Tamron SP 24-70mm f/2.8 VC USD

Tamron SP 24-70mm f/2.8 VC USD Performance

At maximum aperture and 24mm, sharpness in the centre is already approaching excellent levels and the clarity towards the edges of the frame is good. Stopping down improves performance across the frame and peak clarity is achieved between f/5.6 and f/8 where resolution across the frame is outstanding.

Zooming to 35mm results in very similar performance at maximum aperture, which centre sharpness approaching excellent levels and good clarity towards the edges. Sharpness towards the edges doesn't improve as quickly when stopped down at 35mm, with peak sharpness being achieved at f/8.

Finally, at 70mm, overall sharpness is reduced a little, but clarity in the centre at maximum aperture is still very good. Towards the edges resolution drops down to fair levels at maximum aperture, improving as the lens is stopped down. Again peak quality across the frame is achieved at f/8, where resolution is excellent across the frame.

MTF @ 24mm

MTF @ 35mm

MTF @ 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 5D Mark II using Imatest.

Chromatic aberrations are well controlled throughout the zoom range, thanks to Tamron's use of LD glass in the optical design. Fringing is most prevalent at 24mm and maximum aperture. Fringing of 0.7 pixel widths should not pose too many issues, even in images with high contrast edges towards the peripheral areas of the frame.

CA @ 24mm

CA @ 35mm

CA @ 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 5D Mark II using Imatest.

Falloff of illumination towards the corners of the frame is very pronounced. At 24mm the corners are 2.9 stops darker than the image centre and at 70mm the corners are 2.5stops darker. Stopping down to f/5.6 results in visually uniform illumination across the frame throughout the zoom range.

Distortion is very well controlled throughout the zoom range. At 24mm only 1% barrel distortion is present, which is replaced with 0.02% pincushion distortion at 70mm. If straight lines are paramount, then you'll be pleased to learn that the distortion pattern is uniform across the frame, making it relatively easy to correct in image editing software afterwards.

During testing, there were very few issues with flare and ghosting, even when shooting into the light. A petal shaped hood is supplied with the lens, which does a reasonable job of protecting the front element from extraneous light that may cause issues. However, there is one small caveat. Contrast is noticeably reduced when shooting at maximum aperture increasing as the lens is stopped down past f/3.5.

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