You may find this link of some use for a review and suggested basic set up guidelines of your sp4805 projector.
http://www.projectorcentral.com/infocus_screenplay_4805.htm
I have my sp4805 connected to my Sony DVD player via component input connections and have adjusted the colour image on the projector to match these colour settings recommended on this web site.
The picture colour and skin tones to me now looks more natural and a vast improvement on the manufactures factory settings.
Give it a try and see if you notice any improvement to your current picture settings.