Sigma 28-105mm f2.8-4 mini review

Picked up this lens from Park Camera recently and as it seems fairly uncommon I thought I'd post some thoughts here.

I found the lens buried in the middle of Park's large used equipment list. I don't think it was even in the Pentax section! I didn't know much about this lens but i thought for £49 even if it was average I should be able to resell it without losing any money. I was pleasantly surprised!

It's sharp wide open in the middle of the zoom range, slightly less sharp wide open at the short and long ends of the range. It sharpens up nicely at all focal lengths when stopped down one stop or so. It's f2.8 until around 35mm, f3.5 until around 70mm, f4 to 105mm.

The only real flaw that I have found so far is significant barrel distortion at 28mm, probably quite easy to correct but still a hassle. A lesser problem is that it also loses a bit of sharpness at 105mm - it's still good, but not as good as it is at 70mm. This copy also suffers from slight zoom creep when pointed directly downwards. It also has a 72mm filter thread which seems unnecessarily large when compared to the size of the front element. Other than the filter size it is similar in size to my Tamron 17-50 (perhaps 10% smaller and lighter).

All in all I'm quite pleased with it considering the price. I'm hoping it will be useful as a candid portait lens at parties etc.

A couple of pics:

That was a good find, good price.