Loss of sharpness due to image stabilization?

[ken schwarz]

Hi,

 

I am using a 17-55mm F2.8 zoom on a Canon 30D body. I am finding that I get

noticibly sharper results with IS turned off when I shoot handheld at

reasonably high shutter speeds (1/125", for example). Of course, at very slow

speeds, IS is a big help. I had assumed that IS would never subtract from image

quality, but it looks like I should use it only when needed.

 

Are others finding this to be the case with this lens or others in the Canon

lineup? Or, does this indicate a problem with the lens that I should be able to

have fixed?

 

Thanks,

 

- Ken

[beauh44]

Hi Ken, I'm not sure if it indicates a problem but it *sounds* like one to me. I leave IS on all the time on almost all (but my oldest) lenses that have it with no problems like you describe. (Older IS lenses didn't like being put on tripods with the IS turned on; newer ones don't mind) I'd thoroughly check it again and if it consistently misbehaves at higher shutter speeds, at least give Canon service a call and see what they say. It's very odd because it would seem the IS would work fine or just fail altogether. I dunno... Good luck!

[sheryl_bury_michals]

Beau - how old are you talking about? I have a Canon 100-400 IS lens I use for rugby match shooting, and my understanding was when I got the lens (per Canon info), that the IS goes on when you're not using a tripod. Most of the time, I use a tripod, as it's not a lightweight lens (including the 30D attached to it)- but I love it regardless.

 

BTW - I've had the lens since 2001, if that helps.

 

sheryl

[gary petersen]

It is odd. I do not have this problem with either of my IS lenses.

[brian_goodman]

I have the 17-55 F/2.8. If what you are describing is truly happening; then yes, you have a problem with your 17-55 that needs to be fixed.

Good luck.

[mars c]

When you use IS, you should wait at least 2 seconds for it to stabilize, otherwise , you'll get softer image.

 

Try shooting with IS on and half press the shutter button for at least 2 seconds, and shoot, then compare it with IS off.

 

Keep us posted about the result.

[william_fong]

Do you have a sample picture? One with IS on and one with it off?

[scottelly]

I would like to see some comparisons of similar pairs of shots taken while walking, running, moving in a car, standing still, and tripod mounted with IS on and off at 1/15 sec., 1/30 sec., 1/60 sec., 1/125 sec., and 1/250 sec. That's just 10 photos in each situation for a total of 50 photos (25 pairs in 5 groups of 5 pairs per group).

 

Then I can help you. lol

[lester_wareham]

I have done sharpness tests on IS lenses to see how effective the IS system was, the top end of the test shutter speed range was about 3 stops above handholding speed and did not show any loss of sharpness.

 

Also I have never noticed any loss in everyday use.

[musubi1000]

Maybe it's not the lens fault at all since 125th of a sec isn't all that fast. How did you shoot the shot? was the subject moving? Were you panning the camera? A 125th of a sec shutter w/ IS won't stop anyone moving quickly. Are you misinterpreting the subject/and or movement blur for lens focus/ sharpness?

[beauh44]

Hi Sheryl,<P>

 

<I>Beau - how old are you talking about? I have a Canon 100-400 IS lens I use for rugby match shooting, and my understanding was when I got the lens (per Canon info), that the IS goes on when you're not using a tripod. Most of the time, I use a tripod, as it's not a lightweight lens (including the 30D attached to it)- but I love it regardless.</i><P>

 

Ya know, I couldn't give you an exact date but it was the earliest IS implementations that didn't get along with tripods. In fact, to this day, much of Canon's documentation (inaccurately) warns against leaving IS on when the lens/camera is mounted to a tripod!<P>

 

I <I>think</i> (but could be wrong) that my 28-135mm IS lens doesn't like it if I leave IS on when it's on a tripod... something about the lens's "brain" is expecting movement of some kind and if there is none, something goes awry.<P>

 

I believe both my 70-200 f/2.8L IS and 500mm f/4L IS (again, incorrectly) warn users to turn their IS off if mounting the lens(s) on a tripod, when in fact, it's fine. This, I believe, is a hold-over from the days when it wasn't fine.<P>

 

In fact, even when my 500mm "bazooka" is mounted on a tripod, it's such a huge thing that a gust of wind can move it a bit, so IS helps even when it's on a tripod. I think Canon finally figured that out.<P>

 

I honestly have no clue about your lens as to whether it's OK to leave IS on or off while it's tripod-mounted, but I'm sure someone here does! (You really can't trust Canon's documentation that ships with the lens on this unfortunately) I suppose you could try it - I don't think it'll break anything... you'd just get unsharp images if you leave your IS on and it's one of the older models. Good luck!