Phenix205 said:
Thank you all for your inputs. I have decided to go with a 5DsR as my second camera. The 5D3 will probably still be used as my main camera for casual shots for schools and regular kids activities as those photos are mostly just printed at 4x6 or 5x7 size or simply viewed on computer (or phone) when shared with family and friends. The file size of 5D3 is more manageable and the camera is more forgiving to shaking. If I get a 5DIV, I know the 5D3 will probably seldom get used again.
For travel/landscape or posed family portrait or large group portrait (e.g., kids' team portrait), I think the high resolution of 5DsR will provide tremendous benefit. One, these photos are more likely printed at larger size. Two, the additional leverage in cropping will be very helpful for long day City travel or long distance hiking. I could just mount a wide angle zoom on the 5DsR to crop out unwanted stuff or get extra effective reach when needed.
Considering how my photos will be used/printed, I think the 5DsR has what 5D4 can never offer - the amazing details and more freedom of cropping provided by the 50MP sensor. For other general uses, the 5D3 is still a solid performer, especially for web publishing. Yes, the 5D4 has more dynamic range, but those are software mitigable issues. I have always tried to get the exposure right and never had a need to increase exposure more than 1.5 stops to pull the details out in shadows.
Thanks again.
Good luck, but I wonder about lugging a heavy tripod with a 5DSR for travel. You do not get the benefit of all those pixels unless the camera is extremely stable, like bolted in concrete. A heavy stable tripod with underweight and bean bagged legs would be a starting point for you to to get images that can be greatly cropped.
Sure, it won't give worse results than a 5D MK III, but hand holding it and expecting to be able to crop images greatly is a bit of wishful thinking. Camera testers had to develop new and more solid fixtures while testing the camera in order to get the sharp images it is capable of. In any event, its a great camera, just make sure your expectations are aligned with reality.