IS on or off at high shutter speeds?

[Chris Brennan]

I use a 400mm DO with and without a 1.4x as my prime BIF lens and usually hand-held but sometimes on a monopod. Typically, I shoot at 1/1250 and 1/1600. Although I usually have IS off, I noticed yesterday after returning from a BIF trip that I must have inadvertently set IS on, and when looking at my images on-screen, noticed that some images were degraded somewhat, specifically in areas which are normally sharp. Is it possible that having IS on actually added some movement artifacts?

[Doug Brown]

I'm not sure if IS degrades image quality, although I tend to doubt it. I'm fairly certain that it slows AF acquisition. I no longer use it for the vast majority of my BIF work, and I find that I get excellent sharpness without it.

[Roger Clark]

Chris,

I have confirmed degradation of image quality with IS on on the 300 f/4 L IS at high shutter speeds, but have tested and not found any degradation on 300 f/2.8 and 500 f/4 L IS lenses. The 300 f/4 is an older generation IS. I would think the 400 DO is a newer generation so should not have the problem.

Doug, I'm surprised by your statement that having IS on slows AF acquisition. The IS system is independent of the camera (except getting power from the camera. The stabilization should reduce jitter from vibrations that shift the image around that degrade the image, so IS should help AF, even making it more accurate, as long as there is no feedback at high frequency (like in the 300 f/4).

Roger

[Andrew Merwin]

Check out this thread.

http://www.birdphotographers.net/forums/showthread.php?71364-Image-Stabilization&highlight=Nikon+image+stabilization

[Doug Brown]

Doug, I'm surprised by your statement that having IS on slows AF acquisition. The IS system is independent of the camera (except getting power from the camera.

What I was trying to say was that I think you can get shots off faster without having to wait for IS to kick in. I misspoke.

[Chris Brennan]

Thank you Roger and Doug and Andrew for your advice and suggestions!

I went out this morning and shot the same subject matter as I did a couple of days ago (bald eagles) but this time with IS off, and it made a marked difference in sharpness so there is definitely some truth to the matter that IS be off shooting at high shutter speeds.

[Johan Kruger]

This is a very interesting conclusion you came to Chris, def going to give it a try