ARRI Forum

With Sup 4 a lot of options to shoot anamorphic 2.39 came up in Alexa Mini.

I ´m not sure i´m understanding right the use of all of then. Could someone clarify this to me please?:

So far I see:

- What we had before in Alexas with 4:3 sensor was the 4:3 sensor mode, adding a 2.39 marker and activating de-squeeze. This option is in Alexa Mini the 4:3 2.8K format in Raw and Prores, always recorded squeezed.

- But we can do now the 2.39:1 2K Ana, which is basically the one before but already set up with no need for the marker and recorded de-squeezed in prores and squeezed in raw. Those who want an squeezed prores should use the 4:3 2.8K as indicated above. If shooting raw I understand using 4:3 2.8K make no sense because 2.39:1 2K Ana is also squeezed and the resulting resolution has only 15 lines difference (2.39:1 2K Ana is 2560x2145 and the 2.39 area inside 4:3 2.8K is 2578x2160).

- Now we can use also the Open Gate for anamorphic, which did not have sense before because it was as tall as the 4:3 mode, but now is slightly bigger (we earn 57 lines vertical and 70 horizontal, if it is worth doing it). I would´t notice that option but in the graphics for the sensor areas document they put a 2.39 scope marker inside the Open Gate area, which indicates it is possible and maybe best for some specific works.

Should I assume the 2.39 2K Ana in Prores exist only to have 120fps and that the corresponding 2.39 2K Ana in raw exist only in case you are in a 2.39 2K Ana in Prores project and need some raw shots for fx or something?

What do you think about all this?

Best Regards
Saul Oliveira
AC
Spain

Dear Saul,

I need to throw in some figures here to set things straight:

- ProRes vs. MXF/ARRIRAW Anamorphic
Why these ProRes formats? These are de-squeezed formats for productions that want to use anamorphic lenses in their workflow but not need the whole ARRIRAW shebang in post. HD Ana. for example is designed for HD delivery and anamorphic capture.

Being able to shoot 120fps is a lucky feature in addition.

- 4:3 vs 2.39:1 2K Ana. (OG 3.4K) or 6:5
You got some figures wrong here.
4:3 2.8K is 2880x2160 on the sensor
2.39:1 2K Ana. (OG 3.4K) on the other hand is 2560x2145

In case your target is a 2.39 you are free to use a 4:3 format, but in the end you will have to crop some of these beautiful pixels, because it is simply too wide: 1:2.66 vs. 1:2.39.

- Simply record Open Gate
Yes you can - but in most cases there's no benefit in doing so, because you will only end up with darkened corners (aka your lenses do the vignetting dance on the OG area).

On the technical side all formats with the (OG 3.4K) remark will record a full OG image all the time but apply an active image area information in the metadata that flags the outside area as invalid.

Cheers,
Jan

Why HD Ana, 2.39:1 2K Ana and 4:3 2.8K in Arriraw are recorded over Open Gate?

Thanks
Saul Oliveira
AC
Spain

Hey,

in order to avoid mode changes like in ALEXA.

Best,
Jan