Canon EF 400mm f/5.6L USM

Just curious if anyone here has tried the dot tune method to MFA this lens?

On a 70D my copy of the 400mm required +5 MFA using dot tune and a target at a distance of 55 feet using a tripod.

After determining the dot tune value, I proceeded to shoot at various MFA values to prove to myself that +5 was indeed the value, and it held as true for me.

Interesting, have thought about trying it. How did you measure out 55 feet? Tape measure?

I walked off the distance as my shoes are 12 inches. I believe Canon recommends 50 times the focal length for the distance to use for MFA targets, which is around 65 feet (~20 meters). I was a little short of this, but setting up for 65 would have been more difficult in my backyard.

Sgt: Your shots have looked spot on to me. Are you expecting a higher keeper rate, or do you think you are applying more sharpening in post processing than normal?

I would take my 70D with a grain of salt because nearly every lens I have requires some MFA with it. I think Canon got lazy with the calibration on the early production of the 70D, and I've read several posts of others with the same issue.

I MFA all my lenses except this one, dont know if it is worth trying or not!
I do minimal sharpening in post, however a higher keeper rate would be good!

I just can't get close enough to birds to obtain those popular completely blurred backgrounds.

IMAGE LINK: http://www.ipernity.co​m/doc/diamantstudios/3​8352458

Hello, next Wednesday I'm going to order this lens, Canon 400mm F5.6, but I'm still having some doubt between that and the 100-400 II IS.
The prime lens is cheaper, the 100-400 twice the price and I already own a 55-250 so I do not need attually the range 100-300, at least that's what I think.

As being not an expert, is there any other element I should take into account before buying?

Before I was also considering the 150-600 Tamron or Sigma.

Thank you

Can't say that I'm really happy with this lens: it never fit the camera's mount well (there's play that apparently is normal, but it vexes me: https://photography-on-the.net …howthread.php?p​=16811697), it has no IS, and the AF motor makes some clunky noises from time to time.

I'd probably exchange it for the new 100-400mm zoom lens, but I don't like the latter's variable aperture and change in size when zooming. And I won't touch Tamrons or Sigmas.