100-400 Sharper than 300 f4 !!

I did some comparison shots today between a 300mm f4 that I just got and a 100-400 and I was surprised to find the 100-400 a bit sharper. Shouldn't it be the other way around ? I don't think it is a focusing issue with the 300 as I tried the battery test as well as a yard stick on an angle and found the focus to be spot on. The shots were off a tripod, with a remote, IS off and the 100-400 was set at 300mm. Any ideas why the 1-4 would be sharper ? Below are some 100% crops, without any processing, to judge.

300 f4 @ f4

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looks like that 300 f4 box is over exposed alot more then the 100-400

those arent very good shots for comparing. the picture from the 300mm seems to be a bit blurry from hand shake. the second photo from the 300mm is out of focus. and you are comparing a shot that has an aperture for f/5.6 to f/8. the picture from the 300mm @ f/5.6 has shallower DOF. i believe its caused by user error.

Hmmmm..... a lens wide open vs a lens stopped down a bit. Would you expect any different results?

Use both lenses at the f/stop and then you can compare.

Don't leave out f/5.6 vs. f/8.

And sheesh dude! If your out doors, you give give us eye candy subjects not eye cr@pola!

No hand shake, camera was on a good tripod. I wanted to compare them both wide open as that is where I use them most, then I tried stopping down 1 full stop. I also have other pictures that show the 1-4 being sharper. Sorry about the squirrel cobs.

LeeSC wrote in post #6060718
Hmmmm..... a lens wide open vs a lens stopped down a bit. Would you expect any different results?

Use both lenses at the f/stop and then you can compare.

The 300mm should be a lot sharper then these shots wide open. Something's wrong, user error or a lemon, I don't know

Hmmmm...100-400L 300mm @f5.6 = wide open.

LeeSC wrote in post #6060718
Hmmmm..... a lens wide open vs a lens stopped down a bit. Would you expect any different results?

Use both lenses at the f/stop and then you can compare.

LeeSC wrote in post #6060718
Hmmmm..... a lens wide open vs a lens stopped down a bit. Would you expect any different results?

Use both lenses at the f/stop and then you can compare.

The first 2 are both wide open.

Sorry

Was looking mainly at the second shots!

my 300L was sharper wide open.....but not by much.

ed rader

My 300L f/4 stopped down to f/8. Compare this to the 100-400 at the same stop.

http://www.flickr.com …in/set-72157603259297388/

Nothing shocking at f8.

Here...wide open at 400mm.

ctrain wrote in post #6060892
My 300L f/4 stopped down to f/8. Compare this to the 100-400 at the same stop.

http://www.flickr.com …in/set-72157603259297388/

Looks like your 300 is OOF.

Whether it's user error or the lens itself is off, your two pictures of the 300 L are out of focus.