Buying a new lens.

[kegressy]

I am currently using a Canon 300 mm F 4.0 L IS lens and debating whether I should buy the Canon 400 mm F 5.6 L lens.
I intend to use it with Canon 1.4X extender, or Tamron 1.4X extender, that I have both.
My major interest is bird photography and I find that the 300 mm is not long enough for small birds.
On the other hand, I won't be able to buy the Canon 500 mm F 4.0 lens.
Any suggestions are welcomed.
kegressy

[mdr]

I have the same dilemma, which one do I buy:

300mm f4 L IS with 1.4x TC equates to 672mm f5.6 on my 20D
400mm f5.6 L equates to 640mm f5.6 on my 20D

The five main differences are:

Size/Weight - 400mm is larger/heavier.
Flexibility - 300mm allows both with and without TC.
IS - 400mm hasn't got it.
Image quality - the big question to which the jury is still out.
Price - depends on new/second hand availability/prices.
My inclination is to go with the 300mm IS, although Canon's forgotten 400mm can be snapped up reasonably cheap second hand.

So if you go with the 400mm f5.6 L, I would happily consider buying the 300mm f4 L IS from you ;).

[LouDawg]

This is the exact same question I've been asking myself for some time and I've come to the conclusion that overall a 300mm f/4 would be best for me because it gives me the most general flexibility and also it has IS.

[kegressy]

I am attracted to the 400 mm lens for two reasons. One is that it has no IS. My 300 mm with IS died on me twice already, and had to be repaired. (Only 1.5 years old) It died at a critical time which spoiled my two-day shooting trip. Since then I always carry the 100-300 Canon lens as a back-up.
Number two is that I can attach a 1.4X extender and have a half decent long focus lens.
With the Canon 10D it will be 896 mm. By taping over the first three pins it will retain its autofocus ability.
I was wondering if my argument had any mayor flaws.
Please comment.

[CyberDyneSystems]

You may want to take a look at poll results comparing these lenses and others in our -=Top 10=- lens section here;

http://photography-on-the.net/forum/showthread.php?t=56752

Of particular interst would be the -=Top 1-=- Wildlife primes,. but check out zooms as well...

FYI, the weight and size difference between 300mm f/4 and 400mm f/5.6 is really negligible.

If you are dreaming of a 500mm,.. you may want to look for a used Sigma 500mm f/4.5 EX HSM,.. this lens is on the same playing feild as Canon's $5,500.00 primes,. and yet can be found used for about $2k.

If considering the much more

[Deckyon]

300mm f4 L IS with 1.4x TC equates to 672mm f5.6 on my 20D
400mm f5.6 L equates to 640mm f5.6 on my 20D


Not exactally. The 1.6x crop factor does NOT give you extra REACH - Not Zoom.

400 x 1.4 = 560mm zoom with teleconverter. The difference is the Field of View. The 20D, Rebel, 10D and even the 1D Mark II have smaller chips than a 35mm film negative. You still see just as far, just not as much.

Someone has a great diagram showing the size difference between the chips.

[mdr]

You could also consider the 300mm f4 non-IS version. Plenty good once available for reasonable prices on the second hand market.