Since I sold my last crop body ( 7D) I'm missing the reach, however my other bodies do everything else I require so I'm not going to lug another DSLR around if I can help it. Can anybody recommend a mirrorless body that I could use with a converter with my trusty 400/f5.6? I appreciate that the focus may be manual or slow at best but is it doable?
I would recommend a NEX 7 with Metabones Mark II adapter.
The NEX 7 has the same pixel density as all the 16 MP micro4/3 cameras. But since the sensor is larger, you get a wider field of view when you need it. And the image quality of the cropped NEX 7 image is practically identical to the best 16 Mp u43 sensors.
For the ultimate "reach", a Pentax Q with a chinese EOS-Q adapter. No aperture control, but the 400 5.6 L already has optimal image quality wide open.
Example of image quality with sharpened 100% crop here: https://www.fredmiranda.com/forum/topic/1152646/3#11004477
Thanks Alundeb, I really like the idea of a smaller sensor and will investigate the Q, its only really for the reach that I want an extra body and this really does look like ultimate reach! The OMD should give me the field of view of an 800mm lens with the 400 canon but I can find anybody who has tried the combo. Ta again for your input.