Sensor Rating in B16

[bobbystone]

My testing is showing the sensor to be rated more like 200 than 320. Does anyone else notice this? I've set metering to spot, focused on an evenly lit grey card, adjusted the iris to read an IRE of 50 and compared to my light meter.

Any thoughts?

 

[Stuart English]

ASA rating

ASA rating

My testing is showing the sensor to be rated more like 200 than 320. Does anyone else notice this? I've set metering to spot, focused on an evenly lit grey card, adjusted the iris to read an IRE of 50 and compared to my light meter.

Any thoughts?

Are you getting the IRE value from the camera spot meter?

 

[bobbystone]

ASA and spot meter reading..

ASA and spot meter reading..

Yep, Stuart.. I'm trying to match my Spotmeter with the spotmeter reading on the camera, which is a cool function, by the way. I get them to match stops when I set the handheld meter to 200asa

 

[Jannard]

We need to double check that meter... extensive tests have shown 320 to be native.

Jim

 

[bobbystone]

meters

meters

I'll check it against my MInolta on Monday. Course, in reality, I could just use the spotmeter on the camera!

 

[Rich Schaefer]

I defiantly found build 15 to be 200asa when camera was set to 320.

I am waiting for RedCine before going build 16

 

[Manuel Wenger]

I just tried out Spot Meter together with RAW View and changed also to RedSpace View If i light up a greycard that it gets green in the false color mode the Spotmeter reads 56-58 IRE in both View modes. My lens is set to 5.6 my Seconic set to 320ASA reads 8.
Didn´t test much further yet, only thing i see is, if i expose in RedSpace and go into dark red in false color, in Raw there it´s still yellow/light red. If i overexpose in RedSpace about 1/2 - 1 Stop i can recover the details in Redalert.
Just my first exposing experiences with B16 will go on with testing.
However 58 IRE for 18% Grey seems to much.

Manuel

 

[donatello b]

IMO 58 ire on a grey card is too high ...
seems it should be more in the 42-44ire area ...
also seems IRE is a bit limiting if you think in NTSC terms ..
from what i recall NTSC IRE back in early 80's was approx 5 stop range .. so i don't think the same IRE numbers will apply when you attempt to put 9-11 stops into the same 0-100 ire ...
looking at some 2k film scans i have here - they're placing 18% gery card at 36 ire ...

 

[SF Geek]

That's a good question. What IRE should a grey card read at?

 

[David Battistella]

In post number 76 of this thread
http://www.reduser.net/forum/showthread.php?t=14336&page=8

you can download a bunch of stills of stuff shot at various ISO's. Import these into FCP and you will see that MUCH of it seems UNDER exposed when you open it in FCP in a REC 709 color space.

If you want your QT files to look good stright out of the camera and you DO NOT PLAN on going back and doing a conform you will need to do extensive testing to get the look you want.

The REC 709 color space is OK but not great and there seems to be some translation issues from R3D to QT and the REC709 color space.

I will shoot the EXACT same test on build sixteen and post a new thread so people can see the noise differences, etc, but if you open charts from tiif or QT in FCP EVRYTHING will seem dark and UNDER-saturated.

This is why it is so nice to have the LOOKS built into 16 as you can "program" how you want your QT file to look (IMHO very important to the success of the while RED program)

I hope that this is not as true with REDSPACE and 16.

David

 

[Stuart English]

IRE scale / REC 709

IRE scale / REC 709

IMO 58 ire on a grey card is too high ... seems it should be more in the 42-44ire area ... also seems IRE is a bit limiting if you think in NTSC terms .. from what i recall NTSC IRE back in early 80's was approx 5 stop range .. so i don't think the same IRE numbers will apply when you attempt to put 9-11 stops into the same 0-100 ire ...

More later .. but IRE and REC709 really do not work very well as a numeric scale or a visual reference for a 12 bit RAW digital cinema camera (and btw this does not mean that LOG is necessarily the right answer either)

REDspace is the result of our internal tests to define a visualization LUT that combines what "looks right" and provides optimal exposure of the RAW data.

 

[Miguel "Macgregor" De Olaso]

WHen you say "native" how many stops over and under 18% grey are you getting?