IS vs IQ

[sanj]

I use the following lenses with IS: 300, 600, 70-200, 24-105. The quality of the photos is super even when the IS is on. So am wondering why many believe that IS on a lens reduces picture quality??
Asking because the new 24-70 is without IS and so is my compact Fuji X100.
Thx for any thoughts.

 

[AmbientLight]

Image stabilization reduces unwanted movements of your camera and lens combination. How do you think would this reduce image quality?

If I would use for example my 70-200 for hand-held shots with IS switched off, the only result would be a smaller keeper rate caused by camera and lens shake. You can easily perform some tests to verify IS effectiveness.

 

[Loswr]

So am wondering why many believe that IS on a lens reduces picture quality??

Lots of reasons. First off, it depends on the lens. For example, the 70-200/2.8L non-IS is actually sharper than the 70-200mm/2.8L IS (original) - so in some cases, it's true. Then people extend that logic to other lenses, even though each lens design is unique.

Also, it depends on usage. For example, the IS system in some lenses, like your 24-105mm, is not tripod-sensing. If you leave it on when shooting from a tripod, the IS system will try to compensate for the (almost) nonexistent vibrations, and actually introduce a loss of sharpness to the image by doing so.

 

[Maui5150]

Ever notice something about all of the IS lenses the OP listed? Like they are all long and generally also F/4 or more

IS helps a lot more at longer focal lengths and slower shutter speeds than it does at shorter focal lengths and slower shutter speeds. Makes sense.

One of the reasons I think you don't see the 24-70 with IS is the short range of the lens, as well since it is capable at F/2.8 and looks like it does not have to be stopped down to be affective, it helps address the shutter speed part of the equation.

As well. The fractional shake from a hand movement in terms of sharpness at an object 10 feet away is not nearly the difference of say an object 100 feet away.

I am not sure I would agree that IS necessarily affects IQ, but I can see how IS can be like an Anti-Alias filter and when IS is activated, since the lens has to compensate, it may introduce some slight movement or perhaps even OVERCOMPENSATION which could reduce the sharpness of the lens.

For longer lenses, this over compensation may be mitigated by the correction it enables, i.e. the fractional correction off is much better than the original shake, but in a shorter lens, perhaps in some cases this compensation or over shooting may be equal or greater than the initial shake.

 

[sheedoe]

There's a good article on it here:

http://www.bhphotovideo.com/indepth/photography/tips-solutions/image-stabilization-when-use-it-and-when-turn-it

 

[awinphoto]

I can see the arguement either way... One one hand, it does, in practice does a remarkable job reducing camera shake in a good chunk of situations... But then again, depending on which lens and generation of IS being used, it may do a better or worse job correcting for shake in certain directions and angles and also, it's one extra mechanism in your lens that could impact the performance. And also you are entrusting a machine to look for patterns in movement and counteract those movements, and we all know the saying, if you want something to really screw something up, leave it to a computer...

But in practice it does a pretty good job, assuming you are working with newer IS versions, I think you should be good in most situations. But once again i'd err on the side of shooting with the fastest shutter speeds regardless if I can help it not to tempt fate and if I'm in doubt about the breaking point of the IS when it comes to a critical photo, tripod and or monopod is the best assurance.

 

[tdodd]

This is an article about Nikon VR, but I suspect it is equally valid for Canon - http://bythom.com/nikon-vr.htm.

 

[dstppy]

Let me ask this: are there any Canon lenses with IS (old or new system) that produce a less sharp image when hand-held (excluding, of course, someone who can hold freakishly still)?

I have to say, in the Canon P&S world, I was simply amazed by the images when IS was introduced . . .

 

[awinphoto]

Let me ask this: are there any Canon lenses with IS (old or new system) that produce a less sharp image when hand-held (excluding, of course, someone who can hold freakishly still)?

I have to say, in the Canon P&S world, I was simply amazed by the images when IS was introduced . . .

The only lens I could think of off hand was the 28-135 IS but that is a softish lens to begin with... are you asking if the image is less sharp when handholding and the IS is ON or OFF. I never with happy with the 28-135 with the IS on or off, but have seen differences with other lenses when IS isn't on... such as the 70-200 F4 IS when it is and isn't on...

 

[Loswr]

Let me ask this: are there any Canon lenses with IS (old or new system) that produce a less sharp image when hand-held (excluding, of course, someone who can hold freakishly still)?

Sure. The 70-200mm f/2.8L example I gave above - the non-IS version is sharper than the IS version, even when handheld provided you're using an appropriate shutter speed. It's just that 'appropriate shutter speed' gets much slower for the IS version.

 

[Maui5150]

Let me ask this: are there any Canon lenses with IS (old or new system) that produce a less sharp image when hand-held (excluding, of course, someone who can hold freakishly still)?

I have to say, in the Canon P&S world, I was simply amazed by the images when IS was introduced . . .

Better question.

Does IS make a noticeable difference shooting hand held at above 1/60th at a distance of under 20 feet with a focal length of under 70?

Related to the same question, what is the cost related to implementing IS, the increased defect rate (i.e. more to go wrong) as well as in the manufacturing, design, and other implementations, what is the reduced image quality?

Are the better Prime lenses sharper than their general zoom counterparts?

I think for fast glass and short glass, the potential for IS to hurt IQ, both in the manufacturer and implementation, not to mention cost and defects probably outweighs the usefulness.

 

[bycostello]

surly the whole point and why we buy IS is to improve image quality?...

 

[Marsu42]

One of the reasons I think you don't see the 24-70 with IS is the short range of the lens, as well since it is capable at F/2.8 and looks like it does not have to be stopped down to be affective

I don't understand why people seem to think that f2.8 is *always* better than f4 and above - in many situations, the dof of f2.8 larger apertures is just too thin, and the bokeh of f4 is ok too if there's no irritating object directly behind the dof pane. This is definitely true for my macro lens: 2.8 is just ridiculous if your object is not a flat piece of paper.

Of course I want a medium tele lens with IS - then I can shoot static objects with large dof at iso 100 and no noise! The only reason the 24-70 has no IS seem to be weight considerations - which I can understand given the weight of a 70-200/2.8is2.

Does IS make a noticeable difference shooting hand held at above 1/60th at a distance of under 20 feet with a focal length of under 70?

IS gives more good shots, nothing more - or said the other way round: If you have enough time you can just take a picture burst, one of them usually will be sharp. With a lens w/o IS you can get crystal sharp images, because your hands move from one point and back - at the peak of this sine curve your hand is steady like a tripod. If the shot is steady, only the lens sharpness matters (if you've got a good copy, that is).

 

[zim]

This IS debate thing is really interesting to me. When I was (a lot) younger I could hand hold a 200mm lens at 1/250 quite successfully. I simply cannot do that now. In fact I need IS right down to 50mm now if I want to have a shutter speed less than light speed, I must have a very short frequency ;D, I’m talking sharp 12x10s + not 8x6 holiday snaps. I think in (my) real world you can have all the IQ you like, and I want a lot of that, but without IS it’s wasted on me. That’s why the new 24-70 was such a disappointment to me it’s clearly been designed for pro togs which is fine but where’s my choice? The EF24mm f/2.8 IS USM and EF28mm f/2.8 IS USM lenses do therefore make a lot of sense to me and if the 50 1.4 gets the same treatment then job done Canon that’s my choice (24 & 50) but I’d still rather of had one real high quality zoom to cover that range though, I’ll be amazed if the Sigma/Tamron offerings come close but you never know.

 

[Mt Spokane Photography]

The sharpness of a lens typically depends more on which generation a lens belongs to. It generally has less to do with IS. Designing a lens is about trading off the various characteristics versus the cost to manufacture. Much better lenses can be made, but selling $100K lenses might be difficult.

For example, the 70-200mm f/4 IS is sharper than the non IS version, but thats comparing a newer lens with a older one. The one exception I have had personal experience with is that the 70-200mm f/2.8 non IS was sharper at 200mm than the IS version that replaced it. But the 70-200mm f/2.8 MK II is far better.

That said, a lens without IS is a simpler lens, and using the same generation of technology, IMHO, could be designed to be better than a lens with IS.

We likely did not see a 24-70mm IS, for example, simply because a non IS version could be designed that was sharper and better overall.

 

[Maui5150]

IS gives more good shots, nothing more - or said the other way round: If you have enough time you can just take a picture burst, one of them usually will be sharp. With a lens w/o IS you can get crystal sharp images, because your hands move from one point and back - at the peak of this sine curve your hand is steady like a tripod. If the shot is steady, only the lens sharpness matters (if you've got a good copy, that is).

But at what cost?

Part of what you are missing is the point I was trying to make, which is can a lens with NO IS be inherently SHARPER, with less CA and other defects across ranges.

So yes, IS may help you capture a shot, but if it introduces other flaws to a lens, even minor ones, then potentially every image is lesser than the ones without.

Yes, a keeper image, no matter what is better than one with motion blur, but with fast glass and short focal lengths that tend to be shot at decent shutter speeds because of the combo, the advantages IS are possibly diminished compared to trade off in overall image quality.

there are some freakishly sharp IS lenses, but again, like the 70 - 200, they tend to be longer in which case IS has a much greater need and benefit.

So the question I pose back to you, if the inclusion of IS causes a slight degradation of IQ, say in the MTF chart, especially issues wide open, or at the ends of the zoom focal length, is reduction of IQ?

I say it is. IS may help you get more keepers when you start getting to slower shutter speed or dimmer light, but for cases when you have light, and have plenty of shutter, if your image is lessened because of the inclusion of IS affects the overall lens compared to the same lens without, there is a trade off.

So if you have two 24-70 II lenses, IS and Non-IS, and the IS lens is softer on the edges and more CA throughout do you go with the sharper, better performing lens, or do you go to the lens with IS?

 

[awinphoto]

IS gives more good shots, nothing more - or said the other way round: If you have enough time you can just take a picture burst, one of them usually will be sharp. With a lens w/o IS you can get crystal sharp images, because your hands move from one point and back - at the peak of this sine curve your hand is steady like a tripod. If the shot is steady, only the lens sharpness matters (if you've got a good copy, that is).

But at what cost?

Part of what you are missing is the point I was trying to make, which is can a lens with NO IS be inherently SHARPER, with less CA and other defects across ranges.

So yes, IS may help you capture a shot, but if it introduces other flaws to a lens, even minor ones, then potentially every image is lesser than the ones without.

Yes, a keeper image, no matter what is better than one with motion blur, but with fast glass and short focal lengths that tend to be shot at decent shutter speeds because of the combo, the advantages IS are possibly diminished compared to trade off in overall image quality.

there are some freakishly sharp IS lenses, but again, like the 70 - 200, they tend to be longer in which case IS has a much greater need and benefit.

So the question I pose back to you, if the inclusion of IS causes a slight degradation of IQ, say in the MTF chart, especially issues wide open, or at the ends of the zoom focal length, is reduction of IQ?

I say it is. IS may help you get more keepers when you start getting to slower shutter speed or dimmer light, but for cases when you have light, and have plenty of shutter, if your image is lessened because of the inclusion of IS affects the overall lens compared to the same lens without, there is a trade off.

So if you have two 24-70 II lenses, IS and Non-IS, and the IS lens is softer on the edges and more CA throughout do you go with the sharper, better performing lens, or do you go to the lens with IS?

You know it's hard to speak in hypothetical about if a lens would/could be sharper without IS... because so few examples covers both IS generations but also ages of lenses... The only example other than lets say the 70-200 lenses would be the 70-300 IS (non L) and the 70-300 III but then again, you are looking at lenses that are 6 years apart in production intro dates. I suppose in the same arguement of video where if they put the money into developing video into improving stills was the same as money spent in developing each lenses IS to non IS, would it be any better/sharper... Its real hard to say/predict as lenses and dates are a continuously moving target.

 

[Kernuak]

Many poeple get excited about some of the old designs, because they are legendary in terms of sharpness. If you take away some of the nostalgia and concentrate on the ones that really are sharp, they often have one thing in common, a simple design. Simple designs have less glass and each time you add a new lens element (assuming equal correction etc.), you have a reduction in image quality, albeit negligible in themselves (and probably not noticeable). Add each of those imperceptible decreases in IQ together though and they may become noticeable. So, in the more complicated designs, IQ can suffer and IS lenses have additional IS elements, so extra glass. This is probably why the original 70-200 f/2.8 IS is less sharp than its non IS counterpart. Of course, it's never that straightforward, otherwise all simple lens designs will be sharper than complicated ones and all IS lenses would be less sharp. With newer technology, lens designers have found ways of improving sharpness (and other measures of IQ), so they are now able to create more complicated designs that are equally sharp. The prime example of that is the new 70-200 f/2.8 IS MkII. So, yes IS can reduce sharpness in a lens, in comparative terms, but it isn't always the case.
One other thing to bear in mind, IS can sometime interfere with AF speed, so at faster shutter speeds, you're probably better off switching IS off, to avoid the possibility (even if it doesn't actually cause a problem). You don't want to miss a shot of a lifetime, because you had IS on when you didn't need it. Of course, you also don't want to miss the shot of a lifetime because you forgot to switch it back on again either.

 

[awinphoto]

Many poeple get excited about some of the old designs, because they are legendary in terms of sharpness. If you take away some of the nostalgia and concentrate on the ones that really are sharp, they often have one thing in common, a simple design.

You know, I have on other threads floated the idea that with the older "sharper" film lenses, a lot of them were designed to work with 35mm film and with that medium, few people printed 35mm film at larger than 8x10. You would see the occassional 11x14 and the rarer 16x20, but it was accepted that there would be loss of quality. Now you have the 7D which natively produces a file OOC LARGER than a 11x14 and the the 5d2 producing files close to a 16x20. The point being files are easily able to print large without much if any loss of quality and so flaws with lenses are more greatly magnified. Just about any lens, shot full frame and printed at 8x10 and below should show greatly but I do wonder, but have not tried, older lenses designed for film, shot on modern cameras which demand more from the lenses, and I wonder how those files would hold up compared to modern offerings. It is that comparison which would make us realize if that nostalgia is warranted or not

 

[Kernuak]

Many poeple get excited about some of the old designs, because they are legendary in terms of sharpness. If you take away some of the nostalgia and concentrate on the ones that really are sharp, they often have one thing in common, a simple design.

You know, I have on other threads floated the idea that with the older "sharper" film lenses, a lot of them were designed to work with 35mm film and with that medium, few people printed 35mm film at larger than 8x10. You would see the occassional 11x14 and the rarer 16x20, but it was accepted that there would be loss of quality. Now you have the 7D which natively produces a file OOC LARGER than a 11x14 and the the 5d2 producing files close to a 16x20. The point being files are easily able to print large without much if any loss of quality and so flaws with lenses are more greatly magnified. Just about any lens, shot full frame and printed at 8x10 and below should show greatly but I do wonder, but have not tried, older lenses designed for film, shot on modern cameras which demand more from the lenses, and I wonder how those files would hold up compared to modern offerings. It is that comparison which would make us realize if that nostalgia is warranted or not

I know from reading a few reviews, that many of the old legendary lenses weren't quite as sharp as everyone thought, once they were tried out on digital SLRs. There are the odd one or two though that do seem to be as sharp as the hype suggested (hence my comment about leaving nostalgia aside, as many weren't/aren't). I think the Zeiss Distagon 21mm is testament to the fact that there are a few original designs that hold their own with modern lenses. As I understand it, the basic design is the same as when it was originally released and just the mounts have been changed.