100-400mm vs. 70-300L for basically the same exact price used? Which one?

[neuroanatomist]

what about the 300 f4 IS with 1.4 tC compared to 100-400 and the 400 f5.6?  Basically I love the flex of a zoom but I know that primes have better IQ so I am trying to minimize IQ loss and purchase a zoom.  I think a prime at that range wouldn't see as much use all around, besides I can always rent.

I went through the same decision process some time back, and picked the 100-400mm.  At 400mm, I'd rank the IQ as 400/5.6 > 100-400 > 300/4+1.4x.  I don't think it's a generally good idea to get a lens plus TC and plan to use it with the TC primarily - TCs are for occasional use.  I picked the 100-400mm over the 400/5.6 because of the IS (not needed for fast-moving subjects, but for static subjects with an f/5.6 lens at 400mm, having IS can be a big help), and also for the flexibility of the zoom.

[MARKOE PHOTOE]

I'm fortunate to own both and have used both in similar situations.  The 70-300L is extremely light, focuses fast and is tack sharp.  The 100-400 has a longer reach, is considerably larger, heavier and focuses much slower.
Neither of these lenses function well with a teleconverter from Canon or Kenko.

I used both of these for active sports outdoors and both served their intended purposed well.  I found that I used the 70-300L more since it covered the range I needed most and it was sharper and lighter than the 100-400.

Cons: 70-300L uses a 67mm filter and if you intend to use a step-up filter for any filter larger, like 77mm, its very difficult to use this in the field IF you are using the lens hood.

Price wise, they are very close. Rent them both first if you can to get the feel and experience the IQ of each.

Good luck.

[Marsu42]

Neither of these lenses function well with a teleconverter from Canon or Kenko.

... to be precise: Canon doesn't fit (or destroys your lens), but the Kenko works but you have to af at f8 which doesn't work with all bodies. It does with the 7d and 60d, but at least with the latter it's only for static objects in good light and you have to shoot a couple of pictures in case the af missed. But it works, and the iq is ok.

Cons: 70-300L uses a 67mm filter and if you intend to use a step-up filter for any filter larger, like 77mm, its very difficult to use this in the field IF you are using the lens hood.

Have you actually tried it? I haven't got 77mm filters, but the hood of the 70-300L has some space in it that looks like it's exactly designed to let it be used with 77mm, too. But you'd have to screw it on when the hood is already on.

[DanoPhoto]

Neither of these lenses function well with a teleconverter from Canon or Kenko.

... to be precise: Canon doesn't fit (or destroys your lens),

 
this confuses me...are you referring to the Canon TC?

[Marsu42]

this confuses me...are you referring to the Canon TC?

yup, the Canon tc only fits a couple of lenses while the Kenko fits all ef, but isn't weather-sealed.

[pj1974]

I own the 70-300L and have used the 100-400L also.  They are more different lenses than their numbers suggest.  The 100-400mm is more of a 'bird specialist' and often focal length limited answer, whereas the 70-300mm is more of a general purpose telephoto zoom.

For me, the choice to go 70-300L was mainly on its much superior portability. Furthermore for most of my telephoto shots, 300mm on my Canon 7D (equivalent to 480mm in FF / 35mm format) was sufficiently.

The 70-300L does have much better IS (4 stops vs 2 stops on the 100-400L) which does make a lot of difference.  I don't like the 100-400L's pull-zoom action.

Good copies of both lenses can produce great photos when used by experienced and knowledgeable users. Though I would say that on the whole, the 70-300L has superior IQ (mine is particularly sharp and contrasty at all focal lengths, even wide open).

If I only had a FF camera - then the 70-300L wouldn't probably be enough reach for more of my needs.  I have recently used a 5DmkIII and the difference from 1.6x crop to FF is remarkable, so I would be 'stuck' - because I'm not so keen on the size and handling of the 100-400L. But with my 7D, the 70-300L does the 'trick' - even making a handy candid / portrait lens.

I really appreciate how good the 70-300L is as a travel combination with my 7D and 15-85mm lens.  I fit both in my shoulder LowePro bag often when I'm out taking photos.  And I can shoot all day with this 2 lens combination.

Hope my perspective is helpful. 
Paul

[bycostello]

you answer your own question, you want 400mm on a crop sensor....  not sure about the stalking though!

[bionutcase]

I have the 100-400mm and use on my 7D. I love it particularly for small objects from long distance - birds and small animals. Bikinis? I think I'd go with 70-300 unless you want to get navel shots!

[bycostello]

but the 100-400 is a push pull zoom i think, sucks dust into the camera

[Marsu42]

but the 100-400 is a push pull zoom i think, sucks dust into the camera

All non-internal zooms sucks in air when zoomed out, how else would it work? By creating lower pressure inside the lens - that would be news to me. If you don't want this, get an internal zoom like the 70-200, but the downside is that they are as long when zoomed in as zoomed out, so it's bad for transport and carrying around.

[Kiboko]

I should know! Had a 400mm f5.6L prime which I traded in for a 2.8L and which I regretted instantly. Far too big and heavy and wide open depth of field was too minimal so I found myself stopping down to about f4 all the time. Traded it in and bought a 400mm f4 DO. Still too big and heavy with a lens hood like a waste-paper bin. Traded it in and bought a 100-400mm zoom which I had for about 5 years. Still heavy, didn't mind push-pull zoom though, only 2 stops IS. THEN Canon bought out the 70-300mm L. Smaller/lighter/conventional zoom, over 400mm in 35mm terms on my 7D, - very very sharp, - 4 stops IS, NO CONTEST! 100-400mm zoom goes - swapped it for another (back to square one) 400mm f5.6L prime, for when and IF I need longer reach. I'm not bothered about lack of IS as it's use will be safari photography from a vehicle using support. 

[Marsu42]

THEN Canon bought out the 70-300mm L. Smaller/lighter/conventional zoom, over 400mm in 35mm terms on my 7D, - very very sharp, - 4 stops IS, NO CONTEST!

It's really funny to see how the 70-300L gains reputation. When I first researched what tele lens to get, I was not the only one to think this zoom is a rip-off: no Canon tc usable, only 4-5.6 (vs. primes or the 70-200L) and only up to 300 (vs. 100-400), while there are Canon and 3rd party alternatives that are way cheaper. But it just has the right ingredients for a walkaround tele zoom, I have to give it to Canon, they knew what they were doing here.

[Lnguyen1203]

I too had a100 -400 and I could get sharp pictures up to 300mm, but not at 400mm.  May be it is just me, but I traded it in for the 70-300 for a walk around teleconverter zoom and a 300 f2.8 plus 1.4x and 2x for longer focal lengths.  Just got back from 3 day at Yellowstone and these combos worked well for me.  Most of the time, I shot with the 300f2.8 and the 1.4x or 2x with images of bears, pronghorn, coyotes, birds, and a few wolves.  For closer range I used the 70-300.  The 70-300 is sharper than the 100-400 up to 300 mm and the 300mmf2.8 plus 1.4x is. Just a fantastic lens.  I could shoot handheld, from vehicle, or with a tripod for longer distance work.  Today I walked around the local park and shot a Northern Harriet at 25 yards with the 70-300 and was very pleased with it.  I had a harder time getting similar results with the 100-400 at the same distance.

[bvukich]

The answer is obvious.  You need to either disguise yourself as a bikini-clad girl to get in closer, or you need to construct some sort of "girl blind" to conceal yourself in. 
Or, perhaps you could actually MEET a girl and then you could have her permission to photograph her.

I must have some sort of innate Jedi-ninja girl blind skills... my whole life I've always been completely invisible to them.

[UrbanImages]

Having rented a 100-400 and owning a 70-300L, I would take the 70-300L all day over the 100-400. Lighter, shorter, better IS and tack sharp throughout. I just did a long weekend in Detroit, doing some "urban pioneering" including about 23 building fires. I had my 70-200 2.8L nonIS on my 7D and after the 2nd night fire I changed it for the 70-300. Never put the 70-200 back on. Images were sharper than my 24-70L which was on my 5DII. I highly recommend the 70-300L, truly a sleeper in Canon's L series lineup.