Wildlife Lenses: telephoto-zoom round up

Introduction

Wildlife lens quality compared with the whole database

A quick glance through a couple of makers’ catalogues (or our database) will confirm the plethora of 70-300mm f/4.5-5.6 zoom lenses available. These aren’t particularly fast, and while there are a number of 28-300mm f/3.5-5.6 lenses, the variable maximum aperture will likely be in the same f/4.5-5.6 range over the 70-300mm focal lengths, so there’s nothing to be gained in speed (brightness) for available light.

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We can see from the DxO Mark Score results for our whole lens database plotted on the graph above that, even for primes, it’s very difficult to achieve the same image quality at 300mm than it is at shorter focal lengths. As an example, take Nikon’s two recently introduced 85mm lenses. Both have a higher DxO Mark score than the new $6,600 Canon EF 300mm f/2.8L IS USM (we’ve yet to assess the Nikon AF-S NIKKOR 300mm f/2.8G ED VR II). In fact, the pricey $2,000 AF-S Nikkor 85mm f/1.4G was recently ousted by the newer, cheaper AF-S f/1.8G version.

For those that are interested, we’ve adopted the DxOMark Score system instead of the recently introduced P-MPix metric, as that’s calculated under optimal/ideal shooting conditions. DxOMark Score, on the other hand, is measured according to our low light scene (150 lux and an exposure time of 1/60thsc), a more realistic metric for lenses intended for capturing elusive wildlife.

As the DxOMark score is an average of the whole focal range, zooms with a wide-range could be artificially higher in the ranking. For wildlife, the image quality at 300mm or greater is what we’re particularly interested in, but as images may be captured at any focal length, we believe the average DxOMark score is still relevant for ranking one lens above another. Even so to see how a particular zoom lens performs at a specific focal length, then the reader should check the DxOMark score map.

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The difference in image quality of zooms, and even primes, tails off with an increase in focal length. Incidentally, with a very good score of 18, sitting at the top of the green ‘column’ at 300mm is the Pentax smc DA Star 300mm f/4 ED IF SDM telephoto.

If money is no object, then the Canon EF300mm f/2.8L lenses easily outperform the more versatile 70-300mm f/3.5-5.6 zooms, and can be paired successfully with 1.4x and x2 teleconverters, or extension tubes (to reduce the minimum focus distance) adding to the flexibility. Adding teleconverters to 70-300mm f/3.5-5.6 lenses is possible but with the loss of one to two stops, autofocus operation is likely to be impaired or even impossible. The other downside is the effect teleconverters have on image quality. At 300mm, the optical performance of telephoto zooms will be at its lowest, and adding a teleconverter,    or multiplier will only make this more noticeable. Our graph above shows the results for full-frame cameras, but APS-C cameras deliver slightly lower scores, however the ranking is very close.

Top 5 wildlife zoom (full frame)

Lens DxOMark Score
1 Canon EF 70-300mm f/4-5.6L IS USM 18
2 Nikkor AF-S VR Zoom Nikkor 70-300mm f/4.5-5.6 G IF ED 17
3 Nikon AF Zoom Nikkor 70-300mm f/4-5.6 D ED 17
4 Sigma 70-300mm F4-5.6 APO DG MACRO Nikon 16
5 Sigma 70-300mm F4-5.6 DG OS Nikon 16

With a DxOMark Score of 18.6 on a full frame Canon EOS-1Ds Mk III, the $1,600 Canon EF70-300mm f/4-5.6L IS USM is the best performing full-frame telephoto zoom in our database, closely followed by the more affordably priced $600 Nikon AF-S Nikkor 70-300mm f/4.5-5.6G IFED VR with a score of 17.1 when tested on a D3X. In third position is the direct predecessor to G-series Nikon lens that’s ranked second in our scores. Unfortunately, it is no longer available to buy new although it can be picked up secondhand at around $150 (note this is a Japanese made ED version – a non ED version was also made).

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At maximum aperture and set to 300mm, the Acutance map (above) reveals the Canon EF 70-300mm f/4-5.6L is sharper across the image field than either Nikon model. In fact, the older AF-D-type Nikon lens is sharper at 300mm than the AF-S (G-type) version that replaced it. That’s all fine and well, but most wildlife photographers won’t be using full-frame bodies with full frame lenses, they want the intrinsic advantage of a narrower field of view that APS-C cropped cameras give.

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Although APS-C cameras use the sweet spot of full frame lenses, the acutance is influenced by the sensor and is slightly lower for each model. When measured with an 18-Mpix EOS 7D, the acutance of the Canon L-series zoom is still ahead of the two Nikkor lenses when paired with either the 12-Mpix D300s, or 16.2Mpix D7000.

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When we compare the Acutance maps for the two Sigma lenses on the Nikon D300s to the Canon EF 70-300mm f4-5.6L IS USM, tested on the Canon EOS 7D, the drop is quite apparent. However, the Sigma results can be improved slightly with the higher-resolution Canon EOS 7D, though not to the same level as the Canon optic. At this point, it’s worth bearing in mind the price difference between these.

While we’ve no hesitation in recommending the L-series Canon as a long-term investment, the Sigma APO Macro can be picked up for around one 1/8th of the price at $200, while the DG OS version is dearer at around $360, because of the Optical Stabilization function. Both Sigma lenses appear to be a good value proposition, although the sharpness isn’t that great at 300mm on either. One other lens that is intriging is the $200 Canon EF 75-300mm f/4.5.6 III USM. Like the Sigma APO Macro version, it lacks image stabilization but it has above average image quality for this type of lens.

Image quality vs money  – 3 cheap lenses that provide an interesting image quality

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Value for money ranking (in yellow above): 1 – Canon EF 75-300mm f/4-5.6 III USM, 2 – Sigma 70-300mm f/4-5.6 APO DG MACRO Canon, 3 – Sigma 70-300mm f/4-5.6 DG OS Nikon

Performance summary of other lenses in our database

Although the following lenses have a lower average DxOMark score, we’ve summarized the overall performance of the lens on an APS-C body, as well as the sharpness characteristics at 300mm.