I am waiting for some definitive reviews on the SX40IS and also more on the FZ150.
Mosy of my P&S are Canon; but my superzoom is an FZ28. I used to own the Canon S5IS, and did try the FZ35 and the Canon SX10IS; but went back to the FZ28. Now, I'm not a serious birder; but an opportunity does show up now and then, and I use the FZ28 with a Raynox 1540 Pro telex. That gives about 750 mm and the Raynox is threaded for 67 mm filters and a deep and narrow angle hood I picked up.
I did give the SX30IS a look as I'd like to be able to use my Canon flash with it; but it has Canon's problem of chromatic aberration and a slow lens at longer focal lengths. The S5IS was only 432 mm, equivalent; but was f/3.5. The SX10IS and later models have an f/5.6 or f/5.8 aperture at full zoom, so that one is forced to a higher ISO, negating the advantage of better NR processing in the later cameras. Further, the F# rises very rapidly with increasing focal length. Also, there is no provision for adding a tele extender. I used a LensMate adapter for that on my S5IS.
The FZ150 has far better image quality and lower noise than the FZ100 and at lower ISO rivals the FZ35 for IQ and betters it above ISO 400. Their lenses are not as long as the SX30IS or SX40HS; but they are faster, and like the FZ28 and 35; the F# rises slowly with increasing focal length - being very close to the S5IS in that respect. Further, there is the LA3 adapter for a telex or a close up lens. With my Raynox 1540Pro telex, the FZ150 would give 924 mm, equivalent.
CameraLabs claims that the SX40HS uses the same sensor as the SX230HS; but with a new processor. Using the DPReview comparator, the FZ150 tromps all over the SX230HS at higher ISO. Compare them at ISO 800 and 1600. Can the DIGIC V processor make up the difference? I'm thinking, NO. So in lower light, or where a higher shutter speed is wanted to stop action, the FZ150 should have a 1-2 stop edge.
I don't think the birds will care; but I think the SX40HS is ugly.
--
Jerry