Canon Image Stabiliser

[fox1]

Just purchased a mint 28-135mm IS lens, the initial
results seem disappointing..in fact my 75-300mm non
IS lens performs better.

How can I tell if the IS system is actually working.?

[chris maddock]

When you half-press the shutter release, you may see the viewfinder image jump slightly before stabilising with less shake than you got before pressing the button.
You may also see a jump after taking a shot.
If you're still not certain try half-pressing the shutter button whilst holding the camera with the lens close to your ear - you should hear a slight whirring sound from the lens, that is the IS in action.

This is all assuming you do have it turned on ;-)

KRs
Chris

[fox1]

Yep I can hear the whirring... what's the minimum
speed for hand holding.?

Should I select 'P' of 'M'? My shots today were taken
F8 in 'AV 'mode. ? - Canon D10

[chris maddock]

fox1 wrote:
Yep I can hear the whirring... what's the minimum
speed for hand holding.?

Should I select 'P' of 'M'? My shots today were taken
F8 in 'AV 'mode. ? - Canon D10

One would normally expect to need 1/125 sec at the long end, but taking the crop factor into account that would become 1/200 or even better 1/250 sec. That is, of course, only a rule of thumb and will vary between individuals - and even for the same person depending on fatigue, caffiene intake, etc.

The IS should allow you to cut that by 2 stops - to 1/60 sec.

It shouldn't matter which mode you use, provided that the shutter speed is high enough. I normally use Av @ f8 as a starting point, but adjust aperture or ISO when needed to get the shutter speed I want.

KRs
Chris

[Mark Kemp]

You can also turn off the IS and looking through the viewfinder try to hold a focus spot over a small object far away. Do this at the long end. Then turn on the IS and see how much easier it to keep the focus spot still.

Camera mode doesn't matter, IS really relates to the shutter speed.

Conventional wisdom is that the slowest shutter speed you can safely use (no IS) is 1/focal length, so at 135mm this means 1/180th, but to be on the safe side 1/250th with a digital (small sensor).

Conventional wisdom (which seems about right from my experience) also says that IS allows you to go about 2 stops down on the non IS settings so instead of 1/250th you could get away with 1/125th.

This is not a hard and fast rule - in practice the slower the shutter speed the more likely you are to get camera shake and the worse it will be. IS gives you a better chance to avoid or reduce camera shake when you have no other choice.

It can work - I have a shot that has done well for me in competitions when I had to rely on the IS and handhold at a very low shutter speed. It has done quite well in competitions, so I was very pleased to have IS.

[fox1]

Thanks guys...

I like the bit about Caffiene intake. :D

What about the demon beer.? :D :D

Seriously though, I have taken your advice on board
and look forward to a more successful session than
the initial one experienced today. :(

[topeju]

Mark Kemp wrote:
Conventional wisdom (which seems about right from my experience) also says that IS allows you to go about 2 stops down on the non IS settings so instead of 1/250th you could get away with 1/125th.


Just a minor nitpick here: it is a single stop from 1/250th to 1/125th. It would be two stops to go from 1/250th to 1/60th. I do agree with the rest of your post though.

One way I also notice that IS is operational is to pan the image while the shutter button is depressed halfway down. I tend to get a slight headache (well, not quite, but it does feel "wrong" somehow:)) from the way the viewfinder image lags behind, then jumps when IS can no longer compensate.

[whitema]

I had my 28-135 IS for about 3 years & after the initial excitement of having the lens realised that my shots were not quite as sharp as I would have liked. I initally purchased it to shoot handeld sunsets, etc.

I proceeded to do my own test using tripod, wall calendar, etc then hand held shots.

I discovered it was basically the same optically as my 28-105mm f/3.5-4.5 and considering the 28-135 is flat out at f/5.6 the extra 2 stops supposedly gained through IS would be offset with the max av (f4.5) of the 28-105.

From 70mm-135mm on the 28-135 IS at max aperture the image quality is very poor. Even at f/8 it doesn't get a whole lot better. Whereas the 28-105 at f/8 produces images on a par with my 50mm f/1.4 & 100mm f/2.8 macro.


I've sold the lens now and don't regret it. I shoot basically prime lenses anyway with the 10D & no matter what anyone says you can tell the difference between a prime lens and a prosumer zoom.

Anyway enjoy your lens & remember it's the content & framing of your photo that's really the most important.

[fox1]

>I had my 28-135 IS for about 3 years & after the initial excitement of having the lens realised that my shots were not quite as sharp as I would have liked. I initally purchased it to shoot handeld sunsets, etc.