juzaphoto posted a comprehensive hands-on review of a pre-production Canon EF 200-400mm f/4L IS 1.4x, the lens that’s still not available to the public. No sample pics have been published, it is not allowed by Canon. One interesting fact, they write:
Now it is getting close to release: if everything goes well, it should reach the market in mid 2014.
Mid of 2014? This is new! We didn’t have any hint that Canon may release the Canon EF 200-400mm f/4L IS 1.4x in mid 2014. That is another delay. Will this lens ever be released?
In the conclusion they write:
A lens like that has its pros and cons. Its zoom range is very versatile; AF is fast, and the built-in teleconverter is handy. The main cons are its weight – it is similar to the big 600 f/4 – and the f/4 aperture. In very low light a 300 f/2.8 or 400 f/2.8 have an advantage, even tough with recent cameras as the 1DX you have such great ISO capabilities that you can compensate a bit for the one stop difference.
Even though personally I am a big fan of the 300 f/2.8, I can see two potential customers for this lens: sport photographers and the nature photographer that shoots mainly from hides or car, as in safaris. In these cases the weight of this lens is not a problem, since you don’t have to carry it around, and the versatility of the 200-560mm zoom range is a great plus.
One last thought is about price and availability. Canon has not said anything about price, but it won’t be cheap – my bet is between $9000 and $10000 [...]