Canon EF 24-70mm f/4L USM Lens Review

Handling and features
Performance
Verdict
Specification


This new entry to Canon's L-series of lenses covers the popular 24-70mm focal range. As it has a constant maximum aperture of f/4 it is available at a lower price than the latest 24-70mm f/2.8 lens and also includes image stabilisation technology to allow sharp images to be hand held at lower shutter speeds.

With its relatively slow maximum aperture of f/4 and price tag of around £1270 this lens may appeal to those who don't necessarily require an f/2.8 aperture.

Canon EF 24-70mm f/4L USM Handling and features

The design and build of this lens is typical of Canon's L series, with tough black plastics and metal used throughout. The lens is sealed against dust and moisture and designed to take the rigours of daily professional use. Even with the excellent build quality, thanks in part to the constant f/4 maximum aperture, this lens only weighs 600g, and it balances perfectly with the Canon EOS 6D used for testing.

An Ultrasonic motor powers autofocus and focusing is very fast as a result. Manual adjustments can be made quickly at any point by turning the focus ring. The focusing ring is smooth, precise and well damped, which makes fine manual adjustments easy to apply. A switch on the side of the lens engages a macro mode to allow closer focusing and the lens can focus even closer than the 38cm marked on the distance scale. This function can be incredibly useful for taking frame filling shots as the zoom range isn't limited.

As focusing is performed internally, the 77mm filter ring does not rotate, which makes the lens ideal for use with graduated and polarising filters.

The image stabilisation system fitted to this lens promises to allow sharp images to be taken at shutter speeds four stops slower than would be possible without the system enabled. Sharp images can be produced around half the time with shutters speeds as low as 1/10sec at 70mm, which is roughly three stops slower than the usual rule of thumb would dictate neccessary.

Canon EF 24-70mm f/4L USM Performance

At 24mm, sharpness in the centre of the frame is already outstanding at f/4, but the quality towards the edges of the frame falls behind somewhat, just falling short of good levels. Stopping down the aperture improves sharpness towards the edges of the frame with excellent clarity across the frame being achieved between f/8 and f/11.

At 50mm, the same pattern emerges, with very high sharpness in the centre of the frame at maximum aperture, accompanied by lacklustre performance towards the edges of the frame. Very good sharpness is achieved across the frame between f/8 and f/11 for this focal length.

Zooming to 70mm results in better performance across the frame on the whole, even at maximum aperture. Peak clarity across the frame is achieved at f/8 for this focal legth where sharpness is excellent in the centre and outstanding towards the edges of the frame.

Resolution at @24mm

Resolution at @50mm

Resolution at @70mm

How to read our charts The blue column represents readings from the centre of the picture frame at the various apertures and the green is from the edges. Averaging them out gives the red weighted column. The scale on the left side is an indication of actual image resolution. The taller the column, the better the lens performance. Simple. For this review, the lens was tested on a Canon EOS 6D using Imatest.

Chromatic aberrations are reasonably well controlled, just exceeding three quarters of a pixel width at f/4 at either extreme of the zoom range. This low level should cause very few issues, even in large prints and harsh crops from the edges of the frame.

Chromatic aberration at 24mm

Chromatic aberration at 50mm

Chromatic aberration at 70mm

How to read our charts Chromatic aberration is the lens' inability to focus on the sensor or film all colours of visible light at the same point. Severe chromatic aberration gives a noticeable fringing or a halo effect around sharp edges within the picture. It can be cured in software. Apochromatic lenses have special lens elements aspheric, extra-low dispersion etc. to minimize the problem, hence they usually cost more. For this review, the lens was tested on a Canon EOS 6D using Imatest.

Falloff of illumination towards the corners of the frame is quite pronounced for a lens with a maximum aperture of f/4. Here the corners of the frame are 2.04 stops darker than the image centre and illumination isn't visually uniform until the lens is stopped down to f/8. Falloff is slightly less pronounced at 70mm. Here the corners are 1.82 stops darker at f/4 and illumination is visually uniform by f/6.3.

Distortion is pretty well controlled for a lens of this type. At 24mm 2.07% barrel distortion is present, which is replaced by 0.704% pincushion distortion at 70mm. The distortion pattern is uniform across the frame, which should make applying corrections in image editing software afterwards relatively straightforward.

Even without the supplied petal shaped lens hood, resistance to flare is high and contrast remains excellent, even when shooting into the light.

Canon EF 24-70mm f/4L IS USM Sample Photos

Value for Money

Canon's current trend for high prices accompanying newly released lenses hold true with this optic. The price of around £1270 is what many would reasonably expect to spend on a lens with a maximum aperture of f/2.8 before Canon began refreshing their lens range.

Canon's other standard zoom with a maximum aperture of f/4 puts the current price of this lens into perspective. Their 24-105mm f/4 IS USM offers the same f/4 constant maximum aperture, but over a longer zoom range and for a shade under £700. The price of Canon's latest 24-70mm f/2.8 lens has now dropped to around £1690 also.

Tamron's stabilised 24-70mm f/2.8 VC USD may also be considered. This lens can be picked up for around £860 and sports optical stabilisation, a similar silent focusing motor and weather sealing.

Those on a budget, who require a lens covering this range may also consider Sigma's 24-70mm f/2.8, which can be picked up for around £600. This lens lacks the weather sealing found on the Canon lens but sports a similar silent focusing motor and a faster f/2.8 maximum aperture.

Canon EF 24-70mm f/4L USM Verdict

Again Canon have launched a lens at a relatively high price point for what it offers. Still the performance in the centre of the frame, useful macro feature and lighter weight due to the f/4 maximum aperture may still have enough appeal for photographers who are put off purchasing an f/2.8 24-70mm either due to the weight, price, or lack of necessity for an f/2.8 maximum aperture. If the price drops even a little in time, I'm sure this lens will be a very popular one.

	The Canon EF 24-70mm f/4L lens has good build quality and performs well.

Canon EF 24-70mm f/4L USM Pros

Excellent sharpness throughout the range in the centre at maximum aperture
Good build quality
Relatively lightweight
Reasonably low distortion

Canon EF 24-70mm f/4L USM Cons

Quite expensive for a lens with an f/4 maximum aperture
Sharpness at 24mm towards the edges of the frame falls behind performance in the centre of the frame

FEATURES
HANDLING
PERFORMANCE
VALUE FOR MONEY
OVERALL

Canon EF 24-70mm f/4L IS USM Specifications

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