Mode Comparisons - A Bit Wordy...

[Stuart]

I spent some time comparing three modes today, 1080p (25fps) with Cine mode, 1080p (25fps) and 1080i (50fps - interlaced). It's a PAL version of the camera.

The HV20 was on a tripod, manual focus, manual white balance (daylight) no IS, the shutter speed fixed at 1/50s with f5.6 - and I made sure the camera wasn't adding any gain and using the zebra pattern the brightest parts of the image were just under the clipping point. I used a detailed scene, a flower blowing in the wind against a busy background (leaves of a tree).

I'm viewing on a Dell widescreen monitor and an ISF calibrated Pioneer plasma via HDMI. Observations...

1] The 1080p with Cine mode is soft and lacks contrast. Nothing new here, but using the histogram in Vegas 7 I also noticed that it had hard clipped the bright areas of the image and they were over-exposed. No amount of curves or levels correction can fix that.

2] The 1080p mode without Cine mode is sharper and has more dynamic range. The whites weren't clipped and the histogram showed both shadow and highlight details.

3] To match the sharpness of the 1080p non-Cine mode footage with Cine mode engaged, I needed to add about 0.5 - 0.6 sharpening in Vegas. That's too much and it had an undesirable but predictable side-effect, noise became apparent in the image, probably in part due to compression artefacts as no gain was present. On top of that, any levels adjustment made the noise even worse and it didn't matter whether the filters were Sharpen -> Levels or the other way around.

4] The 1080i mode is all but indistinguishable from 1080p (non Cine-mode), both by eye and on the histogram, but it may be a tad brighter. It is of course, interlaced... and that leads me to...

5] A tentative one this as I haven't done any technical homework, but 1080i looks to have fewer MPEG-2 compression artefacts - in other words it produces a cleaner image - than 1080p.

I think, therefore, that I'll be avoiding the Cine mode, it seems to have too many compromises even though it can have less in-camera processing that other options. I haven't done any low-light tests, so it might come into its own there. 1080i might get the nod over 1080p provided one doesn't mind de-interlacing at some point, but it's a close run thing between it and 1080p.

Anyone echo or disagree with these observations?

[hizbiz]

Great observations Stuart.
I think your observations 2); 3) and 4) are also confirmed by many other posts in different forums.
However about 1) people had entirely different opinion. In fact some people suggested that cinemode shows better dynamic range (uses a more linear gamma) and might have less in-camera sharpening artifacts.

Anyway the comment was entirely based on other's observations and I have not done any test personally! But it might be worth for you to re-check.

thanks for your tests anyway! I have one more reason to avoid cine!! :hv20-smilie84:

[Stuart]

However about 1) people had entirely different opinion. In fact some people suggested that cinemode shows better dynamic range (uses a more linear gamma) and might have less in-camera sharpening artifacts.

I was saying to someone the other day that Cine mode was probably the "purest", and it's true that the histogram is nice and flat, but I was amazed to see the light parts clipped, especially as I'd actually set the exposure with the camera in that mode. I'll run another test tomorrow and deliberately under-expose.

With regard to sharpening, I don't think images in the standard 1080 modes look overly-sharpened, do you? Because post-processing sharpening happens after the MPEG compression, then it's bound to make artefacts worse. I suppose the only way around that is to capture live from the HDMI output.

[hizbiz]

I was saying to someone the other day that Cine mode was probably the "purest", and it's true that the histogram is nice and flat, but I was amazed to see the light parts clipped, especially as I'd actually set the exposure with the camera in that mode. I'll run another test tomorrow and deliberately under-expose.

Hmm... may be the trick would be under-expose in cine and then fix it in post. If that keeps the dynamic range intact!


With regard to sharpening, I don't think images in the standard 1080 modes look overly-sharpened, do you?

No I think the sharpening is perfect in standard modes. well..though I keep it at -1 setting.

[VaNdaL]

I recently did some tests with (pal) 1080i/p & using cinema eq and came up with similar conclusions to Stuart.

I did some low light tests... with cinema eq the grain is a lot finer and much better looking than 1080i/p, however its a bit darker with ambient lighting than using the other modes, decreasing shutter speed past the default setting in cinema eq makes everything stutter/blurry with any movement, but I'd still use it over the other modes at this stage.

I increase the sharpening on the HV20 (under the custom image setting) and it seems to be ok, dont need to use extra sharpening in Vegas at all.