Architect1776 Loc: In my mind

I have the original 24-105 L posted here and it is a very good lens.
If you don't need the L ruggedness get the STM one as it is much quieter than the USM lens. The STM is video centric and provides very smooth accurate focus when doing video.

nadelewitz Loc: Ithaca NY

Another difference is the L is a USM that offers FULL-TIME manual focusing ability without switching it off of AF setting. If you use BBF (back-button focus), you have full freedom of focus method.

Incidentally, not all USM lenses offer full-time seamless manual focusing. Only the ones with a focusing scale in a window. Or at least one new lens, the 70-300 USM, with an LCD display replacing the focus-scale window.

canon Lee

I own a 24-105 F4 because I wanted a fixed aperture at all zooms.

Architect1776 Loc: In my mind

ALL USM have manual full time focusing. What ones don't?

nadelewitz Loc: Ithaca NY

The ones that don't have focusing scales in a window or digital display. Manual focus with lens set on AF is not as simple.

Canon says so.

amfoto1 Loc: San Jose, Calif. USA

The 24-105mm f/4L II lens has a continuous, non-variable aperture.... If you set it to f/4 and zoom, it will be at f/4 throughout the range of focal lengths. The other lens' aperture will vary depending upon focal length, unless it's set to f/5.6 or smaller (while that lens is 1/3 stop "faster" at 24mm, f/5.6 is one stop "slower" than f/4, at 105mm or if set to f/5.6 for the full range).

The 24-105mm f/4L II lens uses faster "USM" or "ultrasonic" focus drive. In fact, it's one of several recently introduced models that use what Canon calls "Nano USM" focus drive, which is both fast like USM and quiet/smooth like STM. Previous to introducing that, you'd choose STM lenses for their quiet/smooth operation (and lower cost) for video... or USM lenses for their faster operation. I haven't seen any claims and comparisons from Canon regarding the speed of focus in the 24-105s... but their EF-S 18-135mm lens that are identical aside from coming with both versions of focus drive, they say the USM lens is 2X to 4X faster focusing than the STM version.

The 24-105mm L-series lens also should be better sealed for weather resistance. One also might expect an L-series to be more durable. However, these are things that are really only proven out over time and with extensive use, and these lenses just haven't been around long enough to say for sure. The older, original version of the 24-105mm f/4L was NOT any more durable than the far less expensive EF 28-135mm IS USM (which "felt" less well made, but actually had equally good image quality, IS and autofocus performance).

The 24-105mm f/4L lens also has a 10-blade aperture diaphragm, which should make for nicely round aperture throughout the range. The 24-105mm STM lens uses a 7-blade aperture which may not give quite as nice background blur effects. HOWEVER, an even number of blades makes for "sun stars" with the same number of points, so the L-series lens would render 10-point stars. Odd number blades make for double that number of points on stars, so the STM lens would render 14-point.

Based on what you mention liking to shoot, you also might want to check out the Canon EF 24-70mm f/4L IS USM lens. It's also an L-series, with the quality build and added sealing that implies. But it's smaller and lighter than the 24-105mm. It's also incredibly close focusing for those flower shots. It's able to shoot slightly closer than 8" and render .70X magnification (nearly 3/4 life size). This is much higher magnification than either of the other lenses can do. In fact, it's nearly triple the .24X magnification maximum of the 24-105L and more than double the .30x possible with the 24-105 STM lens.

Sure, it might be nice to have the additional focal length between 70mm and 105mm.... but that depends upon what other lenses you already have. For example, if you already have and use a 70-200 or a 100-400, the 24-70mm might be a fine addition.

EF 24-105mm f/4L IS USM........ $1100
EF 24-70mm f/4L IS USM........... $900
EF 24-105mm f/3.5-5.6 IS STM... $600
EF 28-135mm f/3.5-5.6 IS USM... $150-$250 (used)

There actually ISN'T any or very much difference in terms of "FTM" or "Full Time Manual" focus (as Canon calls it). Both USM and STM lenses allow that. The only difference is that the STM lenses are "fly-by-wire", which means they need to be powered up to be able to manually focus them (but you DON'T have to turn off the AF at the switch first, the way you do with micro motor lenses... which are NOT "full time manual" capable). When an STM lens is off the camera or when the camera is turned off or "asleep", turning its focus ring on does nothing. In contrast, with MOST of the USM lenses there's a mechanical focus linkage, so the focus ring WILL effect manual focus any time, whether the lens is on the camera or not and whether or not the camera is turned on or "awake". However, a FEW of the USM lenses are also fly-by-wire (EF 85mm f/1.2L II is one example). I don't have, so don't know whether or not the 24-105mm f/4L IS "Nano USM" is also fly-by-wire. I haven't seen any comments suggesting that it is, so I suspect it's not.

BTW, if you want a particularly low cost alternative, check out the recently discontinued Canon EF 28-135mm I mentioned above. Like the STM lens, it's a variable aperture (also f/3.5-5.6), and it doesn't "feel" as well built as the L-series lenses. However, it's far, far cheaper and makes just as good images with IS equal to and USM focus drive just as fast as that of the original 24-105L, in spite of being a carryover from the days of film. I think Canon might have discontinued it last year because it was still too competitive with lenses costing 2X or 3X as much! The 28-135mm can easily be found used for under $250... often even under $200. I've known several pros who chose the 28-135 over the original 24-105, simply for the savings. The 24-105L "II" does offer better IS and quieter/smoother USM, but isn't much different in terms of image quality. One thing, the 28-135mm isn't particularly close focusing.... if I recall correctly, it can only do about .21X on its own (but like any lens, it can be fitted with one or more macro extension tubes to render higher magnification).

If you'd like to do some comparisons and read more detailed reviews of any of these lenses, I recommend you check them out on Bryan's website at The-Digital-Picture.com He has highly magnified test shots done with all of them, which can be compared side-by-side under the "image quality" tool. For example:

There you can see how any two lenses compare at different focal lengths and aperture settings (be careful to choose the same camera for comparison... or at least as close as possible to the same... a 50MP 5DS-R will be much more "critical" of a lens than a 21MP 1Ds Mark III... and shouldn't mix full frame with APS-C either, since the latter will "crop" away the corners and edges of the images... choose whichever format you use for both lenses in the comparison).

amfoto1 Loc: San Jose, Calif. USA

Sorry, but that isn't true of the 24-105L "II" which the original poster is asking about. The "II" uses the new "Nano USM" focus drive, which is BOTH quiet and smooth like STM and fast like USM.

It is true, if comparing the original 24-105L USM with the STM lens. Just not with the "II".

I don't think whether or not a lens has a focus scale display is directly related either. It just so happens that STM focus drive is most often used in lower cost lenses that also don't have a focus scale. On the other hand, USM is mostly used in more upscale lenses that do have a focus scale. In the four I listed above... all three of the USM lenses have a focus scale.... the STM lens doesn't.

Architect1776 Loc: In my mind

Ok mine were easy.

whlsdn Loc: Colorado

Thanks once again, amfoto1. Canon lens school right here. If I can keep the letters and numbers straight, that's going to help me with some decisions.

Oh...any quick thoughts on the EF-S 18-200mm 1:3.5-5.6 IS and the EF-S 55-250mm 1:4-5.6 IS II? I've put the first on my granddaughter's Rebel T6, and I've just gotten the second to alternate on my 60D with the Tamron SP AF Aspherical XR Di LD IF 28-75mm 1:2.8 Macro. Love the Tamron so far. Haven't really tried the 55-250 yet.

Bipod

Flowers and old barns are completely different. If you are asking for the best gear:

Close-up of flowers: macro lens and ring flash.

Old barn or buildings: large format film view camera with sharp, contrasty prime lens
Acoma Pueblo, NM (US National Archives):
https://www.archives.gov/files/research/ansel-adams/images/aaa01.jpg
https://www.archives.gov/files/research/ansel-adams/images/aaa03.jpg

I need a new vehicle. Can you please suggest a good compact racing dump truck? I need to haul gravel,
tow a boat, win the Pebble Beach Road Race, and get the kids to soccer practice. Great mileage is a plus.

whlsdn Loc: Colorado

Hey, Bipod, can I interest you in a converted motorhome? Is Pebble Beach a drag race? The RV has a hopped up 900 hp front diesel, so it hauls OK in a straight line. Curves, not so much...though it can cut across off-road well. Tow a dump trailer or the boat trailer. It looks a little rough and is a bit pricey, but is a bit of a hybrid, so one should expect that, right?