Sigma 120-300 + 1.4x or a 100-400L?

For a combination of daytime sports, birds, airshows, etc. which is a bette choice in IQ? I understand the 100-400 is lighter and has IS (though probably not the best). Anyone have any experience with both?

If I had to choose between the two, the 100-400. If I had other choices, look at the Canon 400 5.6L or the Sigma 150-500 OS HSM.

if I had to choose..id pick the 120-300 2.8 hands down everytime over the 100-400..I really want that lens badly..I had a chance to play with one before and its a great lens.

I've had both lenses and the 100-400L compare to the 120-300 is junk; hope don't offend anyone but is true.

The only thing the Canon has is the lighter weight. The Siggy takes the Sigma 1.4x converter beautifully.

Here are my thoughts so far:
Sigma 120-300
+f2.8 at 120-300
+f4 at 168-420mm
-big and heavy
-no IS so may need to bring a monopod but what to do at air shows? handheld and >1/500 (or more) shutter?

Canon 100-400
+small and light
+IS
-no 2.8
-f5.6 at long end


BTW, I already have a 70-200 2.8IS and two 1.4x (Kenko and Canon 1.4x II) = pretty nice 98-280mm f4 combo

05Xrunner wrote in post #9636738
if I had to choose..id pick the 120-300 2.8 hands down everytime over the 100-400..I really want that lens badly..I had a chance to play with one before and its a great lens.

I see you have the 100-400. Have you tried the Sigma with a 1.4x TC?

The 120-300 is the superior optic, but lacks IS.

If you need IS, get the 100-400. Simple

Maybe I'll hold off until Canon releases their 100-400 2.8IS

If you want to hand-hold, get the 100-400.
If you can committ to using a monopod or tripod, get the 120-300.

RikWriter wrote in post #9637221
If you want to hand-hold, get the 100-400.
If you can committ to using a monopod or tripod, get the 120-300.

I have a very nice Gitzo monopod already. My only concern is longer lengths of time handholding (airshows).

PrimeGlass wrote in post #9637091
I see you have the 100-400. Have you tried the Sigma with a 1.4x TC?

never used a 1.4 on anything.

plasticmotif wrote in post #9637093
The 120-300 is the superior optic, but lacks IS.

If you need IS, get the 100-400. Simple

If sigma added their 4 stop OS to this lens they'd have a cracker

Personally, the 120-300 is probubly better but the 100-400 for airshows is fine..

Think about it, light isnt an issue and you dont -need- f/2.8 for planes...also the push-pull zoom is easier to work quickly, and the 100-400 is easier on the arms for certain...

The Sigma probably has better IQ but it is twice the price, and twice the weight of the 100-400.

crn3371 wrote in post #9637690
The Sigma probably has better IQ but it is twice the price, and twice the weight of the 100-400.

Not used, Used Siggy 120-300s regularly sell in the low $1000 range...

KenjiS wrote in post #9637720
Not used, Used Siggy 120-300s regularly sell in the low $1000 range...

as anything else they have gone up quite a bit 6mths ago when i was looking i found a few on ebay that ended around 1200 - these days its more like 1600-1800...