Canon 300mm f/4 with canon 1.4 or 2X extender (mk3 vs mk2) or 100-400mm

Started Jul 2, 2013 | Questions thread
Howard S Senior Member • Posts: 2,111
Re: Canon 300mm f/4 with canon 1.4 or 2X extender (mk3 vs mk2) or 100-400mm

DGways wrote:

I am presently in the market for my first L lens. I am looking to get a telephoto lens that can get me to 400mm, and potentially beyond, for wildlife photography, mostly birds.

I was convinced that the lens I was looking for was the 100-400mm f/4.5-5.6 because of the l-series build and image quality, and because of the IS. I have also heard good things about the focal range that the lens possesses "saving the day" for some, but I also have my concerns about the lens. I like to manually focus fairly regularly, and when I tried the lens out briefly, the manual focussing capabilities seemed a bit clunky and harder to use than I expected. Also the push-pull design isn't ideal in any way.

When I first got into zoom lenses the push-pull was considered highly desirable, but then we didn't has AF Maybe that's why I still like it.

Then the other day I thought to myself, what if I got a 300mm f/4 which has IS and is definitely easier to manually focus because of the lack of the push-pull design, and theoretically should be sharper than the zoom telephoto because it is a prime. And what if I put a 1.4X canon teleconverter on the lens? then it would be the same as a 420mm lens with f/5.6 and IS. I could also use the lens with a 2X converter to get a 600mm lens with f/8 and IS.

First question: I've seen comparissons like this using the mk2 teleconverters, would autofocus be more usable (on a canon 550d) if I used the mk3 teleconverters with the 300mm lens?

I have a 550D a 300/4 IS, 400/5.6 and Canon and Kenko extenders. I've tried (owned) the 100-400 twice and sold it. The first copy of the 100-400 was sharpest at about the same as my 300/4 +1.4x the second not so good. I convinced myself that I could put up with the focus speed of the 300/4 + 1.4 (Kenko is the fastest focus) and sold my 400/5.6 but I was wrong and had to buy another. It is much faster to focus than the 300/4 1.4x combo on any body I've tried.

So for BIF for me it's 400/5.6 and with a 'pod when general birding with expectation of some BIF. For stuff like dragonflies, butterflies and perched birds the 300/4 + 1.4x combo is my preference.

second question: which will produce better image quality at around 400mm?

third question: how does the 100-400mm lens hold up with a 1.4x or 2x teleconverter on it? how does it compare with a 1.4x teleconverter on it to the 300mm with a 2x on it?

I'm not impressed with any of them with a 2x and of course there's no AF unless in live view. For fun I once put a Canon 2xmk111 on the 400/5.6 and used the Canon M as a lens cap It did AF slowly and here's an image

final question: which is the better choice for me taking my preferences and needs into consideration.

I'd be happy to see any example photos taken in any one of these teleconverter combinations.

thank you for looking! happy shooting.

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