Nathan Troutman
Active member
Have you looked at that compatible lens list? There's quite a few options there. I don't think the pentax can be modified but there are a couple of pentax lenses (the 55mm I think) that are OK. The Olympus OM 50/1.4 is a good one too.
The sigma is f/2.8-4.5 This seemed to be the best price on ebay- http://cgi.ebay.com.au/ws/eBayISAPI.dll?ViewItem&ssPageName=STRK:MEWAX:IT&item=360163368339
There's a huge library of pics taken with it on flickr. Don't know how it compares to the Tamron but if you google I'm sure you can find out.
This lens wouldn't be the best choice for the 5D because of this: "DC lenses are exclusively designed for digital SLR cameras. The image circle (rear of lens) is made to match the smaller dimensions used for the image sensor on digital cameras. As a result these lenses are also more compact and lightweight, and are better matched to digital SLR cameras."
With Sigma, DC lenses are made for smaller sensors not full-frame sensors like the 5D.