Hi--

>Thanks for the response.

You're welcome!

>I could use a recommendation for type and speed film for general outdoors
>shots. My wife and I travel to wilderness areas frequently and shoot a
>lot of film for personal use. I generally use Fuji chrome at 200-400asa
>and a Olympus OM1 camera with a Sigma 35-175 lens .What I am trying to
>accomplish is to duplicate the sharp colors we experience in the outdoors
>and was wondering what filters might help me achieve that.
>Thanks,
>Joe

Ah, now I have some information! ;-)
I would avoid the films above, and the Kodak equivalents - that is part of the problem, since these are low-saturation, high-contrast films of limited sharpness (and are fairly grainy). If you are shooting exteriors in good light,
try one of the slow slide films, like Fuji Velvia (40), Fuji 50 (50), Sensia/Provia 100 (100, with push possible to 200 with higher contrast);
or Kodak Elite 100 (or similar Lumiere 100 or 50) for noticeably sharper, smoother, more briliant images. Kodachrome 200 is a good choice as the light levels fall, if there is not much smooth-tone area to show the large grain.
If you can tolerate using one, a tripod helps, as does very careful focusing
and using optimum apertures (probably f8-11 with the Sigma - avoid wide apertures with it). I assume that the lens (front and rear) is perfectly clean, and the lens has no fungus or haze inside. If you have an Olympus prime lens,
I would suggest shooting the same subject with both lenses at the apertures
you normally use to see if the Sigma is up to par (it may very well not be a particularly good lens, especially in contrast and color saturation [Velvia and/or a polarizing filter may help here, or another lens....]). As noted
before, care is necessary with exposure of slide film (a consistent 1/4 stop error is noticeable, and for me a 1/3 stop error is borderline).
Good luck!
David Ruether (Hope This Helps)