Custom focal lengths

[themosttogain]

Just read this on Robin Wongs latest blog - reviewing the 9mm fish eye body cap lends...

Image Stabilization

The last note, but also a very important one: if you have Image Stabilization on your camera body turned on (whichever IS system, the older 2-Axis or the newer 5-Axis and 3-Axis, on ALL Olympus camera bodies), please make sure that the custom focal length is set to 9mm, or anything closest to 9mm (some cameras have 8mm or 10mm, so please choose that setting). If you have other focal lengths enabled (eg 50mm, 100mm) high chances are you will get blurry images. The ordinary Olympus M.Zuiko lenses have electronic contacts to communicate with the camera, hence the camera would know what focal length it is dealing with. This is not the case with the 9mm Body Cap Lens that does not have electronic contacts. Hence you do have to manually set the focal length you are using. Alternatively, if this is too much trouble to go through (I don't deny it can get cumbersome when you are in a hurry and may not have the time to think about too many things when shooting) then just turn the Image Stabilization OFF.

Have I missed a trick here? I've got a few legacy lenses (don't use them as much as I should probably!), and generally IBIS is switched on in my camera, but i've never heard anything about setting a custom focal length with non electronic glass.

Does everybody else set a custom focal length when using OM lenses? Does it have a noticeable effect?

[StephenL]

Re: Custom focal lengths

Yes, if you're using IS on a "legacy" lens the camera needs to know how much stabilisation to apply according to the focal length.

Never thought about it on the pinhole lenses, but it makes sense as they are manual lenses.

[themosttogain]

Re: Custom focal lengths

Well that's something i've learned today! I'm gonna have a play when I get a chance...

[David Morison]

Re: Custom focal lengths

If you mount a 400mm plus legacy lens and try to frame an image without adjusting the IBIS focal length you will soon find out why it is a necessary step, which I learned very quickly!

David

[themosttogain]

Re: Custom focal lengths

That may explain why I've had issues with the 400mm lens I have.. I don't think it's a great lens anyway, but i've had some very odd results with it when I have tried it (which isn't very often at all!)

[OM USer]

Re: Custom focal lengths

Well done for bringing it to our attention although I'm unlikely to ever invest in a bodycap lens - its money better spent on a small pancake prime. For legacy lenses I wish they would either..
a) bring out an adpater with a "focal length" ring to make it quicker/easier to plug in the data
b) make it a button assignable function - press button and spin dial
c) combination of (a) and (b) have a L-Fn2 button on the adapter (so it can be seperately assignable and not take up the L-Fn1 button on recent MFT lenses).

[Magus]

Re: Custom focal lengths

Very useful info but how does this work out if you are using an EC-14 or EC-20? Do you have to go back to setting the focal length manually?

Gus

[David M]

Re: Custom focal lengths

If using an EC between a legacy lens and the body you have to set the focal length. The EC has now way of knowing what the focal length of the lens is.

[StephenL]

Re: Custom focal lengths

With a non-legacy lens such as the 50-200 there's no issue. The EC will pass the focal length through automatically.

[OM USer]

Re: Custom focal lengths

With a non-legacy lens such as the 50-200 there's no issue. The EC will pass the focal length through automatically.

Presumably it corrects by either 1.4x or 2x !

[StephenL]

Re: Custom focal lengths

Presumably it corrects by either 1.4x or 2x !

I would presume so, although you can only tell when you look at the subsequent Exif what focal length is being reported.

[benvendetta]

Re: Custom focal lengths

You are less likely to need IS on wider angle lenses anyway, with or without electric contacts.

[Falk]

Re: Custom focal lengths

Have I missed a trick here?
Does everybody else set a custom focal length when using OM lenses? Does it have a noticeable effect?

Now that is interesting, showing how different peoples perception can be. The possibility of using IS with manual lenses by setting their focal lenght via the menue was one of the reasons which made me chose the E-System in the first place. Good thing you discovered this feature before trashing all your legacy glass. Now have fun

[Guest]

Re: Custom focal lengths

Not only does the EC unit pass on the Focal Length, but it applies the correction of 1.4 or 2. So the screen on my EPL5 tells me at maximum zoom my 70-300 (FT lens) with EC14 and MMF2 is 425mm. Yes I know 300x1.4 = 420 but that's what the screen and EXIF say.

[David M]

Re: Custom focal lengths

That's because the EC14 is rounded down. It's actually a 1.415x. The 50-200 reports 283mm at the long end with the EC14.