Kristian Sundsvalen

I appreciate the time and effort you have put into this. All the best luck with your ongoing movie.

I only have one of the clips from the images. But I have made a new quick test. Her is links to download the ArriRaw- files: https://wetransfer.com/downloads/d4c2c0b8f905f641148f5c559ca0a8aa20210607203655/f4dec92746429f170f7a8e42f91b88c020210607203655/78b417 https://wetransfer.com/downloads/1c22e88b951391016383c484cd1102ad20210607204640/e9a6d99d3e37080403e50bc1f39e8e1a20210607204640/b3b9ea On clip A004C045 you should see the patterns on the white curtain. The sky outside the window is clipping, so I believe that is what is trigger the patterns. This are JPEG from the images I posted previously in this thread: https://we.tl/t-UTyRlem9TQ

I use light meter readings to determine the exposure and check the highlights with the spot meter. Occasionally I use the built inn false colors to check the highlights. The window in the top image is not clipping as far as I remember (it only looks like it due to the grading). But there is a tweenie as a backlight in that same image (that is cropped out) which is clipping.

Hi Tyler, I have been in contact with Arri Service regarding this. They are saying it is a normal behavior whenever there is objects klipping in the frame. And that there is nothing that can be done against it. Based on Arri's feedback I reckon this should be visible on all Alexa cameras. But I am starting to worrying that there is a quality deviation with my camera.

No net behind the lenses on this footage.

Totally agree with you there Phil. I have been experience flicker from LED fixtures, even if it was shoot with "safe" shutters. However I can´t observe any flicker on the clips I have shoot regarding this topic.

Hi Phil, I have been getting feedback that this patterns can appear whenever there is objects clipping in the frame, and that it is considered normal. Which I believe, considered this comes from Arri . My agenda with this post is to get an acknowledgement that others shooting Alexa is experience the same. I have been shooting 25 fps (180 shutter) with European current (50 Hz). So flicker should not be occurring.

The light sources was a 8 by 8 ultrabounce key. I can`t remember if i used a LED with fresnel or a ETC Leko Source 4 (750w tungsten) to bounce from it. The image with the light fixture in it as a backlight is a tungsten 650w fresnel. I used ND´s for sure. .6 or .9 Schneider as far as i remember. Can´t remember the stop on the lens (SLR Magic APO Hyperprime). The low pass filter is clean and have no visible debrises. This patterns is also visible on outside footage with the sun as the only light source. I can see the patterns appearing around the sun for instance.

Hi Joel, So you are observing the same patterns? Whatever difference there may be between ArriRaw and ProRes 4444, the difference is as far as I know negligible. In situations where heavy grading is necessary I have read that ArriRaw has it advantages.

This was ArriRaw and 16:9 2.8K. 25fps, 180 shutter. But it is also visible in ProRes 3.2K, and with difference fps and shutter. I have not tested it in Open Gate. It is visible pre grading, and in different software. The images is exported from DaVinci, but the patterns is also visible with ArriRaw Converter. I have been given feedback on that this is a normal behavior when there is objects clipping in the frame. But if this is a behavior that is normal I would be reassured that this is observd by others shooting with Alexa. In other words that it is not a quality deviation.

Hi Gregory, It is also visible on areas in the frame that is not flaring:

Hi David, Yes that is a good point. I was afraid the compression would make the images too blurry. But this works fine.

Sorry. I`ll try again: https://we.tl/t-UTyRlem9TQ

Hi, Is anyone familiar and have experienced "pixel gridding" from Alexa footage? I see this appearing around bright objects in the frame. Footage is from an XT Plus. Link to images: Regards, Kristian Sundsvalen