I have a Cokin filter holder and ND grad filter #4 I can use with the Sigma 15-30mm EX DG lens on the Pentax K20D. So I've taken the K20D on several of our walks... the holder shows at anything wider than about 24mm. So back to Penn Camera to look for a different holder for wide-angle lenses. The 15-30mm EX DG is a big heavy lens for me, with an 82mm thread .. and I don't have that large filters nor can you use a regular screw-on filter with the 82mm 15-30mmEX. Thus the Cokin.
I also wish to set up the 10-20mm EX DC (77mm thread) and 17-35mm EX DG (77mm thread) lenses I have for the Sigma SD14 to use the Cokin holder with the ND grad filter.
We're off on a trip to the Seattle area in October (N's reunion group) and so I need to decide whether to take the K20D, which lenses, and what it's good for on outdoor situations which will be most of my 'photo opps' around Seattle. Generally I use the K20D as my indoor-museum camera as it's definitely easier to get decent ISO800 results indoors with dance and performance programs with it (with the Pentax 100mm F2.8 lens) than with the SD14/DP2. The DP1 is just too wide for stage shots. The DP2 can do them with its F2.8 if we're close enough (ref lots of Folklife Festival stage shots with DP2).
I can see using the Pentax K20D in deep-woods situations ... but will be have those at Mt. Rainier National Park? Or will there be a lot of what I call big sky shots? So I've been taking the K20D out to experiment with evening light big sky shots.
My reaction to using the K20D recently is that the K20D doesn't have the dynamic range as large as the SD14/DP1/DP2 for big skies + green foreground situations. This is what I do a LOT of on our evening walks and have tons of photos in the SD14 and DP1 and DP2 sets on http://www.flickr.com/photos/sandyfleischmann The Sigma cameras handle the skies + ground situations beautifully without blowing out the skies or underexposing the foreground.
But the Pentax K20D does very nicely with the ISO400-800 dark area foliage shots... as long as there isn't the sky throwing off the dynamic range. See the latest Pentax photos on flickr .. from IMGP2367 to IMGP2400. No ND filter or anything else on the 15-30mm EX DG.. just the lens hood. I had a lot of badly exposed shots.. these were the best.
More comments and photos will follow. I'm using this blog as my 'notes to self' on upcoming experiments.