I appreciate Pacerr mentioning my website, but there are many more wildlife shots on my Photoshelter website. Just Google Ron Kruger and click on any link to Photoshelter.
My standards may be higher than some, because I shoot for publication and 30X40 prints, but this is how I approach wildlife photography.
Generally, the closer you can get, the better the shot. For real wildlife, I think it is more important to be a good hunter than to be a good photographer. Have your father teach you all he can about hunting. Use the clothing, blinds and methods hunters use. Learn as much as you can about the species. Learn to read deer signs and call turkeys. If water is nearby, use a kayak, belly-boat or someting you can float in with a low profile. Animals and birds are less lery of you when you're in the water.
Photgraphing with a 200mm requires getting as close to deer, for example, as during bowhunting (within 30 yards), but you won't be happy with shots from tree stands. If possible, shoot up at wildlife, not down--much more dramatic. But hunting, or photographing, from the ground is even harder than from a tree. Not only are you on their site plane, so is your scent. The direction of the wind is most important, and while you can easily shoot a bow into the shadows (where deer often stand), a camera doesn't work as well. I use spot metering most of the time.
If you can afford 25-60K for a good, super-long lens, go for it, but the longer you go the more atmosphere (or the physical distance from the subject) will degrade IQ. Generally, the closer the better. 200mm is the longest lens I own, and sometimes I use 100. I saw a documentary some months ago about the best Nat Geo images of the past decade. Every one of the wildlife pics featured were under 50mm (most from film cameras, about 35mm crop sensor equivilent).
If you are shooting real wildlife, many (if not most) of your best opportunities will come during low light, so the faster the lens the better. The Pentax 300 f-4 is a great lens, but it's just not fast enough. Sigma 300 f-2.8 would be a better choice.
For maximum quality, I shoot most everything at 100 ISO and never above 400 ISO (K20D). Not just noise, but everything is better at lower ISOs. I'm hoping to get a K5 to boost that to a max of 800, maybe even 1,600, which means an f-4 lens would be more usable, but because I often find f-2.8 not fast enough, I'll probably stick with f-2.8 and shoot further into the fading light. When the light is good, I use 100 ISO and stop down. Even lenses that are good wide open, are even better stopped down a click or two.
I've learned the hard way that AF can't read my mind, so I use MF at least 80 percent of the time to control the focus point, especially in the woods. AF is good for simple, uncluttered scenes where the subject is the only thing in the foreground, but not for a deer standing in foliage. Most people, I suspect, don't realize that a twig, leaf or even a blade of grass just in front of the subject is where the focal point is centered. I always concentrate on the eye for the focal point. I even use MF on BIF.
Even if you know the habits and habitats of your intended species, plus know a lot about where and how to set up to avoid being smelled, seen or heard, patience is the main ingredent to good, close wildlife shots. I often read a book while waiting.
If you don't have that all-important patience, go to zoos, semi-domesticated fenced areas or on an African jeep ride.
