100-400 wide open sharpness

I am debating on this lens vs. the 400mm f/5.6 prime. I have heard from some that the 100-400 needs to be stopped down and from others that it doesn't. Thought I would leave it up to a poll and let the general consensus decide. Please DO NOT comment if you've never actually owned/used the 100-400.

40Driggs wrote in post #7901537
I am debating on this lens vs. the 400mm f/5.6 prime. I have heard from some that the 100-400 needs to be stopped down and from others that it doesn't. Thought I would leave it up to a poll and let the general consensus decide. Please DO NOT comment if you've never actually owned/used the 100-400.

Had 2 of them over the years and both sharp wide open at 400mm

malla1962 wrote in post #7901547
Had 2 of them over the years and both sharp wide open at 400mm

Just what I was looking for. Thanks!

I just got the lens last week. This is the only copy of 100-400L I've owned. So I have nothing to compare to but it looks sharp enough to my eyes at 400mm f/5.6.

yeah, it is sharp at the long end wide open. I dont own the lens, but i have used it alot, to be honest I was not that impessd by the lens, plus i did not like the push pull zoom.

xander2188 wrote in post #7901592
yeah, it is sharp at the long end wide open. I dont own the lens, but i have used it alot, to be honest I was not that impessd by the lens, plus i did not like the push pull zoom.

What didn't you like about it?

My dad has this lens and I have used it several times. The picture quality is great wide open and zoomed all the way out. I would buy this lense if I didn't have access to it for free.

Mine at 5.6 is fairly sharp but i still like to stop it down to f/8

The prime is likely sharper, but I dont think i can apreciate the difference on my 30D

I love mine. Sharp at f/5.6, but a little sharper still at f/8. Perfectly good enough for me.

I voted yes. The lens is at it's softest wide open at 400mm, you will get greater sharpness by stopping down of course, just as with pretty much any lens.

Equally, like most zooms it doesn't match the sharpness from the best primes.

However, the key point (for me) is that it is still sharp enough to give great results. Here's a 100% crop from a shot of a fox, taken at 400mm, wide open at f/5.6, straight from the camera apart from RAW to jpeg conversion. Pixel peeping at this size shows slight softness, however once PP'd, sharpened and viewed at normal size the images are plenty sharp enough.

At web size (most of what I do) I sharpen most 500L photos to 175 USM, .6 radius. most 100-400L shots I normally sharpen to 200 USM, .6 radius. In other words, the 100-400 is pretty damn sharp and I only shoot wide open.

I was amazed at how sharp it was wide open at 400mm. Here is a small test I did. Both no addictional sharpening. Only set on 3 in camera sharpening.

This is at 5.6 400mm....... http://i6.photobucket.​com …k/2009_05_10_IM​G_1568.jpg

this is at 8.0 400mm...... http://i6.photobucket.​com …k/2009_05_10_IM​G_1569.jpg

The 5.6 is more than acceptable. Now the subject of the photo, that's a different story, lol. Just demoooonstrating.

I found this photo I took with a 50D and the 100-400L at 400m and f/5.6. I don't remember how much it was sharpened though. The image had one side cropped off to get a 4:5 aspect ratio, but was left full height and then resized.

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Use mine continually wide open. Nice and sharp. Just a great lens over all!

Mine looks good to me (100-400 that is) here's a 125% crop wide open with no post processing of any kind. (it wouldn't accept the file at 100% which is 600 pixels wide).