[davidmanze]

Currently I mostly use up to 400mm on APS-C and also like birding. Nice photos there BTW. I'm not ready to give that up, but unless I'm intentionally doing that, I think there is room for a lighter bag for me.

 

As for bayer sensors, red channel has always been a funny one to me. They red part of bayer filter by itself covers quite a broad range of spectrum from green into NIR. It should be pre-filtered to attenuate the longer wavelengths by additional filters on top of the sensor, such as the IR block and possibly separate red shaping filter to help with colour balance. But it still retains some significant green sensitivity that have to be taken care of by the raw converter. So given that, I can well imagine depending on the scene and imaging chain design reds may run into problems in particular. Canon in particular have a relatively weak red filter in their bayer pattern so this usually results in weaker colour separation scores on DxOMark not that I care about their overall values. In relatively unprocessed side by side images I think Canon can have warmer looking images than Sony based sensors, but this may also be contributed elsewhere other than the sensor and I couldn't prove there was a link.

Hi Popo,

           You obviously have a greater knowledge than I on the technicalities of sensors, however what you say about the red band including other parts of the spectrum makes nothing but sense to me, yellows figure strongly also with the problem with Pentax. 

   For some while I was frustrated trying to get some sort of detail out of red flowers which were to all intents and purposes correctly exposed, but showing up 255 in the red band. I tried underexposing but as soon as you bring up the exposure again in PP your back to square one, the bottom line is I got no further with curing the problem than just taming it with the HSL colour control in CS6, reducing red and magenta saturation as a standard setting for all RAW images.

  The big surprise was that Nikon was only a little better, luckily not blowing into magenta, so a least I realized that reds are problematical, at least the major brands, I just learned to live with it.

Thanks for your comments!