K20D

Hello, I have bought a 800m lens for my K20D, however when i take pictures, they are not very clear and have a grain effect.
Could anyone tell me what am i doing wrong? Or what settings i should change on the camera? Thanks Kosh

Which 800mm lens is it?

At 800 mm you need to use a tripod, or have a high shutter speed.
Do not push the ISO over 400 unless there is plenty of light.
Sharpest images on most lenses tend to be a couple of stops smaller than maximum aperture.
Why don`t you post an example pic with the exif info.

Davex.

Unless it's a mirror lens (fixed aperture). In which case you just have to wait for better light!

But tripod use (or equivalent) still holds. And remember that at 800mm (1200mm in 35mm equivalence) that focus is critical for any lens - DOF (depth of field) is very, very shallow - and on top of that a mirror lens means establishing focus at a relatively small aperture. Another reason for a tripod/support. And if using a tripod you should try turning SR off for a cleaner image, and perhaps use a cable release or the camera's timer to trip the shutter.

Av should work with your lens. First set "Using Aperture Ring" to "permitted" and the shutter speed will vary according to the light level.

It may be that the lens will not expose accurately, but just adjust the exposure compensation if this is the case.