Where do those stabilization f-stops come from?

[scott kirkpatrick]

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If you think about it, the numbers that you read in reviews for image stabilization, can't apply to all photographers and all situations.  Success of stabilization has to depend on the focal length the fraction of the image that the thing you want to steady takes up, how hard you are shaking the camera and maybe even how you shake.  For the last two things, the S1 and S1R have a menu entry that brings up a target with a red dot jumping around that shows how the camera is compensating for its motion.  This should let you know if there is any hope that the camera can compensate for the motion that you are providing. 

But where do the numbers come from?   Sure enough there is a standard for this, and it's a standard for marketing folks to keep the competition fair,. It only controls what you can say in an advertisement.  It's called DC-X011 and controlled by CIPA, a camera-makers' organization.  But it does suggest ways in which to do your own experiments to see what IBIS or OIS can do for you.  There is a standard "vibratory apparatus" and standard wiggle tracks recorded for the pitch and yaw excursions that a group concluded would represent typical camera motions.  And this target:

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which should be just far enough away that the four center rectangles fill the frame top to bottom.  The idea is to see how much blur the shaking table adds to the clarity of the target rectangle outlines as you slow the shutter speed, first without the stabilization, then again with it turned on.  The black line in the figure below is blur without stabilization, and the lower red line is blur reduced by stabilization.  Draw a red dashed line across and the distance between the point where it crosses each curve  (showing that you have the same blur with stabilization but at a lower shutter speed) is the number of stops gained by stabilization:

Of course this distance can depend on at what height you draw the red dashed line across.  It takes several pages of definitions to spell that out, and I am still not convinced that it isn't set just to get a fairly large number.  I would just cut the top line at 1/f and see where a horizontal line hits the stabilized performance.  In the lab you aren't supposed to change ISO (noise changes) or change aperture but only change the light level.  If you do this experiment in a scene that you might want to photograph you will probably change both as you lower the shutter speed.

The bottom line is that these numbers are gathered in a systematic, reproducible way, but there is no reason that they predict what you will actually experience.

Edited August 12, 2019 by scott kirkpatrick

[ron777]

And yet despite all that technical data, lol, the S1 and S1r’s IBIS works, but Sony’s, not so much.

[scott kirkpatrick]

Leica's not making any strong claims about OIS, either.  Deep in a text paragraph in both the 24-90 and the 90-280 instruction sheets they say that OIS (at a focal length which is not specified) could permit as much as 3.5 stops slower exposures, according to the CIPA test procedure.  Since any number between 0 and 3.5 will satisfy that claim, it's a safe statement.

[jaapv]

I read it as : if you could have taken the shot at a given shutter speed, O.I.S. will allow you to take the same shot at an x times longer shutter speed.- if you haven't had a cup of coffee between the shots

[LocalHero1953]

2 hours ago, scott kirkpatrick said:

Leica's not making any strong claims about OIS, either.  Deep in a text paragraph in both the 24-90 and the 90-280 instruction sheets they say that OIS (at a focal length which is not specified) could permit as much as 3.5 stops slower exposures, according to the CIPA test procedure.  Since any number between 0 and 3.5 will satisfy that claim, it's a safe statement.

Leica's claim is not unreasonable: I have shot the 90-280SL at 280mm and around 1/50s, which is about 3 stops from 1/f and 4 from 1/2f. But at that speed, the main problem is not shake but subject movement.

[thighslapper]

Presumably the weight and inertia of the gear also comes into play, damping down 'human vibrations' to an extent. 

The S1/S1R jumping bean is interesting .... but there is no explanation as to what the concentric rings signify ..... I originally thought that if you kept the red dot within the centre circle you could assume IBIS would work 100% ..... but possibly that is being too simplistic as it doesn't seem to vary at all with whatever settings are on the camera. Maybe you have to keep it within the crosshairs .... which is a tall order. 

I can manage 5 stops consistently and a bit more with combined OIS+IBIS but anything better needs to rely on machine gun tactics in the hope that a few will be sharp. 

 

[scott kirkpatrick]

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When I want to boast, I sit in a chair and shoot a wall of books with IBIS, using a wide angle lens and braced elbows or a table-top tripod stuck against my chest.  That gets me a 2 sec exposure, which is 6 stops below 1/f.  Outdoors is harder, and you really need this for longer lenses, not wideangles. I like to use an R APO 180/2.8, which is pretty light and has extremely light focus ring movement, so I have to hold it gingerly. But the light was good recently so I shot every thing at 1/f or faster.

[scott kirkpatrick]

3 hours ago, jaapv said:

I read it as : if you could have taken the shot at a given shutter speed, O.I.S. will allow you to take the same shot at an x times longer shutter speed.- if you haven't had a cup of coffee between the shots

Maybe even better, if you are a stone cold marksman, drink only vodka, and know how to breathe properly.  I think the IBIS value that you use should be personally determined.  Actually, Jaap, you do a form of surgery/sculpture so don't you have extra-steady hands?

[scott kirkpatrick]

19 hours ago, thighslapper said:

Presumably the weight and inertia of the gear also comes into play, damping down 'human vibrations' to an extent. 

The S1/S1R jumping bean is interesting .... but there is no explanation as to what the concentric rings signify ..... I originally thought that if you kept the red dot within the centre circle you could assume IBIS would work 100% ..... but possibly that is being too simplistic as it doesn't seem to vary at all with whatever settings are on the camera. ...

I wondered if it sets the rings according to the focal length of the lens that is on the camera, but I haven't checked yet.  I could compare the 35 and 75 SL SC, or the 16-35 at its two extremes.

P.S. It does seem that the bean jumps about more with the 75 mm lens than with the 35 mm lens.

Edited August 13, 2019 by scott kirkpatrick

[scott kirkpatrick]

This morning I see that Mike Johnston on TOP is marveling (qvelling, indeed) that his new Fuji 100-400 which has both OIS and IBIS on the X1H can take sharp pictures of the screen in the window at 1/20 sec.  Well, 1/f for a 600 mm-eff lens is 30x shorter than that , so this is just under 5 stops of stabilization.  No big deal!

[jaapv]

I'm with Mike. Being able to take 800 mm  equivalent wildlife shots handheld at 1/60th  (even being able to frame them properly) with the DG Vario-Elmar 100-400 is a new experience.

It is not just the number of stops, but also the number of axes. 5-axis is the most advanced and effective.

[scott kirkpatrick]

I agree on the question of impact.  Very long lenses, even for M43 and APS-C need to be shot at f/8 and up to make every hair on the mane of a yawning lion come out sharp, so getting a shot at 1/50 or less is a great help.  And watching the view stabilize once you half-press is very impressive.  I've used the Fuji 100-400 on an X-T2.  It locks in on distant critters dramatically:

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XT2F0302 by scott kirkpatrick, on Flickr Fuji 100-400@300 with OIS