IS lenses not so stable?

LongLensPhotography

LongLensPhotography

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I am having some hard time understanding the real point of IS.

While they seem to prevent horrible camera shake, at slower speeds (1/40s for 200mm for example) the images still seem to have a little softness. They are just usable for web or 5x7, and certainly no good for large printing. Even at very high speeds (1/4000s) they seem to throw in some duffers if I don't let it stabilise for a second, but just shoot on the move :cuckoo:
It is still almost like it's best to use flash when it's darker or move to the 'safe' 1/160s+ by that time IS is just no more necessary.

I just got a deal on 70-200/4 IS, but I honestly fail to see how it is any better over my non-IS optically. Each has a very slight edge at different settings, and both are just as bad with 1.4x (slightly soft wide open, awful bokeh). The IS was supposed to be the killer feature, but I just don't get it. I briefly had 24-105 and came to similar conclusions.

Please explain.
 
It seems that perhaps IS is just not for you? Better for your wallet.
 
IS or VR in my case is not something I have switched on if I am shooting at 1/4000s.

It serves no purpose and there is plenty of anecdotal evidence that suggests it does introduce softness if used at such speeds.
 
If you are shooting at 1/40th at 200mm, you are likely to be shooting wide open. When wide open, you may have softness inherent in the lens design anyway but when printing something very large and viewing it closely, the standard DoF rules don't apply. What you are probably seeing in that case is the out of focus areas in the image. A lens only has a single plane that is completely in focus. Everything else is out of focus to a greater or lesser degree. It's just whether you see it or not when you print the image.
 
daugirdas said:
I am having some hard time understanding the real point of IS.

While they seem to prevent horrible camera shake, at slower speeds (1/40s for 200mm for example) the images still seem to have a little softness. They are just usable for web or 5x7, and certainly no good for large printing. Even at very high speeds (1/4000s) they seem to throw in some duffers if I don't let it stabilise for a second, but just shoot on the move :cuckoo:
It is still almost like it's best to use flash when it's darker or move to the 'safe' 1/160s+ by that time IS is just no more necessary.

I just got a deal on 70-200/4 IS, but I honestly fail to see how it is any better over my non-IS optically. Each has a very slight edge at different settings, and both are just as bad with 1.4x (slightly soft wide open, awful bokeh). The IS was supposed to be the killer feature, but I just don't get it. I briefly had 24-105 and came to similar conclusions.

Please explain.
Click to expand...

Several things that spring to mind, the basic principals of photography still apply, the lenses may not be at their sharpest wide open, poor lighting or position of the lighting can lead to the image appearing soft, the low shutter speed allows subject movement.

The skill and experience of the photographer will also have a bearing on the image captured and it's quality.

Personally my main concern with a lens is it's optical quality, I do not care for IS/VR, it is of no importance to my choice of lens, in fact the majority of my lenses do not have it, and on the two that do, I rarely switch it on.
 
arad85 said:
If you are shooting at 1/40th at 200mm, you are likely to be shooting wide open. When wide open, you may have softness inherent in the lens design anyway but when printing something very large and viewing it closely, the standard DoF rules don't apply. What you are probably seeing in that case is the out of focus areas in the image. A lens only has a single plane that is completely in focus. Everything else is out of focus to a greater or lesser degree. It's just whether you see it or not when you print the image.
Click to expand...

Obviously it is wide open, but then it is 70-200mm so that shouldn't matter.

I have comparison shots of the same target shot at 1/200s with bounced flash. The sharpness difference is overwhelming. The lens is razor sharp wide open at decent speeds, or else it would be on it's way back this afternoon.
 
Wide open with a 1.4x TC is a mistake, you need to drop at least one stop from maximum aperture to get anything like a decent result. Nothing to do with IS at all.

As for soft images if you don't wait for it to spin up - YES! Don't do it, spin it up, then release.

Canon's IS is very good... unlike Nikon's VR or at least on every lens I've had with it. On Canon I used to shoot with it on all the time on both 70-300 IS and 300 f4 IS.

You can see some odd bokeh effects with IS/VR, but thats never been a problem for me to be honest.
 
daugirdas said:
I have comparison shots of the same target shot at 1/200s with bounced flash. The sharpness difference is overwhelming. The lens is razor sharp wide open at decent speeds, or else it would be on it's way back this afternoon.
Click to expand...
In which case it's your technique.

Razor sharp with a bounced flash means the flash (at 1/xxxxth of a second pulse duration) is what's taking the picture - NOT the 1/200th shutter speed.

The fact it isn't sharp is saying you can't handhold at 1/40th with a 200mm lens and still have the IS system totally compensate for your technique. Try taking the same photo with the non-IS version of the lens at the same setting and see which you prefer - that's the point of IS ;)

FWIW, for me to be happy with my photos not being blurred by motion I try to use a different 1/focal length rule. I try to use 1/(fl x 1.5) - and that's on a full frame camera.
 
I must admit that I've only had two DSLR IS zooms and one for MFT so my IS lens sample is rather small but I've always found IS to be little short of amazing, allowing me to use unbelievable shutter speeds compared to non IS. Even the IS on my LX5 is impressive.
 
Technique is key to using any zoom or long prime. Master the technique and things like IS and higher ISO become an aid not a requirement.

Although i do not have it on my 70-200, i did not see the point and it kept the cost down, i do have it on the 100-400.

I can count on the fingers of one hand the the times that i have turned it off. Sometimes it can mean the difference between getting a shot and not.

Here is an example,
[url=http://www.flickr.com/photos/mjkcanon/6526924877/] Irina by MJK Canon, on Flickr[/URL]
Shutter Speed: 1/200Sec.
Aperture Value: F5.6
ISO Speed: 800
Lens: EF100-400mm f/4.5-5.6L IS USM
Focal Length: 400.0 mm
 
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desantnik said:
Wide open with a 1.4x TC is a mistake, you need to drop at least one stop from maximum aperture to get anything like a decent result. Nothing to do with IS at all.

As for soft images if you don't wait for it to spin up - YES! Don't do it, spin it up, then release.

Canon's IS is very good... unlike Nikon's VR or at least on every lens I've had with it. On Canon I used to shoot with it on all the time on both 70-300 IS and 300 f4 IS.

You can see some odd bokeh effects with IS/VR, but thats never been a problem for me to be honest.
Click to expand...

^^^ This.

Obviously if you don't wait for it to stabilise (all of half a second) then you're liable to get blur as the image shifts up as the system centres into position. If you're pointing and shooting very quickly, then engage the IS immediately you start to raise the camera to your eye with half pressure on the release and it will be ready before you are. Then AF on the back button.

There is another argument, popular with some Nikon users but I've never seen any pictorial evidence to support it, that at shutter speeds when IS is not necessary, the movement of the system itself can induce very fractional blurring. The critical speeds are alleged to be around 1/1000sec.

I did a load of tests around this when the now absent (and missed :() Arkady raised it with his usual vigour, and couldn't find any evidence. I've just tried it again, with the same 70-200L 4 IS, at 200mm on FF and 1/1000sec, then with flash, and the most notable observation I can make is that they are so similar, time after time.

At longer speeds, the advantage of IS is massive. I do turn it off on a tripod though. This stuff about tripod sensing isn't true ;)
 
Thanks, a bit of patience does help a lot with that lens.

I managed to go out to Clevedon today and try out the lens in the windy conditions. On 1DsII I managed pin sharp shot all the way down to 1/13s, a couple at 1/30s, but also had a number of slightly blurry ones at 1/60s. The non-IS lens would have been on tripod, although with a 100% hit rate. The shutter is very powerful on 1Ds and clearly induces more shake than needed.
I've had a play with 1DIII at home using 's' for slow or silent (?) mode and the hit rate at 1/30s was very high. It also seems to make a very positive difference for all my non-IS lenses, the shorter ones can work great down to 1/50s or even 1/30s. I think my new main body should have this feature.
 
Remember though, IS is just another tool to use. Starting with higher shutter speeds in windy conditions and learning how to deal with camera shake are better than trusting anything else or used in combination with IS give consistant results.
 
daugirdas said:
While they seem to prevent horrible camera shake, at slower speeds (1/40s for 200mm for example) the images still seem to have a little softness.
Click to expand...

Doesn't surprise me in the least, and I've seen the problem mentioned before!

Optical Image Stabilisation is an ugly kludge - a legacy from film days when there was no other way to do the job. If Canon and Nikon were to start again with a clean drawing board they would use In Body Image Stabilisation. No doubt about it.

Ever since Galileo Galilei, lens system designers have taken great pains to align lenses on a common optical axis, and secure them such that they stay aligned. Moving a lens out of alignment must inevitably result in optical compromises with consequent image degradation.

Jim
 
Jim Ford said:
If Canon and Nikon were to start again with a clean drawing board they would use In Body Image Stabilisation. No doubt about it.
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Not sure about that. While sensor stabilisation is good for shorter focal lengths, Lens stabilisation is better for longer focal lengths, and longer focal lengths is where stabilisation is more important.
 
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