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Author Topic: A900 vs 5DII image stabilisation  (Read 3614 times)
PHeadland
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« on: January 05, 2009, 02:28:33 PM »
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In his A900 vs 5DII comparison our generous host says:

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On the Sony side of the ledger there's built-in image stabilization accomplished by using sensor vibration. This has been shown to be every bit as good as stabilization systems built into lenses. The big advantage though is that it applies to any lens mounted, not just specific lenses. And though wide angle lenses tend not to need stabilization as much as long lenses, having these stabilized as well is a real bonus.

This is a sentiment I see expressed frequently. I think it is misleading and should always be qualified. When shooting with long telephotos, having image stabilisation in the lens is extremely valuable, having image stabilisation in the body is worth far less. The only exception would be if you are using a camera with an EVF, such as the Panasonic G1. The reason is simple, you need a stable image to focus (somewhat when using AF, very much when focusing manually); stabilising the sensor doesn't help with that.

No matter what the focal length, I find it easier to compose when the image isn't jiggling around, but that may just be me - heck I actually like the "swimming" motion caused by stabilisation.

The paradox with Panasonic's M4/3 system is that it doesn't benefit by placing stabilisation in the lens - quite the reverse, in fact, for the reasons Michael gives above - but Panasonic opted to do so. In that regard, I think Olympus may have the more compelling M4/3 body offerings. Indeed, the lack of sensor-based stabilisation is the major reason I haven't been able to convince myself I should buy a G1.
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Farmer
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« Reply #1 on: January 05, 2009, 05:30:09 PM »
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Quote from: PHeadland
In his A900 vs 5DII comparison our generous host says:

This is a sentiment I see expressed frequently. I think it is misleading and should always be qualified. When shooting with long telephotos, having image stabilisation in the lens is extremely valuable, having image stabilisation in the body is worth far less. The only exception would be if you are using a camera with an EVF, such as the Panasonic G1. The reason is simple, you need a stable image to focus (somewhat when using AF, very much when focusing manually); stabilising the sensor doesn't help with that.

I'm sure all those people who used long lenses and manual focus for decades on film will be interested to know that "you need a stable image to focus".

For some people, there's an advantage in having a swimming image because they prefer it (and even though I don't really like it, to me there is clearly an advantage for composition).  But AF has no problem and if you're moving around so much you can't manually focus then I'd suggest bracing or a tripod because you're going to be exceeding what the stablisation (be it lens or body) can counter anyway.

I think it's fairly clear that Michael was talking in terms of results of image for sharpness and lack of movement blur.
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Ray
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« Reply #2 on: January 05, 2009, 05:53:56 PM »
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I guess one can't expect any camera to beat the competition on all fronts. Each camera has its strengths and weaknesses. I consider the sensor based stabilisation in the A900 a major strength, especially for people like me who already own a few Minolta-fit lenses with no optical IS.

On the other hand, the significantly lower DR of the A900 at high ISO (compared with the 5D2) is a bit off-putting, as well as the lack of a Live View.

One really has to weigh the relative significance of such strengths and weaknesses. One third of a stop higher DR of the A900 at ISO 100, compared with one and one 3rd stops higher DR of the 5D2 at ISO 1600 and above.

One amazing feature of the Canon 50D with its high resolution Live View screen, is just how much detail one can see through a 400mm lens when the image is magnified 10x. Another amazing effect is just how unstable and wobbly that image can be, even with camera on a tripod, without in-lens image stabilisation. With no magnification (basically the same FoV as one sees through the viewfinder) the image appears stable when camera is on tripod without IS activated.

However, at 10x magnification, which is like looking through a 4,000mm lens, the image wobbles with the slightest breeze or vibration. Image stabilisation is essential for critical manual focussing in such circumstances.

Designing a full frame sensor with anti-vibration was a major technological challenge for Sony. To also provide an image stabilised Live View feature was just too difficult or too expensive, I guess.


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Guillermo Luijk
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« Reply #3 on: January 05, 2009, 06:02:28 PM »
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To complement the discussion sensor stabilization vs lens stabilization (which I think is a plus on the Sony for being effective in many situations and applied to all lenses, even if for tele lens estabilization is more adequate), I would say that the 5D II has an advantage over the A900 that could face the advantage of the sensor stabilization in some cases: lower high ISO noise.

In a typical indoor situation with a shortage of light, we must rise ISO to have proper RAW exposure, otherwise underexposure would cause signal to noise ratio to fall. But rising ISO is more dangerous in the A900 for being a noisier camera than the 5D II from ISO600 (Michael said it on his own review).

In that situation, an A900 user could decide to keep a lower ISO but set a longer exposure time trusting his camera's stabilization, while the 5D II user could afford a higher ISO that would allow him faster shutter speed.

This would mean the advantage of 5D II in noise could make the A900's stabilization advantage vanish or at least be not so clear in certain situations where stabilization seemed a plus. It's just a matter of measuring how many f-stops of image stabilization/noise improvement each camera has.
« Last Edit: January 05, 2009, 06:06:25 PM by GLuijk » Logged

PHeadland
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« Reply #4 on: January 05, 2009, 07:29:09 PM »
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Quote from: Farmer
I'm sure all those people who used long lenses and manual focus for decades on film will be interested to know that "you need a stable image to focus".

Perhaps "need" was too strong a word. Let's say "benefit considerably from". I was one of those people shooting manual focus with long lenses (by which I mean 400mm and up), and it got a heck of a lot easier once we got IS. And I have certainly observed that, with longer lenses and smaller apertures, AF works better when IS is engaged. Sure, modern AF with a 300/2.8 in good light can focus when you can't see enough to compose, but put a 1.4x on a 500/4, shoot a low contrast subject at dusk and compare speed and reliability of AF with/without IS. That's a pretty typical scenario for bird photography, BTW, and birds are pretty popular subjects.

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I think it's fairly clear that Michael was talking in terms of results of image for sharpness and lack of movement blur.

In this specific case, and to a knowledgeable reader, perhaps. The problem is that "body IS is better than lens IS" is becoming accepted wisdom. My point was simply that, in the situation where IS is most helpful, lens IS has distinct advantages (absent an EVF), and this is something that reviewers ought to mention once in a while so that people who don't have the benefit of our experience can make better choices.

PS: For what it's worth, casual rudeness reduces the credibility of a post.
« Last Edit: January 05, 2009, 07:30:33 PM by PHeadland » Logged
Farmer
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« Reply #5 on: January 05, 2009, 07:50:56 PM »
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Quote from: PHeadland
Perhaps "need" was too strong a word. Let's say "benefit considerably from". I was one of those people shooting manual focus with long lenses (by which I mean 400mm and up), and it got a heck of a lot easier once we got IS. And I have certainly observed that, with longer lenses and smaller apertures, AF works better when IS is engaged. Sure, modern AF with a 300/2.8 in good light can focus when you can't see enough to compose, but put a 1.4x on a 500/4, shoot a low contrast subject at dusk and compare speed and reliability of AF with/without IS. That's a pretty typical scenario for bird photography, BTW, and birds are pretty popular subjects.



In this specific case, and to a knowledgeable reader, perhaps. The problem is that "body IS is better than lens IS" is becoming accepted wisdom. My point was simply that, in the situation where IS is most helpful, lens IS has distinct advantages (absent an EVF), and this is something that reviewers ought to mention once in a while so that people who don't have the benefit of our experience can make better choices.

PS: For what it's worth, casual rudeness reduces the credibility of a post.

I think the wisdom is that the previous assertion that body IS was a very poor cousin to lens IS is reasonably well debunked.  In specific situations, one will perform better than the other.  Overall, though, both solutions work well.  There's a lot of discussion about IS around and I think that to rehash it with every review would be tedious (yes, you suggested "once in a while" I know) so then it begs the question of when do you go over the technology?  It's not a simple call without repeating the same things over and over and I imagine that reviewers are seeking to write interesting copy that engages the reader throughout, rather than to have them stop part way because they feel it's the same old story.

Regarding casual rudeness - if that is how my post came across, then I apologise as it was certainly not my intent.
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PHeadland
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« Reply #6 on: January 05, 2009, 08:34:36 PM »
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Quote from: Farmer
There's a lot of discussion about IS around and I think that to rehash it with every review would be tedious.

In effect, Michael rehashed the subject in his piece. The same goes for every review I have read lately for a body IS camera - body IS is unfailingly stated to be a positive advantage. On reflection, I'd settle for reviewers simply saying "both systems have their advantages", or - better yet - simply stating the IS type without commentary. As you say, let people who don't know go and read a specialised article on the subject.

As I noted, the ideal solution is a (really good) EVF with body stabilisation. What a pity Panasonic muffed it on the second point in the G1. I fear that Canon and Nikon will not move to body IS any time soon, much less switch to the new lens mount that getting rid of the mirror enables. I can only hope Olympus gives us a really good M4/3 body with a first rate EVF in the next few months - the "retro" pseudo-rangefinder prototype they have been showing doesn't fill me with hope, though.

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Regarding casual rudeness - if that is how my post came across, then I apologise as it was certainly not my intent.

Thank you - it was just that first sentence that came across a little sarcastic/dismissive.
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dseelig
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« Reply #7 on: January 06, 2009, 12:35:12 AM »
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I think the real point of this review is you get the camera that is best for what you shoot. Me I am a pro who does many different things.But If I just shot landscapes after this review i would defitnely want the sony over the canon and mind you I have a 2 1d mk111's a 1ds mk111 and a 5d mk11. I am  a working pro though and I shoot action, street people, and landscapes. So I will keep my canons. David
 www.davidseelig.com
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ErikKaffehr
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« Reply #8 on: January 06, 2009, 01:47:41 AM »
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Hi,

I guess that the issue is more like ideological with Sony. They developed a live view system with a secondary sensor reading direct of the focusing screen. That concept is not really useful for focusing but allows for fast operation in "live view". Because that solution is based on a moving mirror on a porroprism it would not work with an all glass pentaprism.

A couple of years ago, when live view was introduced there was much scepticism on different review sites. It seems that nowdays it is widely accpted that live view is eminently useful for critical focusing, something that was quite obvious to anyone except most of the reviewers.

It seems that camera manufacturers have some favorite foibles. Michael Reichmann was discussing MLU on Canon DSLRs for a long time but nothing really has happened.

Something that Nikon has which I think all makers should adopt is the virtual horizont, it's should be really helpful.

Best regards
Erik


Quote from: Ray
I guess one can't expect any camera to beat the competition on all fronts. Each camera has its strengths and weaknesses. I consider the sensor based stabilisation in the A900 a major strength, especially for people like me who already own a few Minolta-fit lenses with no optical IS.

On the other hand, the significantly lower DR of the A900 at high ISO (compared with the 5D2) is a bit off-putting, as well as the lack of a Live View.

One really has to weigh the relative significance of such strengths and weaknesses. One third of a stop higher DR of the A900 at ISO 100, compared with one and one 3rd stops higher DR of the 5D2 at ISO 1600 and above.

One amazing feature of the Canon 50D with its high resolution Live View screen, is just how much detail one can see through a 400mm lens when the image is magnified 10x. Another amazing effect is just how unstable and wobbly that image can be, even with camera on a tripod, without in-lens image stabilisation. With no magnification (basically the same FoV as one sees through the viewfinder) the image appears stable when camera is on tripod without IS activated.

However, at 10x magnification, which is like looking through a 4,000mm lens, the image wobbles with the slightest breeze or vibration. Image stabilisation is essential for critical manual focussing in such circumstances.

Designing a full frame sensor with anti-vibration was a major technological challenge for Sony. To also provide an image stabilised Live View feature was just too difficult or too expensive, I guess.
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NikosR
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« Reply #9 on: January 06, 2009, 01:53:57 AM »
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There are a multitude of situations where an advantage in high ISO noise performance would be more welcome than the existence of stabilisation. Any scene which involves any movement, be that animate subjects or leaves moving in the breeze, calls for a higher shutter speed something which automatically provides an advantage to noise performance vs. stabilisation if one has to make the tradeoff.

IMO, the better cameras become in terms of noise control, the less relevant any kind of stabilisation becomes.


Another point is Liveview with contrast detect focusing on any part of the scene paired with high magnification. For any slow working photographer taking his time with a tripod, mirror up and cable release, LV is major help in getting the focus absolutely right. Photographers like these, once they've tried and mastered LV can never look back. This I see as the Sony's greatest failure given its intended audience and the competition.
« Last Edit: January 06, 2009, 02:23:35 AM by NikosR » Logged

Nikos
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