Setting the Focal Length for I.S.

[holidaydom]

I know we'll need to set the "Focal Length of the Lens" in IS for non-oly lenses.

But do we set the actual focal length or the 35mm equlivant?

Meaning, when I attach my Sigma 105mm f2.8 - do I set the IS at 105mm or 210mm?

The manual just says "Focal Length of the Lens" but it was specific...

[Mikefellh]

Originally Posted by holidaydom I know we'll need to set the "Focal Length of the Lens" in IS for non-oly lenses.

No, you only need to set the focal length for non-FourThirds mount lenses, i.e. Olympus OM lenses.

Originally Posted by holidaydom But do we set the actual focal length or the 35mm equlivant? The manual just says "Focal Length of the Lens" but it was specific...

You set it for the actual focal length of the lens, not the field of view...if it's a 105mm you set it to 105mm no matter if it's an OM, Pentax K, or whatever.

If you're using a Lensbaby you'd set it to 50mm.

Originally Posted by holidaydom Meaning, when I attach my Sigma 105mm f2.8 - do I set the IS at 105mm or 210mm?

Does that Sigma have a FourThirds lens mount...then you DON'T need to set this setting. However if that Sigma is an OM or other mount, then yes you do set it.

[phyrewall]

I believe it's focal length of the lens and not the 35mm equivalent.

The 35mm equivalent is sort of just for reference and comparison with other cameras. As far as your Olympus camera is concerned, it sees the focal length of the attached lens, and it doesn't convert it to 35mm equivalent.

This is why in the EXIF, even if you attached a 500mm for example, it is still marked as 500mm. Despite the fact that its 35mm equivalent is 1000mm.

Same goes for the Olympus flashes, if you use manual zoom on the flashgun. You set the actual focal length instead of the 35mm equivalent.

[holidaydom]

Thanks for the info...

Contary to popular belief - you'll need to set the focal length in IS for SIGMA 4/3rd lenses as well.

I remember reading this somewhere on another forum (can't remember which one) but another thing that points to this is that when I attached my SIGMA 105mm lens - the option to set the focal length in the IS menu was available. When I attach an OLY 4/3rd lens it's not.

[mactigasuku]

So .... how would one set the focal length for a zoom lens .....

[Mikefellh]

I have to say this was a surprising revelation to me...wonder if Panasonic/Leica lenses suffer from the same issue.

Originally Posted by mactigasuku So .... how would one set the focal length for a zoom lens .....

Well, you don't need to be 100% accurate...the idea of feeding this information to the IS system is so it can anticipate the movement it has to compensate for.

With that in mind, GUESS what it should be...if it's 1/4 of the way between 25 & 35 enter 27. If you're like me and you have a 60-300mm OM lens and it's 1/4 the way between 135 & 200 enter 150.

You won't wreck anything if you're off by a few mm...who knows how this factors in exactly into the IS function.