Blackmagic Forum

Hey Everyone. I am new to the Ursa G2 but not new to live production. I have been doing it for over 20 years. We decided to try the Ursa G2 broadcast cameras and just got them in with a few lenes. I am having a few issues. One I can't seem to get a good back focus. I've gone through it, other camera ops and the foreground is still soft. (yes it is within the focal distance of the lens). I have the fuji 20x with extender. Another issue I am having is with memory cards. I bought SD cards that BMD recommends and just 1 of the cameras see the memory card. I have never seen this before so I am wondering if anyone else has. I really want to make these cameras work but not having a good start. Currently we use JVC HM 700's and those have a sharper picture with less Chromatic Aberration than the BMD cameras. I also noticed the CA on/off setting doesn't do anything to the image. Any tips or tricks that you guys/girls have would be greatly appreciated. Cameras have been updated to the latest firmware.

You don't say what actual lens you are using but backfocus has been no problem here on a variety of lenses I have tested on the UBG2. I have an old JVC HD101E (same senor as the HM700) and it is a world less sharp than the Ursa, even using the UBG2 with SD B4 lenses. Chromatic aberration is again down mostly to the lens, only certain newer lenses can be used with the UB's CA compensation feature too. Again no issue with any media either SD of CF 2.0 cards here, maybe you should send it back?

Can you show a recorded video from the Ursa when you are close-up on an object and then zoom out full?

Are you sure the switch is set to SD-card instead of Cfast?

The CA switch works great for my old Canon HJ11 lens, so maybe CA isn’t supported by your lens?

I have three G2s, IMHO with a decent lens, the G2's detail, contrast and sharpness are perfectly good for most requirements.

In the two photos, one is a Canon KJ20x8.2B KRSD HD lens costing £2800, the other is a Canon CJ25ex7.6B IASE S 4K lens costing around £18500. The quality difference is plain to see. The UB G2's settings were identical for both lenses, albeit they were hastily shot through a window. Both lenses have manual back focus (had no issues there). CA ON/OFF made no discernable difference to either lens.

Wow, what a terrible picture is the first one, not only a very lot of CA but also lot’s of blue fringe. That’s a very bad lens which also doesn’t support the CA correction of the Ursa.
If you have a good lens which support CA correction you get beautiful pictures!

BennoZ wrote:Wow, what a terrible picture is the first one, not only a very lot of CA but also lot’s of blue fringe. That’s a very bad lens which also doesn’t support the CA correction of the Ursa.
If you have a good lens which support CA correction you get beautiful pictures!

Admittedly, the lens is close to maximum zoom in, but for a £2800 Canon lens, it's not brilliant. I was equally surprised at not being able to see the wood grain.

I'd be interested to know which lenses the CA switch does work on, as we have a variety of lenses for our G1/G2's and the CA switch has no discernable effect on any.

Well I’ve tested several Canon lenses and they all work very well with the CA correction. As I mentioned in my post above my old (but very, very good) Canon HJ11 works great with this correction, but to work with it I had to update the software of this lens at Canon. (because it’s an older one).

Maybe it's a flange focal distance issue? Did you experiment with the shims?

Yes, with some lenses you will not be able to set the back focus. For example, on the first version of the canon hj22 (but on more recent lenses of the same, everything is ok.).

Removing shims will help, but there will be problems with the vignette.