No in-body stabilization in Nex. Stupid!(?)

Started Oct 10, 2011 | Discussions thread
SteveGJ Senior Member • Posts: 1,422
Re: Is this the real reason for no IBIS??? source...

The degree of sensor movement is nothing to do with the register - it's simply down to the amount of movement and the focal length. If you have a 50mm lens on an A77 and the same on an NEX the sensor would have to move exactly the same distance for the same level of camera rotation. Note that with a 500mm lens the sensor would have to move 10 times the distance for the same camera rotation. However, we tend to use shorter exposures with longer lenses so the effects roughly cancel out.

It's certainly true the image circle has to be slightly larger than the sensor diagonal. I did some measurements once, and I found the degree of movement required for a 200mm lens was a maximum of about 1mm in any one direction (just photograph a very small specular highlight with a longish-exposure many times and examine the pixel-level detail to see how much the trail has "wandered").

It's a bit different if you want a stabilised viewfinder image though - in that case, you aren't compensating for hand shake over a period of tenths or hundredths of a second, but seconds. Then you have to deal with much larger accumulated movements and the greater capability of OS lenses comes to the fore.

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