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JVC 4K Pro Handheld Camcorders
GY-LS300, GY-HM200, HM170 and HM-Q10 recording 4K Ultra-High Definition video.


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Old March 2nd, 2016, 11:56 AM   #1
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jvc gy ls300 aliasing

I already shot a wedding with this camera and then I didn't notice anything weird but when I just received the camera I made a test film with a slider and I noticed a artifact that I was able to replicate today, because I have to shoot with that same slider this Saturday and because it's also architecture I have been looking into decreasing that effect today.

If you look at below video starting at 01:21 when I do that sideways slideshot in that big hall, look at the big windows at the left and see how visible that aliasing is on vertical lines in those windows.

Originally I thought it has something to do with the downscaling from c4K to HD but during some tests today I noticed the aliasing on edges is visible in every shooting mode, only when I shot in Jlog the aliasing almost completely disappeared. What did help to reduce that effect considerable was to decrease the sharpness to at least -5.

Are there others that see that same problem as well? I wonder if there is any difference if you use lenses that use the entire sensor.

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Old March 3rd, 2016, 05:03 AM   #2
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Re: jvc gy ls300 aliasing

I'm going to put links of great LS300 videos into my Part 2 of my review and your video is the best corporate video I've seen! I wondered if it might be you.

The problem is it's on Vimeo in HD. So I saw no aliasing last night or just now.

All the other videos I'll link to are in 4K and so they are on YouTube. Which I watch on a 4K display.

Frankly, I find it difficult to watch HD after watching UHD. There's one good video, but I kept having the sense there were parts out of focus -- which may have been true. Or it may be just my feelings seeing in HD.

I've reviewed several Sony 4K consumer cameras. They show unwatchable aliasing with any movement of fine detail. The reason is that Sony did not use an effective optical filter and/or they boosted the sharpness to overcome a cheap lens with low MFT.

I have seen TINY bits of aliasing with the LS300. But it's so little I wouldn't worry. Do you have this video in 4K. If so please post on YouTube so I can link to it.
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Old March 3rd, 2016, 05:20 AM   #3
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Re: jvc gy ls300 aliasing

I don't do corporate videos so not sure to which video you where referring to?

I"m not sure if any else is noticing this but the playback quality of the embedded video in this site is really bad at this moment, the playbackqualities I can choose from are 266, 534 and 800p?? The film directly on my vimeo account is higher quality: vimeo.com/148631918

The aliasing I am referring to can be seen in the screengrab: it's particular visible on vertical lines and gets very visible when there is controlled cameramovement like on a slider.
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Old March 3rd, 2016, 05:27 AM   #4
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Re: jvc gy ls300 aliasing

Here is a part of the video that I have enlarged which clearly shows the problem, you have to bear in mind that this comes from a c4k source, was then downscaled in post to 1080p and then uploaded to vimeo where the further apply compression to it.

password is test:
direct link for maybe better playbackquality: vimeo.com/157566150
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Old March 3rd, 2016, 08:09 AM   #5
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Re: jvc gy ls300 aliasing

noa-

i appreciate your efforts to create conversation about the effective use of the ls300.

i am a fan of your "luchtfabriek" piece.

i had previously "liked" it on vimeo.

but this morning, i was pixel peeping to see the concerns you raised.

i also saw at 01:18 the arched window on the right had some funkiness.

as you suggested, i wonder if lowering the detail and/or the use of jlog will eliminate these issues.

that said, i initially watched "luchtfabriek" twice on vimeo and didn't "see" any issues as i was so involved in watching your work.

pixel peeping is helpful and often necessary but plenty of times only we see what others don't or don't care.

i'm making no excuses.

i'm just saying.

be well.

rob
smalltalk.productions
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Old March 3rd, 2016, 06:59 PM   #6
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Re: jvc gy ls300 aliasing

I agree, pixel peeping can drive you nuts - not as nuts as color correction, but close.

As for aliasing, the LS is way less than the BM Pocket Cinema Camera (I own two) which everyone raves about - even in a non-log mode.

However, from the start I have thought the detail is really amped on every camera I see from a major manufacturer - it's like the 4K TVs at Costco, they make your teeth hurt.

If I'm shooting Cinema Gamma, I dialed the Detail down to -10 or -12 (I don't remember now). However, since the firmware upgrade I have shot exclusively in log, and as you pointed out, the aliasing virtually disappears. You can't adjust the Detail in log, so it's only a guess, but I'd say it's down to about that -10 -12 I was using originally.

I realize weddings can be a problem - mothers of brides want to see every detail. But for my work, documentaries and doc-style TV spots, I prefer the detail to mimic a 1/2 SoftFX on 35mm... It's just nicer.
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Old March 3rd, 2016, 09:18 PM   #7
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Re: jvc gy ls300 aliasing

"this comes from a c4k source, was then downscaled in post to 1080p and then uploaded to vimeo where the further apply compression to it."

When you downscale you are at the mercy of your NLE scaler. Worse, CK4 has to be scaled to go into either UHD or HD. Hopefully you simply cropped the image. CK4 and CK2 are ONLY to be used when creating a production for digital movie projection.

I've also got to ask why downscale at all?

You don't say how uploaded it. I only use ProRes 422 which is a high bit-rate codec -- about 100Mbps if I remember. In other words, I treat an upload as though it were a movie I was making for a UHD TV.

YouTube accepts this and 48k PCM audio with no problem.

Please post at 4K on YouTube so we can see what you shot as you shot it. Oh -- I hope you did not downscale your sources before you edited. Hopefully you edited at 4K and then cropped to HD.

If you have a 4096x1080 version it would be interesting to see if YouTube plays it at that frame-size or does a crop to HD.

Sorry, it looked like a "artful" corporate video about a company's past. Oh, well it still is fine piece of video.
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Old March 4th, 2016, 01:05 AM   #8
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Re: jvc gy ls300 aliasing

Quote:
Originally Posted by Rob Katz View Post
i am a fan of your "luchtfabriek" piece.
Ah, so you are that one person that saw the video acc to my vimeo stats :) To be honest, I don't like the video, don't exactly know why but something doesn't feel right to me, that's why I had been keeping it in the background.
Quote:
I realize weddings can be a problem - mothers of brides want to see every detail.
Lowering the sharpness doesn't make much difference for a weddingvideo, at least not to the client as I find the perceived sharpness even in HD to be more then sufficient. It only looks the jvc is oversharpening things even when sharpness is set at zero but I didn't see aliasing then, there is one shot of the church on the outside and it has very small bricks and even those are displayed without any aliasing.
Quote:
so it's only a guess, but I'd say it's down to about that -10
I think that's the case too, just by visually comparing when I shot in another preset then jlog and when I turned the sharpness to -10 it looked the same as Jlog.
Quote:
I've also got to ask why downscale at all?
I always edit my 4k source in a 1080p project in edius so edius handles the downscaling when I export, it edits easier and gives me a possibility to crop in post so that's why I always have found the 1080p output more then sufficient for my needs but for the shoot I have planned tomorrow I"ll shoot in 4K (not c4k), edit in 4K and export in 4K as well and upload that master to vimeo (don't even know if vimeo accepts 4K?) or might use tmpgenc mastering works to downscale to 1080P as that is the resolution the clients expects, see how that works out. I"ll also dial the sharpness down to -5 in camera.
Quote:
it looked like a "artful" corporate video about a company's past.
Ah, ok, so it was my video :) I have done corporate video in the past but stopped doing that a few years back, this video (luchtfabriek which means airfactory) is indeed from a coalmining company that stopped it's activities around 1990, most of the stuff you see in that museum was used above ground. I have worked there during the 80's but I worked in the underground (800 meter deep) so I still feel "connected" when I visit that location.
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