Beware - SR induced shake - Oops!

I've just spent a frustrating few minutes trying to work out what was going wrong with my pictures. Long-ish exposures (around 1/15th) on a 28mm lens showed signs of shake. Upping the ISO to get 1/60th didn't help and the resulting images showed far more shake than I'd experienced before. I checked specifically to make sure SR has ready before shooting.

Then I realised my focal length had been set to 500mm yesterday and I hadn't changed it - oops...

I've done it the other way round SR 28mm.... Lens 400mm

28mm setting for a 400mm lens is the "correct" way to make the error though - the other way round would have the camera adding excess correction! Must have been worrying for a bit John!

Naturally I've, um, never made this mistake. Nope.

Definitely not.

After the third time...

Just got a K-5, very impressed so far. Am I right in thinking that if I use A-series 35mm lenses (which I do), then when I turn the camera on and it asks for a focal length, I put in the nominal length plus 50% rather than the straight value, in the same way that my 50/1.7 turns into a 75mm on digital?

Thanks all.

No, use the actual focal length of the lens. Forget the crop factor!

Your 50mm/1.7 is still 50mm whether it's on a film camera, a digital camera, or whatever the film or sensor format is.

Many thanks for the feedback. Looking forward to getting to grips with the K-5.

I have made that error with my K10 not yet with the K5 but it is probably just a matter of time

What do you put in for focal length with say a 1.5x converter? DO you add the additional 50%. Also any changes for extension tubes?

You enter the focal length of the lens multiplied by the converter magnification. 28mm x 1.5x T/C = 42mm.

I'm not sure how you would work out the change in focal length, if any, when using extension tubes.

If you're using the shutter speed = focal length rule do you include the 1.5 crop factor in the calculation

Barrie's question is answered in the instruction manual, and refers to the slowest "safe" shutter speed when hand holding.

For a 35mm film camera this is taken as the reciprocal of focal length, so for a 200mm lens that would be 1/200sec. For an APS-C DSLR it would be 1/300sec (200mm x 1.5 = 300mm.

When entering an SR figure for a lens, just use the actual focal length.

Logically, when using say a 2x converter you would presumably use 200 x 2 = 400mm as the starting point, although I have never actually tried that myself.

If a converter has all the electrical contacts it just passes
the lens FL straight through.... so basically your stuck with
that... It seems to work though.

With a basic TC you can enter the FL so you can allow for the TC.

You only need one, can't see the point in getting any more.

Oh, that's bad!!