Imaging and display technologies have advanced in recent years, bringing new possibilities beyond the traditional ways of working thanks to high dynamic range standards (HDR). HLG Photo - as available in the Panasonic S1, S1R and S1H full-frame mirrorless cameras - is one such standard. But what exactly is it, how does it work and why might you need it?
HDR content - that's high dynamic range to display not only a fuller range of peak brightness and shadow detail all within a single frame, but also a wider colour gamut - is talk of the town for the top Hollywood movie and streaming services content. All the latest TVs are able to display HDR content, which many see as more integral than the ongoing resolution race.
But there are a range of HDR formats used. HLG - which stands for hybrid log gamma - is a royalty-free HDR standard co-developed by the BBC, widely designed for live HDR broadcast, which is also backwards compatible with lesser capable non-HDR displays (more recently called standard dynamic range (SDR)).
For the Panasonic Lumix S1, HLG Photo represents a fuss-free way to capture an HDR image for screen-based display, saved as an HSP file. The file is an addition to the Raw/JPEG files also captured, so needn't impact working practice - it's simply toggled on or off within the menu settings.
Full dynamic range preview
Being a display format means exactly that: you can only show an HLG Photo via an HDR display. Whether that's a wirelessly linked HDR TV, a tethered Atomos screen, or other output format.
Why might this be useful? Think of an HLG Photo as a raw-like file that shows the full dynamic range within a single shot, without you needing to process the file (indeed, it's not possible to edit an HSP file).
Studio photographers using a relevant display will be able to see if that critical highlight has clipped too much and adjust accordingly, for example. Landscape photographers will be able to see if that sunlight breaking through the cloud cover has just enough detail recoverable within it. It's a great preview method, knowing you can more thoroughly work a still image later down the line.
Screen display with wide colour
As the world moves away from paper and into an ever more digital environment, a number of photographers will shoot with the sole intent of showing on a display. HLG Photo acts as a great output format: whether to digital billboards, TV screen slideshows and so forth.
Because HLG is an HDR standard it also utilises a wider colour gamut than the sRGB of a JPEG file. That means a wider palette and more natural colour rendition without over-saturation in addition to those higher peak highlights.
What about metadata and processing?
At this stage the Panasonic Lumix S1 captures an HLG Photo and it's contained within the HSP file format.
Those familiar with other HDR formats typical for moving images - HDR10, HDR10+, Dolby Vision - may wonder whether the associated metadata in an HSP file is available to edit. At this stage it's not - as that's the point of HLG being a standard that's designed to deliver consistent results, hence it being a closed file that's not editable.
HLG Photo is a no-brainer feature to activate within the Panasonic Lumix S1, S1R and S1H. It can be captured in a choice of full-resolution or 4K sizes (with the file-size equating to roughly half that of a JPEG) alongside your usual Raw/JPEG workflow.
For pros in the studio or in the field it represents a great way to preview full dynamic range - art directors and editors can quickly see the full range on a screen output, for example - while those wishing to quickly display HDR images with truer, wider colour profile can make best use of slideshows in HDR.
HLG Photo is the first step into the future of where digital imaging is headed; it's a foot into an HDR future that's affecting visual imagery the world over.