16-35 f4 IS 'tripod sensing' IS

Skipmaster J wrote in post #17296649
Try a 30 second exposure and post your results
2 seconds doesn't give enough time for the IS to screw things up

Damn! I posted the wrong image. When I did the test I saw there was zero difference at 2s, so I repeated it with a longer exposure. I didn't realise I'd processed and saved the 2s data.

Here's a comparison of the 24-105 and the 100-400 with a 22s exposure....

Are these on a tripod? If so how come the bottom left one is so badly blurred? Assuming that's IS off should it not be sharp (I'm not trying to be argumentative here, I'm just wanting to know what these are showing me)

xpfloyd wrote in post #17297133
Are these on a tripod? If so how come the bottom left one is so badly blurred? Assuming that's IS off should it not be sharp (I'm not trying to be argumentative here, I'm just wanting to know what these are showing me)

They are both shot on a tripod. The left one of each pair is with IS on, the right one of each pair is with IS off. The top pair is the 24-105 (with tripod-sensing IS), the bottom pair is the 100-400 (with non-sensing IS).

With the 24-105 the IS senses that the camera is on a tripod so it switches the IS into a special 'Tripod' mode.

The 100-400 doesn't know that it's on a tripod. The IS system starts looking for some movement for which it can compensate. It ends up in a feedback loop where it slowly wanders about, resulting in a horribly blurred image.

The pair of images demonstrate the difference between 'tripod-sensing' and 'non-sensing' IS systems. It's easy to test and pretty darn obvious which you have. It's not the subtle difference that some people seem to expect.

hollis_f wrote in post #17296015
Er, excuse my skepticism, but... Says who?

I've never heard either allegation before.

I don't use second hand information. I only speak from personal experience (respected 30 year pro with 25,000 publications including National Geographic).

I don't shoot charts.

That's pretty conclusive frank, thanks for posting. I haven't actually tested my lens like that yet

Great test, Frank. That is one of the things I do not like about the current 100-400L. I sometimes forget to turn the IS back on after using the lens on a tripod, and I wonder why the image is moving around so much in my viewfinder. I will be taking care of that little problem soon, as the I have a sale pending on my 100-400L, and am sure the MKII version will be better on a tripod with the IS on.

I guess it's an old school thing, I keep IS off unless I need it. The only time this hasn't worked out was last summer while photographing a black bear on my deck from about 30 ft. away. Apparently I had the shakes