IS blurry pictures

[alexturton]

I've been shooting with canon 7d and 17 55 is2.8 for a while and find that At slow shutter speeds it definitely improves hit rate but at faster shutter speeds IS actually makes my shots more blurred, is that normal? Or am I doing something wrong?

[J.R.]

Unlikely that IS should degrade shots. What was your focal length and shutter speed? Also, what were you shooting?

[bjornjd]

Something is wrong, I have been using that lens for years and almost always had IS turned on, slow shutter speed or not. My experience is that the 17-55 IS is fast to lock on and nails the focus almost every time.

It's a truly great lens

[tron]

How much faster speeds? Faster like 1/125 or faster like 1/1500?

[Marsu42]

ut at faster shutter speeds IS actually makes my shots more blurred, is that normal?

There are broken IS systems out there, but at high sutter speeds some IS system certainly have the potential to degrade the shots - at least this is the case for Nikon's VR, read "VR should normally be off if your shutter speed is over 1/500": http://bythom.com/nikon-vr.htm ... I don't see the Canon IS should do otherwise:

Indeed, if you go down to the sidelines of a football game and check all those photographers to see how their lens is set, you can tell the ones that are really pros: VR is usually off (unless they're on a portion of the stadium that is vibrating from fan action). Those pros have all encountered the same thing you will some day: if you have a shutter speed faster than the sampling frequency, sometimes the system is running a correction that's not in sync with the shutter speed. The results look a bit like the lens being run with the wrong AF Fine Tune: slightly off.

Personally I'm always turning off IS on my 70-300L when expecting to shoot faster than at 1/500s, and if for the reason alone to extend the IS lifetime. Probably the latest IS systems on 10k+ tele primes might behave better, but I wouldn't know about that :-p ... the IS on the op's ef-s 17-55 an older generation.

[rs]

Unless I'm shooting on a tripod, I leave IS on my 17-55 turned on. I never get any blurring like you describe at higher shutter speeds.

Unlike you I'm only using a 10MP sensor behind that lens, so I'm not able to examine what the lens resolves in such detail. Having said that, the 7D only has 33% extra horizontal and vertical resolution, so I wouldn't have thought it makes blur I can't see that much more noticeable.

Have you got any example shots showing the problem?

[Marsu42]

Unless I'm shooting on a tripod, I leave IS on my 17-55 turned on. I never get any blurring like you describe at higher shutter speeds.

Innocent question: How would you know since you always enable IS? The difference is not that large, but noticeably when comparing shots side by side @100% crop with IS on and off. And of course the lower resolution might make the problem even harder to detect.

[sanj]

Something seems wrong. I have been shooting at high shutter speeds 1/1000 and above for years and have never noticed IS making a picture soft.
I believe you should get the lens checked.
Attached is a photo shot at 1/1250

[bjornjd]

This is what I get with a Canon 50D and 17-55 with IS turned on and fast shutter speeds.



(Click the crop to get 1:1 res)

I have always left IS on when handheld so I can't compare it to non-IS pictures unfortunately, but I have always found the lens sharp and never felt a lack of sharpness

edit: I uploaded the crop as a .png to avoid compression, but I see that imgur has converted the file to a jpeg.
Therefore, I have included the png as an attatchment to this post.

[bdunbar79]

I shoot sports only and I hate IS.  My hit rate in lower-lit gyms is actually a lot lower with it on.  I just shoot at slowest 1/500 and leave it off and I'm absolutely fine.

[East Wind Photography]

Might not be the IS at all.  Could just be normal wear on the AF system.  Have you tried a micro focus adjustment to see if it's front or back focusing?

[7enderbender]

That wouldn't surprise me at all. I don't like the whole idea and I don't understand why so many people are screaming to get even more IS lenses. It's really one of the more useless features in my opinion. Yes, you can use it in low light to turn a completely useless shot into something that may pass as a good enough snapshot. Other than that it has no practical value.

[East Wind Photography]

One of the biggest benefits I have seen for IS is when I use my big telephoto on a tripod and the wind is blowing like mad.  The IS seems to dampen the effects of the wind not only allowing slower shutter speed but also giving the AF system a chance to get focus on something.

I've been told it also helps the camera recover from shutter vibration in drive mode.  From a practical sense I just haven't experienced that but I could also see the possibility that at some shutter speeds the IS could jump when the shutter fires.

My general rule of thumb is to only use IS when the light is poor and I don't want to sacrifice IQ by raising the ISO.  Other than that try for 1/2000 or faster and no IS.

That wouldn't surprise me at all. I don't like the whole idea and I don't understand why so many people are screaming to get even more IS lenses. It's really one of the more useless features in my opinion. Yes, you can use it in low light to turn a completely useless shot into something that may pass as a good enough snapshot. Other than that it has no practical value.

[alexturton]

Might not be the IS at all.  Could just be normal wear on the AF system.  Have you tried a micro focus adjustment to see if it's front or back focusing?

Thanks everyone for your responses

Can af wear over time? Can accuracy decrease over time?

I know my 7d front focuses by 8 mfa points following a service by canon (grrr) but I've adjusted for that

[agierke]

i agree with others that IS is totally overrated and i tend to avoid using it at all costs.

its one of those things that if the situation absolutely calls for IS then fine but i think those situations are rare. its not a cure all intended for all situations all the time. the best solution is to increase your shutterspeed and compensate exposure through other variables.

also, practice steadier handholding techniques and breathing...these things can help more than you could imagine. i taught a class where one of my students was former military and i was asked how do i hold my camera. when i demonstrated wrapping the strap around my arms for steadiness and keeping both my eyes open when looking through the viewfinder, my Ex-military student commented how thats exactly how the army teaches steadiness when shooting a rifle. he also added that they teach controlled breathing in that the body is most at rest at the end of an exhale. the body tends to get jittery when you hold your breath and he advised against doing that. interesting stuff....any Rifle experts in here that can corroborate that?