IMHO, the best bang for the buck out there is the Xenotar 3.5. They are expensive, but are half the price of the Planars, and just as good IMO, especially at f stops like f/8 and f/11. 3.5Fs with the Xenotar can be had frequently for under $500, and that is for a very clean one. If you can swing that much, I might suggest splurging. However, if yo are on more of a budget, any one that has been properly cared for, on a camera that has been serviced for proper focus, and that wears a proper lens hood should work just fine for what you want.