Canon HF-G40: Highlight Priority Revisted at DVinfo.net

Bryan Worsley · November 24th, 2020, 10:29 PM

With naff-all else to do during the "lock-down" than go out for walks in my locale I thought I would capture the autumn colors last month, before the leaves fell, and take the opportunity to compare the 3 'looks' (Standard, Wide DR and Highlight Priority) available on my HF-G40, before and after grading in DaVinci Resolve.

Here's a montage of some of the (many) clips, all shot with auto exposure (Program AE), auto AGC, auto focus, AWB and default 'picture' settings, on a video monpod (Sirui 204s). When there was no wind, I was able to let go of the monopod (takes 5-10 secs for the wobble to settle) and record with the wireless remote. Where there was wind I had to brace the monopod as best, with the aid of a Manfrotto shoulder brace, so there's a bit of shake in some shots. No 'people' shots I'm afraid, other than other 'socially distant' travelers passing by.

So here's 'Ungraded' i.e. the original clips cut-edited in DaVinci Resolve, exported to Cineform (Best = Film Scan 2) and transcoded to x264 for uploading to YouTube:

And the same clips after 'grading' in DaVinci Resolve 16:

Color adjustments were minimal - for the most part I just balanced the blacks where needed; there were only a few scenes with a reliable 'neutral' reference where I could white balance. Also boosted the saturation a pinch in a couple of the 'Highlight Priority' shots. But that's all.

Wide DR is probably the most 'flexible' of the three and works very nicely with skin tones (sadly none here) and textured gradients. Looks glorious up on an HDTV, but personally I find it a bit too soft when viewing on a computer screen, especially after uploading to YouTube. The 'wider dynamic range', as perceived, comes at the expense of reduced local contrast and some loss in fine detail. So I experimented quite a bit with various sharpening techniques (in Resolve and post-edit) to try and bring back as much detail as possible without looking 'over-sharpened'. The best outcome, I concluded, was to apply a quite generous dose of 'mid-tone detail' (equivalent to 'Clarity' in Premiere Pro) to help restore local contrast, topped off with very light, scaled-back sharpening. Doesn't quite match the detail in Standard mode, but acceptable I think, and still looks glorious on an HDTV screen. I did try increasing the in-camera sharpness (in the 'Picture' settings) but it's counter-productive - it doesn't bring back any more detail and only accentuates sharpening artifacts (ringing). I also added a little 'mid-tone detail' to the Standard and Highlight Priority shots, but no sharpening per se. No 'denoising' was applied to any of the clips.

I hadn't paid much attention to 'Highlight Priority' before. The implementation on these Vixia/Legria camcorders is rather different to the 'Highlight Tone Priority' on the Canon EOS cameras, from which it derived. The camcorder clearly under-exposes to defend the highlights (arguably too much) but does not compensate, to an appreciable degree, in normalizing the shadows, as it does on the EOS cameras - probably because it would introduce an unacceptable level of gain noise in the process. So instead Canon promoted it as a 'look' that is best viewed on a monitor with increased brightness and boosted lower mid-tones - I mean, who is going to do that ? Perhaps not surprising then that it's appearance on the Vixia/Legria line models was short lived.

Which is a pity; when I got to grips with it in Resolve I found that the shadows could be boosted appreciably before noise becomes conspicuous and I was surprised at the level of fine detail that could be revealed - that was using the 'Shad' control in the 'Primary' color tool-set, not the log 'Shadow' wheel which lifts the black-point. In low-contrast scenes that can create a slightly unnatural "pseudo HDR" effect (adding back a little contrast helps) and in high-contrast scenes, with dark foregrounds (of which there are several in the montage), I had to resort to preliminary 'exposure compensation' (using the 'screen blend' technique) at the expense of some loss in highlight detail and a little clipping in some cases. But I think it works very well for preserving background detail (branches against sky line etc ) and bringing out fine textures in close-ups (not many in the video unfortunately). It definitely picked out more detail on the plumage of that Great Blue Heron at the end of the video, shot with full 20x zoom. Perhaps not surprising that many wild-life/landscape photographers use 'Highlight Tone Priority', or so I've read.

Anyhow, there it is. It's not 4K, but, hey, I love this camcorder and I've learned a lot from the exercise. Maybe of interest to others. Would welcome any comments.

Stay safe.

Rich Woodrick · November 30th, 2020, 11:48 PM

Thanks for doing this and great job. To me this shows that the HF-G40 can put out some great looking footage right out of the camera. After color grading I thought the HLP looked the best of the 3 settings.

Bryan Worsley · December 6th, 2020, 10:20 PM

Thanks. I have to say, Highlight Priority is growing on me. I really need to test in a wider range of scenarios, but from these tests I was surprised at the detail that can be pulled from the shadows; I expected there to be a lot more noise.

I also wondered how it would look upscaled to UHD (2160p60) using the 'Super Scale' function in DaVinci Resolve. In Resolve 16, and now 17 beta, this feature is only available in the Studio version, but when it was first introduced in Resolve 15 it was available in the free version also. The 'improved algorithm' in Resolve 16 does recover a bit more fine detail, but the original implementation in 15 is still very good. Of course a lot depends on the quality of the source. In earlier tests with HF-G30 footage I found that setting the level of Sharpness and Noise Reduction to Medium gave the most satisfactory results. The processing is very slow though.

So, using clips from the same test series as before, here are the original 1080p60 Resolve grades lightly post-sharpened with the AVISynth filter 'Fine Sharp':

Here upscaled to UHD with Resolve 15 'Super Scale' (2x, Medium Sharpness and NR):

And here the UHD export down-scaled to QHD (2560 x 1440) using the AVISynth 'Spline36Resize' filter:

Both the YouTube videos and the original graded videos, streamed over my home network from an NAS (MyBookLive), look very nice on my Roku UHD TV, and without any need to boost the brightness. I'm under no illusion that these 'Super Scaled' UHD videos could pass off as '4K' but they do look better 'psychovisually' than the HD videos upscaled by the TV.

It's a shame Canon decided to drop 'Highlight Priority' mode on the 4K Vixia/Legria models, as it's definitely gradable.

Bryan Worsley · December 7th, 2020, 10:55 PM

Quote:

Originally Posted by Bryan Worsley

So, using clips from the same test series as before, here are the original 1080p60 Resolve grades lightly post-sharpened with the AVISynth filter 'Fine Sharp':

A slightly sharper version of the second video - looks a bit better (crisper) on YouTube:

Bryan Worsley · December 10th, 2020, 11:13 PM

Quote:

Originally Posted by Bryan Worsley

It's a shame Canon decided to drop 'Highlight Priority' mode on the 4K Vixia/Legria models, as it's definitely gradable.

But the XA50/55 and HF-G60 do now get CLog3, as well as EOS Std and Production Camera color matrices, with the latest firmware update (1.0.1.0):

https://www.dvinfo.net/forum/canon-x...ml#post1962737

Bryan Worsley · January 12th, 2021, 05:37 PM

No new footage to test so, in an idle 'lock-down' moment, I wondered if I could tweak the above Wide DR clips some more, and see how they look upscaled:

Tweaked 1080p60 Resolve grade, post-sharpened with the AVISynth filter 'Fine Sharp':

Looks better (crisper, tad more contrast) than the original grade I think, after uploading to YouTube at least.

Upscaled to UHD with Resolve 15 'Super Scale' (2x, Medium Sharpness and NR):

The UHD export down-scaled to QHD (2560 x 1440) with AVISynth 'Spline36Resize' filter:

Again, I think the Resolve 'Super-Scale' function does a pretty good job, but it would be fair to say that the upscaled videos look best when viewed at the 'picture quality' matching the upload resolution; the UHD upload viewed at 'HD 1080p60' quality is softer than the native 1080p60 upload - as you might expect.

Highlight Priority still looks better though.

Bryan Worsley · February 18th, 2021, 08:31 PM

FWIW, some further tweaks - should probably have called this thread "attempts at making WDR look better"

'Difference analysis' revealed that the level of 'Mid-tone Detail' (local contrast, clarity) I was applying was generating subtle, diffuse 'macro-halos' around high-contrast edges, notably objects (trees etc) set against the skyline, which were clipping. I'm calling them 'macro-halos' as distinct from halos seen at the micro-level around the edges of sharpened detail, but it's essentially the same phenomenon - overshoot:

https://www.duncanfawkes.com/blog/avoiding-halos

So I reduced the 'Mid-tone Detail' to a more acceptable level - from around 40 to 25.

Also I had applied no noise reduction (NR) in the Resolve grades, largely because I am using the free version and NR is only available in the Studio version; denoising before importing into Resolve would mean transcoding the native clips to a compatible intermediate (I've always used Cineform), which is a royal PITA.

So I've spent some time (re)evaluating denoise and sharpen filter combinations available in AVISynth for the best outcome in this case. Of those tested, KNLMeansCL (an optimized Open CL implementation of the Non-Linear Means algorithm) gave the most satisfactory results for treating 'white (gaussian) noise' - hadn't tried it before; very impressive, especially when the Cineform exports are processed with a 10bit pipeline - some say on par with NeatVideo (for 'white noise'), but I haven't used it myself.

As for sharpening. The 'FineSharp' filter I used above is a 'generic' sharpener that was originally intended for real-time sharpening on playback. It's main strength (as the name implies) is that it avoids line thickening, the tell-tale sign of digital sharpening The downside is that it will sharpen (amplify) any noise and existing (in-camera) sharpening artifacts as well. So denoising helps, but not completely.

Another sharpening filter, Limited Sharpen Faster-Mod (LSFMod) aims to achieve better control of halos and other sharpening artifacts (aliasing, 'confetti' artifacts), and does to a large degree, but the results are not as 'crisp' as FineSharp.

So here the tweaked Resolve grade, denoised with KNLMeansCL and sharpened with FineSharp:

The same denoised with KNLMeansCL and with sharpened with LSFMod (non-linear sharpening mode):

In both cases, the post-processing was all done in (planar) 10-bit 4:2:2 (p210) and the resulting Cineform encodes were uploaded directly to YouTube. Which looks better on YouTube I guess is matter of personal taste.

And also the Resolve grade upscaled to UHD using the 'Superscale' function (Medium NR & Sharpness):

And the UHD upscale downscaled to QHD with AVISynth Spline36Resize:

I don't think I can improve the Wide DR footage anymore than that. Highlight Priority still looks better IMO.

Anyhow, just putting this out there if anyone is interested.

Bryan Worsley · February 22nd, 2021, 09:03 PM

And a revised grade of the other series of Wide DR clips, similarly denoised (KNLMeans) and sharpened (FineSharp and LSFMod) in a 10bit 422 (p210) pipeline:

LSFMod - the original file played on my PC and streamed to HDtV and 4K TV looks really nice. Big improvement on the original footage IMO.

FineSharp - 'crisper', but more residual sharpening artifacts. Better for YouTube ?

And the Resolve Grade upscaled to UHD using the 'Superscale' function (Medium NR & Sharpness):

And the UHD upscale downscaled to QHD with AVISynth Spline36Resize:

Bryan Worsley · March 7th, 2021, 01:26 PM

Coming full-circle, I also revised the original series comparing Standard, Wide DR and Highlight Priority, incorporating the various tweaks.

The original, ungraded clips (again):

The revised graded version. As in the original grades, light sharpening (with the Resolve sharpen tool) was applied only to the Wide DR clips:

The highlights are a tad darker in some of the Highlight Priority scenes compared to the original grade - I applied a little more 'highlight pull-down' in an effort to offset some clipping; arguably, I should have left it as is.

And then the Resolve grades (with no internal sharpening applied) further processed (NR, sharpening) with AVISynth filters (KNLMeansCL, LSFMod):

I'd be inclined to leave the Standard and Highlight Priority grades un-sharpened for playback on PC and HDTV, but it for YouTube it gives them a bit more punch.

November 24th, 2020, 10:29 PM	#1
Bryan Worsley Major Player Join Date: Oct 2005 Location: Canada Posts: 439	Canon HF-G40: Highlight Priority Revisted With naff-all else to do during the "lock-down" than go out for walks in my locale I thought I would capture the autumn colors last month, before the leaves fell, and take the opportunity to compare the 3 'looks' (Standard, Wide DR and Highlight Priority) available on my HF-G40, before and after grading in DaVinci Resolve. Here's a montage of some of the (many) clips, all shot with auto exposure (Program AE), auto AGC, auto focus, AWB and default 'picture' settings, on a video monpod (Sirui 204s). When there was no wind, I was able to let go of the monopod (takes 5-10 secs for the wobble to settle) and record with the wireless remote. Where there was wind I had to brace the monopod as best, with the aid of a Manfrotto shoulder brace, so there's a bit of shake in some shots. No 'people' shots I'm afraid, other than other 'socially distant' travelers passing by. So here's 'Ungraded' i.e. the original clips cut-edited in DaVinci Resolve, exported to Cineform (Best = Film Scan 2) and transcoded to x264 for uploading to YouTube: YouTube (Short URL) And the same clips after 'grading' in DaVinci Resolve 16: YouTube (Short URL) Color adjustments were minimal - for the most part I just balanced the blacks where needed; there were only a few scenes with a reliable 'neutral' reference where I could white balance. Also boosted the saturation a pinch in a couple of the 'Highlight Priority' shots. But that's all. Wide DR is probably the most 'flexible' of the three and works very nicely with skin tones (sadly none here) and textured gradients. Looks glorious up on an HDTV, but personally I find it a bit too soft when viewing on a computer screen, especially after uploading to YouTube. The 'wider dynamic range', as perceived, comes at the expense of reduced local contrast and some loss in fine detail. So I experimented quite a bit with various sharpening techniques (in Resolve and post-edit) to try and bring back as much detail as possible without looking 'over-sharpened'. The best outcome, I concluded, was to apply a quite generous dose of 'mid-tone detail' (equivalent to 'Clarity' in Premiere Pro) to help restore local contrast, topped off with very light, scaled-back sharpening. Doesn't quite match the detail in Standard mode, but acceptable I think, and still looks glorious on an HDTV screen. I did try increasing the in-camera sharpness (in the 'Picture' settings) but it's counter-productive - it doesn't bring back any more detail and only accentuates sharpening artifacts (ringing). I also added a little 'mid-tone detail' to the Standard and Highlight Priority shots, but no sharpening per se. No 'denoising' was applied to any of the clips. I hadn't paid much attention to 'Highlight Priority' before. The implementation on these Vixia/Legria camcorders is rather different to the 'Highlight Tone Priority' on the Canon EOS cameras, from which it derived. The camcorder clearly under-exposes to defend the highlights (arguably too much) but does not compensate, to an appreciable degree, in normalizing the shadows, as it does on the EOS cameras - probably because it would introduce an unacceptable level of gain noise in the process. So instead Canon promoted it as a 'look' that is best viewed on a monitor with increased brightness and boosted lower mid-tones - I mean, who is going to do that ? Perhaps not surprising then that it's appearance on the Vixia/Legria line models was short lived. Which is a pity; when I got to grips with it in Resolve I found that the shadows could be boosted appreciably before noise becomes conspicuous and I was surprised at the level of fine detail that could be revealed - that was using the 'Shad' control in the 'Primary' color tool-set, not the log 'Shadow' wheel which lifts the black-point. In low-contrast scenes that can create a slightly unnatural "pseudo HDR" effect (adding back a little contrast helps) and in high-contrast scenes, with dark foregrounds (of which there are several in the montage), I had to resort to preliminary 'exposure compensation' (using the 'screen blend' technique) at the expense of some loss in highlight detail and a little clipping in some cases. But I think it works very well for preserving background detail (branches against sky line etc ) and bringing out fine textures in close-ups (not many in the video unfortunately). It definitely picked out more detail on the plumage of that Great Blue Heron at the end of the video, shot with full 20x zoom. Perhaps not surprising that many wild-life/landscape photographers use 'Highlight Tone Priority', or so I've read. Anyhow, there it is. It's not 4K, but, hey, I love this camcorder and I've learned a lot from the exercise. Maybe of interest to others. Would welcome any comments. Stay safe. Last edited by Bryan Worsley; November 25th, 2020 at 01:28 AM.

November 30th, 2020, 11:48 PM	#2
Rich Woodrick Regular Crew Join Date: Jun 2004 Location: La Porte, IN Posts: 43	Re: Canon HF-G40: Highlight Priority Revisted Thanks for doing this and great job. To me this shows that the HF-G40 can put out some great looking footage right out of the camera. After color grading I thought the HLP looked the best of the 3 settings.

December 6th, 2020, 10:20 PM	#3
Bryan Worsley Major Player Join Date: Oct 2005 Location: Canada Posts: 439	Re: Canon HF-G40: Highlight Priority Revisted Thanks. I have to say, Highlight Priority is growing on me. I really need to test in a wider range of scenarios, but from these tests I was surprised at the detail that can be pulled from the shadows; I expected there to be a lot more noise. I also wondered how it would look upscaled to UHD (2160p60) using the 'Super Scale' function in DaVinci Resolve. In Resolve 16, and now 17 beta, this feature is only available in the Studio version, but when it was first introduced in Resolve 15 it was available in the free version also. The 'improved algorithm' in Resolve 16 does recover a bit more fine detail, but the original implementation in 15 is still very good. Of course a lot depends on the quality of the source. In earlier tests with HF-G30 footage I found that setting the level of Sharpness and Noise Reduction to Medium gave the most satisfactory results. The processing is very slow though. So, using clips from the same test series as before, here are the original 1080p60 Resolve grades lightly post-sharpened with the AVISynth filter 'Fine Sharp': YouTube (Short URL) YouTube (Short URL) Here upscaled to UHD with Resolve 15 'Super Scale' (2x, Medium Sharpness and NR): YouTube (Short URL) YouTube (Short URL) And here the UHD export down-scaled to QHD (2560 x 1440) using the AVISynth 'Spline36Resize' filter: YouTube (Short URL) YouTube (Short URL) Both the YouTube videos and the original graded videos, streamed over my home network from an NAS (MyBookLive), look very nice on my Roku UHD TV, and without any need to boost the brightness. I'm under no illusion that these 'Super Scaled' UHD videos could pass off as '4K' but they do look better 'psychovisually' than the HD videos upscaled by the TV. It's a shame Canon decided to drop 'Highlight Priority' mode on the 4K Vixia/Legria models, as it's definitely gradable. Last edited by Bryan Worsley; December 7th, 2020 at 10:30 AM.

January 12th, 2021, 05:37 PM	#6
Bryan Worsley Major Player Join Date: Oct 2005 Location: Canada Posts: 439	Re: Canon HF-G40: Highlight Priority Revisted No new footage to test so, in an idle 'lock-down' moment, I wondered if I could tweak the above Wide DR clips some more, and see how they look upscaled: Tweaked 1080p60 Resolve grade, post-sharpened with the AVISynth filter 'Fine Sharp': YouTube (Short URL) Looks better (crisper, tad more contrast) than the original grade I think, after uploading to YouTube at least. Upscaled to UHD with Resolve 15 'Super Scale' (2x, Medium Sharpness and NR): YouTube (Short URL) The UHD export down-scaled to QHD (2560 x 1440) with AVISynth 'Spline36Resize' filter: YouTube (Short URL) Again, I think the Resolve 'Super-Scale' function does a pretty good job, but it would be fair to say that the upscaled videos look best when viewed at the 'picture quality' matching the upload resolution; the UHD upload viewed at 'HD 1080p60' quality is softer than the native 1080p60 upload - as you might expect. Highlight Priority still looks better though. Last edited by Bryan Worsley; January 12th, 2021 at 11:44 PM.

February 18th, 2021, 08:31 PM	#7
Bryan Worsley Major Player Join Date: Oct 2005 Location: Canada Posts: 439	Re: Canon HF-G40: Highlight Priority Revisted FWIW, some further tweaks - should probably have called this thread "attempts at making WDR look better" 'Difference analysis' revealed that the level of 'Mid-tone Detail' (local contrast, clarity) I was applying was generating subtle, diffuse 'macro-halos' around high-contrast edges, notably objects (trees etc) set against the skyline, which were clipping. I'm calling them 'macro-halos' as distinct from halos seen at the micro-level around the edges of sharpened detail, but it's essentially the same phenomenon - overshoot: https://www.duncanfawkes.com/blog/avoiding-halos So I reduced the 'Mid-tone Detail' to a more acceptable level - from around 40 to 25. Also I had applied no noise reduction (NR) in the Resolve grades, largely because I am using the free version and NR is only available in the Studio version; denoising before importing into Resolve would mean transcoding the native clips to a compatible intermediate (I've always used Cineform), which is a royal PITA. So I've spent some time (re)evaluating denoise and sharpen filter combinations available in AVISynth for the best outcome in this case. Of those tested, KNLMeansCL (an optimized Open CL implementation of the Non-Linear Means algorithm) gave the most satisfactory results for treating 'white (gaussian) noise' - hadn't tried it before; very impressive, especially when the Cineform exports are processed with a 10bit pipeline - some say on par with NeatVideo (for 'white noise'), but I haven't used it myself. As for sharpening. The 'FineSharp' filter I used above is a 'generic' sharpener that was originally intended for real-time sharpening on playback. It's main strength (as the name implies) is that it avoids line thickening, the tell-tale sign of digital sharpening The downside is that it will sharpen (amplify) any noise and existing (in-camera) sharpening artifacts as well. So denoising helps, but not completely. Another sharpening filter, Limited Sharpen Faster-Mod (LSFMod) aims to achieve better control of halos and other sharpening artifacts (aliasing, 'confetti' artifacts), and does to a large degree, but the results are not as 'crisp' as FineSharp. So here the tweaked Resolve grade, denoised with KNLMeansCL and sharpened with FineSharp: YouTube (Short URL) The same denoised with KNLMeansCL and with sharpened with LSFMod (non-linear sharpening mode): YouTube (Short URL) In both cases, the post-processing was all done in (planar) 10-bit 4:2:2 (p210) and the resulting Cineform encodes were uploaded directly to YouTube. Which looks better on YouTube I guess is matter of personal taste. And also the Resolve grade upscaled to UHD using the 'Superscale' function (Medium NR & Sharpness): YouTube (Short URL) And the UHD upscale downscaled to QHD with AVISynth Spline36Resize: YouTube (Short URL) I don't think I can improve the Wide DR footage anymore than that. Highlight Priority still looks better IMO. Anyhow, just putting this out there if anyone is interested.

February 22nd, 2021, 09:03 PM	#8
Bryan Worsley Major Player Join Date: Oct 2005 Location: Canada Posts: 439	Re: Canon HF-G40: Highlight Priority Revisted And a revised grade of the other series of Wide DR clips, similarly denoised (KNLMeans) and sharpened (FineSharp and LSFMod) in a 10bit 422 (p210) pipeline: LSFMod - the original file played on my PC and streamed to HDtV and 4K TV looks really nice. Big improvement on the original footage IMO. YouTube (Short URL) FineSharp - 'crisper', but more residual sharpening artifacts. Better for YouTube ? YouTube (Short URL) And the Resolve Grade upscaled to UHD using the 'Superscale' function (Medium NR & Sharpness): YouTube (Short URL) And the UHD upscale downscaled to QHD with AVISynth Spline36Resize: YouTube (Short URL) Last edited by Bryan Worsley; February 22nd, 2021 at 10:30 PM.

March 7th, 2021, 01:26 PM	#9
Bryan Worsley Major Player Join Date: Oct 2005 Location: Canada Posts: 439	Re: Canon HF-G40: Highlight Priority Revisted Coming full-circle, I also revised the original series comparing Standard, Wide DR and Highlight Priority, incorporating the various tweaks. The original, ungraded clips (again): YouTube (Short URL) The revised graded version. As in the original grades, light sharpening (with the Resolve sharpen tool) was applied only to the Wide DR clips: YouTube (Short URL) The highlights are a tad darker in some of the Highlight Priority scenes compared to the original grade - I applied a little more 'highlight pull-down' in an effort to offset some clipping; arguably, I should have left it as is. And then the Resolve grades (with no internal sharpening applied) further processed (NR, sharpening) with AVISynth filters (KNLMeansCL, LSFMod): YouTube (Short URL) I'd be inclined to leave the Standard and Highlight Priority grades un-sharpened for playback on PC and HDTV, but it for YouTube it gives them a bit more punch.