EF 100-400mm f/4.5-5.6L IS II USM Review WOW!

Pondrader wrote in post #18368317
What makes you think it would need to be twice as big as a 1200mm, The Sigma can do 600mm in a lens a bit bigger than a 100-400mm ?? Ok so I did forget about the f2 part of my problem.. but thats up to the geniuses of the world... Not me. I just do the wanting

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Exactly, it's not mostly (or even primarily) about focal length; it's about the size of the front element.

1200/5.6 = 214 (roughly)
800/2 = 400

The front element is almost twice as big across, which also means that much thicker and MUCH more than twice as heavy. Think of the difference between the 400/5.6 and the 400/2.8. That difference is two stops. An 800/2 is equivalent in front element to a 400/1, which is a whole three stops bigger than the 400/2.8.

I stand by my statement on the size of such a lens!

LonelyBoy wrote in post #18368340
Exactly, it's not mostly (or even primarily) about focal length; it's about the size of the front element.

1200/5.6 = 214 (roughly)
800/2 = 400

The front element is almost twice as big across, which also means that much thicker and MUCH more than twice as heavy. Think of the difference between the 400/5.6 and the 400/2.8. That difference is two stops. An 800/2 is equivalent in front element to a 400/1, which is a whole three stops bigger than the 400/2.8.

I stand by my statement on the size of such a lens!

Theres nothing to stand on,.. In the dream world all things are equal Just sayin

Pondrader wrote in post #18368343
Theres nothing to stand on,.. In the dream world all things are equal Just sayin

I always take things too literally...

LonelyBoy wrote in post #18368345
I always take things too literally...

I just want to shoot in the dark lol Last night across the pond from my house in fading light needed the bigger hole as there was a sow with three cubs and I wanted better than the 100-400LII could deliver. period

LonelyBoy wrote in post #18368340
Exactly, it's not mostly (or even primarily) about focal length; it's about the size of the front element.

1200/5.6 = 214 (roughly)
800/2 = 400

400mm! (ish) That's big

Thank you all for the well wishing. I guess I did not intend fro this thread to get so O.T. there, but I truly appreciate the kind words at this difficult time.

Off track but I know that a lot of you have a 1.4 extender. I bought a new one today and auto focus will not work. Its with a 6d and 100-400 f/4.5-5.6 is 11. I called the dealer and will try and get it back to them tomorrow.
Anyone else have this issue.

If the 6d won't autofocus at f/8, you're out of luck. I don't believe my original 5D would. Even the 5D3 can only AF with the center point with the 1.4x installed.

He musta got some bad seed

Douglas Conway wrote in post #18369624
Off track but I know that a lot of you have a 1.4 extender. I bought a new one today and auto focus will not work. Its with a 6d and 100-400 f/4.5-5.6 is 11. I called the dealer and will try and get it back to them tomorrow.
Anyone else have this issue.

The 6D will not autofocus with Canon TCs, either 1.4x or 2x. Only manual focus possible. Here on POTN you may find tricks how to tape some pins on the TC to make it (kind of) work, but it does not work very well. I tried other TC's by Kenko and Tamron. They work, but unreliably, and only whe the light is very bright. I had to ditch them all.

I used to have a 70DII until recently - that one auto focused only with a center point or assisted center point focus. The 5DIV that I have now focuses with all focus points. Pro cameras do it too. But not 6D.

Got my MFA tweeked last evening and headed to the lake this morning. Blooms have begun falling from a trumpet vine in an old tree that leans over the lake. It reminded me that I had seen a hummer at a trumpet vine earlier in the week so I went over to take a look. Sure enough the hummer was there. Those little guys are hard to photograph when in stead of one feeder located where you plan to stand in the shade there's a hundred blooms scattered all over the tree and the wind blowing my boat, the sun beating down on the back of my neck. It was typically about a thirty feet shot give or take.

7DII + 1.4II

Douglas Conway wrote in post #18369624
Off track but I know that a lot of you have a 1.4 extender. I bought a new one today and auto focus will not work. Its with a 6d and 100-400 f/4.5-5.6 is 11. I called the dealer and will try and get it back to them tomorrow.
Anyone else have this issue.

You are out of luck. It is intrinsic to the 6d no af at f8. I have the same combo. No go.

I'm going to try a firmware upgrade and see if that works. Thanks for the reply.

Douglas Conway wrote in post #18371828
I'm going to try a firmware upgrade and see if that works. Thanks for the reply.

As far as I'm aware there's no way to (officially) get the 6D to AF at f/8 with any points. The hardware may be capable of it (the 5D3 was released without that feature, and it was added later in firmware) but it's entirely possible the AF hardware in the 6D couldn't do it - regardless of the firmware.

You can AF with TCs on a 6D; you just need a combination that keeps you at f/5.6 max; i.e. an f/4 lens with a 1.4x TC or an f/2.8 (or faster) with a 2x TC.