Do you need a 300mm lens?
 

Just a little example of the difference between a 46mm and a 300mm lens when taking a picture of the same thing from the same distance,just to show the actual size if anyone is contemplating buying a bigger lens(including me!)
I currently only have a cheap 300mm fixed lens,to see if I would actually use it,well I think the answer is yes and I would prefer a 400mm!

From you gallery I see you have a D70, then why not consider 300mm f4 and 1.4 TC. Best of both worlds. A 300mm f4 and with tc on a 420mm f5.6.

Sometimes 400mm is just a bit too long.

Don

Thanks for that Don,I`ll look into it.

I use a 300mm f4 plus the option of a 1.4 TC for my bird shots. Because this combo is on the camera frequently a number of other wildlife subjects such as flowers and insects are taken with it. The close focus on 1.5M makes it a fairly useful macro lens for subjects larger than an inch or so.

A bit more friendly for close focus distance than the 4 metres on my 400mm. :D

Don

One thing to remember tho....despite what people and publications say, using a teleconvertor is always gonna be a compromise.
e.g, my 300mm Tamron f/2.8 with tamrons 1.4 convertor is never gonna be quite as sharp as a Tamron 400mm f/4....
but, yes, I agree, the 300mm option plus a good quality convertor does open up a bit more flexibility

The only problem I've found using a tcon in the past is deciding when to use it - I was always taking it off and putting it back on. I like the look of the new Olympuis 2x - that would take my 50-200 out to 800mm!