An IS Question

Been reading about how the 24-105 IS L has a 3-stop IS? Does this mean that with IS on that it is compareable to a f1.4? Some how I think I am greatly confused. And I know I should have asked this question before I bought it, and it really doesnt matter to me but I am curious if someone can tell me (and others) what the 2-Stop, 3 stop and new 4 Stop IS really means. Thanks.

It has nothing to do with aperture. Is what they are talking about is shutter speed.

The rating of IS is how many stops slower you can handhold the lens with IS on vs. what you could normally handhold the lens with IS off without getting blurry images.

So either 2 stops slower than what you normally could handhold the lens at or 3 stops slower than what you could normally handhold at. Obviously more stops is better as it means you can shoot at even slower shutter speeds handheld

I see so

Say with out IS you need 1/600th to take the image. With it on you can go to 1/125 second or whatever 3 stops would be. If that is what that is, makes a whole lot more sense to me then what I was thinking because Aperture Stops wouldn't make any sense. Because why would anyone waste any money on a 1.2 or 1.4 L lens if it went down to that. LOL

Exactly

cjm wrote in post #3153994
I see so

Say with out IS you need 1/600th to take the image. With it on you can go to 1/125 second or whatever 3 stops would be. If that is what that is, makes a whole lot more sense to me then what I was thinking because Aperture Stops wouldn't make any sense. Because why would anyone waste any money on a 1.2 or 1.4 L lens if it went down to that. LOL

DOF and IS won't stop action. But i guess I see where you got confused.

Also forgot to add that another good thing about newer IS is that it takes less time to engage fully. For example some older IS systems will take 1 - 2 seconds to fully stabilize. The one on the 24-105L which is newer takes around half a second or less!

Greetings,
There is one important thing that many fail to see the advantage when comparing IS and large aperture lenses. I do indoor events, and required to take group photos. Therefore, I need to have smaller aperture for that DoF. IS helps tremendously as shutter speed has to be slow. This is something large aperture lenses alone without IS won't cut it in this case. Enjoy...

As noted IS lets you use lower shutter speeds without camera shake, or at least with reduced camera shake. It is not the same as a faster aperture which would help freeze action and reduce depth of field for subject isolation. Also as noted this can have an advantage of providing more depth of field is subject movement is not an issue.

My tests for the 24-205 indicate more like 2 stops although it might stretch to 3 stops if you lower the standard of sharpness.

I was out taking pictures today in the wild and I was thinking about this thread.

The 3 Stops are more like ISO stops then any other. Any of us knows that if you increase ISO you get a faster shutter speed. The IS on a lens simply allows you to get a shot at 200 ISO that you would have to have it on 400 ISO or 800 ISO to get.

Does this make any sense?

Yep.

cjm wrote in post #3157367
I was out taking pictures today in the wild and I was thinking about this thread.

The 3 Stops are more like ISO stops then any other. Any of us knows that if you increase ISO you get a faster shutter speed. The IS on a lens simply allows you to get a shot at 200 ISO that you would have to have it on 400 ISO or 800 ISO to get.

Does this make any sense?

Your line of thinking here is quite incorrect in my opinion. It's true that if you used a higher ISO speed, you could have a faster shutter speed. However, IS does NOT provide a faster shutter speed or even the equivalent of a faster shutter speed. IS will do absolutely nothing towards stopping motion of the subject like an actual faster shutter speed will.

All IS does is compensate for actual camera/lens movement and prevents or reduces blur of your image due to camera/lens movement. Too often folks think that IS is the same as cranking the shutter speed to a faster setting, and it isn't that at all.

If you understand the basics of how IS works, it all makes sense. There are at least two gyroscopes spinning in the lens. They detect movement in either (or both) of two directions (up/down or side/side) and actually move a lens element to counteract the effect of the movement on the image. In other words, you can deliberately wiggle the camera/lens around a little and see in the viewfinder that IS is keeping the image relatively steady.

Does this help answer the questions?

Yup Skip. Thanks.

IS is the most confusing thing I have come across with lenses to date.

cjm wrote in post #3157800
Yup Skip. Thanks.

IS is the most confusing thing I have come across with lenses to date.

there's plenty of confusion and misinformation about IS on these forums. bottom line is the 24-105L is a better low light lens than the 24-70L if you are hand holding.

i see you have another IS lens. did you not use the 300L f4 IS much?

ed rader

I use the 300mm IS all the time on a monopod and out doors in bright weather. It seems to make a difference, I think sometimes. I had a 28-135 IS (1st generation IS, I think) but to be honest I only used the IS at the very end of me owning that lens so I couldn't say either way if it worked or not.

Guess I will find out the differences when I get the 24-105 L some time this week. Then let the side by side comparisons begin!