View Full Version : Sigma 18-50mm f2.8 lens 4/3
15-03-11, 08:49 PM
Is anyone using this lens or does anyone have any history with it? I have and use a 70-200mm f 2.8 (140-400mm in 4/3) and I find it to be remarkably sharp with very crisp detail. I was wondering about the shorter zoom.
Yes, I have used this lens on Four Thirds - it's nice in that it's 2.8 through the range, but it's not as sharp, especially wide open, as any of the Zuikos.
Mine is very sharp at f4.
Indeed, the lens does sharpen up by f/4, but if it's soft at 2.8, then I wonder what the point is of having a lens that offers that aperture? The saving grace for the Sigma 18-50 is that it's an inexpensive and affordable lens and is a an interesting choice instead of a kit standard zoom.
Think you answered your own question there Ian.
Imo its better than any standard kit zoom.
I thought lenses were designed to be at their sharpest halfway through the aperture range.
Ive had an expensive nikon zoom lens and that was not super sharp at 2.8.
I think to say there is no use having a 2.8 zoom lens unless its sharp at 2.8 is a bit daft.
You can be alot more creative than with a standard kit zoom and take shots in alot less light when required.
The Sigma 18-50 does indeed, get sharper as you stop it down. But the modern trend for lenses in digital cameras is to be sharp wide open. The cheap Olympus Zuiko Digital 14-42mm (28-84 equiv) standard kit lens, for example, which is a much more modern design than the Sigma, is almost at its sharpest at full aperture, and is sharper than the Sigma throughout the range. The Zuiko is also better at controlling vignetting and CA. Photozone.de gave the 18-50 3/5 stars and the 14-42 4/5 stars.
There are some truly bad standard kit lenses out there. The Sony 18-70 is one, and the original Canon 18-55 is another (though the revised 18-55 IS versioin is much improved). The Nikon 18-55 is not bad.