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-   -   Dark output (https://www.dvinfo.net/forum/jvc-gr-hd1u-jy-hd10u/47463-dark-output.html)

Allen Lu July 9th, 2005 06:29 PM

Dark output
 
I'm new the forum and have received my GR HD1 a while ago. I've been trying to get to know it better.

One item I dont know if its the way it is or not, the LCD shows the scene pretty bright but when I play it directly on the TV or on the PC, it is very dark. It looks as if gamma is incorrect.

Is there anyway to get the picture to show what it looks like on the LCD?

Im playing back directly with component, Svideo on the TV, on the PC I'm playing back with Windows media (using RemuxTS) and Adobe Premiere 1.5.1.

Ken Hodson July 10th, 2005 11:18 AM

If you PC and TV are calibrated (both equally dark) so you know that isn't the problem, reduce the brightness on the LCD untill it matches the same level as your TV/PC display, then add more light for your shoot.

Allen Lu July 11th, 2005 12:56 PM

Thanks for the reply, Ken.

Im just curious on the fix as you suggested. I havent held a camcorder since a old model Sony Hi 8 cam. Why would the LCD give a false reading of what is on the tape? My Sony tv is plenty bright and the video from the cam is still dark.

The thing I dont understand is if this cam does not have good low light sensitivity, then how does the LCD show a picture that is supposedly from the same sensors? I would have thought that the LCD has a pretty good estimation of the actual video on tape.

Ken Hodson July 11th, 2005 01:18 PM

The LCD, just like your TV has a brightness controll and it appears to be cranked up as it is showing to be brighter then your footage. What level is it set to?
On bright days you might want to up the brightness on the LCD to help you see it outside. Otherwise you will want it set to a lower level that matches your footage.

Allen Lu July 11th, 2005 03:42 PM

The LCD brightness is in the default middle position. Even with it all the way down, the LCD is still brighter than the output to my TV.

Ken Hodson July 11th, 2005 11:28 PM

Well something seems odd. How is it through the viewfinder? Same as LCD or not?

Greg Boston July 12th, 2005 12:30 AM

The problem here is the issue of setup level. Most new digital camcorders output a signal that is equivalent of 0 IRE. NTSC setup is 7.5 IRE standard. Therefore, your picture will look too dark coming through the s-video or rca video jack.

You should be able to capture to your pc, burn the video to DVD and play it back with no problem. Why? Because the DVD player knows to add the 7.5 IRE setup to the output signal which will 'lift' the signal luminance to what it should be for your tv set.

Your camera's vf is giving you the most accurate picture. Some cameras will allow you to shift the setup level for output only, but most that have adjustable setup level will adjust the recorded signal which is not what you want. Try the method I suggested above and see what you think.

regards,

-gb-

Allen Lu July 12th, 2005 02:49 PM

I thought that it may be due to the 0 IRE and 7 IRE differences but also thought the JVC would be modern enough to compensate for this with Svideo or component. I tried the straight output on my Benq 7800 projector component as well as my Sony 36HS510 (Svideo) but both came out dark.

I suppose theres no way to get the cam to compensate for this difference?

This cam was purchased from B&H, so I assume its for the NTSC market. Why would they sell a cam with outputs that are at 0 IRE and not the 7 IRE NTSC standard?

My main issue (before trying the DVD method) is that its also dark on my PC. I cannot turn up brightness without distorting everything. I use a nVidia card (6600GT), is there a way I can tune this in Premiere?

Ken Hodson July 12th, 2005 03:29 PM

The IRE issue may cause some issues crushing some blacks, but it won't make the whole screen darker. I don't think that is your problem. It never has been for me (HD10)
Can you ever make the output bright? Is it always, always dark? Even outside on a bright day? Are you shooting Auto or Manual, and if so are you using any presets or locking your shutter very high or locking the exposure to low? Are you using any filters?

Allen Lu July 12th, 2005 04:33 PM

What I did to test this is to hookup my HS510 as the monitor through Svideo.

While indoors, with the cam on and pointed to a bright sunny window, I can see that what I see on the LCD (not vf), is much brighter than what I see on the monitor. The colors are muddy on the monitor. I only use a UV filter at this point but do have other filters. This is the part where I'm thinking why isn't it as brighter? It seems that what I see on the monitor is what ends up on tape - dark.

My videos are indoors right now because of my newborns. While I thought theres plenty of sunshine coming in, I would be surprised to find that the cam's playback would be very dim on the PC or with monitor. It is near black and I wouldnt be able to edit anything unless I added gamma adjust to each clip.

I will try to look in the vf tonight to see how it compares to the LCD. So my areas to look at are LCD vs VF, IRE level, or simply this cam really needs it's 30 lux.

Allen Lu July 12th, 2005 07:34 PM

I'm disappointed, I guess, to report that the VF output is the same as the LCD. Nice n bright.

I also tried to un-pin the 7.5 IRE in Premiere and it made no difference. IRE 7.5 is default to on with my HDV capture.

The only fix is to set the gamma at a default of 10 to 8 or 7 to get the picture to lighten up at the proper level.

Is there something wrong here?

Ken Hodson July 12th, 2005 11:56 PM

You never mentioned what settings you had set. This cam needs light and the LCD may be showing it better due to its brightness level. Please do shoot outside and let us know your findings, but at leasat tell what mode settings you are using for you indoor tests.

Allen Lu July 13th, 2005 10:21 AM

Sorry I didnt indicate it but in my previous message it was my thought after shooting outside.

Outdoors in auto mode

Output on my PC and monitor is dark but not as dark as indoor due to the brightness of the sun. It is like turning down brightness while contrast is up on a monitor.

If I corrected the gamma on Premiere from a default of 10 to 8 or 7 , it restores what it should be. At the same time, the edge enhancement diminishes. So I know that the camera is doing this.

I will try the same shoot again today with shutter lock at 1/30, then exposure lock.

I believe the cam just naturally takes in dark images and what I am seeing is correct. Its just disappointing to see how much light it needs and that it still darkens the image even when Im out in the sun. I think most interprets this darkened image as edge enhancement because after a gamma correct in post, it looks fine.

Let me just make clear that after burning the clips to DVD, the image is brighter however not as bright as the LCD/VF. I found that the brightness between the LCD and VF to be pretty close. But neither matches what I see on tape in playback on the PC or TV monitor.

I believe that the HD10 may not show this issue that is on the HD1 since many report that the HD10 doesnt have the "edge enhancement" as the HD1 consumer model does.

Ken Hodson July 13th, 2005 10:55 AM

It could still be a technical problem but give this a try first as my feelings are that the cam is not defective.
I would recommend doing some shooting with the exposure locked. Leave the cam in a set position not aiming directly at a light source set to manual mode and lock the exposure. Don't make any other settings (do not attempt to lock the shutter). Record and adjust the exposure while speaking into the cam so you can verify how each setting looks on playback. This would best be done outside, with ample light. If you do it indoors do not aim at a window or such(too bright) and turn on as many lights as you can.
Did you check to make sure no presets were selected (program auto exposure)? Having any of the presets selected can have a major impact on image. Sports mode for example will up the shutter making the image dark. Snow and Spotlight will as well affect image. Also make sure the backlight isn't selected.

Allen Lu July 13th, 2005 09:54 PM

Outside shoot

- Manual 1/30 is the best. Video playback is almost as bright as LCD, under sun light.
- 1/60 darker with sun light but panning is smoother - as expected.
- Exposure lock - I guess it works when you first lock on a specific exposure. Looks like its never intended to go from bright to dark. My screen turns all black. Seems to be meant for going from dark-med to bright without overexposure.

I guess I can conclude that this cam is naturally dark and requires lots of light. Still I have this feeling its within the cam's ability to be able to get the right brightness with a bump or two in the gamma area.


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