Currently, after much readings, I'm pretty sure that Tamron have alot of issues with low light focusing + slow inaccurate AF. Really not sure how the sigma version fare...And no lens rental shops I've seen rent this Sigma 17-50 OS lens. It would be great if can rent to try first...at least my heart won't be so confused/lost.
Personally, I'm not very particular about IQ (e.g. Chromatic distortion, Barrel Distortion etc) as I don't pixel peep that much (I only "peep" if I crop too much). Well, the few times I complaint about the IQ of photos is
- when using my tele zoom (55-250) on the far end (250mm) in the Singapore Zoo, where it gets really soft and the flaws of the lens starts to show (esp in lesser light. overcasts and FURRY CREATURES!). *Heck, I didn't even notice the CA on my 18-55..if there's any, probably due to the blessing that I've yet to seen a L in action*
- Too high ISO (e.g. 1600) used and the photo turned out noisy but aperture already at wide open on that lens (e.g. 18-55 @ 55mm f/5.6).
Stuffs that I've noticed for quite sometime already is, for my kit 18-55 f3.5-5.6, most/many of my shots are done at the both ends (18mm and 55mm), aperture wide open at high ISO of 800-1600. Stuffs that I shoot under these conditions are like objects/food photos in a restaurant like environment.
Many times my shots (candid shots) turn out underexposed (even @ ISO1600), this is leading me to believe that I need a lens with wider aperture as I believe that using flash will "kill" off the ambiance, still I will use my ext.flash if ambiance light is really not enough). At the same time, I find prime lens abit restrictive for my liking (that said, my only prime lens experience is with my 50 f1.8, which wasn't exactly what I would call pleasant).
Below are some examples of what I considered to be low light...
*Indoor Candle Light*
*Indoor Hotel wedding dinner table shot*
*Outdoor Night lantern*
*btw, low light landscape will not be taken into consideration for this lens, cos I will be on tripod and "any" lens that have the required focal length will do. Focusing wise, at the most MF lor...not very hard on tripod, but I find it a challenge when handholding it and MFing at the same time*
I guess the burning question now is
- do I need the f/2.8 or it's just my camera's ISO limit. My heart was pretty much going in for the Sigma 17-50 cos of the OS and f2.8. But yet at the same time confused which is the problem.
- Will the AF of Sigma "hunt" in this kind of lighting? The last thing I want is the AF keep hunting when I want to do a group photo in lighting like in shot #2
i'm currently looking at body. there is only how much u can get with 1600 at 2.8 (in my experience). sure a good lens is nice to have, but how much more light can it allow? sometimes higher iso is really the only solution apart from tripodding the shot.
I think I understand that there is always a limit to what 1600 @ f2.8 can achieve. But I think probably I'm just hoping that some "magic" appears in the math formula. I wonder if this is one reason why many start picking up primes lens.
If there is a reason why I picked up Sigma 17-50 this time, I think it will be under the impression that it's AF works in low light as compared to tamron's hunting AF in similar conditions.
Since u are using 500D, a better lens will be good. Bare in mind, f2.8 will has shallow DOF.
Picture taken wif Sigma 17-50.
Last edited by SamTac; 24th September 2011 at 12:36 AM.