Yes, knights were still knights. And as for armour, it depends on the date(s) you are trying to portray. There is a ton of information on period weapons, armor, and warfare at www.myarmoury.com
. Check out the Features
section for spotlights on Renaissance armies from 1480-1650. These articles have photos and illustrations that I think you will find quite helpful. I cannot recommend this site enough. MyArmoury also has a lot of photos located in the Albums section that you might find handy. MyArmoury is the best resource of its kind on the internet, IMO. Another site that might be helpful is www.armourarchive.org
--a site on armor!
Some images from the myArmoury article on the English armies from Henry VIII to Elizabeth:
Greenwich Armour for Henry VIII c.1540:
Italian armour of 1550, typical of that worn by Enlglish demi-lances:
Google image searches are helpful for pics of various siege engines including siege towers
and battering rams
Good luck and happy reading!
Added: There are also some top-notch reenactors out there who portray Renaissance armies of various centuries. Lord Grey's Retinue
portray a 15th century household, and The Guild of Saint Michael
portray and Elizabethan Trayned Bande.
Added again: Sorry, here is one more link to a nice gallery at the Arador Armour Library