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12-11-2011, 11:31 AM   #1
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In body I.S (Pentax) as opposed to Lens I.S

I've been having this chat with with a mate who has Nikon cameras and we were comparing in body image stabilization as opposed to the lens doing it.
His opinion is that lens I.S superior and that these days the price difference between an I.S and non I.S is not as great.
Not needing to buy those sorts of lens I can't comment, he went on to say that inbody I.S has been around for a while and is old technology, again being new to any modern DSLR I don't have the knowledge to agree or disagree.

He thought that in body I.S only took place after the photo was taken, I was able to correct him on that as unless I've got it wrong the Pentax is active I.S unless your switch it off.

So who can bring me up to speed on the various merits of in body as opposed to lens I.S and their individual strengths and weaknesses.

Thanks.

12-11-2011, 12:19 PM   #2
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In-Camera IS pros:
-works with all lenses
-uses less power
-makes lenses cheaper

In-Lens IS pros:
-stabilized image in the VF
-arguably a bit more effective at tele focal lengths (>300)

When I tested the Sigma 70-200mm OS HSM I was unable to find any practical difference between its OS an the in-body SR. On top of that, the "stabilized" viewfinder image was actually quite annoying, as it was shifting around all over the place.

If you ask me, the bottom line is that having in-camera SR is really quite nice. There are tons of lenses for Canon and Nikon that aren't stabilized: for example you can't get a stabilized 85mm 1.4, which is otherwise my favorite focal length.

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12-11-2011, 12:26 PM   #3
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Mychael - I hope your friend doesn't plan on using the Nikon 24 1.4, 50 1.4, 85 1.4, 24-70 if he thinks lens IS is that superior.
12-11-2011, 12:34 PM   #4
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QuoteOriginally posted by Mychael Quote
He thought that in body I.S only took place after the photo was taken, I was able to correct him on that as unless I've got it wrong the Pentax is active I.S unless your switch it off.
He's confusing the real IBIS with the "digital stabilization" that some P&S cameras have. Which is of course crap.

But according to some independent tests, the lens based IS/SR tends to be a bit more effective than proper IBIS. And according to one test I read, Sony's IBIS may be a bit more effective than that of Pentax. And in addition to being slightly more effective, the lens based IS also stabilizes the view in your OVF. Then again, as Adam posted, the IBIS works with any lens. In theory one could expect the non-IS lenses for Pentax and Sony to be cheaper than the same lenses with IS for Canon and Nikon. Unfortunately the market does not work that way and the lenses cost usually the same.

12-11-2011, 01:05 PM   #5
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QuoteOriginally posted by Mychael Quote
Not needing to buy those sorts of lens I can't comment, he went on to say that inbody I.S has been around for a while and is old technology, again being new to any modern DSLR I don't have the knowledge to agree or disagree.
The technology is matured, but still improving. SR in my K10D was not as efective as the one I have now in K-5. It is normal to buy a new body every few years but no one wants to buy new set of lenses so quickly to get new improved stabilizer in them. Only in body stabilizer is able to correct for rotational blur - in lens IS can never do that.
Also the moving chip in K-5 allows for some shift effects using the composition adjustment. Automatic horizont correction is also useful.
You also mentioned cost but the price you pay buying the lens is only part of it - the in lens stabilizer gets weared over time and needs servicing every few years to maintain the image quality. Pro's often sell used lenses and Canikon amateur buy them thinking how good deal it was - it usually isn't as good, because the service is expensive.
12-11-2011, 01:07 PM   #6
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Between the two technologies, the lens based stabilization was developed during the film era. It enabled Nikon and Canon to stabilize the image prior to exposing the film. This technology was brought forward to today. The In Body Stabilization permits any lens to be effectively stabilized, since it floats the sensor in response to detected movements of the body itself. I like it because there are few if any wide angle lenses that are stabilized available, on the other hand stabilization is much more effective on the longer focal lengths. Also, lens based stabilization only works when you have a lens with the capability, and only if there is a lens in that focal length actually manufactured and sold, otherwise you are SOL.

Contax had developed two technologies for film, one sucked the film "flatter" against the back for exposure (thus providing a "flatter" exposure surface), and the other one added a capability to mechanically tilt the film backing just a bit (sort of like a lens tilting mechanism in the body).

Then there is this article by Thom Hogan on why you only turn VR (Nikon's lens stabilization) on when its absolutely necessary. That tends to go against what we do by leaving SR on all the time other than when its on a tripod. I tend to think that its in implementation, and I leave my SR on all the time other than when its automatically turned off by the 2 second mirror up delay.
12-11-2011, 02:05 PM   #7
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QuoteOriginally posted by Mychael Quote
So who can bring me up to speed on the various merits of in body as opposed to lens I.S and their individual strengths and weaknesses.
The in-body system is the best because it is the one I have.
12-11-2011, 03:14 PM   #8
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Am I correct that only in-body IS can cope with "rolling" motions? Also I suspect that you can reduce weight by using in-body IS with lenses without any stabilization than the opposite, correct?
Also I doubt that lens based stabilization is better than in-body as a technology as they both do practically the same thing, just at different places in the system.

12-11-2011, 09:26 PM   #9
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QuoteOriginally posted by VisualDarkness Quote
Am I correct that only in-body IS can cope with "rolling" motions?
Of course, you are correct. Lenses are rotationally symmetric so no matter what you do to a lens, it won't be able to counteract camera roll.

In-body image stabilisation systems, like that of the K-5, can counteract camera shake in the "roll" plane and can also automatically correct for crooked horizons (with no loss in image quality).

QuoteOriginally posted by VisualDarkness Quote
Also I suspect that you can reduce weight by using in-body IS with lenses without any stabilization than the opposite, correct?
What is more important to me is that I don't have to pay for a lens-based solution with every stabilised lens and that a lens cannot develop an IS-related defect.

Lots of good points have already been made by other posters. Here are three complementary ones:
  1. Lens-based image stabilisation have been suspected to mess up bokeh. I could imagine that moving the corrective lens element during exposure may cause some bokeh havoc, but haven't tried to validate this conjucture myself.
  2. A few select lens-based stabilisation systems optimise image stabilisation for macro shooting (which requires very different counter-movements compared to normal shooting). In-body systems could do the same, but to the best of my knowledge, no current camera-based IS system attempts to provide accurate correction in macro shooting situations. The K-5, for example, lacks the respective motion sensors; its acceleration sensors only measure rotational acceleration.
  3. Lens-based solutions not only stabilise the image for the viewfinder, but also for the AF system. There is at least one patent for camera-based system that not only shifts the sensor but also the AF system, but I don't think anyone has realised anything like it yet.
BTW, many people make a "lens-based system is better for longer focal lengths" comment, but I have never seen convincing support for that. Most image stabilisation comparisons are poorly done and do not allow any solid conclusions to be made.

Personally, I think a camera-based system easily wins the contest on points (just think of all the lenses that otherwise would never get stabilised, like classic lenses, small & fast primes, and wide-angle lenses). I believe Canikon are stuck to their lens-based solution because they started that paradigm in the film area already. I think it works for them financially but I'm not convinced that they actually believe that they've got the superior system.

Last edited by Class A; 12-11-2011 at 09:45 PM.
12-11-2011, 10:34 PM   #10
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An interesting thread but a complicated situation.

IS lenses seem to be significantly heavier and larger than non-is lenses. From the Sigma lens website

50-500 f4-6.3 Weight 1650 gm
50-500 f4.5-6.3 with OS Weight 1970 gm
19% increase in weight

17-70 f2.8-f4.5 Weight 450gm
17-70 f2.8-f4 with OS Weight 530gm
=========================================
Unfortunately, in many cases, the pentax version of lenses also designed for Nikon and Canon use also seem to have the same large volume and weight as the Canikon versions - not totally sure if they have the same weight if OS isn't included as a feature.
=======================================

Where one is dealing with the motion of humans, such as actors on a stage, the IS with the K20 was not always deemed to be useful as there was a sig. startup time involved in SR. I always did better setting a fast shutter time like 1/160 or higher with the camera than worrying about whether SR was active yet or not. My concentration had to be on stage action, not the indicator lights in the camera. K5 has a faster startup time, but i'm not sure it helps the situation or not.

Lens IS probably doesn't always help where rapid movement of the lens is needed to follow subject movement, i think, although lens IS is always on which helps in startup time.
=======================================

I can say for sure that Pentax SR leads to less need to straighten horizons, I noticed that one day after recognizing i was doing a lot less horizon correction than with my K20.

Both systems have pros and cons.

I don't know for sure, but i suspect that Sony gets better heat transfer out of a solidly mounted sensor in their Nex series cams, than a sensor suspended with SR mounts.
12-11-2011, 10:44 PM   #11
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Lots of good info. Thanks everyone.
12-12-2011, 05:27 AM   #12
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QuoteOriginally posted by Just1MoreDave Quote
The in-body system is the best because it is the one I have.
Absolutely agree - you go to war with what you have...... If you ain't got it - you can't use it...

QuoteOriginally posted by VisualDarkness Quote
....Also I suspect that you can reduce weight by using in-body IS with lenses without any stabilization than the opposite, correct?
Also I doubt that lens based stabilization is better than in-body as a technology as they both do practically the same thing, just at different places in the system.
The IS lenses are much larger, both size, weight and volume wise. I was over at Costco the other day getting a passport photo done, and playing with the cameras while it was being processed. While playing with both the Canon and Nikon cameras, I was really surprised at how large and heavy the lenses were. Took nice photos, but I was still somewhat lost with the controls. The ergonomics of the K20 and the two wheels are just much better for me - a personal preference.

I like smaller lenses. I guess that is why I have been picking up older MF ones - non SDR. Nothing really to break, just metal and glass. I do like the screwdrive AF. I guess since bodies are designed obsolescence, its probably better to only change out just one side (bodies) as opposed to both bodies and lenses where you have a high degree of electronics in both.

QuoteOriginally posted by Class A Quote
.....
BTW, many people make a "lens-based system is better for longer focal lengths" comment, but I have never seen convincing support for that. Most image stabilisation comparisons are poorly done and do not allow any solid conclusions to be made.
I made the "lens-based system is better for longer focal lengths" comment, essentially based on the moment arm effect. For a unit of movement with the sensor, there is a much larger movement in longer focal lengths when compared to the shorter focal lengths. That said, since I like wider angle lenses, I still see and perceive value in using SR or stabilization in the shorter lengths. Logically you need to move the sensor more to compensate for a movement change in a short focal length - however, with the shorter focal lengths, you should not be seeing a large set of movement change in the scene, in that it is closer. So it all works out. When I was designing a star tracking system for a telescope, and Pentax's floating sensor is similar but not as complex, the lever arm or moment arm effect really comes in to play - especially when you have a minimum focusing distance of the Moon.

QuoteOriginally posted by philbaum Quote
......
I don't know for sure, but i suspect that Sony gets better heat transfer out of a solidly mounted sensor in their Nex series cams, than a sensor suspended with SR mounts.
That is an interesting observation, and now that I read it - it makes a lot of sense, especially for long shutter times, as well as video.


Last edited by interested_observer; 12-12-2011 at 05:36 AM.
12-12-2011, 05:49 AM   #13
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I think when looking at how a canikin user would present their equipment, they would start by saying it is the best, as would a pentax or sony user.

everyone has a certain level of "brand pride" that biases their feelings, or more appropriately is used to justify their decisions.

In all honesty I can't say which is better, in absolute terms.

here is my situation.

As a pentax shooter for 30 years I have a large collection of lenses. Many of these lenses still perform well optically on my K5.

Why should I be forced to trade them all, to get image stabilized versions as I would have with Canikon?

to me, that is the advantage of in body IS.

I have posted shots from my K7 using a 510mm (lens plus teleconverter) hand held at 1/40, and shoot regularly at between 1/60 and 1/100 with my K5 and that lens. While I understand that technique has a big part to shooting at 3-4 stops below the "rule of thumb" of 1/(Fl x 1.5) the truth of the matter is that for me, any further improvement of IS is a waste of money because my subjects don't stay still for that long, and no matter what you do to take camera shake out of the equation SR can't and never will address subject motion.

As for the pros and cons for each system, I think the only real tangable points are,
- in body every lens you own has SR, each new body gives you improved SR performance over past bodies, and you do have the benefit of rotational motion compensation
- optical SR gives a steady viewfinder and presents a consistent target for AF to work from.

in a nutshell that is it, forget the argument ofhow many stops you get, both are adequate, the points above are what matters
12-12-2011, 07:23 AM   #14
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Anything I can stick onto my K20D (including modded Nikon lenses) is stabilized. Anything I want stabilized on a Canikon cam must be built that way and purchased deliberately. What a choice.
12-12-2011, 12:33 PM   #15
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for any one who thinks that in lens IS is better.

please post an equivelent shot

510mm hand held at 1/60



as I said in an earlier post, I think that in body IS is sufficient for anything you need. even if optical stabilization is "techincally" better
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