Can I measure Lux with my SLR? at DVinfo.net

Matt McConnell · March 7th, 2003, 01:46 PM

My question is simple, but the answer may not be. Is there a way to convert my SLR light meter reading to Lux? For example if I set my SLR to F1.2 and read a correct exposure at 1/60s shutter speed, that would convert to X many Lux.

Background to my question.
I am in the research phase of picking a Digital Video camera in the $1500 - $2500 range for recording family and church events. I have time because I plan to buy either this summer or early fall. I find that I am most interested in getting the most versatile camera, because I would like to record all aspects of life... both indoors and outdoors, far and near to the subjects, and be able to carry it to remote locations (portable). I realize that every camera has its strengths and weaknesses, so I would like to test what my "REAL" limits are and how they compare to the camera specs... how low of a Lux value will I need, how large of a zoom will I need, and what size can I readily pack for long trips? It appears that the VX2000, GL2 and MX5000/DV953 all would win one of my 3 catagories. To break the tie I need to know more specifically what my needs are.

Thanks for your help and opinions.

Jeff Donald · March 7th, 2003, 02:30 PM

Lux can be precisely determined give certain variables. However, manufactures are under no obligation to measure the picture quality under a given illumination (lux). One manufacture may decide there needs to be 75% color at a given lux, while another manufacture thinks only 25% color is sufficient at the same lux. Because there is no standardization of lux ratings the manufactures ratings are useless. You would also need a waveform monitor/vectorscope to do fair comparisons.

Frank Granovski · March 7th, 2003, 03:23 PM

More expensive cams require slightly less lux, like a JVC DV500 compared with a consumer PV-DV953. But with a well-lit set or sunshine, video will always look better. Often, it's in the positioning of the cam in relation to where the light is which makes the difference.

Don Donatello · March 7th, 2003, 05:15 PM

i wouldn't believe any of those min LUX listings that manufacturers rate their camera's ... perhaps if they would show a image from a clip that was recorded at their min lux rating we could decide ourselves what's accepable ...

i have to admit i've never have heard/seen LUX used on a set ..
foot candles are used a little on sets in hollywood ... but no LUX ??

IMO there is no reliable way to use your camera to determine F stop on video camera ...

Frank Granovski · March 7th, 2003, 06:08 PM

Yeah. I agree. Read what I wrote here:

http://www.dvfreak.com/lux.htm

Matt McConnell · March 7th, 2003, 06:43 PM

Thanks for the replies, I would have wasted a lot of time figuring out what my personal min Lux value is only to be possibly disappointed.

Hmmm... now what. So then what is a guy to do? Is there any way to determine what camera will meet my low light requirements without purchasing each of the candidate cameras and testing them head to head in a variety of conditions?

Or do you use the process of elimination technique... just buy the cheapest camera you believe might suit your needs and test it, if it meets your satisfaction then keep it, if not return it and try the next model up until you hit your budget limit?

Is there any way to set up a simulation at the store? I have looked at the VX2000 and GL2 at Fry's Electronics.

Frank Granovski · March 7th, 2003, 07:39 PM

For lowest lux, check out the VX2000 and XL1S. If you want to spend more, look at a cam which has 3, 1/2" CCDs, and get a nice, wide, clear, $80,000 US lens for it--that should drop the lux by 1/4 of a candle.

Jeff Donald · March 7th, 2003, 08:34 PM

Matt, how do you buy a car? Do you make your purchasing decision by numbers alone? Did you buy the car with the biggest gas tank, the biggest tires, lowest ground clearance or maybe the most horsepower? Probably not and I think you get my point. The best way to pick out a camera is to test drive them. Go to a big camera retailer or one the trade shows that go to the major metropolitan areas. Then you you'll have a chance to pickup, play with and feel all the cool toys, err I mean tools, you've been reading so much about.

March 7th, 2003, 01:46 PM	#1
Matt McConnell Regular Crew Join Date: Mar 2003 Location: Scotts Valley, CA Posts: 33	Can I measure Lux with my SLR? My question is simple, but the answer may not be. Is there a way to convert my SLR light meter reading to Lux? For example if I set my SLR to F1.2 and read a correct exposure at 1/60s shutter speed, that would convert to X many Lux. Background to my question. I am in the research phase of picking a Digital Video camera in the $1500 - $2500 range for recording family and church events. I have time because I plan to buy either this summer or early fall. I find that I am most interested in getting the most versatile camera, because I would like to record all aspects of life... both indoors and outdoors, far and near to the subjects, and be able to carry it to remote locations (portable). I realize that every camera has its strengths and weaknesses, so I would like to test what my "REAL" limits are and how they compare to the camera specs... how low of a Lux value will I need, how large of a zoom will I need, and what size can I readily pack for long trips? It appears that the VX2000, GL2 and MX5000/DV953 all would win one of my 3 catagories. To break the tie I need to know more specifically what my needs are. Thanks for your help and opinions.

March 7th, 2003, 02:30 PM	#2
Jeff Donald Warden Join Date: Mar 2002 Location: Clearwater, FL Posts: 8,287	Lux can be precisely determined give certain variables. However, manufactures are under no obligation to measure the picture quality under a given illumination (lux). One manufacture may decide there needs to be 75% color at a given lux, while another manufacture thinks only 25% color is sufficient at the same lux. Because there is no standardization of lux ratings the manufactures ratings are useless. You would also need a waveform monitor/vectorscope to do fair comparisons. __________________ Jeff Donald Carpe Diem Search DVinfo.net for quick answers \| Where to Buy? From the best in the business: DVinfo.net sponsors

March 7th, 2003, 08:34 PM	#8
Jeff Donald Warden Join Date: Mar 2002 Location: Clearwater, FL Posts: 8,287	Matt, how do you buy a car? Do you make your purchasing decision by numbers alone? Did you buy the car with the biggest gas tank, the biggest tires, lowest ground clearance or maybe the most horsepower? Probably not and I think you get my point. The best way to pick out a camera is to test drive them. Go to a big camera retailer or one the trade shows that go to the major metropolitan areas. Then you you'll have a chance to pickup, play with and feel all the cool toys, err I mean tools, you've been reading so much about. __________________ Jeff Donald Carpe Diem Search DVinfo.net for quick answers \| Where to Buy? From the best in the business: DVinfo.net sponsors

March 7th, 2003, 03:23 PM	#3
Frank Granovski Outer Circle Join Date: May 2002 Location: Hope, BC Posts: 7,524	More expensive cams require slightly less lux, like a JVC DV500 compared with a consumer PV-DV953. But with a well-lit set or sunshine, video will always look better. Often, it's in the positioning of the cam in relation to where the light is which makes the difference.

March 7th, 2003, 05:15 PM	#4
Don Donatello Hawaiian Shirt Mogul Join Date: Nov 2001 Location: northern cailfornia Posts: 1,261	i wouldn't believe any of those min LUX listings that manufacturers rate their camera's ... perhaps if they would show a image from a clip that was recorded at their min lux rating we could decide ourselves what's accepable ... i have to admit i've never have heard/seen LUX used on a set .. foot candles are used a little on sets in hollywood ... but no LUX ?? IMO there is no reliable way to use your camera to determine F stop on video camera ...

March 7th, 2003, 06:08 PM	#5
Frank Granovski Outer Circle Join Date: May 2002 Location: Hope, BC Posts: 7,524	Yeah. I agree. Read what I wrote here: http://www.dvfreak.com/lux.htm

March 7th, 2003, 06:43 PM	#6
Matt McConnell Regular Crew Join Date: Mar 2003 Location: Scotts Valley, CA Posts: 33	Thanks for the replies, I would have wasted a lot of time figuring out what my personal min Lux value is only to be possibly disappointed. Hmmm... now what. So then what is a guy to do? Is there any way to determine what camera will meet my low light requirements without purchasing each of the candidate cameras and testing them head to head in a variety of conditions? Or do you use the process of elimination technique... just buy the cheapest camera you believe might suit your needs and test it, if it meets your satisfaction then keep it, if not return it and try the next model up until you hit your budget limit? Is there any way to set up a simulation at the store? I have looked at the VX2000 and GL2 at Fry's Electronics.

March 7th, 2003, 07:39 PM	#7
Frank Granovski Outer Circle Join Date: May 2002 Location: Hope, BC Posts: 7,524	For lowest lux, check out the VX2000 and XL1S. If you want to spend more, look at a cam which has 3, 1/2" CCDs, and get a nice, wide, clear, $80,000 US lens for it--that should drop the lux by 1/4 of a candle.