Lens works on URSA, not on BMCC

Hi!

Recently I tested some different lenses on the URSA EF.
One of them was the canon 24-70 mark I which never worked on the BMCC EF but guess what; it suddenly started working! Aperture and autofocus controls, both no problem.

Can somebody explain how this is possible?
Both EF cameras had the newest firmware installed. So, the lens should work on both right? I wonder if some of the other lenses from the incompatible lenses list do work on the ursa compared to the bmcc..

I'm sure the guts of each camera are different enough that even unified firmware will only be able to support certain functions on certain hardware. 3:1 compressed raw, for example.

Hi!

Recently I tested some different lenses on the URSA EF.


Can somebody explain how this is possible?

There are slightly different power demands is what I understand. Some lenses require a lot more power than what the BMCC can deliver.

jb

Thanks for your replies.

If that's true there should be different compatibility lists for each camera I suppose.
Also, some users report the lenses to work and some doesn't, isn't it possible that it is software related and lenses like the 24-70, the 70-200 usm mk1 and the 85 are going to work in the nearby future?

Did you test the same version of software on both cameras? BMD is apparently adding lens support to new versions of software, but not documenting it. I have the same lens, and lack of support for it moved me to the BMPCC with metabones.

Thanks for your replies.

If that's true there should be different compatibility lists for each camera I suppose.
Also, some users report the lenses to work and some doesn't, isn't it possible that it is software related and lenses like the 24-70, the 70-200 usm mk1 and the 85 are going to work in the nearby future?

I think it's even more messy and complicated than that ebcause not only are there some cameras that will work and won't work, canon themselves also make different versions of the same lens, which is why some users can get them working on some cameras.

Canon don't publish any of the EF info or specs so it all has to be reverse engineered (aka hacked) so it's not always easy, plus the EF-S and M mounts are still protected so it' puts anyone in a difficult position when they want to try and say they support that mount or discuss why they don't or can't.

This is the same for anyone like metabones etc as well...


JB

My circa 2000 Canon 24-70 f2.8L MK1 works fine on metabones, although it's not listed in their compatibility chart. As does my circa 2000 70-200 f2.8L. Would these have worked directly on the BMCC or BMPC? I'll never know, as I wasn't willing to spend the money to find out. And Blackmagic can't answer the question for you, because they don't know either.

So, at the end of the day nobody knows whether lenses will work or not. It's just based on experiences, documented by users. I still find it kind of strange that there's no information from blackmagic design about the lens compatibility. And off course; I understand that it's actually pretty awesome that the developers can reverse engineer the glass and make them work, but still it's very frustrating.
Hopefully they add additional lens support in future updates, but it's never mentioned on the list of update changes, so I suppose we have to find out ourselves!

Luckily we have communities like these..