K5d or D300s

Wow, will the K5 not even manage to autofocus on a stationary passenger jet?

I jest - probably just needs a 'post-resize sharpen'....

Are you sure it is not sharp? Looks sharp to me. No PP done only straight from camera.

Correct, it looks a bit not in focus, and/or quite soft what I can see from that small picture.
If this isn't a heavy crop (I doubt it), then worth also to check if you don't have problems with hardware, or maybe your pp workflow needs some improvement.

Thanks Piotro, looks like I need to learn Photoshop to sharpen some of the pics after taking them. I am usng a Mac and using a free software called iResize to reduce the image size. Can you recommend a better one?

After resizing for the web, always sharpen!

Thanks. Will do that for all the pictures I took.

Slight correction. After resizing, always resharpen!

G

Gimp is free and quite good. This is what I use. Also there's plenty of plugins for it to give more features.
If you want you can also use Ufraw to open RAW files and do basic adjustments there, then it can import picture directly into gimp where you can finish it up with sharpen, precise corrections, etc.

Felix, you should post-process EVERY image you take. Free programs like Picassa are fine, there is no need to leap into Photoshop until you feel you want to.

Your computer is much more powerful than the camera, so don't play with the camera's settings. Leave everything on neutral, then adjust exposure, contrast, colour and sharpness afterwards.

It takes suprisingly little time once you get the hang of it, and your pictures will look a hundred times better.

G

Thanks George!!

If your considering the Pentax and Nikone, then I think you have to include the new Sony A77 looks like it has a very fast AF system for fast action motorsports.

For what it's worth - I had a similar choice when I bought the K5.

Handled various Canon, Nikon, Pentax and Sony bodies, but of all of them the Pentax just felt right. For me the ergonomics are second to none (admittedly that's fairly subjective) but for motorsports etc your going to be holding (and moving) it for quite a while! Tried the Pentax system with motorsport, go-karts, horse trials and a few others and can't fault it - but then any problems may be covered up by user error!!

From a newbie to all of this; it seems that all the major systems have the lenses that allow you to shoot what you want - you just have to go for the one that feels right. Also, if you've already got a Pentax you presumably have glass already??

Matt

I have recently been comparing these two on DPreview, as I want to upgrade from a KR, the K5 swings it for me (also I'm loath to change systems). But assuming sensor issues have been sorted, I will be upgrading soon.

Felix there are other approaches other than the above,He dosent know everything.

Personally I'm with George, I shoot raw and all my processing is done on the computer but I'm sure everyone would be interested in these other "approaches" ... please feel free to share