[quote:7f4497891d="hkwongkit"]
My advice is to have IS switched off whenever shooting birds in flight as IS introduces some sort of time lag before it stablizes enough.
[/quote]
Thank you for the advice!
quote="hkwongkit"]
The EF300/4L IS incorporates a first-generation IS with a claimed gain of 2 f/stops for hand held photography. This can easily be verified shooting stationary subject handheld under relatively poor lighting conditions.
The IS system in this lens has 2 modes - one for static shooting (both horizontal and vertical stabilization) and a panning mode (horizontal or vertical stabilization - the panning direction is automatically detected). Unlike the 2nd generation IS used in EF400/2.8L IS, EF500/4L IS & EF600/4L IS the variant of the 300mm f/4 L IS has no tripod detection so IS needs to be switched off here in order to avoid interference effects.
[/quote]
I have just done a prelimary test on the lens (IS mode 1 on & off) +1.4x with 20D and 1D2n
ISO 800 1/60s --- not much difference.
ISO 200 1/10s --- it seems that it works ok.
I will do some more static shooting to test the lens (with IS mode 1 on & off ) with following:
300 1/30s to 1/125s; 300+ EF1.4x 1/40s to 1/200s - effective shutter speeds, as mentioned in the instructions booklet. (as the lens & 20D had a short distant dropped inside a vechicle in earily this year.
)
Thanks a lots KK!