Big ticket telephoto decision

[uplander]

I need some input here to help make a major decision by having gathered as much info as I can.

I am in a position right now to purchase either a Canon EF 400mm f/2.8L IS USM or the Canon EF 500mm f/4.0L IS USM.

I already have an EF 100-400 f/4.5 - 5.6 L IS USM and find f/5.6 at 400mm a problem many times shooting at dusk or dawn, when a good majority of my shooting ops. take place ( my passion is wildlife photography).

What i'm seeking is , personal expirience and / or technical knowledge.

I am leaning towards the 400 f/2.8 because I can really appreciate the large aperture light gathering aspect and capturing many previously missed photo ops.

On the other hand, I like the added reach I would gain with the EF 500mm.

My main questions are.
#1 If I went the 400 f/2.8 route and added a 1.4 x TC I would get a 560mm f/4 lens when needed but at what loss of IQ? How much worse would a 2x TC be and what would the max aperture be with the 2x

#2 If I went with the 500 f/4. Would f/4 be enough of a light gatherer for what I want, knowing that my EF 100-400's main sore point with me is its f/5.6 aperture. And would the IQ be better than the 400 f/2.8 with a 1.4x TC?

Please discuss.

I an hoping a good discussion here might bring up points I haven't even thought of.
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[snappingturtle]

Are you photographing animals too? If you are, I would say go for the 400mm f/2.8. The extra stop can mean a difference since you have more light for faster shutter speeds in case the subject moves. If it is going to be landscape type wildlife, the 500 f/4 would do fine as long as you have a tripod. But I prefer the additional aperture opening just in case.

How much image quality a TC will degrade varies much on the lenses. I would imagine however that a native lens without the TC would most likely beat one with it.

Check theses out:

http://www.the-digital-picture.com/Revi ... eview.aspx

http://www.the-digital-picture.com/Revi ... eview.aspx

[neilhs]

I have both a 1.4x and a 2x TC and use them with my 70-200 f2.8 IS and to be honest it is hard to spot any IQ degredation. I use them on a 40D body. I like the flexibility the TC's give, so my recommendation would be the 400 2.8 plus a TC

HTH
Neil

[jniemann]

The 400mm f/2.8 and a 1.4x TC would give you the most versatility.
The quality of the Canon TC is excellent, and I doubt you would notice any degradation in IQ.

[billrobinson]

Putting anything in front of the lens is going to effect it's performance.
I don't know anything about the IQ of the 400 f/2.8 compared to the 500 f/4.

I do know I gave up on a 1.4 converter for the 70-200 f/2.8 because of the slight drop in IQ.
For reference purposes, I have 3 UV filters, a Tiffen, Hoya and a B+W.
I use none of them anymore because I like to retain maximum detail.
(ps: I'd use a uv filter for something like a rally sport event where there's a much greater risk of damaging the lens from flying debri)

[dang]

Brian,
I'd suggest checking this thread also: viewtopic.php?f=18&t=37383
There's some good comparisons with and without a TC. I think it can take some serious pixel peeping to see a huge difference when using L lenses
with the Canon 1.4. on most bodies.

I think much of your choice depends on your needs. Required printing size should help decide, since cropping isn't always a bad thing, considering higher pixel count & resolution of newer bodies. This is something people should be aware of when investing in expensive lenses. If you're using a 10D, it's doubtful you'll tell much difference either way. But on a 5D, or Pro body, lack of corner sharpness might also figure in.

[uplander]

I ended up getting the EF 400 f/2.8L. I use it with a Canon 40D and so far the shots with a 1.4TC have been very good. This lens is really ,really sharp.
Here is one of the first pics I got at 560mm
Hummingbird

and here is one without the TC

and another


And this is one with my 100-400-L