Mirrorless Lens/System for Flying Bird

[NancyP]

Well, give me an optical viewfinder any day for BIF! My BIF kit, Canon 60D plus 400mm f/5.6, weighs 2.0 kg. or less. It is long, though. BIF shooting is exceptionally demanding of a camera/lens' smooth and fast operation.

 If you aren't talking BIF, you would be surprised at the large number of birders that slap a compact onto the end of a spotting scope - and the pictures can be quite good. Of course, the good spotting scopes are quite expensive. And using the high end of the zoom on the spotting scopes is good for visual but not so great for camera ("empty magnification"). Some fine photos have been taken with high-zoom ratio point and shoot cameras and with Sony NEXs kitted out with old mirror lenses. Will the photos be of the technical quality of ones taken with a 1DX and a supertelephoto costing >$10,000.00? No, but do you need to have the ultimate? For screen use, no, for 8 x 10 no, for 20 x 30, possibly yes.

[LesPalenik]

Has anybody tried the compact superzoom cameras, for instance Canon SX50 or other cameras around 1000mm effective focal length?
How would the image quality at the long end (1200mm) compare with a 400 or 500mm lens on a DX SLR?

[Deep]

Well, give me an optical viewfinder any day for BIF! My BIF kit, Canon 60D plus 400mm f/5.6, weighs 2.0 kg. or less. It is long, though. BIF shooting is exceptionally demanding of a camera/lens' smooth and fast operation.

Funny you use a 60D.  I just sold mine because I had trouble focussing on a stationary bird, let alone one flying past.  Those dirty great focus points just wanted to grab focus on the nearest branch, the birds rump ... anything but where I wanted focus.  Even with my lovely 70-300L, it would frequently rack focus up and down while the bird stifled a yawn and flew off!  And that was the best of several long lenses I tried on that body.  After coming from an Olympus E3 with equally lovely 50-200 lens, which just instantly focussed exactly where I wanted to without a glitch, it was very disappointing.  That is actually why I moved to an EM1 and less lovely 75-300 lens.  It has a tiny and deadly accurate focus point which never misses and the combination weighs nothing by comparison, which means it is with me far more often.  Turns out I'd rather take a slight hit on image quality than not get the photo at all (though the Canon combination was quite wonderful when it all came together).