What zoom to buy?

[Norm53]

I put up a bird feed at the edge of a woods about 80 feet from my lunch table behind a french door. My Canon EOS Rebel T3i with EF 75-300 mm 1:4-5.6 will not bring into focus the birds, large and small.

What lens do I need to buy that will do the job? Cost is no object.

Thanks, Norm

[ebiggs1]

Another option that was glossed over is the Canon EF 300mm f/4L IS USM Lens.  Yes it is only 300mm.  Add to the fact I don't like tele converters but in certain cases they work.  This is one where it works.  The Canon 2x tele converter and EF 300mm f/4L IS USM Lens combine to make a 600mm f8 lens with IS !  This combo is very good.  The only other tele combo I ever recommend is with the Canon EF 70-200mm f/2.8L IS II USM Lens but then only with the Canon 1.4x, yields a 98-280, f4 lens.

But it is way too short for birding.

The Canon  EF 300mm f/4L IS USM is a fantastic lens by itself.  Very sharp and quick AF.  Everybody raves about the Canon EF 400mm f/5.6L USM Lens and how sharp it is but most over look the 300mm, which is better.  Plus the 300mm gives you IS and the 400mm doesn't. The EF 400mm f/5.6L USM Lens doesn't handle tele converters very well. So, if you must limit it to the 1.4x version.  Remember no IS with that combo!

[Norm53]

"Another option that was glossed over is the Canon EF 300mm f/4L IS USM Lens.  Yes it is only 300mm.  Add to the fact I don't like tele converters but in certain cases they work.  This is one where it works.  The Canon 2x tele converter and EF 300mm f/4L IS USM Lens combine to make a 600mm f8 lens with IS !  This combo is very good."

Sorry, but I don't see how this option is any better than the 600mm Sigma or Tamron because they both have IS, according to the specs. Therefore, why buy the 300 w/converter unless it adds something significant to the photo? Also, since the 600's cost around $1080 at B&H, what would the 300 w/converter cost? And we have to consider weight: I can't use a tripod because it limits my shooting flexibility.

Norm

[ebiggs1]

"Please explain what's below from your post because I don't understand it. I assume you are recommending another configuration.

Canon 6D, Canon T3i, EF 70-200mm L f/2.8 IS mk2; EF 24-105 f/4 L; EF-S 17-55mm f/2.8 IS; EF 85mm f/1.8; Sigma 35mm f/1.4 "Art"; EF 1.4x extender mk. 3; 3x Phottix Mitros+ speedlites

Norm"

That is his signature which includes his gear.  Has nothing to do with recommendations for birding.