HV20: Cinemode Softness (loss of image detail) Pic - Page 5 at DVinfo.net

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Canon VIXIA Series AVCHD and HDV Camcorders
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Old August 9th, 2007, 03:03 AM   #61
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I am a sucker too: http://eugenia.blogsome.com/2007/08/...ding-tutorial/
However, clarity of picture is every bit as important. ;)
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Old August 9th, 2007, 07:52 AM   #62
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Stu,
Care to share some thoughts on why you chose CINE over Tv on your recent shoot?

Euginia,
Yeah, the AUTO mode and strong natural light don't mix all that well. Oversaturated colors and blown-out highlights are what I've noted. Maybe Tv mode with a contrast filter and and ND filter (or 2) will be the answer.

With any luck I'm going to do the more careful, comprehensive testing today. I'm going to use a lot of well balanced light.
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Old August 9th, 2007, 11:20 AM   #63
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Originally Posted by Joseph H. Moore View Post
Stu,
Care to share some thoughts on why you chose CINE over Tv on your recent shoot?
I did, here.

-Stu
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Old August 9th, 2007, 11:27 AM   #64
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Thanks, Stu. yes, I had read your entry previously. I was curious if there was anything other than the gamma response that attracted you to CINE. What's your opinion on the apparent low pass filtering and poor compression that's going on?
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Old August 9th, 2007, 11:35 AM   #65
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My opinion is that I need to do some tests of my own. What it looks like to me is that the HDV compression, which is significant, is clobbering the high frequency detail in CINE MODE. It seems to me that Auto mode adds enough sharpening that the heavy compression has a harder time obliterating it.

An interesting test would be to compare the modes via HDMI out, so we could take HDV's gnarly compression out of the equation.

I'm not convinced that any softening is being added by CINE MODE, but that's just a hunch.

One downside of sharpening in post is that it happens after compression, wheras the camera's sharpening happens before.

I realize that tack-sharp images are or paramount importance to some people, but if I were one of them I a) wouldn't be shooting with a 35mm adapter and b) wouldn't be shooting to a highly compressed format with a sub-$1K consumer camera.

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Last edited by Stu Maschwitz; August 9th, 2007 at 05:45 PM.
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Old August 9th, 2007, 11:36 AM   #66
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I did 53 set-ups this morning, including a reference file from a DSLR. Gonna take me some time to edit and compile, but when done, I'll post here.
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Old August 9th, 2007, 11:42 AM   #67
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Alas, I could not record via HDMI, but I was able to monitor it via HDMI at 1080P, and I think that there might be something to Stu's theory about the compression sucking away the low contrast detail ... that's definitely a common side-effect of MPEG/JPEG style compression schemes.

Still, I think people will be able to garner alot about the different characteristics of the different modes, even with the HDV compression. I'll post as soon as I can, but I want to do this right. ;-)
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Old August 9th, 2007, 11:59 AM   #68
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It seems unlikely that the cinemode is really lowering resolution. Typically like cameras a lot of pp sharpening is applied to make the picture look sharper. But looking at Nathan's pictures that's not the case (there's definitely resolution loss).

So did anyone check if the gain is equal? If you crank up the gain I can see the CCD sensor would capture more resolution yet also more noise (and you can clearly see additional chroma noise in some of the posted pictures)?

So I'm curious how does the comparison look like in bright sunlight? Are the resolution results still that different?

Luc
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Old August 9th, 2007, 01:33 PM   #69
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Stu, please post your findings when you do your tests. Either here, or on your blog. Thanks.
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Old August 9th, 2007, 02:34 PM   #70
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Quote:
Originally Posted by Eugenia Loli-Queru View Post
To evaluate yourselves in full mode, here is the normal picture:
http://osnews.com/img/vegas/1.png
and here is the cinemode one:
http://osnews.com/img/vegas/2.png
The pictures are true 1:1, but they are not 1920x1080 just because I grabbed my visible screen while having frame-by-frame paused a progressive LOSSLESS version of the video rather doing it inside Vegas which does not let me grab in 100% quality/size (so I had to export in lossless first and then grab my screen).
I took the cinemode image you posted and adjusted the contrast and added some sharpness and it ended up looking much closer to the normal image.

I really do (at least from these samples listed above) think it is just a lack of electronic sharpness that is going on here. I will try some of the other images.

For what it's worth as a visual effects artist I have always shot video with the sharpness turned all the way down or off. To me it create the most raw image I can work with for FX work. I would rather have a soft raw image to key then one with a black or white ring around my subject.

I have to give props to Canon for at least having the vision to think of giving people the option of having as close to a raw mode as you can get with a HDV camera.

I have seen unprocessed film footage and it isn't pretty either. In fact even a lot of Hollywood SD DVD's will be sharpened because after the film transfer they still are not sharp enough. I remember similar threads with the JVC HD100 camera. In it's normal settings the images looked sharp but you could tell there was a lot of sharpening going on in the camera. With the electronic sharpness turned off the image became super soft almost out of focus looking. No the JVC camera was not softening the footage either. It is just how a chip readout looks like in it's raw form. The SONY Z1 has the same thing going on. Most people will tell you who have tried it that if you turn the sharpness off on the Z1 the footage becomes almost too soft to use. The fact that the HV20 still looks like a nice HD image even with the sharpness turned off says a lot about the level of raw detail from the chip.
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Old August 9th, 2007, 03:21 PM   #71
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>it ended up looking much closer to the normal image.

Well, upload the fixed image so we can conclude that ourselves too. IMO, this is lost detail, not recoverable, no matter what sharpen algorithm you use. Please, prove me wrong. :)
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Old August 9th, 2007, 03:24 PM   #72
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Originally Posted by Thomas Smet View Post
I really do (at least from these samples listed above) think it is just a lack of electronic sharpness that is going on here.
Unable to test my own cam, and rather using what I've seen here, I agree.

The HDV encoding happens AFTER the CINE mode (or after the footage would be sharpened, or not). RAW IMAGE > PROSESSED BY CUSTOM SETTINGS (incl Tv or CINE mode) > HDV compression. If it's not sharpened before it gets hit by HDV compression, it'll be gone - though it was there.

The HDV encoder is thinking "nah, there's not enough detail there.. they won't notice - lets make that area one large mass of blur to save data space in case I need it for the next frame of footage".

We need to find out if it's the HDV compression that's causing this! Someone needs to bypass HDV and do an HDMI LIVE capture for this to be proven!
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Old August 9th, 2007, 03:58 PM   #73
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Here's what I think.

If the HV20 (and maybe other HDV cams) work with the same principle as Wiki describes for DV cameras, then the following is true:

"To avoid aliasing, optical low pass filtering is necessary (although not necessarily implemented in all camera designs). Essentially, blurry glass is used to add a small blur to the image. This prevents high-frequency information from getting through and causing aliasing. Low-quality lenses can also be considered a form of optical low pass filtering.

Sharpening is often used to counteract the effect of optical low pass filtering. Sharpening can be implemented via finite impulse response filters."


This would mean that the 'in-camera sharpening' is actually necessary to get a decent image. HV20's CMOS is bigger than 1920x1080 so a soft image from a higher resolution that is sharpened as compensation for its bluriness and then downscaled to 1920x1080 would actually preserve detail that would otherwise be lost by downscaling an image that's slightly blurred and low contrast in the first place.
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Old August 9th, 2007, 04:12 PM   #74
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Originally Posted by Eugenia Loli-Queru View Post
Well, upload the fixed image so we can conclude that ourselves too. IMO, this is lost detail, not recoverable, no matter what sharpen algorithm you use. Please, prove me wrong. :)
Here's what i ended up with simple curves adjustment and smart sharpen filter in Photoshop:

http://eki.pp.fi/temp/Eki/HV20/Cinem...nd_sharpen.png

Not ALL of the detail is as sharp, probably due to the compression. But i'd say it's close enough.

Personally, my eyes hurt when watching overly sharpened imagery, i'd be perfectly happy with much softer images than cinemode without sharpening, as long as i can keep my highlights intact for color correction, and my edges fringe free ;-)

To me, cinemode was the number one reason for getting this cam, and i haven't changed my mind yet...

It was rather easy to make this Cine Mode shot look similar to the TV mode shot. But it would have been simply impossible to do it the other way - one can't get back the detail from blown out highlights, and getting rid of the sharpening artifacts (fringe, ringing) in the edges is very hard if not impossible too.

So, it's cinemode all the way for me ,-)
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Old August 9th, 2007, 04:25 PM   #75
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The SONY Z1 has the same thing going on. Most people will tell you who have tried it that if you turn the sharpness off on the Z1 the footage becomes almost too soft to use.
That is true - like you, i'm a visual effects guy, and i always shoot as low-contrast, sharpening free stuff as i can.

Except with Z1.

The footage is SO soft without sharpening that it's practically impossible to restore it decently after HDV compression.

So, i shoot with sharpening at 6 or 7 with that cam - luckily Sony's sharpening algorithm is really good, and there's not too much artifacting going on at this setting.
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