On this trip (Saturday 14 Sept), Mick Roderick allowed me to borrow his 100-400L IS because his 40D was bung. I was really grateful that I had the opportunity to test this lens at sea, because so many people use it as a pelagic lens.
I was extremely impressed with the lens overall. It operates really well on the boat. On the times when the focus locks on, it is always sharp, unlike other lenses (including the Bigma) where it is sometimes sharp or sometimes almost-focused. Having said that, the amount of detail the 100-400 was capable of resolving was less than that of the 300 f4, but it operated at its highest resolution much more frequently than the other lenses.
The push-pull mechanism works very nicely on the boat, very easy to work with, and the zoom was an excellent range for the conditions. The focus limiter (to 6.8m) is a must, the lens focuses a lot quicker with the limiter on.
This bird is a Southern Giant-Petrel, the first photo of the species I have uploaded so far. It was only the second time I had seen one. Love the detail from the 100-400 here. You can see the very pale green that tells this bird from the similar Northern Giant-Petrel (which is more reddish-brown). In some birds (rarely), it is impossible to tell because the colour hasn't developed yet. The birds we get off Wollongong are all (nearly all) young birds like this one. The dark brown plumage is a feature of both young Giant Petrels.
Africa (entire continent rather than south of Sahara)
AN
Antarctica
AO
Atlantic Ocean
AU
Australasia (Wallacea (Indonesian islands east of Wallace's line), New Guinea and its islands, Australia, New Zealand and its subantarctic islands, the Solomons, New Caledonia, and Vanuatu)
PAL
Eurasia (Europe, Asia from the Middle East through central Asia north of the Himalayas, Siberia and northern China to Japan)
IO
Indian Ocean
LA
Latin America (Middle and South America)
MA
Middle America (Mexico through Panama)
NA
North America (includes the Caribbean)
NO
Northern oceans
OR
Oriental Region (South Asia from Pakistan to Taiwan, plus Southeast Asia, the Philippines, and Greater Sundas)