why does the manual suggest turning off the antishake option when using a tripod?

[Cogentia]

I have just purchased a KX and have have been trying out an old Pentax 400mm screw thread lens that is 35 years old. It works well but I am surprised that the KX manual recommends turning off the anti-shake option when using a tripod. What is the problem with using anti-shake and a tripod?

[Tannin]

Hi Cogentia,

Unless the stabilisation system includes a tripod-detection mechanism like the Canon and Nikon optical (in-lens) systems, when you mount it on a tripod it tries to compensate for movements that are not there, and ends up making matters worse.

[landteacher]

Cogentia. In layman's terms. The cameras anti shake system is searching for vibrations associated with movement, be it hand held of mirror slap. This searching action by the camera cause ultra sonic vibrations that cause movement even when on a tripod, which can cause motion blur in your photo. Hence the advice to turn it off on a tripod. Catch 22, Causes movement while looking for non existent movement. Hope this didn't make it muddier.

Mick.G.

[Cogentia]

Thanks for the responses. It is ironic that the main reason I purchased the Kx was because it's anti-shake mechanism was in in the camera body and so I could use it with my old 400mm Pentax telephoto. Of course this lens is too long for hand held use so I will always use a tripod and therefore turn off the anti-shake. Oh well just as welll I really like the KX and the 55-300 and 100mm Macro lenses I bought with it.

[Tannin]

400mm too long for hand-held? Not a bit of it, Cogentia.

Given good light and image stabilisation, you can successfully hand-hold a much longer lens than that. In-body anti-shake isn't as effective as in-lens stabilisation with the longer lenses, but I'd be absolutely astonished to discover that the Pentax stabilisation wasn't still doing useful work at and beyond 400mm.

Naturally you need to use good long-lens technique, but that is always true, no matter what equipment you have or how it's mounted.

Nope: experiment with hand-holding your 400. Heck, I sometimes hand-hold my 500/4 with a 2X converter on it (= 1000mm total), though not for long and not often. You can hand-hold an unstabilised 400mm lens (with difficulty), never mind one on a body wit AS. Go for it!

[Kym]

I use my SR on a tripod (with the 500) and it works.

The main reason it is discouraged is that it *may* hunt when on a stable platform; especially body mounted tripod.

But... with a long lens, the tripod mount is on the lens and not the body, so there is some movement at the sensor.

Diagram... (Picture here http://www.ausphotography.net.au/for...081#post261081)

[B][LLLLLLL]
____^

B = Body
L = Lens
^ = Tripod mount

So there is slight angular movement possible at the body in the above setup.

C&N users have IS/VR in some lenses and that is a different story. They also say (sometimes) don't use IS/VR with a tripod.
Pentax have body based SR which means every lens is stabilised.

Edit: I've used the 50-500 @500 handheld with good results.

Edit 2: 500mm hand held: http://www.ausphotography.net.au/for...ad.php?t=27129

[Kym]

These may be of interest as well...
http://forums.dpreview.com/forums/re...ssage=19647176
http://www.pentaxforums.com/forums/p...on-tripod.html

[HansPeter]

Using a tripod!! Can you do damage to your lens if you forget to turn of the stabilisation system??

[ving]

no, but it doesnt do anything for the picture... infact it may wreck teh picture.

[ving]

as for hand holding 400mm, with stabilisation it should be easy enough. I hand hold 500mm

[mudman]

Cogentia. In layman's terms. The cameras anti shake system is searching for vibrations associated with movement, be it hand held of mirror slap. This searching action by the camera cause ultra sonic vibrations that cause movement even when on a tripod, which can cause motion blur in your photo. Hence the advice to turn it off on a tripod. Catch 22, Causes movement while looking for non existent movement. Hope this didn't make it muddier.

Mick.G.

Isc this why i can't get good sharpness with the K7 when i zoom the 18-250?
i thought that with anti shake in the body and not the lens that because the body is stable it would not matter.

[arthurking83]

Isc this why i can't get good sharpness with the K7 when i zoom the 18-250?
i thought that with anti shake in the body and not the lens that because the body is stable it would not matter.

Not necesscelery!

The lens itself may be the culprit in this case.

Try zooming back a little form the full reach that the lens is capable of.
use the marked focal lengths at say, 200mm 180mm 135mm... etc and see if that makes a difference too(to sharpness).

Most of these consumer kit type lenses, especially the superzoom types will be at their worst at the longest marked focal length.

And be sure to try stopping down by at least one stop from maximum to 2 stops from max aperture too.

There are too many other variables to consider as well, why a lens is not producing maximum sharpness when it matters most.. such as focus accuracy... tripod quality(when using a tripod that is!) .. etc, etc....

[Roof]

i've have my anti shake turned off at all times

[ChrisN]

I tend to leave the anti-shake on all the time. I'm not convinced there's any problem when shooting off a tripod, or at least I've never seen any evidence of it in my shots.

Here's a shot of a water dragon that posed nicely for me, and sat still long enough for me to set the tripod and line him up. Camera was K20D with an old Schneider-Kreuznach 360mm telephoto in M42 mount.



And a 100% crop. I was lucky and managed to just about nail the focus.



Cheers!

[JorgD]

That's a seriously crisp lizard photo

I have had problems with leaving the IS turned on while on a tripod with my 70-200 f4 L IS lens (Canon), and have learned from that bad experience that even though the lens is supposed to detect that it is on a tripod, it is better to turn the IS off to make sure.

The IS introduced enough movement that at 200 I could see the image move in the viewfinder.