Does IBIS (sensor shift) make precise backfocus of manual lenses moot?

[zuiko85]

Title says it all. If I get an Olympus mirrorless body with a 5 axis sensor shift will it be non effective to adjust older manual lens adapters to the stated 19.25 mm lens flange to sensor of Olympus mirrorless cameras so that the lens infinity mark lands on that mark when focused at infinity.

 

[Godfrey]

Title says it all. If I get an Olympus mirrorless body with a 5 axis sensor shift will it be non effective to adjust older manual lens adapters to the stated 19.25 mm lens flange to sensor of Olympus mirrorless cameras so that the lens infinity mark lands on that mark when focused at infinity.

Of course it works fine to obtain as close to original mount register calibration as possible. IBIS systems generally don't move move the sensor off-plane at all; they move the whole sensor in all directions in the focus plane. A "5 axis" system tries to respond to movement by sensors arrayed in five axes, but it only moves the sensor in the (x,y) plane, never the z axis.

Personally, rather than shimming and otherwise modifying lens adapters, I calibrate my lenses with an additional distance registration mark so that I can focus by scale accurately without modifying anything. I focus normally, and then shift the focus by the difference between the supplied distance index and my new one. 🙂

G

 

[splitimageview]

As @Godfrey stated, sensor-based stabilization allows the sensor to move freely in the x/y plane, while maintaining perfectly flat alignment with respect to the lens, within a few microns.

So, the choice to adjust is the same whether the body has IBIS or not.

 

[zuiko85]

Thanks, I had an obvious misunderstanding of what was meant by '5 axis' stabilization.
And Godfrey, great idea and simple to implement. (I find most good ideas are thus.)
In theory, shimming one of these inexpensive Chinese made lens adapters is straightforward. In practice, finding a shim material of suitable thickness, well, I can usually come close, but hitting the right measurement exactly without overshooting? Not so easy.
I have an EM10 and a gob (not sure of the exact quantity but more than half a gob for sure) of older, manual focus lenses. Some, like my humble 135mm f3.5 OM Zuiko, $15 at a camera show some years past, are really very good on my micro 4:3.
Some of the others are......shall we say, at least interesting.