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-   -   Use of Light Meter in XL2 (https://www.dvinfo.net/forum/canon-xl-gl-series-dv-camcorders/117037-use-light-meter-xl2.html)

Ashok Mansur March 15th, 2008 08:52 AM

Use of Light Meter in XL2
 
This question has raised several times still I have doubts, I checked my friends Sekonic Meter L 308s. I have XL2 (pal)system & need a clarification on that.
I'm confused with fs (frames per second) as XL2 has 50i i.e 1/50 & 25p 1/25, the light meter needs fs & it'll give the aperture nos. If the light intensity is more ND has to be used even the light is more then we have to increase the shutter speed as the lowest aperture is f11.Does it effect the EV?
My question is what is the use of shutter speeds of XL2? when we set at A auto priority XL2 sets shutter speed at 1/50 in other settings Tv, Av, M we can set different shutter speeds. Does that effect the exposure value too?
Is it really beneficial to use a light meter?
What is the shutter angle? how does it applies to video.

Ashok

Jay Gladwell March 16th, 2008 06:16 PM

Sounds like you may need to go back and read some basics to gain a better understanding of how exposure works.

I'll start with the last question first...

Don't worry about shutter angle. It has no bearing on your work with the XL2. You can't change it.

There is no benefit to using a hand-held light meter with the XL2, although others will jump up and down, hold their breath, and protest there is. At best, it's a matter of personal choice.

I really don't understand what you're asking in the main question. Of course changing the aperture and shutter speed will have an effect on the EV. The (proper) different combinations will give you the same exposure, but it will effect the final image's characteristics--depth of field, motion blur, etc.

Michael Nistler March 17th, 2008 12:09 AM

Quote:

Originally Posted by Jay Gladwell (Post 843550)
There is no benefit to using a hand-held light meter with the XL2, although others will jump up and down, hold their breath, and protest there is. At best, it's a matter of personal choice.


Hi Jay,

So if Ashok wants to obtain a 3:1 key-to-fill light ratio on his subject using a reflector, how would you propose he do so without an incident light meter? How would you quickly change it to a 4:1 ratio with the XL-2? Ditto on silhouette shot contrast ratios - how do you gauge the f-stop delta/change with your XL-2?

Regards, Michael

Ashok Mansur March 17th, 2008 01:25 AM

Hi Jay......
 
In still photography the combination of iris & curtain elements decide the picture, but here in video there is one more element i.e. fs & the LMeter insist on it that confuse me more. If only on shutter & aperture I didn't mind but there is an option on fs 25p, 50i and I'm unable to understand it.
The question on shutter angle still haunts me plz clarify it, even it doesn't effect to XL2.

Ashok

Jay Gladwell March 17th, 2008 07:59 AM

Quote:

Originally Posted by Michael Nistler (Post 843669)
Hi Jay,

So if Ashok wants to obtain a 3:1 key-to-fill light ratio on his subject using a reflector, how would you propose he do so without an incident light meter?

Regards, Michael

I light by eye and monitor. If you absolutely must be worried about ratios, then you would need a meter. In 35 years of lighting stills and motion, I have yet to have a client, or anyone else for that matter, ask for specific lighting ratios.

Jay Gladwell March 17th, 2008 08:02 AM

Quote:

Originally Posted by Ashok Mansur (Post 843691)
In still photography the combination of iris & curtain elements decide the picture, but here in video there is one more element i.e. fs & the LMeter insist on it that confuse me more. If only on shutter & aperture I didn't mind but there is an option on fs 25p, 50i and I'm unable to understand it.
The question on shutter angle still haunts me plz clarify it, even it doesn't effect to XL2.

Ashok

Ashok, there are tons of books and web articles that have been written on the subject. Do a search. Go to the book store. Read all about it. You will learn more and remember it longer if you do it yourself!

Ashok Mansur March 17th, 2008 11:00 AM

Thanks Jay.
 
Can you give me some of the web addresses b'cos here in my place it's difficult to get books? As you said reading will definitely long lasting even if I had doubts you people are there to guide.

Ashok

Jay Gladwell March 17th, 2008 01:12 PM

Ashok, go to www.google.com and search anything you have questions about. Search "shutter angle," for example, and you'll get over 250,000 hits!

Jack Barker March 18th, 2008 09:40 AM

Quote:

Originally Posted by Jay Gladwell (Post 843926)
Ashok, go to www.google.com and search anything you have questions about. Search "shutter angle," for example, and you'll get over 250,000 hits!

As fine a search engine as Google is, you might want to start with Wikipedia first. They cover an amazing number of subjects, including cinematography and videography. I typed in "shutter angle" in Wikipedia and got a pretty thorough explanation, and a nifty animation of how the shutter actually works in a film camera. There was also an explanation of the video equivalent, and there are almost always links to further reading on a subject.

http://en.wikipedia.org/wiki/Main_Page

Ian Stark March 20th, 2008 10:00 AM

I believe a light meter might also be useful for checking the evenness of light falling onto a greenscreen for keying work (a spot meter would be most appropriate in this case so you could position yourself by the camera and take readings around the screen).

Michael Nistler March 20th, 2008 11:33 AM

Quote:

Originally Posted by Ian Stark (Post 845615)
I believe a light meter might also be useful for checking the evenness of light falling onto a greenscreen for keying work (a spot meter would be most appropriate in this case so you could position yourself by the camera and take readings around the screen).

Hi Ian,

While Jay and I have different views on the usefullness of a light meter, I wouldn't claim that validating uniform illumination of a greenscreen is much of a benefit for those of us with zebras.

Light your screen, stop down your XL-2 until you detect zebras across the entire screen (any IRE is fine), back off one stop and validate the zebra shuts off. If you have hot-spots or shadows, it will visually standout.

Using zebras, it's quick and easy to ensure your lighting is correct.

Warm Regards, Michael

Ian Stark March 20th, 2008 11:37 AM

Of course, completely agreed Michael. I was thinking broader than XL2 and other cams with zebras . . . which is dumb in the XL2 forum!

Ashok Mansur March 22nd, 2008 08:59 AM

Zebra.........
 
I find there are different zebra displayed in 80- 100 zebra settings,
like in 80 setting the zebras are prominent when you go higher at 100 zebras are very less. Can any body explain this & when in what situation which zebra setting to be used. As for my little knowledge concerned zebras display contrast ratio.
How to shoot slow motion in XL2 i.e. using fast frames other than shutter speed to capture Eagle diving on it's pray.

Ashok

Matt Newcomb March 22nd, 2008 11:19 AM

Google is your friend dude.


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