Advice: EF 300 f4L or EF 400 f5.6L?

[Lionheart]

I've decided after many tests that my 70-200 f2.8L with the 2x II converter is decidedly soft, not to mention the slowdown in AF tracking in AI servo mode. I'm not a big guy, so I'm not looking at the big fast expensive "L" glass that requires a monopod or tripod at all times. That plus the fact that I can't write the purchase off as office equipment, so I'm not about to plunk down that kind of cash for something I won't use everyday. So I'm looking at these smaller, lighter but very capable (according to the reviews) lenses for a little extra reach for wildlife shots without sacrificing sharpness from a teleconverter.
Appreciate any input.

[Michael Fanelli]

I've decided after many tests that my 70-200 f2.8L with the 2x II converter is decidedly soft, not to mention the slowdown in AF tracking in AI servo mode. I'm not a big guy, so I'm not looking at the big fast expensive "L" glass that requires a monopod or tripod at all times. That plus the fact that I can't write the purchase off as office equipment, so I'm not about to plunk down that kind of cash for something I won't use everyday. So I'm looking at these smaller, lighter but very capable (according to the reviews) lenses for a little extra reach for wildlife shots without sacrificing sharpness from a teleconverter.
Appreciate any input.

In my experience, 300mm just starts to get into the wildlife area. I often wish I had more. Of the two, my vote is for the 400mm.

[Lionheart]

In my experience, 300mm just starts to get into the wildlife area. I often wish I had more. Of the two, my vote is for the 400mm.

Thanks, Michael. I was leaning towards the 400, but that f5.6 bothers me a little,even though it is sharper wide open at 5.6 than my 70-200 + 2x wide open at 5.6, and faster focusing too. The other thing that bothers me is why the 400 is $50 cheaper than the 300. Is the image quality not as good as the 300? I couldn't really discern that from the reviews of these lenses, hence the indecision, although the 400 makes a more logical choice for focal length.

[Van A]

Thanks, Michael. I was leaning towards the 400, but that f5.6 bothers me a little,even though it is sharper wide open at 5.6 than my 70-200 + 2x wide open at 5.6, and faster focusing too. The other thing that bothers me is why the 400 is $50 cheaper than the 300. Is the image quality not as good as the 300? I couldn't really discern that from the reviews of these lenses, hence the indecision, although the 400 makes a more logical choice for focal length.

Yeah, it seems strange that the 400 costs more than the 300. Is it because the 300 offers IS? I am also debating between the 2 lenses. Many wildlife photographers agree that 400mm is the minimum length (I really could have used this when I was in Colorado in September photographing elks). I start to lean towards the 300 + 1.4x converter mostly because of the IS, but I am not too sure yet. Have you thought about this combo?

[Lionheart]

Yeah, it seems strange that the 400 costs more than the 300. Is it because the 300 offers IS? I am also debating between the 2 lenses. Many wildlife photographers agree that 400mm is the minimum length (I really could have used this when I was in Colorado in September photographing elks). I start to lean towards the 300 + 1.4x converter mostly because of the IS, but I am not too sure yet. Have you thought about this combo?

Thanks
The 1.4x is why I was considering the 300 in the first place, since I don't seem to get much image degradation at all with the 1.4x. I usually only see it at the edges, but that was back in the film days. With the cropping factor of the 10d, and the 1d MkII, most of that edge softness is minimized or outright eliminated. I'm just concerned with how much AF will be affected by the converters, but as my post below indicates, I'm going for the 300.

[another view]

why the 400 is $50 cheaper than the 300. Is the image quality not as good as the 300?

Price and image quality don't necessarily go together. You've got those two focal lengths covered with your 70-200 + 2xTC. When you use it, do you stay more towards 300 or 400? With wildlife, it's hard to have too much focal length so I'd go with the 400. Use a higher ISO if you need the shutter speed, but 5.6 should AF just fine unless the light level is low (then even 2.8 won't be great).

Think of image quality this way - if the 300 is a little sharper than the 400 but you have to crop the 300 to get the shot you want, then you're better with the 400 unless it's a real piece of junk! I'm sure it's not the case, so again I'd go for the 400.

One other thing to consider is technique to get the most sharpness in an image. A 200 is pretty hard to have a problem with on a tripod if you're careful. A 300 isn't bad either but a 400 IMO is a lot harder to shoot. I don't use focal lengths over 300 very often so it's probably my fault. And I say this because I have gotten sharp images at 400, but not consistently. Check out Moose Peterson's site for info on technique: www.moose395.net

[Lionheart]

Thanks for the link to Moose Peterson's site. That was very informative.Good thing I haven't placed the order at B&H yet. I am definitely at the 400 end 99% of the time when I stack the 2x on my 70-200. Guess I'll have to mull this over some more. Well, back to the drawing board.

[paulnj]

http://birdsasart.com/bn117.htm

[Lionheart]

QUOTE=paulnj]http://birdsasart.com/bn117.htm[/QUOTE]
Thanks Paul. Now I'm really undecided. The reach of the 400 is nice, but the 300 is sharper wide open according to Canon's mtf charts, plus one stop faster, so theoretically faster focusing because of better light, plus the IS and only marginally more expensive. Of course the 300 f2.8L IS is only 4x more expensive for one more stop of light, so I guess $50 is worth the extra stop, + 1.4x converter shouldn't degrade sharpness or AF too much. OK, 300 it is! (no, not the 2.8L-wishful thinking)

[straightarm]

is Canon's 100-400 IS zoom. This gives you the reach of a 400 and has IS to counteract camera shake.

Simon

[paulnj]

He sold me his 100-400IS a few years ago.

HONESTLY, both the 300 and 400 are SHARPER and LIGHTER

The 100-400IS is a great lens(I use it 90% of the time), but he wants a long prime for REACH, not versitility ;)