Full Frame Sensor I mean Full Frame Processing
Introduce in Nuke 8, the Full Frame Processing feature allows the user to toggle between rendering the visible area of your comp (which is the default behaviour in Nuke) or render the full size frame regardless of the active visible area in the Viewer.
To enable it, refer to the header image where it is represented like a ‘hamburger’ icon in between the Proxy and Refresh icon.
I find it handy to use Full Frame Processing especially when you need to prepare a shot for roto, paint or keying job. Obviously when one need to prepare a matte (mask), it is preferable to process the whole frame as this allows the user to quickly zoom in to 100% view to verify the accuracy of the matte edges.
Useful during preparation of matte
So what happened in prior version of Nuke is that if someone is rotoscoping a talent at 50% view, Nuke only process 50% of the view or the active visible area of the 50% view if it get cut off. If the user change the zoom level, Nuke need to recalculate the active visible area again. It doesn’t help that what have been cached can’t be reused if the user frequently pan and zoom around the plate which is common for roto, paint and keying job.
The Full Frame Processing forced Nuke to calculate every scanlines of the current frame. The drawback here will be the longer calculation and bigger cached filesize although if this is a roto job, the performance impact is negligible IMHO. For paint and keying job, the performance impact depends on the complexity of your script and shot so enabling Full Frame Processing can affect your productivity output.
Once the full frame has been cached by Nuke, just pan and zoom around without worrying about Nuke recalculating again.
Not an alternative for flipbooking in Nuke
You need to be careful though that Full Frame Processing is not recommended as an alternative to flipbooking in the Viewer. Better to render the full size preview and use a proper flipbook software (e.g.: JefeCheck, Pdplayer) as Nuke eat up LOTS OF RAM AND STORAGE for caching purpose. Depending on the frame size of the project, full frame 4K playback in Nuke can grind most workstations to a halt so keep testing to see which full size resolution that your workstation can handle easily at the desire frame rate.
Also do take note that this feature is only available from Nuke 8.0 and newer. If you are still using older version of Nuke, I highly recommend to upgrade to at least Nuke 8.0 unless your pipeline is strictly limited to the older Nuke version for unavoidable reasons.