Blurryeyed wrote:
...100-400 IS II is a great lens, albeit heavier than either of the primes and not as sharp at either 300mm or 400mm but awfully close it is certainly more versatile.
I have both the 300mm f/4L IS USM and the 100-400 II.... and I disagree with the above statement. The 300mm f/4L is nice & sharp, but it is not quite as sharp as the 100-400 II.
The 100-400 II uses a fluorite element... the 300mm (and 400mm f/4) does not. That's probably the differences.
I agree, though, that the 400mm f/5.6 and 300mm f/4 are lighter than the 100-400mm II. That's true. They are both under 3 lb. and the 100-400 II is closer to 3.5 lb.
The biggest problem with the 400mm f/5.6 is that it doesn't have IS. It's going to be difficult to use hand held. You'll need to keep shutter speeds up to around 1/500 minimum and preferably even faster... or use it on a monopod or tripods.
I opted for the 300mm f/4L instead because it does have IS... and I often use it hand held. It's also a little more versatile, having 300mm and 420mm when I pair it up with a Canon 1.4X II teleconverter, and it''s still stabilized. It's not as versatile as the 100-400mm zoom (I almost always paired up the 300mm on one camera with a 70-200mm on a second camera). I would note too that the 300mm f/4 uses an older form of IS. In fact, it is one of the earliest lenses Canon added Image Stabilization to, in the mid-1990s, and has been in continuous production ever since. But it's one of five Canon lenses where the IS needs to be manually turned of if using the lens locked down on a tripod (or in any other way that there is no movement for the IS to correct). This is because when there is no movement, this form of IS will go into sort of a feedback loop where it actually causes movement that will effect images. All the other lenses that have this type of IS have been discontinued (the earlier EF 75-300mm IS USM, original EF 100-400mm "push/pull" zoom, EF 28-135mm IS USM and the original EF 24-105mm). Only the 300mm f/4 remains in production. It's IS is rated for 2 to 3 stops worth of assistance (the 100-400 II's IS is rated for 3 to 4 stops.. and it's the very fast, modern type as being used in all the super telephotos.)
By the time you add a teleconverter to it, the 300mm f/4 is a bit over 3 lb., so not that much lighter than the 100-400 II.
I now rarely use my 300mm f/4 (I actually have two of them, one needs repair). Mostly only when I need the extra stop of its f/4 aperture, versus the f/5.6 of the 100-400mm.
The image below was shot with 300mm f/4 with EF 1.4X II attached, wide open at f/5.6 on Canon 7D (same APS-C size sensor as T4i)...
And this shot was done with the same lens and teleconverter combo on full frame 5D Mark II, in this case stopped down to f/8 & using a monopod...
Yes, the 300mm f/4L IS USM is good sharp lens. But by the time you also get a quality 1.4X teleconverter to use with it the cost and weight are both increased significantly. The lens alone sells for $1350 and the current Canon 1.4X III costs $429... so will total very close to what the 100-400mm is selling for right now. And the 300mm + 1.4X
I haven't had the 100-400 II as long and haven't used it for a lot of wildlife/bird photography yet.... But it's actually as sharp or sharper than the 300mm f/4.... and a lot more versatile. The EF 400mm f/5.6L is probably the sharpest of the three (even though it doesn't use fluorite), and the lightest & most affordable. But lacks IS and is the least versatile.
Compare image quality yourself.
100-400mm II at 400mm versus 300mm f/4L IS USM with 1.4X teleconverter (effectively 420mm f/5.6)...
https://www.the-digital-picture.com/Reviews/ISO-12233-Sample-Crops.aspx?Lens=972&Camera=979&Sample=0&FLI=4&API=0&LensComp=111&CameraComp=979&SampleComp=0&FLIComp=1&APIComp=1100-400mm II (at 400mm) versus 400mm f/4...
https://www.the-digital-picture.com/Reviews/ISO-12233-Sample-Crops.aspx?Lens=972&Camera=979&Sample=0&FLI=4&API=1&LensComp=278&CameraComp=979&SampleComp=0&FLIComp=0&APIComp=0Note: above test images are magnified and were shot with 50MP 5Ds-R, which, of all Canon cameras is about the most demanding of lenses. You can change the camera, if you wish. But I'd recommend looking at tests done with the same or very similar cameras in each case.
Any of these options can work, make excellent images and give you 400mm or 420mm, which is important for birding in particular.
The 400mm f/5.6 is the sharpest, lightest and least expensive option, but unstabilized & more difficult to shoot handheld and not very versatile with the single focal length. You'll likely want a 70-200mm to complement it.
The 300mm f/4L with a quality 1.4X is also very good, a little heavier and more expensive, but a bit more versatile with two focal lengths and a stop larger aperture at 300mm, and with IS. Still, you will probably want a 70-200mm to use along with it.
The 100-400mm II is also very, very good and by far the most versatile (it's largely replaced my use of
both 70-200 & 300mm with 1.4X). However, it's the most expensive, largest and heaviest of the options. Except that by replacing two lenses and a teleconverter, the 100-400 II is a cheaper and lighter solution for me.