Oly 75mm for

Sure, if you happen to have a bird that close to the camera you can get a nice shot with the 75mm, but I wouldn't buy an $850 lens for that reason when you can get a much better lens for birding for less money.

However, if you already have the lens, might as well use what you've got. I'd buy a 75-300 though if I didn't have either and that was my intended use of the lens. 75mm is a bit short.

 

I haven't done any serious birding, just goofing around here and there...but I wouldn't use something as short as the 75.

I used to use around 300mm (either 70-300s or 70-200s with a 1.4x TC) on APS-C bodies, which gives you roughly 450mm equivalent. Even that's on the short side by birding standards.

I'd look into the Panasonic 100-300, if I were you. It's not great at the 300 end, but at 200-250mm you're still at around 400-500mm equivalent, which is plenty for birding.

 

I love shooting birds with my Oly 75, just not the flying kind. wink wink.

On a serious note, I agree with JamieW, why spend $900 on this when you can get the Panny 100-300 for much less?

 

Here's one I took with the 75:


Raven with a hazelnut by Paul Kaye, on Flickr

Makes a nice short telephoto (because that's what it is!!)

 

This is an1525 x 1144 pixel crop of a shot taken with the 75mm so that's roughly equivalent to a 225mm field of view. Don't know how big you could print it to but the detail is fairly amazing to me. The bird is a mynah, not overly small—I'd guess a body size of around 20cm/8" or so including tail, and from memory the distance was probably around 6 or 7 metres or so to give you an idea of what the situation was.

I had been using the Oly 40-150mm for birds and was feeling a bit unhappy with it because I was finding the widest aperture too slow and the 150mm focal length too short. There were no reasonable faster and longer options available so it came down to whether I wanted faster or whether I wanted longer the most. I went with faster and got the 75mm. It's not good for long distances but if you need a fast lens for low light or stopping action and you can shoot at a reasonable distance then it can work and it can deliver impressive results.