URSA Mini Pro Tint setting vs. URSA Mini 4.6k (Green Shift)

We've used the URSA mini Pro paired with a standard 4.6k on a few shoots now and have noticed that the tint setting always has a higher number on the Pro (with the clear filter in) when performing a custom white balance. Wondering if this is due to the IR filter in the Pro.

The shift we see is in the range or +8 to 12 points of tint on the Pro vs. the mini 4.6k. I believe the presets also have a higher tint number dialed in from the factory but will have to confirm with a Pro owner. We own the 4.6k and rent the Pro from another operator.

If anyone has had similar experiences or if BM could comment on the tint offset between the cameras this would help us understand that issue better.

I'm quite sure that it is a side effect of the IR filtering. No optical filter can divide strictly between IR and red, so any IR filter will eat into deep red to some degree. The camera will need to compensate.

I have no Ursa Mini to compare, but this is my experience from different filters on a Red (their OLPFs).

There's a normal variation sensor to sensor. I have one camera that's minus -39 to match another camera.

The tint level doesn't indicate anything other than sensor to sensor variation.

JB

Thanks John!

I also think age of the URSA Mini 4.6K is a factor as I believe my camera exhibited more magenta when new than it does 16 months later. I subscribe to the Evaporating Fluid conspiracy as one of the causes of the asymmetrical magenta curse of the Mini 4.6K.


Sent from my iPad using Tapatalk

There's a normal variation sensor to sensor. I have one camera that's minus -39 to match another camera.

The tint level doesn't indicate anything other than sensor to sensor variation.

JB

I've had exactly the same experience on a the few shoots I've done with multiple Ursa Mini's. There is quite a range of variation.

Why this sort of variation (which I think is relatively normal in the sensor world) isn't evened out in the assembling / testing / calibrating process during the production of the camera?

I also think age of the URSA Mini 4.6K is a factor as I believe my camera exhibited more magenta when new than it does 16 months later. I subscribe to the Evaporating Fluid conspiracy as one of the causes of the asymmetrical magenta curse of the Mini 4.6K.


Sent from my iPad using Tapatalk

ha, yeah. i, at one point, had a green and a magenta cast on the outer edges. Even started an RMA. and now, it's not noticeable. so i don't know. weird.

Thanks, Adam. BMD has stated some complex optical reasons which may also be a factor, but they never admitted the obvious simple faux pas in manufacturing. I can't think of any other physical cause that would improve your image over time.


Sent from my iPhone using Tapatalk

Why this sort of variation (which I think is relatively normal in the sensor world) isn't evened out in the assembling / testing / calibrating process during the production of the camera?

I have seen similar variation in Alexas. The last show three were close but one of the Alexa's was very green.

I am not sure people realise that sensor's are very hard to make and for sensors this size they typically have a high rejection rate. I think I saw someone for RED saying on their higher end models it's something like only 15% of sensors delivered that pass QC.

The important question is, does this affect the end result ? I think if you know the offset, then it doesn't. If shooting RAW then you can easily change this later.

JB