Canon 100-400 v 400 f5.6 prime

I have a 100-400 ISUSM at present and overall am very pleased with it - except for its AI servo AF performance at between 250/300-400mm, which is very hit 'n miss: as I understand things 250ish is where the f-number hits 5.6 on this lens.

Below 300mm it's AF tracking is great, and in OneShot it's focus is great at all lengths, and as a video lens used manually on the XL2 it's superb - all round it's really versatile so I want to keep hold of it.

Now I'm thinking about purchasing the 400mm f5.6 prime - basically for 'in flight' - I've read that it's AF speed is quicker than that of the 100-400 and that it's supposedly sharper.

So I'd like to ask all the Canon folks here for their opinions - is it faster & sharper ?

Thanks in advance

Andy I have both lenses. I bought the 400 prime to use as an over the shoulder BiF etc lens when I'm out and about with my 500. A very brief answer to your question is that yes the AF is a fair bit faster and it's a very sharp lens - I'm lucky that I have a nice sharp copy of the 100-400 so I didn't really buy the prime for want of a sharper lens.

If you do decide to get one let me know because I'm selling mine - 2 months old, as new and with a camo lenscoat It was a spontaneous purchase and I have to fund my new 40D

I too have both lenses. The prime is head and shoulders over the zoom for focussing speed and sharpness on the copies that I have. Comparing them side by side the prime is slightly longer (I think the 1-4 is actually about 380mm).

My 1-4 is not great wide open and at 400mm, but I have no hesitation in using the prime wide open.

I went for the 400 as my 100-400 just wasn't giving me sharp enough results, and I have to say that although I still take my 100-400 along for more compositional options, it hasn't been used since I got the 400 which is a lovely, light, sharp, fast-focussing lens. I can totally recommend it.

Mark

Hi Andy

Never owned the 100-400 but have been using the 400 prime since April, I can honestly say that on the 40D it is stunning. It is sharp, fast, light, and manouverable or was that quote from a recent Ferrari ad?, seriously you would find it hard to get a sharper lens at any focal length. Take Paul's hand off!

Brian

It is also worth considering the 300f4 I.S used in conjuction with a 1.4x gives 420mm and you have I.S and the versatility of having a 300 which works well with extension tubes for butterflies etc

Thanks for the input guys - I've just put it on order

Yes Gary, you're right, it is 380mm.

Paul - got a sweatheart price for a new one with full uk warranty.

Dave - I understand where you are comming from re the 300 - good idea and would be a smart move, once I've saved my pennies and got a 1D3 + 600mm ( ) I'd proberbly take that route - but for now I've got that situation boxed off with my Nikon gear - right now I'm just chassing sharp BiF images with as much HH mag as I can get without resorting to tc's, and in as small and light a package as I can get.

Thanks for the input chaps

The 5.6/400 is a fine lens for birds in flight. It might not sport the latest Canon technology, it has a good AF and more importantly it is easy to work with as it is so light.

Close focus isnt great but then for birds in flight it is not a big issue. Dave mention the 4/300, which is a good choice as well but i think you will always use it in conjunction with a converter, slowing down the lens a bit. Ofcourse it has its advantages: close focus and the IS.

Anyway, i use the 5.6/400 for flight shots and i love it.

Rene de Heer

Hi Andy I use a the 400mm 5.6, its fast and super sharp etc. With 30-50mm of extension tubes it works fine for dragons and butts/lizards, although I prefer to use 300mm for such purposes. With some teleconverters, extension tubes and a monopod the 400mm makes an extremely versatile and light bit of kit. Have fun John

Ok Andy no worries, I'll just have to keep it