Sony DT 30mm f/2.8 SAM Macro

Available for under £160, Sony's 30mm Macro will surely appeal to photographers on a budget who would like a lens to give them a good introduction to macro photography. It is only compatible with Sony SLRs that have an APS-C sized sensor such as the Alpha A230, A330, etc.

None of the third-party manufacturers currently offer a Sony-compatible macro optic comparable on price or specification at the moment. The nearest match is Sigma's 50mm f/2.8 macro lens, which costs around £240 but offers almost double the working distance, so your subject may be easier to light when shooting at 1:1 magnification.

Sony DT 30mm f/2.8 SAM Macro: Handling and features
Weighing only 150g, this lens is very compact and lightweight indeed. Injection moulded plastics have been used for much of the construction of this lens, including the lens mount. The fit and finish is good though, with an attractive silver stripe finishing the lens barrel off nicely.

Focus is powered by Sony's new Smooth Autofocus Motor, known as SAM to its friends. Although the motor is not a silent one like their SSM lenses have, focus is quite quick at normal distances. No focus limiter switch has been provided, so if the lens struggles to lock on, it may end up tracking back and forth through the entire focus range, which takes a while.

At its closest focus distance the lens provides life-size magnification at a working distance of just two centimetres. Care has to be taken not to shade your subject from the light and getting photos at such close distances can be a challenge in itself. At the closest focus distance the lens extends by about two 2cm, compared to when it is focused to infinity. The lens accepts 49mm filters and the front filter thread does not rotate during focusing, making this lens ideal for use with polarising filters.

Overall, I really enjoyed using this lens. Its light weight means it's barely noticeable in my camera bag and the build quality is good considering the low price tag.

Sony DT 30mm f/2.8 SAM Macro: Performance
For its price, this lens puts in a very respectable performance when it comes to resolution. At f/2.8 images may appear a little soft, but things improve as the lens is stopped down, with F/4 giving good resolution across the frame. Peak performance is achieved between f/8 and f/11 where the resolution is very good from edge to edge. At smaller apertures the effects of diffraction start to soften images slightly, but the sharpness yielded at f/22 is still good.

Resolution at 30mm

How to read our graphs 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 inidication of actual image resolution. The taller the column, the better the performance. Simple. For this review, the lens was tested on a 12Mp Sony Alpha A500 using Imatest.

Levels of chromatic aberration are higher than I expected, exceeding 1.1pixel width towards the edges at f/16. This may pose a few issues, especially with high contrast images. The lens appears to perform the best in this area at around f/4, where colour fringing drops below acceptable levels.

Chromatic Aberrations at 30mm
	How to read our charts Chromatic aberration is the lens' inabiity 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 to minimize the problem, hence they usually cost more.

Fal-loff of illumination towards the corners is quite pronounced at maximum aperture as the corners of the image are 2.23 stops darker than the image centre. Stopping down to f/5.6 evens up the illumination across the frame sufficiently to not be noticeable to the naked eye.

Surprisingly for a fixed-focal length lens, this optic suffers with quite pronounced barrel distortion. Imatest recorded levels of 5.99% barrel distortion, which will be very noticeable in situations where straight lines are important and would make this lens unsuitable for copy stand work, unless you have the time to correct the distortion on each image.

Click on the thumbnails for a high resolution image
Life-size magnification is possible, but you are very close to your subject at the lens' closest focus distance.	With a short focal legth such as this more background tends to show making it more difficult to isolate your subject.

Due to the simple optical construction of this lens, it is very resistant to ghosting and flare. Strong point sources of light in the frame may cause a slight loss of contrast, but only in extreme circumstances. Light sources outside of the frame barely pose a problem at all in most cases.

DxOMark provides objective, independent, RAW-based image quality performance data for lenses and digital cameras to help you select the best equipment to meet your photographic needs. Visit the DxOMark website for tests performed on the Sony DT 30mm f/2.8 SAM Macro.

Sony DT 30mm f/2.8 SAM Macro: Verdict
Overall, this is a very interesting lens, especially when its price is taken into consideration. It offers a macro solution that is capable of producing images of very good quality, so long as it is used within its limitations.

Those photographers looking for a budget introduction to macro photography with their Sony digital SLR should be very pleased with the performance and value this lens offers.

Sony DT 30mm f/2.8 SAM Macro: Pros
Lightweight
Compact
Capable of very good results
Excellent value for money

Sony DT 30mm f/2.8 SAM Macro: Cons
Short working distance can be a challenge to work around
Barrel distortion
Chromatic aberrations may be visible in high contrast images

FEATURES
HANDLING
PERFORMANCE
VALUE
OVERALL

Sony DT 30mm f/2.8 SAM Macro: Lens specification

Price	£159
Contact	www.sony.co.uk
Filter size	49mm
Format	APS-C
Construction	6 elements in 5 groups
Angle-of-view	50 degrees
35mm equivalent focal length (on APS-C body)	45mm
Internal focusing	No
Image stabilisation	No
Minimum focus	12.9cm
Maximum aperture	f/2.8
Minimum aperture	f/22
Weight	150g
Size	45x70mm
In the box	Front and rear lens caps

The Sony DT 30mm f/2.8 SAM Macro costs around £159 and is available from Warehouse Express here:

Sony DT 30mm f/2.8 SAM Macro

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