@Liz22012 wrote:
Help....Canon ef 24-70mm f/4l is usm lens vs 24-105 f/4l is usm?
I shoot a lot of barns and landscapes. Not sure if I should upgrade from myCanon EF-S 15-85mm f/3.5-5.6 IS USM Lens .
The EF-S 15-85mm is one of the sharpest, most versatile and compact lenses available for Canon APS-C cameras, such as your 7D Mark II. It's main drawbacks are a relatively high price and variable aperture (f3.5-5.6). The price obviously isn't an issue for you, since you already have it. The variable aperture is of little or no concern for the type of photography that you say you want to do with it.
There would be little to be gained and potentially a lot to be lost by instead going to one of the full frame capable lenses with your present camera. In one case you'd be losing focal length range both at the wide end and the tele end, and in the other case losing out at the wide end with only a slight gain at the tele end.
I think you may be the very first person I've ever seen or heard refer to the 15-85mm as "sometimes soft". Frankly, I'd look to your techniques, rather than blame the lens. While faulty lenses aren't unknonwn, it's pretty ulikely and the 15-85mm is considered by many to be one of the sharpest lenses available. Have you got a "protection" filter on it that's compromising your image quality? Do you have and regularly use the lens hood with it? Do you use a tripod? Do you usually try to stop it down a little for optimal image quality? The only slight "issue" sometimes observed with the 15-85mm is a little chromatic aberration that tends to mostly occur at either the wider or more tele focal lengths.... but is very easily corrected in post-processing (even by some automatically applied lens profiles, such as Lightroom uses).
The 24-70/4L IS is a very high quality lens and might slightly out-resolve the 15-85mm at a few of the focal lengths they share... but not by much. And, seriously, is it enough difference to be worth giving up the 15 to 23mm and the 71 to 85mm ranges? Stop the 15-85mm down to f5.6 and it's image quality should rival any L-series.
The older 24-105L IS has been a venerable and versatile full frame capable lens, but has it's faults too. I don't think it will be as sharp as the 15-85mm or 24-70. And it has some fairly strong optical vignetting at the 24mm end. It also loses the 15 to 23mm focal lengths, though it gains 86 to 105mm. To me, the wide end in particular would be more valuable for landscape/architecture photogrpahy, such as you want to do.
The EF-S 15-85mm is also considered one of the best built of the EF-S series lenses. The 24-70/4L might be a little better sealed. The 24-105/4L actually might be about equal to the EF-S 15-85mm.
Note: No EF-S lens is an "L-series", nor will one ever be. Canon's definition of what constitutes an "L" makes it impossible. One of their three criteria is that "an L-series lens must be compatible with and usable on all EOS cameras past, present and future". EF-S lenses are not. They are limited to use on APS-C crop sensor digital cameras only. So, no EF-S lens can ever get the red stripe of an "L"... But this doesn't mean that an EF-S lens can't rival "L" performance... and the 15-85mm is one of several that do (EF-S 10-22mm, EF-S 17-55mm and EF-S 60/2.8 Macro are some others).
Which brings us to one other thing... Your EF-S lens is only usable on APS-C crop sensor cameras, while either of the EF lenses could be used on a full frame camera such as 6D or 5D Mark III (or the new 5DS). For architecture/landscape a full frame camera might be a desirable upgrade to eventually consider (7DII is a great camera and capable of many things, but especially excels at sports/action shooting).
However, if you ever go to a full frame camera, for architecture in particular you also might want to check out the TS-E "Tilt-Shift" lenses. Canon offers17/4L, 24/3.5L II, 45/2.8 and 90/2.8 TS-E lenses... and the first three, in particular, are especially ideal for architectural photography. These are manual focus lenses, but all are highly corrected and have lens "movements" that can be used to correct for keystoning and other optical effects when shooting buildings, as well as means of controlling the plane of focus in interesting ways.
Frankly, if it were me, I'd stick with the 15-85mm for use on the 7DII and only reconsider the other lenses if changing to a full frame camera, too.
***********
Alan Myers
San Jose, Calif., USA
"Walk softly and carry a big lens."
GEAR: 5DII, 7D(x2), 50D(x3), some other cameras, various lenses & accessories
FLICKR & EXPOSUREMANAGER
