her autofocus suddenly was fooled and thrown off by foreground subjects, or if AF suddenly begins to “hunt” because of momentary lack of detail at the actual AF point during continuous focus.  (For instance, a football shooter could pre-focus on the middle of the field, and if his or her AF was suddenly thrown off, they could quickly return to a normalized focus distance with a quick turn of the Playback Ring.)


Now Equipped with the 52mm Drop-in Screw Filter Holder

Because of the large diameter of the front elements of these super-telephoto lenses, for many years filter attachment has been through a metal, drop-in holder at the rear of the lens, rather than attempting to locate an overly large accessory front filter.

The Version III 400mm f/2.8L IS and 600mm f/4L IS are now equipped with a 52mm Drop-in Screw Filter Holder 52 (WIII), which includes a clear, 52mm filter already attached.  With the entire Drop-in holder removed, this can be unscrewed from the holder, and replaced with different standard 52mm screw-in filters (as long as their metal rings are not too thick in size).

Previous versions of the Canon EF 400mm f/2.8L IS and 600mm f/4L IS have included a Drop-in Gelatin filter holder, which included a flat piece of optical glass, and a snap type, hinged metal frame that could be lifted…a pre-cut (by the user) photographic gel filter could be laid over the flat optical glass, and then the metal frame lowered and clipped in place to secure the gel filter.  (Up to 3 pre-cut gelatin filters could be installed simultaneously.)

With the Version III super-tele lenses, users can buy the Drop-in Gelatin Filter Holder 52 (WIII) or a Drop-in Circular Polarizing Filter 52 (WIII) as optional, separate accessories.  The latter has its own external ring to rotate the polarizing filter, with no need to remove the holder from the lens.

Just to clarify, regardless of which Drop-in 52mm Filter Holder is used, a flat glass filter is required, and is considered part of the lens’ optical system.  Canon strongly recommends against using no filter, or shooting with no Drop-in Filter Holder in-place.

Filter Holder

The Drop-in Screw Filter Holder 52 (WIII) is now the included filter with both the 400mm and 600mm Version III super-tele lenses (previous versions of the EF super-teles included the gel drop-in filter holder). It includes a clear 52mm, screw-in filter — which can be easily replaced with other standard 52mm screw-in filters. Separate drop-in filter holders for user-cut gelatin filters, and a dedicated circular polarizer are also available, as optional accessories. The “(WIII)” indicates these have the same new white coating as the Version III lenses.


A Canon Super-telephoto First — a Soft, Portable Case Included

The EF 400mm f/2.8L IS III and 600mm f/4L IS III lenses will now come factory-equipped with a completely new, soft case.  This speaks loudly to the new portability of the Version III lenses, and offers a much lighter and more practical way to personally carry or transport the either lens.  This case is padded throughout, has a prominent hand strap on its top, as well as a single, large strap (similar to one strap on a backpack) to allow easy carrying over a photographer’s shoulder.

Soft, Portable Case Included

The included soft case for the 400mm f/2.8L IS III and 600mm f/4L IS III emphasizes portability. There’s a separate version for the 400mm and 600mm lenses, and each has a wide, padded shoulder strap at the rear of the case.


The hard polycarbonate shipping case, previously included with past versions of Canon’s super-telephoto lenses, is now an optional accessory for the Version III 400mm and 600mm lenses.  This hard case is definitely the way to go for shipping either lens, or if the lens has to be flown as checked baggage on airlines.  The included soft, portable case is a preferred choice for actual hand-carrying and transporting to and from shooting locations where actual shipping isn’t involved.


Other New Accessories

Several other accessories, included or optional, are noteworthy — especially to Canon owners who are considering stepping up to either of these lenses from previous EF super-telephoto lenses:

dedicated lens cap

The 400mm and 600mm lenses each have a dedicated lens cap included. For the first time, this cap can be installed over the lens hood (as shown here); with the lens hood reversed; or over the front of the lens alone, when a hood is not being used. The E-180E cap for the 400mm f/2.8L IS III is shown here; the 600mm f/4L lens uses the slightly larger E-185C lens cap.


carbon-fiber lens hood

The Version III lenses ship with a standard, detachable carbon-fiber lens hood (ET-155 [WIII] for the 400mm, and ET-160 [WIII] for the 600mm). A new short lens hood is available as an optional accessory, for use in confined situations where a hood is still desirable, but shorter lens length is required — such as when working in a crowd of spectators or other photographers at an event. These short hoods are Lens Hood ET-155B (400mm version), and ET-160B (600mm version). Each is about half the length of the standard hood.


tripod mount

As with previous versions of Canon’s EF super-telephotos, the latest Version III lenses are equipped with a long, standard tripod mount (shown here, with its black cushion for carrying the lens). This mount has both 1/4-20 and 3/8-inch tripod mount sockets, for attachment to most monopods and tripod heads. New to the Version III lenses is the option to have Canon’s service department install a short monopod mount (service fee required). This smaller, lighter mount further enhances the already excellent portability of these lenses, and directly targets photographers who primarily work with monopods.



What Hasn’t Changed

Just as important to working professionals is what hasn’t changed in these new 400mm and 600mm lenses.  Among the features carried over in the Version III lenses:

•     Weather-resistant design
Like the previous Version II lenses, these new 400mm and 600mm lenses are gasketed and sealed against moisture throughout the lens barrel, at the switches and switch panel, and lens mount.  Their level of weather-resistance matches that of Canon’s top-of-the-line EOS-1D X camera series.

•     IS modes 1, 2 and 3
We discussed earlier that the entire Image Stabilization system in the Version III lenses has been upgraded, and both now provide up to 5 stops of stabilization for still images (vs. about 3.5 stops in the Version II lenses).  The new lenses continue to provide a 3-position switch on the side of the lens barrel, allowing different stabilization operation during shooting.  As before, Mode 1 is for general shake-correction, especially for monopod operation.  Mode 2 is specifically for intentional panning or following moving subjects, such as birds in flight, or motor sports — stabilization occurs for any camera/lens movement that’s perpendicular to the direction of panning.  And Mode 3 provides optical image stabilization at the instant of actual exposure, but does not actively stabilize when viewing through the finder, in between shots.  Some photographers find it easier to keep erratically-moving subjects composed within the frame when IS is not actively trying to limit camera movement.

•     AF Stop buttons on the lens barrel
Four buttons, positioned 90° apart, in front of the focus ring and metal Playback Ring.  Press any of them during AI Servo AF, and focus is momentarily locked (ideal for photographers who use the shutter button for AF activation, and need to halt AF because of a foreground obstacle or similar problem).  With most EOS cameras, these can be customized to perform a different function.

•     Power focus mode
Intended for smooth video focus transitions, sliding the 3-position AF-PF-MF switch on the side of the lens to the “PF” position lets users turn the Playback Ring to very smoothly drive focus in either direction (toward infinity, or toward closest focus distance).  Two drive speeds are available…the faster speed is by turning the spring-loaded ring farther to the left or right.  This is completely manual focus, so it’s up to the photographer to stop focus drive when he or she has reached a desired focus distance.

•     Security slot
Here’s a feature we had in the previous-generation EF super-telephoto lenses, and many users didn’t even know it was there.  The adjustment knob for rotating the tripod collar doubles as a socket for attaching a (commercially available) security cable, for situations where a photographer may be in a fixed position for prolonged periods, and occasionally needs to leave the camera and lens unattended.  The types of cables used to lock laptop computers can be attached into the socket, that’s hidden under a flip-up cover on the adjustment knob (see illustration, below).  Obviously, such cables have limits on the level of security they can provide, but they can discourage quickly grabbing an unattended camera in some situations.

Security slot

•     Fluorine coating on outer lens surfaces
The front and rear-most surfaces of the lens are additionally treated with fluorine coating (not to be confused with fluorite lens elements, discussed previously!).  This coating resists moisture and dust, and especially on the large-diameter front lens element, makes cleaning much easier.


Tele Extender Compatibility

The EF 400mm f/2.8L IS III and 600mm f/4L IS III are compatible with Canon’s EF Version III 1.4x and 2x tele extenders. 

With these new super-tele lenses, Canon engineers specifically do not recommend use of previous Canon-brand extenders (either the original EF 1.4x and 2x extenders, or the Version II tele extenders).  While these older extenders can be physically attached, Canon cannot guarantee AF or operational reliability.



Canon’s “big white lenses” have been a foundation of the line’s professional presence, and for decades have been a fixture among Canon’s highest-end customers.  The latest, third-generation EF super-teles with Image Stabilization bring new levels of performance and incredibly lightweight designs to the EF lens system.  Even with the exciting advent of Canon’s EOS R mirrorless system, and the outstanding series of initial Canon RF lenses for it, these EF super-telephotos are a clear and definitive statement from Canon engineers and product planners that the EF system remains a vital element of Canon’s strategy to put professional-grade tools into the hands of our most demanding customers.