Who Chose the 300 f4 over the 100-400 for Birding and Why?

I agree with most of what drj3, phocal and calnature have said.

Since I have become a an avid bird shooter I have mainly used the 4/3 50-200mm SWD + EC20 on the E-30, E-5 and E-M1 with good results.

I long coveted the 4/3 300mm F2.8 but it was always out of my price range.

So with the introduction of the mZuiko Pro range of lens I acquired 12-40mm and 40-150mm + MC14. I became very impressed with the quality, handling, AF and IQ on the E-M1.

I found when I got the 40-150mm + MC14 I used it more then the 50-200mm. I could crop the images far greater and still get the quality the same or better then the 50-200mm.

The when the 300mm F4 was introduced it immediately became the lens I desired as I knew it would exceptional sharp prime allowing me to shoot at the f4 aperture and f 5.6 with the teleconverter.

I made the 300mm f4 my choice because of basically the 50-200mm + EC20 was giving me similar results to that of the Panny and I knew how limiting shooting f7.1-f8 with the 50-200mm + EC20 combo.

In addition the 5 Axis Sync IS is very impressive and makes shooting handheld at low shutter speeds very achievable.

Here is an example on a very overcast day where I was able to shoot at 1/50 sec handheld and at a reasonable ISO 400.

With my 50-200mm + EC20 this would not have been possible unless I was on a tripod and my ISO would have been much higher.

With regards to the choice between the 300mm f4 and Panasonic 100-400mm that is a personal preference. Its a matter of weighing up the cost, weight, speed, IQ and zoom vs prime. Lots of good examples shown on this forum by people using the Panny on the E-M1.

People wil espouse the versatility of the zoom, but as I mainly shoot birds and mostly small birds I knew I would be always shooting at full focal length as I did with the 50-200mm +EC20 combo.

Since I have got the 300mm f4 I have not used the 50-200mm and I do not miss the zoom one bit! Only big birds like the pelican or darter may pose a problem if I get too close, so I don't!

At is MRP of USD 2,500 there was a lot of consternation/debate about the lens being too  big and expensive and not what The Micro Four Third system is all about.

There is no doubt it’s the most expensive m43 lens on the market but it is a speciality lens aimed at sports/action and wildlife shooters. It is the most expensive piece of photography gear I have purchased.

You need to ask yourself do I really need this lens and am I prepared to pay the price for a high quality lens. If you can’t justify the need and/or price then it is clearly not for you.

For those who are fortunate enough to be able acquire this lens, than it will reward you handsomely over many years, and justify the premium paid.

I have no doubt it has paid for itself already.

Hope that helps, a gallery of my 300mm f4 images here:

http://dwehner.zenfolio.com/p932217077