Did I miss something?? No IBIS with MF lenses?

Started Jun 21, 2012 | Discussions thread
clengman
Senior MemberPosts: 1,297Gear list
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Re: Image stabilization is a lie
In reply to MadsR, Jun 23, 2012

MadsR wrote:

You can't violently move the camera around and get clear images...

The system is built for micro vibrations, the stuff that gives a few pixels worth of blur in your images, a few pixels is a few micro meters, the system simply tries to keep the sensor in the same place regardless of the movement of the camera...

Wrong. That's not how IBIS works. The traditional 2-axis IBIS senses pitch and yaw and slides the sensor up or down or left or right to compensate for the rotational movement. The distance that the sensor must move to compensate for a particular angular camera movement scales along with the focal length of the lens. That's why the IBIS system has to know the focal length of the lens in order to function properly.

it will never be perfect... So you argue that it does not work based on the theoretical view, and you are quite right... You are also wrong in that simply knowing what is in focus would help, but it does not...

Yes it does. In fact it's the only way that stabilization in the two translational axes can work as I explained before. I'll get back to that in a minute.

you need to be able to angle the lens too (possibly wobble it) so it does not change the light path entry to the sensor/film in the first place... None of this will likely ever happen, and in pracsis isn't needed. You get a good 3½ stops worth of slower shutterspeeds from the E-M5 regardless of lens used (YMMV, focal length matters, distance to motive matters too but is currently not handled AFAIK) this is better than any prior system I have used (Olympus or Canon)...

What the OP asked is if the image stabilization system worked when he took stills, and it does! Confusing this with theoretical babble on focus planes and axis of movement does not add anything to usability of experience of the system.

Sorry if my "theoretical babble" was over your head. I thought my language was pretty simple and transparent. How about a thought experiment then...

Say you're using (for instance) your 14-42mm kit lens at the long end and your subject is the moon. If you move your camera a millimeter to the right and the cameta moves the sensor a millimeter to the left to compensate, it's going to seriously eff up your nice photo. If the camera is moving only parallel to the sensor plane, it would have to move many miles before the moon changed position within the frame.

Now say your using the same lens at the same focal length at the minimum focus distance. The magnification ratio is about 0.24. Now if you move the camera 1 mm to the right, if the camera moves the sensor 1 mm to the left... it's still going to eff up your photo. You want the camera to move the sensor about 0.24 mm to the left to compensate.

If you're using a 1:1 macro lens, the camera movement and compensatory sensor movement should be about equal in magnitude. So now you see (I hope) that in order for x-axis and y-axis stabilization (two of the 5 axes in 5-axis IBIS) to work properly, the camera has to know both the focal length and the subject distance.

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Olympus PEN E-PL1 Olympus M.Zuiko Digital ED 14-42mm 1:3.5-5.6 Olympus M.Zuiko Digital ED 40-150mm 1:4-5.6 Rokinon 7.5mm 1:3.5 UMC Fisheye CS +4 more
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