Optical Stabilisation

Hi,
I`m looking at new lenses and am wondering what happens when you use a lens with built in stabilization with a body with built in stabilisation?

Is there some magical formula that says you get double the stops or 1.5x stops or does it not work like that?

If you look at, say Sigma, they do not build stabilization into the lenses for Pentax. not sure about other makes.

You have to choose between one stabilization method and the other - using both at the same time would wreck your images.

Sigma now make one or two lenses in KAF mount with OS - you must disable SR to use them (or turn off OS). If you don't, then the SR mechanism moves the sensor enough to adjust for the shake when the lens is producing a stable image, so your image is artificially blurred.

Thanks, i was wondering if it would cancel each other out.

More like over compensate would be the word, if you move a bit to the right the one in the camera compensate and the one in the lens.
You're most likely better of with non on then have both on.

Sigma do make lenses in Pentax fit with OS - their 18-250 has OS.
They advise not to use the in camera OS if you use the lens OS.
I have heard that the lens OS is better than the in camera but I can't confirm that.

I am toying with the idea of getting the Sigma 18-250 as a holiday lens. The Pentax one is no longer available and the Tamrom one is getting to be like hens teeth, at least here in NL. I'm not sure I'll get one yet though. It's just easier, especially when flying CheapoAir somewhere.

Hey Gwyn, welcome back
Hopefully the forum has calmed down enough for your liking, it seems the new year and Christmas has done wonders here and maybe the message when you left did also some good.

Yes they indeed say that OS in the lens is better but now with the K7 I think the in camera has the edge since it can compensate for more directions of movements. It can compensate for camera roll which a lens based OS would never be able to do.

I know you had an eye for the pentax version for when going on holidays.
The sigma version has HSM if I'm not mistaken, I really missed the quick-shit with the DA and it was quite slow with AF so hopefully HSM does the trick for the Sigma.
I haven't found a review about the lens that compares it to the Tamron or Pentax version, but it's quite some time that I've searched.

A feature in this weeks AP (23 Jan) suggest lens based systems perform better than K7 SR.

Davex

In what kind of conditions and which lens, those are all variables of course.
I don't believe there is a lab test for this is or is there?

The K7 lens used was Sigma 50-200, with Sigma OS on it performed much better than with the Sigma OS off and the K7 SR on. There is so much data that you need to see it on the page, but basically the article demonstrates that lens OS produces more "acceptable" shots than in camera SR. It does not however talk about cost weight implications.

Davex.

sometimes...
I've an old keyboard I want to convert to Dvorak layout to see if that types better, if you see less errors the end of the week you know it works.

@Davex was it test by a form of vibration or really in hand?
If it's just vibrations you don't have the rolling motion, which the K7 can correct but not the Sigma, I was hoping that would give it the edge certainly when you press the shutter.

In hand, they do seem to have done it fairly, if you PM me your address I`ll post it to you, you may find it interesting.

Davex.

Okay will do that