I have the Tamron SP 17mm, and it's okay--best stopped down around f:8 or so. I had the Tokina long ago, and the Tamron seems a bit sharper, but neither is really fantastic. The build quality on the Tamron is a little better, and the earlier version has built-in filters, which are handy for B&W. The later version, which I have, requires a hood that has threads for filters and is usually lost, and as I recall, it takes very large filters, like 82mm, but check before taking my word on that. I usually just use 3" gels in a clip on filter holder that also has barn doors to act as something of a shade. The Tamron is also an Adaptall II, so you can use it on various camera bodies. The original Adaptall II-EOS mount is something of a rarity, but it's just a solid metal adapter, and you can find Chinese knockoffs on eBay that are perfectly usable. You may even be able to find one that is chipped for EOS, which will give focus confirmation on bodies that offer that feature (not sure if that applies to any film bodies).