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

Started Jul 2, 2013 | Questions thread
bhollis Veteran Member • Posts: 3,735
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.

Actually, a lot folks--me included--really like the push-pull design.  Perhaps it's an acquired taste.

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.

The 300 f/4 will be sharper--until you put a TC on it.  With a 1.4x TC, the 300's IQ is about on a par with the 100-400.  But the AF is slower.  OTOH, the 300's IS is better.

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?

Most reviews I've read put the IQ of the 1.4x II and III TCs as too close to worry about, while the 2x III is supposed to be noticeably sharper than the 2x II.

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

As noted above, about on a par.

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?

Not well.  The first thing you need to understand is that if you put a 1.4x TC on the 100-400, you've turned it into a 560mm f/8.  Similarly, if you put a 2x TC on the 300, you've turned it into a 600mm f/8.  And the fact is, most Canon cameras don't AF well, if at all, at f/8.  You can try taping pins on TC's so the camera doesn't know the TC's there and will continue to try to AF at f/8, but the results will be hit and miss at best.

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

If your primary interest is birds, I'd recommend the 400 f/5.6L.  Although it doesn't have IS, for birds in flight, you don't really need IS.  If you're interested in all kinds of wildlife shooting, I'd recommend the 100-400L for its versatility.

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

I recently tried shooting my 5D3 (which just got a firmware upgrade to allow it to AF at f/8) with my 100-400L and 1.4x TC II.  Wasn't happy with the results--AF was so slow/inaccurate that I didn't get any shots I thought were worth keeping.

thank you for looking! happy shooting.

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