Old44 wrote:
Has anyone upgraded from the Nikon D750 to the D780 and if so, is it worth the money?
It totally depends on why you would be upgrading to determine if it is worth the money.
If you care about video at all and you don't want to go with the Z system for any reason then it is definitively worth the money, as it is a far superior video camera in every relevant respect. The D750 has terrible video AF and doesn't do 4k whereas for example, the D780 does up to 4k 30FPS at full frame (no crop) and has excellent video AF.
From a purely stills perspective, the D750 is an excellent camera - I shot with one for years. It has excellent IQ and dynamic range - far ahead of its time which is why it is still relevant today 6 years after release.
That said, there are reasons to upgrade (again depending on your use case). For example, the D780 goes 2 stops higher natively in ISO than the D750 - the former being 51,200 and the latter 12,800. Obviously, one should never really use ISO 51,200 unless you must get some shot as opposed to nothing, but the real issue is that at 12,800 the D780 is far superior to the 750 - in fact it is superior for any ISO north of about 3200. This could really mater if you were, for example an event photographer.
The IQ at high ISO is better because the D780 has the Expeed 6 processor which is two generations newer than the D750's Expeed 4, and it has a backside illuminated sensor as opposed to a standard CMOS sensor like the D750. To draw a similar comparison, the Z6 has about 1 stop better ISO performance than the new Z5 and the only difference is that the Z6 has a backside illuminated sensor and the Z5 does not - they both have Expeed 6 processors. So, you can see that the D780 with a BSI sensor and a much more recent processor has several advantages over the D750 in low light, which is saying a lot as the D750 was/is great in low light - especially for its time. Still, as an event photographer every little bit of low light performance matters and the D780 is definitely better in this respect.
Also, the D780 has two SD cards that are UHS II whereas the the D750 has two that are UHS I - the UHS II cards are up to three times faster so that combined with a slightly better buffer means that the D780 can shoot continuously somewhat longer than the D750 - so if you are an action/wildlife photographer then this could be really relevant to you.
If you are using a camera for general all around/walking around type shooting then the D750 is great and you probably do not need to upgrade.
Hope this helps.
-Baron