300 f/4 IS or 400mm f/5.6

[copper]

Right now I am looking for a birding lens. I am looking at getting the Sigma 1.4x APO DG to go with my 70-200 2.8. That will get me to the 280mm F4 area.

I shoot mostly backyard birds in my yard (Blue Birds / Purple Martins / Red tailed hawks or red should hawks / American Kestral / and Hummers. I would like to go to Brazos state park maybe with you guys...

So now to the question. I could get the 300 f4 IS and use the TC to get to 420 f5.6 IS or get the 400 5.6 which I hear is a great in flight birding lens (fast and accurate lens). I am lost on which lens..... Does anyone have any input on this....

Also what do you think about the Sigma 1.4x APO DG?

Please Help!!!

Thanks

Copper

[Jim Victory]

On the TC it has been awhile since i have used the sigma TC so i don't know how it works on other lenses but it is a good choice for sigma lenses.

I would probably go with a Tamron Sp or a Kenko Pro because they both can be used with any lens. not sure about the sigma.

If your going to use the long tele just for birds then the 400 f/5.6L is the best choice. It requires good long lens technique to use it HH so a tripod may be your best bet. Also it gives good results with the cheap (black) Tamron TC giving you 560mm and AF on your XT.

The IS on the 300 will be very good for HH in low light conditions and the MFD makes it great for semi-macro work. The TC on it doesn't degrade IQ much but the AF speed does take a hit.

[Richard DeYoung]

I USE A kENKO TC THAT I BOUGHT ON EBAY FOR $100.00 WORKS GREAT WITH MY 300 MM LENS. VERY SATISFIED. I PHOTOGRAPH BIRD EXCLUSIVELY AND USE A TRIPOD WITH A BALLHEAD FOR JUST ABOUT ALL MY SHOTS.

[ldelacruz]

The only complaint I have about my 300 f4 IS with the 1.4 tc is that it is still not long enough...it would be great for backyard stuff but if you are going to state parks it will be a bit short for most subjects.

Th good thing...the AF and IS still work and I shoot handheld all the time. Below is an example of a few shots taken with this setup but keep in mind I was able to get within 20 feet of all the subjects.

http://www.texasphotoforum.com/forum...ad.php?t=67796