Oliver Temmler

I sent you a PM.

Correct, the camera measures whatever you set the MON OUT to show (Rec 709 or Log C). So if you are recording ARRIRAW or ProRes Log C, there is more highlight information than what is already indicated as clipping you use the false color tool with MON OUT set to Rec 709. Switch MON OUT to Log C if you want to see what's left in the highlights. Please note: Film Matrix has been removed from the camera menus. So now it's always no film matrix.

Hi Olivier, for ProRes 2K recording, an ALEXA uses 2868 x 1612 raw pixels to create a 2048 x 1152 output (2868 x 2150 for 2K 4:3). At 8.25 microns per pixel, that equals an 22.16 x 13.3 mm aperture. When you take a 1920 x 1080 crop from this 2K image, the corresponding aperture is 20.77 x 12.47 mm. You can find detailed technical information in the camera data sheets, available at www.arri.com/alexa/downloads. If you require details about the angle of view of ARRI lenses, there are handy tables in the ALEXA Pocket Guides, which you can also find in the download section. Best Oliver

In Time also was an ALEXA show. Maybe he was referring to that.

Hi Eric, the operating temperature range for an ALEXA is -20° C to +45° C or -4° F to +113° F at maximum 95% humidity, non condensing. For the ALEXA Studio the low end is -10° C or +14° F. You can find an interview with Rolf Steinmann on our website. The article is called "Shooting Wild". I think I am not allowed to post a direct link to a manufacturers page, so please google for it or use the search function on the ARRI website. Best regards, Oliver

OK, sounds like you two spotted a problem no one else is having. Please describe in what way the output does not look correct. It looks very strange because a 1D LUT can only provide the tonal mapping, but not the conversion of ALEXA Wide Gamut Color Space to Rec 709. Hence also the very little less saturation you describe. That's why the color space should be Rec709 and not "None", i.e. ALEXA Wide Gamut. Selecting "3D LUT Forced" makes no sense if you are not touching the color space. So, the correct conversion would use the parameters (Advanced) Log C Extended Input, Video Extended Output, Rec 709 Color Space Output, 3D LUT is set automatically, file format DaVinci Resolve. Well, it should work and a 1D LUT, as said, could not apply a color transformation. Therefore a 3D LUT is required. There's nothing wrong with it. You find a LUT, generated with the settings I described above, in the attachment to this post. Please let me know if you still are seeing this problem, send me a screenshot if possible. If the problem persists, we'd be happy to have a look at one of the original camera clips (not graded, trimmed or anything). Please send us an email to digitalworkflow[at]arri.de and we'll open up an FTP account for you. Kind regards, Oliver AlexaV3_K1S1_LogC2Video_rec709_EE_davinci.zip

I wouldn't go below ProRes 422 (HQ) to avoid running into problems with compression artifacts on stronger image adjustments in grading.

Because it looks awesome!

Hi Eric, the mechanical shutter acts as global shutter on the ALEXA Studio. It eliminates the partial exposure/split white frames effect rather than just reduce the effect. Also, you can find the information about when ARRI is planning to provide ProRes 2K 4:3 on the front page, where it says "ALEXA tomorrow, A roadmap of ALEXA software updates to come in 2012". You could also go to www.arri.com/alexa if you just want information on what's new about ALEXA. Cheers Oliver

Hi Kevin, it sounds to me like you took the Log C material and applied a grading on this without using a Log C to Video conversion Look Up Table. Please visit the ARRI website's digital camera section and use the LUT Generator to create a conversion LUT for whatever system you apply your grade on. Typically, you want to switch to the Advanced Tab, then set Camera (source): ALEXA, V3 color, Log C, Extended Range Image (destination): Video, Extended Range Conversion param.: Rec709 color space, Photometric, Knee shoulder 1 for a harder/ 2 for a softer highlight and blacks roll off. LUT Param: Auto (will create a 3D LUT), default Dimension and Bits, File Format for your Grading Tool. > Generate Then put the created LUT into your grading tool as a viewing & output/rendering LUT to go to Rec709 Video color space. Or just as a viewing LUT if you want to leave the graded material in Log C for output to film. Hope this helps.

Hello Michael, when you are recording ProRes to the SxS cards, you can set the sensor speed to e.g. 30 fps and the project speed (MENU>PROJECT>Project Fps) to whatever your deliverable needs to be. If you set project speed to e.g. 24 fps, the clips will then play back at 24 fps and have a 24 fps time code. The TC is provided internally from the camera in either rec run or free run. If set to rec run, you can directly see how long the shot will be when played back. Cheers Oliver

Hi Reg, ghosting occurs when the filters in a matte box are tilted towards eachother/not parallel. It doesn't matter which camera you stick into that matte box though. Works with digital cameras, 35mm cameras and even if you look through the matte box with your own eyes. Tried it. Kind regards Oliver

Hi everybody, ALEXA will deliver it's full dynamic range regardless of the Gamma setting. The (big) difference, however, is how the different dynamic range distribution affects what you can do with the image afterwards. Please have a look here. In the LogC signal, the stops above middle grey are distributed evenly in the signal, all the way up to white clipping. In the Rec709 video signal, each stop above middle grey is represented by a decreasing difference in the signal with the highest one or two stops being compressed to a very small signal difference. This makes fine-tuning your highlight detail almost impossible. I think Saul pretty much nailed it when he called it "being saddled with whatever information the rec709 retains". The Rec709 characteristic is supposed to provide a tonal balance which is pleasing to the eye and/or looking visually correct on a monitor. On the other hand, the compressed highlight roll-off resulting from this requirement can't deliver the amount of control you get from a LogC characteristic. Yes, shooting Log C does require the extra step of creating video rushes/files for offline edit, but doing this using a "simple overall LUT" as David suggested makes it a quick and rather affordable process with the benefit of much better control over the image once you get into grading. Until we have our LUT section back online at arridigital.com, us guys at digitalworkflow@arri.de will do our best to provide you with the LUTs you need. Just tell us how the signal was recorded and which tool you are using to convert LogC to video.

speaking of which, I'd like to point out a new document on ARRIdigital which I hope you find interesting: http://www.arridigital.com/downloads -> D-21 Workflow Guidelines Cheers Oliver

Hi Sid, in terms of sensitivity there isn't much difference between 3200K and 5600K on the D-21. 1/3rd stop max and more noise in the blue channel, due to WBal set to 3200K. A tungsten to daylight filter will costs you about 2 stops. If you'll have enough light to compensate, you may get slightly better results with filtering. Best regards, Olli