24-70 or 24-105

[flyrccg]

Thinking about upgrading my 70D to a 5D mk III. on ebay, I found that I can get a 5D body for $2300 or 5D/24-105L for $2600. I already own a a 24-70 2.8L and dont know which one I would sell and which one to keep.
I understand that the 24-70 is better but I dont know why.

 

[bratkinson]

Shortly after getting my 60D (and 2 years ago, a 5Diii), I got a 24-105 f4L. Perhaps 2 months later, I also bought a 24-70 f2.8L mark 1 (the mark ii was still a year in the future). In my experience, with these senior citizen muscles, I decided the 24-105 was the keeper and sold the 24-70. I preferred the longer zoom range of the 24-105 and it's IS. With the capabilities of the 5Diii, f4 is no problem whatsoever.

The attached shot (JPG SOOC) was taken at 1/160, f4, ISO 25,600, hand held, moving subjects, in a totally dark room with the 5Diii/24-105 f4L. My limited Lightroom expertise with the RAWs didn't come out as well! <edit> I forgot to mention, manually focused as not enough light for the AF.

 

[enerlevel]

Depending on what you shoot... if you take plenty of still pics, go for 24-105.. the IS helps alot. If you have shaky hands and shoot around 1/100 or lower, go for 24-105...
If you shoot moving objects in low light, then I would suggest 24-70

Also you can buy it and try it .. if you don't like it, I am sure you can sell it for more than $300

 

[TCampbell]

It depends on what you want to do with the lens. The optics in the 24-70 are better than the 24-105. Also it gathers a full-stop extra light -- when trying to freeze action that means you can double the shutter speed (or halve the ISO). It does not have image stabilization.

If you want one lens as a standard general-purpose zoom and you don't own a 70-200mm then the 24-105 will probably be better for that use.

I have the 70-200mm and that's the lens that lives on my camera most of the time. I prefer to stand farther away and get the advantages of a longer focal length (compression, depth of field, background blur, etc.) So while tend to not use the focal lengths below 70mm very often. Given that situation... I opted for the 24-70 f/2.8 because when I do need something less than 70mm, it's probably not for general-purpose shooting and I prefer the f/2.8 focal ratio.

Image stabilization isn't as important at lower focal ratios. The lower the focal length, the easier it is to hand-hold a camera at slow shutter speeds and still not have blur caused by camera movement.

But if you do not own a 70-200mm then I suspect you'll prefer the 24-105 range.