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Sunday, December 10, 2006

More on In-Camera vs. In-Lens Image Stabilization

Reader Scott W. notes that Canon explains why it doesn't use in-body image stabilization in the "Rebel XTi White Paper." Oddly, I didn't find this doc at Canon's own website (at least a search for "Rebel White Paper" yielded nothing), but you can get it from Rob Galbraith's Public Files. (WARNING: the link is a PDF download.) Scott quotes the following from the white paper:

"Some of Canon’s competitors have chosen to use in-body image stabilization. The technique involves moving the image sensor in a controlled fashion, based on signals from movement detecting sensors in the camera body. The obvious advantage of this system is that users have some sort of stabilization available with almost any lens they connect to the body. Short focal length lenses require smaller sensor deflections; 24 or 28 mm lenses might need only 1 mm or so. Longer lenses necessitate much greater movement; 300 mm lenses would have to move the sensor about 5.5 mm (nearly 1/4”) to achieve the correction Canon gets with its IS system at the same focal length. This degree of sensor movement is beyond the range of current technology. Short and 'normal' focal length lenses need stabilization much less often than long lenses, so the lenses that need the most help get the least."

It seems to me that there are advantages and disadvantages to each alternative, but one thing that Canon's explanation sidesteps is whether the two implementation styles are necessarily mutually exclusive. The vast majority of photographers will never buy an image-stabilized 300mm or longer lens. For those who do, is it beyond Canon's technological prowess to make an in-camera IS that simply has to be turned off if and when you mount lenses that have their own IS? Plus, with five digital SLR bodies in its current lineup (30D, 5D, Rebel XTi, 1D Mk. II and 1Ds Mk. II), it wouldn't appear to be impossible for Canon to offer an in-body IS version of one of them, and let its customers choose.

Call me cynical, but I've been observing this business a long time, and how I translate Canon's explanation is more or less like this: "We make more money on in-lens stabilization, and since we're the biggest dog in the pack we're going to stick with that. Like it or lump it." (I hope the good folks at Canon will forgive my colorful mode of expression. But you get the point.)

Another objection I'd raise to Canon's explanation is that I think you need another clause behind the statement "Short and 'normal' focal length lenses need stabilization much less often than long lenses..." to wit: "...when you're shooting in good light." When you're shooting in low light, on the other hand, image stabilization can come in just as handy, just as often, with shorter lenses as when you're using long lenses in normal daylight. That's how I use the feature, anyway.

This was taken handheld by the light of two candles at 1/3rd sec. Don't try to tell me
that Anti-Shake doesn't help when using short lenses!

It would be just as easy for the manufacturer of an in-body IS system to point out at that when you're shooting with 300mm, 400mm, and 600mm lenses, you'll most often be shooting from a tripod. In an event, I think all these are arguments as much as they are technical considerations.

In-Lens Systems
1. More effective with longer lenses
2. You don't pay for it except with the lenses you need it for
3. You see the stabilization effects through the viewfinder

1. More expensive, especially if you want the feature in more than one lens
2. Not available with all lenses

In-Body Systems
1. Works with every lens you mount to the body, and may be the only option for many shorter and faster lenses
2. Less expensive, especially if you want the feature with more than one lens

1. Progressively less effective with longer and longer lenses
2. Progressively harder to implement with larger image sensors.

The only really decisive choice consideration would be that you'd choose the in-lens type if your overriding need is to hand-hold long lenses in normal light, and you'd choose the in-body type if your overriding need is to shoot hand-held with normal and short lenses in low light. Again, probably the best eventual capability would be to have it available in both the body and in certain long lenses, then just switch off the in-body IS when mounting an IS telephoto.

Cynical again: Canon or Nikon will do this just as soon as not having an in-body IS option starts looking like an obvious sales liability.

The Pentax Option
I did make a trip to my local photo emporium, Mike Crivello's, yesterday, to take a look at the new Pentax K10D. It's particularly unsatisfactory to simply handle DSLRs at a camera counter, because you just don't know enough about how it works to feel like you've learned much about it. Apart from being a nice-looking, ergonomically well-designed body that has approximately the build quality of the Canon 30D or Nikon D80, all I can really tell you about the Pentax is that the viewfinder is much better than those of entry-level cameras, but not as good as my K-M 7D, and the shutter noise is what I'd call moderate—not loud, not soft. See, that doesn't really tell you all that much, does it?

The wee D40 fits even the ham-handed

The other camera I looked at while I was there that impressed me was the Nikon D40, of all things. It's large by digicam standards and positively wee by DSLR standards, yet it fit my large hands surprisingly comfortably. The viewfinder is of decent size and quite bright for an entry-level camera, focusing and shutter noise are remarkably quiet, and the LCD screen is big and pleasing. Barring any undetected major flaws, I don't think this would be a bad option as a main camera for many photographers, and especially if my main camera was one of the big-dog D2's I'd pick this up in a heartbeat as a small, portable, carry-all complement to the larger body.

But it did highlight (if obliquely) one of the real strengths of the Pentax. Like a draft horse switching horseflies with its tail (again, I hope the good folks at Nikon will forgive my overly colorful locution), Nikon severely limited the lens compatibility of the D40 to try to encourage D40 buyers to stay away from pesky Tokina and Sigma et al. and buy real Nikkor lenses. The K10D, on the other hand, really makes sense with in-body IS (it calls its version SR, for Shake Reduction, unless I'm confused), because Pentax has the greatest range of body-lens compatibility of any manufacturer. You can't even autofocus on the D40 with an ordinary AF-"D" Nikkor, but you can get IS on the Pentax with any Pentax lens back to, and including, M42 screwmount lenses, regardless of what other automatic functions may or may not be compromised. For this reason, it really makes sense that Pentax chose to put its IS-type SR function in the body and not in the lens.

Posted by: MIKE JOHNSTON, thanks to Scott W.


Blogger plabby said...

Thanks for your take on the current scene Mike, its a good summary and reference. One thing that can certainly be said... at least we have options!

I get warm and fuzzy when you talk about your K7, because I think you reflect the desire in all of us to have a system that we can learn and grow with in the digital age, something that will be stable for more than 18 months, something we can get attached to. Its a breath of fresh air that you don't hear about too often.

With regard to d40... I really only have one gripe, as Nikon seems to have another winner on its hands.

Why another battery type?

If you think about it, Nikon forces you to choose a battery system when you go on vacation. If I want to bring the d2's... its one charger, the d80, another... you realistically can't have a d40 backup a d80, or a d80 backup a d2 series because of this, unless you want to power 2 chargers and a laptop charger (assuming most of us travel with laptops) when you get to your hotel/hostel.

Also, if I brought two systems, what do you think they say to me at the X-Ray machine when I walk on to the plane with all these chargers AND the 6-outlet extension strip I need to power them? Nikon boxes me into a corner in this regard.

Its just annoying that there are such high margins in batteries that companies choose to do this.

2:27 PM  
Blogger juze said...

You are of course forgetting the best argument of them all - "Just use a tripod, you can't get a good picture without a good tripod", the mantra of all old flatulent emissions (the age in this case is very much mental and very much from the grumpy school of thought).
That being said, I do hope Canon introduce an in-camera image stabilisation system - they'd most likely make it not work beyond a 100 mm focal length in order to prevent cannibalisation of their long, IS equipped telephotos - because I really do miss it at wide-angle-to-normal-to-slightly-tele lenses.
Sometimes, I just want to shoot at ridiculously slow times to introduce some motion blur, and my hands are not those of a sniper, I'm afraid, so all I get is camera shake.

3:19 PM  
Blogger Peter said...

Again, probably the best eventual capability would be to have it available in both the body and in certain long lenses, then just switch off the in-body IS when mounting an IS telephoto.

If Sony starts doing some in-lens optical stabilization for their revamped G-series zooms (at competitive prices), then you can bet that Canikon are going to start rethinking their positions about in-body stabilization. Maybe not enough to do anything right away (being the market-leader has some perks after all), but they'll definitely be watching it closely.

With both ex-Minolta and Zeiss engineers now "in their stable" so to speak, I got to believe that Sony has more than enough technical chops to do this, so the decision to go that way would come down solely to strategy not engineering. That being said I'm not sure that Sony has the vision (or at the moment, presence of mind) to make such a choice and execute on it.

3:33 PM  
Blogger Rich said...

Another objection I'd raise to Canon's explanation is that I think you need another clause behind the statement "Short and 'normal' focal length lenses need stabilization much less often than long lenses..." to wit: "...when you're shooting in good light." When you're shooting in low light, on the other hand, image stabilization can come in just as handy, just as often, with shorter lenses as when you're using long lenses in normal daylight. That's how I use the feature, anyway.

Maybe Canon's high ISO performance helps offset the lack of internal IS. My 5D at 3200 with a 50mm f1.4 attached shoots darn near in the dark (see

3:36 PM  
Blogger Mike Johnston said...

"Maybe Canon's high ISO performance helps offset the lack of internal IS"

It sure does, but regardless of ISO, IS takes you 1.5 to 3 stops further into tripod territory. The improvement is applied across the board. So you could have made that nice moonlit shot at f/2.8.


3:58 PM  
Blogger Michael Canyes said...

For me, IS is essential. I have to take a couple of meds that make my hands shaky and I can not hand-hold a camera at normal speeds without IS. Since a lot of my photography is done running behind my family a tripod in not an option. I use a Nikon D200 and a 24-120 VR for 90% of what I shoot and I can easily print A3 size.

4:47 PM  
Blogger Allen George said...

There's also the fact that moving another component around introduces a new mechanical failure point. What's worse is that this failure point is right at a DSLR's most expensive (?) electronic component.

That said, there are probably some other reasons why Nikon/Canon still choose to use in-lens stabilization.

Keep in mind that their first VR/IS lenses came out in the film days. At that point, in-lens stabilization was the only option. I wouldn't be surprised if they've significant R&D tied up in that technology and from a business point of view, it's hard to justify throwing it all out and starting from scratch. It'd be lax however, of both Nikon and Canon's R&D if they weren't at least evaluating or experimenting with in-body stabilization.

In-lens VR/IS is also useful for stabilizing your viewfinder image and improving the efficiency of the AF sensors in those conditions.

I think Pentax had to go with in-body IS because of its exemplary backwards compatibility. I also suspect it's target market doesn't include a lot of long-lens users (sports, wildlife) so the current limitations of sensor-based stabilization aren't a major issue.

So, in conclusion...concerning in-lens vs. in-body stabilization...I have no conclusion :) I think we're on the verge of non-sensor improvements, which should be very interesting. It'd be neat to see how stuff plays out in the market.

On the D40 lens note, I'm not too bothered by Nikon's decision to drop AF-D support on the D40. It opens up the possibility of even lighter, more inexpensive DSLRs - which is nice. Hopefully it's also a prelude to a long overdue revision of Nikon's prime lineup...

The battery's different because of the D40's diminutive size . The D40's grip is smaller than the D50's and probably can't accommodate the larger EN-EL3*.

5:29 PM  
Blogger John Roberts said...

Perhaps in-camera stabilization in a Canon body making a sunstantial portion of their line of lenses obsolete has something to do with it? I'm sure this is not just a technology issue for Canon, but a marketing one as well.

6:11 PM  
Blogger jeffn said...

Image stabilization is useful for more than low light.

An image requiring a lot of depth of field will want to be shot at f11 or f16. That puts you 5 stops off f2.8 and IS helps a lot.

6:20 PM  
Blogger Eolake Stobblehouse said...

"Nikon severely limited the lens compatibility of the D40 to try to encourage D40 buyers to stay away from pesky Tokina and Sigma et al. and buy real Nikkor lenses."

I am sure this was not the reason. I think Nikon saved a lot of space and money by not including an autofocus motor in the body.

Apart from that I agree. The D40 is certainly good enough to use as a main camera even by advanced users, it has pushed my D200 back from position as a walk-around camera.

It is compact indeed, and with the low high-ISO noise it makes an excellent all-light camera, especially if you use a stabilized lens. (I use my 18-200 VR zoom.)

6:36 PM  
Blogger robert e said...

Not only does Canon's explanation make no case for not having sensor IS, it suggests that the two methods are complementary--lens IS for super-pricey super-long optics, with sensor IS being the more sensible solution for shorter optics.

Further, the argument convinces me that potential market cannibalization is less of an issue for Canon than I had thought. AFAIK, all of Canon's current IS primes are super-longs (over 200mm), and only one of its IS zooms is under 200.

Perhaps what they mean is that they will hold off on sensor IS until they sell out the shorter IS zooms. I had wondered if they might float the dubious argument that sensor movement compromises focal plane integrity, but apparently not.

Their argument may in fact be more applicable to fixed-lens compacts, though that's not to say it's an effective one. Most of Canon's competitors now trumpet "anti-shake" in at least some compacts, via IS or ISO. Either method done right gives real, immediately verifiable benefits, so I expect Canon's going to have to take this seriously pretty soon. I don't think digicam shoppers read white papers.

10:15 PM  
Blogger ottluuk said...

Call me Captain Obvious but...
Canon`s current range has two major selling points that I can see - full frame cameras where it would be quite difficult to squeeze IS in and a lineup of big IS super telephotos. Neither is really necessary for most users but both appear very desirable for those who get the XTi-s and dream of "upgrading".

The IS in 500, 400 and 600mm big boys was and still is a major reason for Nikon-shooting nature and sports photographers to switch systems. On the other hand, landscapers and product photographers are drawn by the bigger sensors and availability of tilt-shift lenses.

The general-interest shooters would obviously benefit from in-body IS but where`s the hurry for Canon? They seem to lead the consumer market DSLR sales anyway. And take a look at all the hype around their 24-105 IS!

10:32 PM  
Blogger Dierk Haasis said...

Do I understand this right: You'd rather live with another part in the camera that can go bonkers forcing you to send your whole camera in for repairs?

Personally I find the idea of having a lens been gone for a week of repairs instead of the camera body more tempting.

1:52 AM  
Blogger David said...

Maybe I'm missing something here, but as a low light people shooter, I often bump up against 1/15 or 1/8 shutter speed using 400 or 1600 asa film. I shoot 35mm - 85mm, f/1 lenses to f/1.4.

I've often thought to myself, "Dave, with an IS lens or body I could shoot in even blacker rooms!

Well, no, I slap myself. Those shots I take often have motion-blur. Subject motion-blur.

Most subjects can't stay still for 1/15 sec, much less 1/8, 1/4, 1/2, or god forbid, 1sec. If you 'bump' up against a minimum shutter speed, IS ain't gonna help.

IS's (body or lens) usefulness is for slow lenses in darkness shooting stationary (or very slow) subjects, or for long vibration inducing lenses shooting in enough light to freeze the subject.

Of course, if you want blur like I do sometimes, all bets are off.

2:23 AM  
Blogger Vlad Eckligt said...

An additional advantage for in-lens IS is that it works for film bodies, of course.

I also believe that an additional advantage for in-body IS is that it introduces the new point of failure into the component that most photographers see as more disposable, relatively speaking. Lenses are generally seen as longer-lasting and more long-term investments than bodies.

Interestinly, this might also explain some of CaNikon's reticence towards in-body IS, because if these IS lenses do turn out to have a shorter life span, they'll need to be replaced sooner and this will, on balance, increase turnover in the future. People will tend not to notice the connection, because the effect comes quite a bit later than the cause, because the effect will appear randomly so many people will dismiss a failure as a fluke, and because they are, afterall, happy to have IS hardware available at all. It is a smart move on their part, if this indeed is their reasoning.

Overall, I agree with your assessment, Mike.

5:47 AM  
Blogger RobertoC said...

Sure engineers at Canon and Nikon are smart enough to realize you can switch off the in-camera IS when you mount a lens with an optical one. So the decision not to have in-camera IS is only marketing (and wrong in my opinion).
I'm wondering if it would be possible to combine instead the two systems, and get smaller coherent movements of both actuators, hence a faster, even more effective operation. And something new to market, which does not harm.

5:47 AM  
Blogger Mike Johnston said...

"forcing you to send your whole camera in for repairs"

What solid evidence have you seen that IS causes any increase in incidence of repairs, whether in-lens or in-body?


6:26 AM  
Blogger Mike Johnston said...

Yes, it's just a virtual tripod, nothing more. Still, my experience has been that it helps often.


6:28 AM  
Blogger Olaf Ulrich said...

'robert e' wrote:
> I had wondered if [Canon] might
> float the dubious argument that
> sensor movement compromises
> focal plane integrity ...

Body-integrated image stabilization may or may not compromise focal-plane integrity ... but lens-integrated image stabilization definitely DOES compromise optical integrity. Most lenses with IS perform worse than their IS-less counterparts, even when the IS is switched off.

And in theory, body-integrated image stabilization indeed helps the least when it's needed the most, i. e. with long focal lengths. But in real life, it's good enough. With my APS-C-format D-SLR (a Konica-Minolta Dynax 7D by the way) I routinely use my 500 mm lens (750 mm-e) hand-held at shutter speeds around 1/100 s or 1/200 s with perfect results. Once I even got a sharp image with a 400 mm lens (i. e. 600 mm-e) hand-held at 1/15 s. So this argument is only useful for those who don't have body-integrated image stabilization and still want to feel good.

Overall, body-integrated image stabilization is way more useful than lens-integrated IS. Of course, the latter does have a point ot two in favour ... but the former has more points. I will never again consider a digital camera without body-integrated image stabilization ... umm, with the possible exception of the Leica M8 ;-)

-- Olaf

6:51 AM  
Blogger Mike Johnston said...

"I will never again consider a digital camera without body-integrated image stabilization"

It's funny how using the K-M 7D has that effect on people. I can say the same thing as you said above. From now on, in-body anti-shake is a must for me.


7:01 AM  
Blogger Eolake Stobblehouse said...

A new LL article on Dec 10:

... claims that image stabilization in lenses reduce image fidelity. I find that hard to believe. My Nikkor 70-200VR is the sharpest lens I've used.

7:34 AM  
Blogger Thomas Passin said...

"You are of course forgetting the best argument of them all - "Just use a tripod, you can't get a good picture without a good tripod"

That seems like a good argument until you actually start taking pictures with in-camera IS. Then you don't want to do without it. I take long telephot shots handheld all the time, sometimes in low light. I wouldn't be able to use a tripod for most of them even if I wanted to.

I commonly use 200-300 mm handheld, often at 1/80 - 1/200 sec. And that's with a sensor crop factor of 1.5 (is that the right number for a Minolta 7D, or is it 1.6? Well, no matter). Small grandchildren across a large soccer field become possible. Dusk shots (with a wider lens) become feasible, even without a top of the line Canon.

My first IS camera was a Minolta A2 digicam, a fine camera except, of course, for noise at higher sensitivities. Because I was so happy with the A2, I went out and got a Minolta 7D (replacing my Canon Digital Rebel), and I've been happy since then.

Like Mike, I don't want to get another SLR without in-body IS.

7:59 AM  
Blogger John said...

I'm with Mike on this one. I also have a Minolta 7D and use it very often indoors in low light (I don't much like flash). I will not get any future DSLR without in body IS unless I can buy the following 2 IS lenses, an f/2.8 midrange zoom (preferably about 35-100 equivalent) and at least one f/1.4 lens in the 40-60mm-e range.

Using the Minolta 28-75/2.8 and 35/1.4 lenses with IS has allowed me to finally be routinely sucessful making photographs that I was always struggling to make in the film days with much less success.

By the way, the rare times I've put my 75-300 zoom on the 7D (generally fairly bright conditions), the in body IS has worked fine.

John Sparks

9:03 AM  
Blogger Jeremy said...

Canon and Nikon will do it once dpreview starts lamenting loudly about it, the way they did with off-center tripod mounts.

1:13 PM  
Blogger Dierk Haasis said...

"What solid evidence [...]"

Mike, I did not write that the feature in question does actually show up more on repair sheets, I only wrote about possibilities.

It's quite simple, regardless of the place where current image stabilisation happens - lens or body - mechanical parts are involved. Any mechanism has a failure rate, actually every kind of implementation, incl. electronic and even software, will have circumstances under which they break.

Now, there are essentially two different types of breakdown, let's call them reboot and repair. The former we can solve ourselves with the switch of a, well, switch. An example is complete unresponsiveness of my D2x to me pushing the shutter button. Turns out the memory card was filled to the brim; just format it.

Problematic is the second category, where you have to send in the broken part so an engineer can overhaul it. The more 'moving parts' you have the more likely is a breakdown needing repair.

Hope that clears the matter up a bit.

There is, BTW, another aspect often forgotten when it comes to feature requests: it may be that the exsting patents forbid implementation or development. Not that anybody can forbid you to develop, as long as you don't infringe on patents, but it may be too expensive to do it. In the end it's neither a matter of 'good sense' [as Canon and Nikon claim] nor marketing [as some have said]. It's down to price - how much are my customers willing to pay.

2:04 AM  
Blogger Curtis Clegg said...

The Canon White Paper for the Rebel XTi is pretty well hidden on the Canon site, but it's there for anyone who wants verification. Discussions about IS begin page 12 of the PDF file.

6:06 PM  
Blogger Mike Johnston said...

Thanks Curtis.


6:08 PM  
Blogger Olaf Ulrich said...

In the PDF document pointed to by Curtis above, Canon foolishly states:

"Longer lenses necessitate much
greater movement; 300 mm lenses
would have to move the sensor about
5.5 mm [...] to achieve the correc-
tion Canon gets with its IS system
at the same focal length. [...]
Further, in cameras with smaller
than full-frame [...] sensors,
equivalent focal lengths become
longer, by a factor of 1.5 or 1.6,
exacerbating the problem by making
all lenses longer."

I wonder if Canon is so dumb, or do they think we are?

Of course, a camera's form factor does not make any lens any longer. Consequently, 'the problem' is in no way exacerbated; instead, the distance the sensor has to move to compensate for a certain amount of shake always is the very same for all sensor sizes.

Only the required accuracy of the compensation movement is higher for smaller sensors. But that's true for in-lens systems just as well. And a smaller sensor is easier to push around quickly and precisely, due to its smaller mass, so for in-body systems the higher accuracy for smaller sensors comes just naturally for any given technology.

Obviously, Canon is really struggling hard to justify not making in-body image stabilization systems ... they don't even shy away from plain mis-information.

-- Olaf

8:32 AM  
Blogger splatt said...

Under disadvantages of lens based stabilization, you missed out the most important point for me.
Almost every lens with IS/VR/PMS etc seems to be larger and/or 1/2 to 1 stop slower than its non-stabilized counterpart.
In-body stabilization allows smaller, faster, probably higher optical quality lenses. It's the lenses which take up most of the space in my camera bag and anything I can do to make them lighter and less conspicuous without reducing image quality is most welcome.

8:15 PM  
Blogger Unknown said...

Have to disagree with splatt, the canon EF 70-200 L series with 2 apertures f4 and f2.8 have IS versions, giving 4 possible choices, an f4, f4 IS, f2.8 and f2.8 IS... the only difference really between the IS and non-IS versions is about 100g in weight... not max aperture, or physical dimensions.

And as well the f4 IS is considered one of canons sharpest Zoom lenses, compared to its non-IS version... ,despite it having more lens elements (for the IS) which could potentially degrade quality

5:37 PM  
Blogger Unknown said...

From the XTi White paper

"At some point, in-body stabilization may improve to the point at which such technology
may be appropriate for certain segments of Canon’s DSLR range. It would be senseless
to rule out such a possibility. Even now, differences in unit cost are not enough to be
significant factors in such a decision. The bottom line is performance."

It shows they arn't shoving aside the idea of in body stabilization

5:49 PM  

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