5DIII and 100-400 Question

Started Jun 1, 2013 | Discussions thread
bhollis Veteran Member • Posts: 3,429
Re: 5DIII and 100-400 Question

qianp2k wrote:

bhollis wrote:

qianp2k wrote:

5D3 works very well with bare 100-400L and AF fast.

I tried 5D3 and 100-400L with 1.4x TC III. It still AF OK under good light but its sharpness is noticeably worse and AF hung under poor light or impractical to track on fast moving subjects. It's not very practical in general to use TC with 100-400L.

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No real surprise that IQ suffers a little with the TC.  But here's the question:  AF issues aside, in focal length limited situations (which are common with wildlife shooting), do you get better IQ with the TC or shooting without the TC and cropping to the same fov you'd get with the TC.  I suspect it's the former.

It depends. I actually have bunch of shots with 100-400L + 1.4x TC III on 5DIII on the above lions at the same spot at the same scene. They are bigger certainly but I still prefer ones without TCs by cropping more as without TC ones are still sharper after cropping. In other side, with small birds I could see the value of TCs although I have not tested myself nor I have seen others' tests to prove 100-400L with 1.4x TC will be better than w/o TC but more cropping in certain scenarios. The only problem is that this lens 100-400L doesn't work well with TC. Depends on what lenses. 300L/4.0 IS (no mention 300L/2.8 IS) or maybe 400L/5.6 works (much) better with TC.

So, you're saying that for the lions at least, you got better IQ by cropping than with a TC.  That's not encouraging.

Well, I'll be giving all this a try myself over the course of the summer shooting wildlife up here in Alaska.  Previously, I shot the 100-400L on a 7D without a TC and got pretty good results.  But I sold the 7D several months ago, and will be using the 5D3 this summer.  I'm hoping to be able to use the 100-400L with my EF 1.4x II to make up for the loss in reach I got with my 7D's higher density sensor.

We'll see how it goes.

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