Hi Everybody,I want to buy a lens for my 400D.I am confused between the 17-55 IS F2.8 & 17-85 IS F4-5.6 & Tamron 17-50 F2.8.I know that the EF-17-55 is the best one but it is very expansive.the EF 17-85 is good but I am concerned with shooting in low light conditions.So my question is the following: --------------------------------------------1-did anyone used this EF 17-85 in low light conditiond (like Cathedral) (No flash)? and what was the outcome??.....was it good?2- is the Tamron 17-50 F2.8 good for this low light conditions?Any advise is welcomed

17-85 is perfectly good for indoor shots. Here are a couple of samples taken inside an Abbey. ISO 1600, F7.1, 1/13 & 1/25 sec.One inside a castle - ISO 200, F4, 1/8 sec

I do not have any of these lens but let's try some computation ... for 17mm you can hold (without IS or mono/tripod) about 1/30s, then you get 5+3-2=6EV (for 1/30s+F2.8+ISO400). I think it is enough for a brighter cathedral, it would be 5-6EV scene there. And you have enough DOF (from 2.4m to 63m) while focusing on 5m. So Tamron 17-50/2.8 is so-so len for the cathedral on its wide end, I think.Canon 17-55/2.8 IS is without any problem (4EV gain due to the stabilization).And Canon 17-85/4-5.6 IS: for 5EV scene you need shutterspeed equivalent to 5+2(ISO400)-4(F4)=3EV what is 1/8s, you should be able to hold it with the IS. For 85mm focal length it is 5+2(ISO400)-5(F5.6)=2EV what is 1/4s, the IS should safe 4EV minimally, I do not think it is so effective in the 17-85 len (the IS is about 2EV ?). Maybe ISO1600 is better for the long end...

can you please send me one of these pictures with high resolution to my e-mail walidadas@yahoo.com..I want to check the sharpnessthank you

Dunno of if this helps, but here:http://www.pbase.com/richt1/image/59667844and/or here:http://www.pbase.com/richt1/image/59667842.IMO opinon.......... after several years of using this lens ......... it's a terrifically versatile lens. I usually prefer longer and faster lenses shot as wide open as possible, and if I had a regret about this one, it would only be that, for DOF purposes, it's a relatively slow lens so it's often optically impossible to get a certain look I'd like, but have never regretted this as my first lens for this camera. The IS ion it is a terrific advantage, btw.

Done

I'm wrestling with a similar issue. For me it's 17-55 f/2.8 IS or 24-105 f/4.0 L IS. I too want to do dim interiors, but I also will use the lens as a walkaround.I was at the Philadelphia Museum of Art recently, and met a young woman carrying a 20D with the 17-85 f/4-5.6 IS. She loved that lens for museum work. Her technique was to set ISO 1600, turn IS on, and take pictures. Personaly, I think she was too enthusiatsic about the 17-85 for dimly-lit interiors.Here's why. I just came from another art museum (Princeton University). Their painting and sculpture galleries are dimly-lit. At ISO 800 and f/4 typical shutter time was 1/3 to 1/20 seconds. Even with a 3 stop IS, 1/3 sec is too slow. I had to go to ISO 1600 for some shots. For me, 1600 is for "emergency only"--too grainy. Yes, at f/4-5.6 you'll be able to get pictures in that gallery, but it's marginal. They often won't look as good as from a faster lens.Like you, I'm concerned that the 17-55 f/2.8 is not long enough outside the museums and cathedrals. At this point, I think I'm going to stay with the slightly slower but wider zoom range 24-105 f/4. It just works in a dimly lit museum, but it's a much better walkaround.If dark interiors are the main reason for buying your new lens, and you can afford it, you should go with the f/2.8 17-55. If not, buy something else and expect varying success--sometimes very good--with a slower lens. -- JerryGSee my galleries at: http://www.pbase.com/jerryg1

The 17-85's range is wonderful as a walkaround lens. However, it is not a low light lens. Yes, you can get decent cathedral interiors with it, but they'll be somewhat noisy and have geometric imperfections.IF you anticipate needing ANY low light capability with any subject movement at all, then just get the 17-55 f/2.8 and be done with it. It's IQ is much superior to the 17-85's in all respects and it is much, much sharper.I have both, and since getting the 17-55, I have only rarely used the 17-85, and have kept it solely because I love it's range and low weight. I'm now thinking of selling it.kopper -- -- http://www.kopperhead.com http://kci.outlander.homelinux.net/CurrentIndex.html http://kci.outlander.homelinux.net/archive.html