[e-scout1]

I bought k5 kit with standard lens18-55mm WR. The first problem was that picture preview on LCD I had to wait about 2 sec when making photos in AV mode. I thought SD card is slow, but when I changed to Pentax 70 300mm lens, preview was very quick as it should be. Then I changed back to 18_55 lens and tried with all modes like AV, TV etc and result was that only in green mode with this lens picture preview is quick.

Any suggestions - how picture preview can vary so much with this lens ?

As I mentioned with Pentax 70-300mm lens, picture preview is quick in all photo modes. I do not use this green mode therefore this issue is important for me whe using that standart lens.
scout

[Wheatfield]

Check to see if you have lens corrections turned on.
If so, turn them off.

[pentup]

Check to see if you have lens corrections turned on. If so, turn them off.

Does that mean that lens corrections are always off for Green mode? (no option for them even appears in the menus for that mode) The OP states that's the only mode in which the delay doesn't happen.
It's funny, but I would have assumed that in Green mode lens corrections would be on, by default. That seems like the more "auto everything" approach that I would have expected. But I don't know; I never use Green mode.

[DAZ]

Does that mean that lens corrections are always off for Green mode? (no option for them even appears in the menus for that mode) The OP states that's the only mode in which the delay doesn't happen.
It's funny, but I would have assumed that in Green mode lens corrections would be on, by default. That seems like the more "auto everything" approach that I would have expected. But I don't know; I never use Green mode.

Green mode seems to be the most safe conservative settings so that you can give the camera to someone and they will have the best chance to get a workable photo into the camera. If you can recover from the mistake (like a little under exposed or do a lens correction PP) then that is what the camera is trying to do. Green mode looks to me like it is not for the camera user but for someone that is not going to be familiar with the camera. A delay in displaying the photo on the screen for the owner of the camera is something the owner would expect as the price for in camera lens correction to someone other then the owner it would just confuse them.

Even not shooting in high speed is an example of this. The K5 is so quick and quiet that when I have handed the camera to someone to try they can fire off 3-6 photos before they know what is happening!




DAZ

[Wheatfield]

Since the manual is a little vague, I turned lens corrections on in my K5 and took 2 pictures, one in P, the other in Green. In P, the write time was about twice as long as it was in Green, and more telling is that upon reviewing the images using the image information option, the picture taken in P is showing lens corrections in use, while the image taken in Green is not.
I go back to my original advice, which is to ensure than lens corrections are turned off.

[e-scout1]

Thanks, it helped !
So it means that for the other lens Pentax 70-300mm, lens corrections setting does not influence, as with that lens picture preview is quick in all modes.

[sterretje]

The camera can only apply corrections if it knows which ones. And it simply does not know about your 70-300, so simply skips that step.

PS see page 219 of the (english) manual which lenses are supported.

[pxpaulx]

Thanks, it helped !
So it means that for the other lens Pentax 70-300mm, lens corrections setting does not influence, as with that lens picture preview is quick in all modes.

Well, Pentax doesn't have a 70-300mm. Sigma and Tamron have made lenses in this focal range with Pentax mount. Pentax has a 50-200mm and 55-300mm lens. If the telephoto lens you have is not Pentax branded (or is a pre-digital lens, something like a 100-300mm), then the camera would not be able to make corrections as the lenses are not made by Pentax (or are pre-digital models that have not been calibrated to use lens correction).