Sigma vs Tamron

I was thinking of getting the Sigma 18-250mm DC OS HSM because it would replace 2 lenses, the 18-55 and 70-300 Tamron I have, but the more I look in to it the more I wonder am I doing the right thing, the shop I'm buying it from will give me the full value back for my Tamron as I only bought it from them a couple of weeks, they are both compared here link

If I get it I will need to order it tomorrow so any advice would be welcome

I've never used the Sigma 18-250mm, but I have the 18-55 kit lens and 70-300 Tamron (albeit it 4-year old versions of them). When these were the only two lenses I owned (because I bought them with the camera), I found myself needing to change over lenses all the time, and usually at an inconvenient moment when my subject wouldn't wait for me. At the time I would have killed for an 18-250mm lens, and I'm still wondering if I should get one. These days I have the same issue with the DA*16-50mm and DA*50-135mm lenses - I've got better at using my legs, and on pre-visualising the kind of shots I want to take (and therefore ensuring I get the right lens on there to start with).

EM

My original dSLR kit was the K20D, 360AF, DA10-17, DA18-250, and FA50/1.4. I now use a Tamron 10-24 more than the DA10-17, but otherwise that's still my most-used kit, 210+ lenses later. I've tried a two-lens kit of DA18-55 and Tamron 60-300 but such just interferes with all my shooting in the 30-70 range. I hate swapping lenses at 50mm.

I can't comment on the Sigma 18-250 other than to repeat hearsay of QC problems. I *can* heartily recommend the DA18-250 or its Tamron twin, both out of production but still available. The DA18-250 is my basic lens; all my others are specialty tools. If I know what I'm getting into, I'll use those specials. If I expect uncertainty, it's the DA18-250.

For IQ check out my gallery on here.

I use a Tamron 18-250 as a walkabout/holiday lens and have not been dissapointed.

As for the Sigma, sorry I can't help you there.

I've ordered the Sigma lens, been up since 6:30 reading reviews of that and other lenses in that range it seems to fair well, I will see when it arrives