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how to use a light meter w/SDX900


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#1 Scott Davis

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Posted 06 September 2005 - 09:32 AM

I am wanting to use a Sekonic L-608 light meter with my SDX900. I am wanting to know how to calibrate the cameras ISO to work with the light meter.I am unsure how to set up the two to work together. Can anyone help?
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#2 Tim J Durham

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Posted 06 September 2005 - 02:38 PM

I am wanting to use a Sekonic L-608 light meter with my SDX900. I am wanting to know how to calibrate the cameras ISO to work with the light meter.I am unsure how to set up the two to work together. Can anyone help?

<{POST_SNAPBACK}>

Start in clear filter (3200k) at "0" dB gain. Light, shoot a white card with your zebras set at 70, open the iris til you just get zebras on the card in your viewfinder, then take a reading with your light meter. Adjust the ASA reading on your meter until the iris reading is the same as it is on your lens. Then, do it in all the gain settings, record your findings, then do it in each filter and record those.

If you are at the long end of your zoom, you'll lose a little aperture, but these settings should be good through most (or 50%, atleast) of your zoom range.
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#3 Sivanesan

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Posted 21 December 2005 - 02:59 AM

Start in clear filter (3200k) at "0" dB gain. Light, shoot a white card with your zebras set at 70, open the iris til you just get zebras on the card in your viewfinder, then take a reading with your light meter. Adjust the ASA reading on your meter until the iris reading is the same as it is on your lens. Then, do it in all the gain settings, record your findings, then do it in each filter and record those.

If you are at the long end of your zoom, you'll lose a little aperture, but these settings should be good through most (or 50%, atleast) of your zoom range.



Hi TimJBD,
Can use this procedure for any video camera..... will it be right....

thank u
Sivanesan
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#4 Lars.Erik

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Posted 21 December 2005 - 03:58 AM

You have to use the spot function on the meter.

You can also use a 18% grey card, which can be found in most major photo shops. I find this approach a bit more exact. You do it the same way. Fill the lens with the card, take a automatic reading on your lens, then adjust the ISO until it reaches the same aperture as the lens. You must remember to have fps correctly before starting. In the US, either 1/24 fps or 1/60. In Europe, it's best to use 1/25 fps.

Word of warning: light meters are not the best tools for digital. Sure, I've had great help in it when shooting digital. But in the end, ALWAYS check your proper calibrated monitor for final decisions. I find that I use them alot when rigging lights. Then just to check the f-stop. The contrast range is always best to do by eye. When I'm shooting, I usually pack the meter away.


Lars Erik
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#5 Rick Shepardson

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Posted 08 August 2007 - 06:24 PM

You have to use the spot function on the meter.

You can also use a 18% grey card, which can be found in most major photo shops. I find this approach a bit more exact. You do it the same way. Fill the lens with the card, take a automatic reading on your lens, then adjust the ISO until it reaches the same aperture as the lens. You must remember to have fps correctly before starting. In the US, either 1/24 fps or 1/60. In Europe, it's best to use 1/25 fps.

Word of warning: light meters are not the best tools for digital. Sure, I've had great help in it when shooting digital. But in the end, ALWAYS check your proper calibrated monitor for final decisions. I find that I use them alot when rigging lights. Then just to check the f-stop. The contrast range is always best to do by eye. When I'm shooting, I usually pack the meter away.
Lars Erik


I'm going to be shooting a piece with the SDX. Do you think that it would help to have a waveform monitor on hand to spot blow out points? It seems that the SDX doesn't handle the upper end of the zone system that well at all.
Thanks,
Rick
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#6 e gustavo petersen

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Posted 09 August 2007 - 02:37 AM

I'm going to be shooting a piece with the SDX. Do you think that it would help to have a waveform monitor on hand to spot blow out points? It seems that the SDX doesn't handle the upper end of the zone system that well at all.


A waveform will certainly help you identify trouble spots both in the highlights and in the shadows. I would have to disagree with you that the SDX doesn't handle highlights well. I've found it to be a among the best of the standard def cameras. It does, however, like any other video camera, have to be dutifully watched and managed.

Something to think about when trying to figure out the relative exposure rating for a camera and that is which lens you're using. Depending on the coating you might get a different rating when using different lenses especially if you're using standard def lenses. It's unlikely to be an issue with, say, DigiPrimes which have matching lenses. And there's also how the camera's internal menu settings have been set. If, for example, you're using one setup with a neutral setting and another that'll very stylized, you might need to rate you camera differently for each setting.

One last thing, if you do use a waveform monitor and a gray card or gray scale chip chart, your middle gray should hit the 55 IRE mark (I have heard some say 50 IRE) but for as long as I've been shooting film and video, it's been 55 IRE.
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#7 Rick Shepardson

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Posted 09 August 2007 - 11:00 PM

A waveform will certainly help you identify trouble spots both in the highlights and in the shadows. I would have to disagree with you that the SDX doesn't handle highlights well. I've found it to be a among the best of the standard def cameras. It does, however, like any other video camera, have to be dutifully watched and managed.

Something to think about when trying to figure out the relative exposure rating for a camera and that is which lens you're using. Depending on the coating you might get a different rating when using different lenses especially if you're using standard def lenses. It's unlikely to be an issue with, say, DigiPrimes which have matching lenses. And there's also how the camera's internal menu settings have been set. If, for example, you're using one setup with a neutral setting and another that'll very stylized, you might need to rate you camera differently for each setting.

One last thing, if you do use a waveform monitor and a gray card or gray scale chip chart, your middle gray should hit the 55 IRE mark (I have heard some say 50 IRE) but for as long as I've been shooting film and video, it's been 55 IRE.


Thanks.
You're actually the second person today that's told me the sdx handles highlights well. I guess I need to watch my waveform better:)
I've seen many people I respect run into issues with blowing out on the SDX. The biggest issue I've noticed are excessive highlights and kickers (rim lights.)
I've been told that you want to avoid going more than two and a half stops above middle gray or 55% ire, and that around 80% is a real danger zone. Camera tests that I've done in the past seem to back this up. (I was at 24p with film like gama 1.)

However, the person I was speaking to today said the camera can handle four stops above middle gray and only three stops below. This just doesn't seem to make sense to me.

As you can see, I'm just getting my feet wet with this.
Thanks,
Rick
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#8 Mitch Gross

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Posted 10 August 2007 - 12:35 AM

All Panasonic cameras have a great little function called Y Get, which is a built in spotmeter. Look in the menus under the controls for the User buttons. Set one to Y Get (Y being luminance) and whenever you push the button you'll get a percentage (IRE) reading of the pixel group at the crosshairs dead center in the frame. A very useful tool.

Even the little DVX100 has this, although there is is under the Marker controls. You can scroll through the zebra controls to display zebra 1, zebra 2, marker (Y Get), or off. Nice.
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#9 Michael Nash

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Posted 10 August 2007 - 04:49 AM

I've seen many people I respect run into issues with blowing out on the SDX. The biggest issue I've noticed are excessive highlights and kickers (rim lights.)... As you can see, I'm just getting my feet wet with this.


No disrespect intended, but I get the get the impression that maybe you're new to the video world, perhaps from a film background. All video cameras have trouble with highlights compared to film, and the SDX is no exception to that. But it deals with highlights just as well if not better than any other SD camera out there. For one thing, you can crush the crap out of the knee signal and never get a green shift the way you do with Sony. I've been shooting video for 20 years and the SDX is hands down the best SD camera I've ever used.

It has been awhile since I've dug into the menus, but I believe one of the FILM LIKE gamma settings allows you to control the knee settings, and the other doesn't (can't remember now which one). You can adjust the knee point, slope, and clip to contour the highlight response however you like (within the camera's range, anyway). I've used this to pull in a tremendous amount of highlight detail in high-contrast scenes.

Regarding the waveform monitor; zebra stripes are your first defense. If your zebras are set to 100% and you see them in the viewfinder, then you know those areas touch or exceed 100% luminance. After that, a properly tuned broadcast field monitor is your best bet for seeing if your highlights are clipped. Assuming the monitor is working properly and and set up properly, a highlight that LOOKS clipped IS clipped. Use a waveform monitor to back up your monitor if you're unsure. The Panasonic BT-LH1700W is the best thing since sliced bread, a great LCD monitor with built-in waveform.

One trick I fall back on in high-contrast settings is to reduce exposure enough to keep the highlights from clipping, and then raise the master gamma and black stretch to compensate for the lowered exposure. You can get away with about 1/2 to one stop adjustment this way before it begins to look "odd." That may not sound like much, but with video a 1/2- to one-stop adjustment can make a big difference in the highlight response.

The claim you heard of "4 stops over, 3 stops under" is dubious at best, though. All video cameras have a very good underexposure range (a nicely-rounded "toe" around -4.5 stops), and a poor overexposure range (rarely getting up to 2 stops). Gamma/black stretch/knee adjustments of course will change this, but never enough to produce +4 stops in the highlights.
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