canon 24-105 f/4 or sigma 17-50mm f/2.8 OS

which one to buy for my APS-C camera..my field of interest is portrait and sometimes landscape....

comments will be much appreciated

If your interest is in landscape then the 24-105 on your APS-C is 38mm at the wide end which is hardly a landscape lens. The Tamron is more suited for landscape and I have heard good things about that Tammy. Also, the Tamron is slightly faster but I don't know how decent it is at 2.8.

You already have a 17-55. Do you use the wide end? If you get the 24-105 you will basically lose having any really wide focal lengths and gain more telephoto. That might make sense if you plan to use it alongside your 17-55 (although there are other choices that give you more reach if what you want is telephoto) otherwise the 17-50 Sigma is basically a direct replacement for the lens you already have.

We can't tell you what to get but your experience with your lens should tell you whether you need another one like it (maybe the one you have broke or you want a better quality version of the same sort of thing) or whether you need the longer 24-105. I know nothing about the Sigma 17-50, maybe it's a decent lens but I do like the 24-105. I just wouldn't pair it with a 1.6 crop camera personally.

I just sold my Canon 17-55 f/2.8 to get a 24-105. I needed something that I could use on my 1D3, as I'd like the option to use all lenses on all bodies. I honestly think I may need to get something wider down the road too, but the 24-105 looks to me like it will be a great lens for the things I like to shoot. The IQ is impressive, other than the distortion, which can be corrected in post.

While most landscape shots are taken with shorter focal lengths, don't think for a second that you can't shoot landscape longer as well. Here's a shot I quickly found with the 24-105 on a 1.6 crop:
http://thedigitalstory​.com …0651_picture_st​yle_lg.jpg

That said, the Sigma you are considering is a great lens as well. I don't think you can go wrong either way, but you might appreciate the longer reach of the 105, and keep the kit lens around for when you need it (I'm betting yours is actually 18-55, not 17-55). If you buy the 24-105 used, you can sell it for very little loss in a year or two, no problem, when you're ready to upgrade and/or split to two lenses.

Do you have a 17-55 or 18-55 at the moment? My guess is the latter as you've called it a kit lens. On a crop I'd get the the 17-50, much more useful range and 2.8

similar discaussion in another thread: https://photography-on-the.net …/showthread.php​?t=1276085

For the same price as a 24-105 you can get a used tammy 17-50 non-VC and 85/1.8 - giving a great portrait lens for a cropper and a wide enough lens for landscape with much better image quality than what you have now.

timbop wrote in post #15616740
similar discaussion in another thread: https://photography-on-the.net …/showthread.php​?t=1276085

For the same price as a 24-105 you can get a used tammy 17-50 non-VC and 85/1.8 - giving a great portrait lens for a cropper and a wide enough lens for landscape with much better image quality than what you have now.

I think the 18-55 IS ii is really similar to the Tamron, in optical quality. It's sharper in the center. With the Tamron, you gain the 17 on the wide end (5%), and f/2.8. But you lose 10% of your focal length on the long end. http://www.the-digital-picture.com …omp=0&FLIComp=3​&APIComp=1

waterrockets wrote in post #15616794
I think the 18-55 IS ii is really similar to the Tamron, in optical quality. It's sharper in the center. With the Tamron, you gain the 17 on the wide end (5%), and f/2.8. But you lose 10% of your focal length on the long end. http://www.the-digital-picture.com …omp=0&FLIComp=3​&APIComp=1

Have to say I disagree. My wife has a rebel with an 18-55IS, and the tammy is a much better lens. I shot weddings for 2 years with the tammy, and it's a very good lens. The fact that it's a constant f/2.8 is a bonus. 5 mm on the long end is irrelevent.. it's a minor crop. Adding pixels on the wide end is a lot harder to do

timbop wrote in post #15616828
Have to say I disagree. My wife has a rebel with an 18-55IS, and the tammy is a much better lens. I shot weddings for 2 years with the tammy, and it's a very good lens. The fact that it's a constant f/2.8 is a bonus. 5 mm on the long end is irrelevent.. it's a minor crop. Adding pixels on the wide end is a lot harder to do

I haven't used the Tamron, but looking at the resolution comparisons, I'd say they are comparable at the same aperture. Certainly you are going to get more compelling images with the Tamron in many situations with the much shallower DoF at the long end, and the ~1 stop aperture advantage. Given the choice, I'd much rather use the Tamron than the kit lens.

My point is that while the Tamron is f/2.8, it's not as crisp as the Sigma or Canon 17-50/55 models. But, as you state, its price allows the purchase of the 85 f/1.8, which would be a great lens to have. I'm not knocking the Tamron, but more giving credit where due for the great little 18-55 kit lens, in spite of its small aperture on the long side.

bryjosh9385 wrote in post #15616335
which one to buy for my APS-C camera..my field of interest is portrait and sometimes landscape....

I would suggest the Sigma 17-50 f/2.8 OS EX DC HSM for your types of photography. Very handy focal length range. Sharp lens second only to the Canon EF-S 17-55 f/2.8 IS USM. You might also consider the Canon 85mm f/1.8 as your next upgrade.

Yogi Bear wrote in post #15617371
I would suggest the Sigma 17-50 f/2.8 OS EX DC HSM for your types of photography. Very handy focal length range. Sharp lens second only to the Canon EF-S 17-55 f/2.8 IS USM. You might also consider the Canon 85mm f/1.8 as your next upgrade.

I have to second the Sigma, but from what I've read it actually exceeds the sharpness of the 17-55 f/2.8 IS by a small amount in the center, while falling behind slightly at the edges and corners. It's so sharp at f/4 that it will exceed the resolution of the 50D's sensor, based on Photozone's testing.

Stopped down even only a little (to f/4), the Sigma goes from being very sharp to cut-your-finger sharp. It's a fantastic lens for general purpose use, which includes portraits and landscapes.


Example landscape shot with the Sigma:

IMAGE LINK: http://www.flickr.com/​photos/n2185x/69355265​56/