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12-24-2007, 11:15 AM   #1
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Sigma 30mm 1.4 DG HSM

Anyone have any experience with this lens? Gets good reviews but seems quite large and heavy ................. I use a K100D.

Actually, it is the 'EX DC HSM 30mm 1.4' lens..........sorry.

Last edited by John Kovarik; 12-24-2007 at 11:33 AM.
12-24-2007, 06:12 PM   #2
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I have bought this lens a few months ago but I don't use it much. It's not a bad lens, it's just not very well suited to my shooting. Wide open, the lens is sharp in the middle and rather soft at the edges. When stopped down to f/5.6 it becomes very sharp in the center of the field but the edges never attain perfect sharpness. The lens has a very pleasant roundness in rendering the out of focus areas. Alas, it also tends to exhibit bad purple fringing around every light source or specular reflection in the picture. Even when stopped down to f/8, a tree photographed against a bright sky would have its leaves surrounded by an ugly purple halo.

This mixed-bag performance makes the lens not very appealing to me. It's not well suited for architecture and landscape work or street photography because of the soft edges and purple fringing. It could be usable for portraiture or photographing social gatherings but only for centered subjects with controlled lighting to avoid purple fringing.

Instead of the Sigma 30/1.4, I would recommend the Pentax FA 31/1.8 Limited or, cheaper, the FA 35/2. Both lenses are smaller that the Sigma and offer better image quality, or at least image quality more even across the board.

12-26-2007, 05:37 PM   #3
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To illustrate my point, here are some sample photographs taken with the Sigma 30/1.4. Please note that this is not a scientific test, but I think it's a fair reflection of the lens performance as I see it.

Wide open (full picture resized). Even when scaled down, the purple fringing remains visible.

Wide open (left side detail - 100% size)

Wide open (upper right corner - 100% size). Image is quite soft in the corners.

F/5.6 (full picture resized)

F/5.6 (left side detail - 100% size). F/5.6 but still some purple fringing

F/5.6 (upper right corner - 100% size). Image is still not very sharp in the corner.

The Sigma 30/1.4 is not a bad lens: it has very good performance in the center of the frame and great bokeh. It is just not very well suited to my style of photographs.


Last edited by Abbazz; 12-26-2007 at 07:37 PM.
12-27-2007, 03:39 PM   #4
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Look at photozone

Have a look on the test of this lens at
THis lens is tested vs other Pentax lenses, results are balanced. Sharp on the center, weak at the edges, CA is present.
The alternative is to invest in the 31mm f1.8 limited. Costs money but everybody agreement to declare is as a great lens.


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