Sony A1 : Video Resolution

When you buy a new camera some time after the initial release date you are lucky to find all sorts of videos of other geeks like you that have been testing.

I was referred to this video that shows quite a few quirks of the Sony A1. Gerald has since confirmed the A1 video is binned not line skipped.

You can’t always rely on third party so here are a number of geek tests.

The first question was do you need to shoot ASPC or full frame. APSC is scaled while full frame is binned which means the first may look better than the second but will have more noise.

Pixel Binning

As usual there is no official documentation of the camera inner workings but this diagram should help explain a few things.

On the upstream the potential flow for a classic bayer filter camera to accomplish binning (it is a guess). On the bottom what a mobile phone may be doing.

In the first case binning results in a reduction of resolution and potential artifacts. In the second only a reduction of resolution.

Now one of the question is what if we just crop the sensor in APSC and then scale down will it look better?

I have done exactly this test and the answer seems to be no.

UHD binned vs APSC scaled

In theory the binning should look much worse but what I have seen is that moire kicks off for both at around 2x the focal length of the other. So if APSC gives moire at 50mm full frame will give it at 100mm. The full frame moire is more severe when it occurs but in most cases you cannot tell the APSC and binned UHD apart in conditions of good light.

other side by side of a dpreview sample shot cropped again there is moire in their situation on the full frame but in effect the image quality is identical.

So personally am not going to bother with APSC unless I need more magnification and I am not in low light. For all the rest I will use full frame binned.

ProRes RAW

The A1 also provides its pixel binning mode in ProRes RAW and it is identical to the internal recording when the lens corrections are off. ProRes RAW does not have a concept of lens profile so you get all the lovely defect of your lens. To my horror e-mount leses have many defects, all are distorted and have significant amount of CA.

ProRes RAW vs Internal

In short unless you have a DSLR adapted lens with zero defects those aberrations are troublesome so with native glass am skipping ProRes RAW altogether.

4K with External Recorders

If you have a Ninja consistent to what Gerald Undone says you can get a scaled down version of 8K setting your HDMI output to Auto or 2160. Auto generates 4k60fps while 2160 gives you the same frame rate of your 8K.

Interestingly if you do not record to card the HDMI output goes back to what you get in internal recording. So in short you need to record 8K to card which means eventually overheating. It is unclear what subsampling is being output howeverthe image does look a bit cleaner.

8K vs 4K

There is no doubt that the 8K mode although only available up to 30 fps is superior however editing the 580 mbps HEVC files is not that easy.

I personally shoot in 4K so I am set on the full frame binned 4K but if you have the hardware to process and the screen to watch 8K is the way forward. Gerald Undone trick of the HDMI 4K while shooting also works but be careful with overheating.

Coming Soon

Next article will break down the codecs available with the A1.

6 thoughts on “Sony A1 : Video Resolution”

  1. HI there,

    Could you explain further what you mean in this comment – ‘Auto generates 4k60fps while 2160 gives you the same frame rate of your 8K.’ when referencing external out? If you are in 8k mode you can’t get 60fps.

      1. ‘Auto generates 4k60fps while 2160 gives you the same frame rate of your 8K.’

        What I meant to say is the A1 in 8K is only capable of 25/30fps so while the Ninja may show UHD50 and create a 50fps file – how can it be genuine 50fps?

  2. I’ve tested this today. It’s just 25/30p with doubled frames on the Ninja. Setting the A1 to AUTO output will give you fake 50/60fps . You should correct that.

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