Kenko 1.4x on my Canon lenses - mixed feelings

Started 6 days ago | Discussions thread
Andy01 Senior Member • Posts: 1,050
Re: Kenko 1.4x on my Canon lenses - mixed feelings

If I had to guess I would say that your 100-400L is almost certainly back focusing. Look at the tree under and behind the pigeon - it is sharper than the bird.

A 100-400L should certainly deliver better results than that, even the original version and the ii should be better again.

This is an image I took recently while traveling for work, so I borrowed an original 100-400L from a friend, so no MFA.

Now this was obviously not as far away as yours and this is where distance, atmospheric conditions etc come in to play, and a poor performing setup amplifies those atmospheric challenges much more than a high-end setup. This might be the point that was trying to made above.

I don't think you can do MFA on a Rebel, so you are either stuck with, send it to Canon for calibration, or buy a better body.

As for the TC, I have no personal experience other than to say that most likely the reason that Canon TCs do not work with lower end bodies and lenses is to avoid people complaining about poor results with them. Even with the best bodies, best big whites and latest 1.4x Canon TC, the IQ is compromised, because that is what a TC is - a compromise. Using cheap versions of the 3 components is never going to yield great results.

IMO, the first image with the 250mm + TC is truly awful and I would certainly not be happy with it, and does not compare with the second image with the 400mm (which is also not great, but significantly better), but there does not seem to be a huge degradation between the bare 400mm and 400mm + TC.

The other comment I would make is that personally I would drop the aperture down to f8 to get the shutter speed up a bit. The IS on the 100-400L ii is very good, but shooting small subjects far away at long focal lengths can usually benefit from the highest possible shutter speed. 1/640th on a APS-C at an equivalent FF focal length of 900mm may be marginal in this situation.


 Andy01's gear list:Andy01's gear list
Canon EOS M5 Canon 6D Mark II Canon EF 24-105mm f/4L IS USM Canon EF-M 11-22mm f/4-5.6 IS STM Canon EF 100-400mm F4.5-5.6L IS II +1 more
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