Your thoughts, Canon 70-300L 4-5.6 or canon 100-400L 4.5-5.6

I have owned the 100-400L for several years, and have no issues with dust in the lens. This lens does not suffer from dust any more than any other zoom lens that extends when changing focal length.

As for the 100-400L vs the 70-300L, the 70-300 is a newer lens with newer optics and a better image stabilization system. It is a better lens than the 100-400L in every way, except for one critical area -- focal length. If you need the reach, the 100-400L will perform much better than the 70-300L with a teleconvertor attached. As others have recommended in this thread, select the lens that meets your focal length needs without attaching a TC.

Some people do not like the push/pull zoom mechanism of the 100-400L, but I find it very easy to use, and much simpler and quicker than a twist zoom once you get used to it (which only took me minutes).

I wouldn't trade my 100-400L for a 70-300L, as I need the added focal length. This is my primary wildlife lens, and reach is critical. While it's a little bigger and heavier, the 100-400L is still quite compact for the reach and versatility it provides.

Thank you Mike M

johnnyvman wrote in post #16755568
Don't need the 400 on a regular basis gonzogolf.

If 400mm is a requirement then of course go with the 100-400L. If not then the 70-300L has a slight IQ advantage as well as being much smaller, lighter, with a more recent and advanced IS system. I haven't had a chance to use the 100-400L, but buying the 70-300L was one of the best purchases that I've made.

One side note: Canon is rumored to be coming out with an updated 100-400L which may be better than the current version - at minimum it will have updated IS. But it will almost certainly cost much more than the current version.

jrbdmb wrote in post #16756140
One side note: Canon is rumored to be coming out with an updated 100-400L which may be better than the current version - at minimum it will have updated IS. But it will almost certainly cost much more than the current version.

That same rumor has been out there for at least six years. Unless something actually gets announced, I would not use that rumor to sway any decision you make. That rumor was out there when I bought the 100-400L several years ago, too. I would have missed a lot of photographs had I waited for the rumor to come true.

You cannot take a photograph with a rumor.

I have both lenses and use both. There is a bit of duplication in FOV but I like the reach and image quality of the 100-400. So far it covers everything I need for my outdoors wildlife photos, but is a bit to carry around.

The 70-300 is much lighter and very good IQ at 70-200 so rather than spend cash on a 70-200 I am very happy with the 70-300 along side the 100-400. The system works well.

I got the 70-300L because of the following reasons:

1) Sharper and can crop to 400mm equivalent
2) Better IS and lighter than the 100-400L
3) Like a 70-200 F/4L w/1.4X teleconverter built in

Thank you everyone for your imput! Will take everything into consideration, probably leaning toward the 70-300L.

johnnyvman wrote in post #16755572
thanks ceegee, good info. Has anyone ever used a TC with the 70-300?

I used mine with a Kenko 1.4 extender. On my 50D the AF was unreliable and slow at best. Manual focus the results were decent. I tested the 70-300 with extender on a 70D and the focus was quick and accurate.

While I completely agree with the previously posted advice on skipping TCs with slow zooms, The 100-400 *will* AF with a 1.4TC on the 5D MkIII as of one of the most recent firmware updates.

I had both the 150-500 is not even in the same ballpark as the 100-400 L. 100-400 has been around a while and there are many deal on them for a great used copy. Go with canon. thats my opinion

The real question is do you need more reach. If you don't need the 400mm reach, the 70-300L has better IQ, 2 stops faster IS, and is better sealed. If you need the reach, then the 70-300 can't do 400 w/o the TC.

If you really want reach and that's your ball park, you should be considering the 150-600 Tamron. It's short end is over twice as long as the 70-300L, so keep that in mind, but it is very long on the long end. In the 150-400 the optics are very nice. By 600, they are comparable to the 400 w/ a TC.

sawsedge wrote in post #16755750
The 100-400 is not sealed, unfortunately.

In all fairness, no lens that extends while zooming can be sealed. That air has to come and go from somewhere. If air moves, dust moves. My 100-400 is almost two years old and has no identifiable dust inside.

SqueekyBoy wrote in post #16761754
In all fairness, no lens that extends while zooming can be sealed. That air has to come and go from somewhere. If air moves, dust moves. My 100-400 is almost two years old and has no identifiable dust inside.

That's not entirely true. There's perfectly possible to make a lens that is hermetically sealed and extends while zooming. Air is a compressible gas after all. However, the forces required to seal the o-rings would create a very disappointing amount of friction.

I had the 70-300L and the 100-400L. Now I have the 70-300L and the Tamron 150-600. The 70-300L is my go to travel lens. It is just perfect for that role. I'm getting very nice results from the Tamron 150-600, but it is a beast!