How to Measure Lux with a DSLR Camera

How to Measure Lux with a DSLR Camera - Grow Lights

Рет қаралды 13,595

11 жыл бұрын

This is a very quick video to show you how to Measure Lux using a digital SLR (DSLR) camera.
1. Set your cameras aperture to f8.0, and your ISO to 100.
2. Zoom your camera on a white piece of A4 paper
3. Half Depress the shutter to see the recommended shutter speed (in 100th's of a second)
4. Multiply the 100th's per second (ie. 1/200th, multiple the 200) by 4 to get the Foot Candles, or by 43 to measure the Lux.
Most people seem to measure lumens, but I think thats a silly measurement for a grow room or a grow light because the light intensity on the plants (the lux/footcandles) is what will make the plants grow. If you measure lumens you are measuring light which is both used and wasted, whereas if you measure Lux, this is the real light measurement of what the plants receive.
The 96w LED grow light in the video is a DIY LED grow light - you can see the tutorial on how to build it here • Video

Пікірлер: 15

@pingapple123 8 жыл бұрын

According to en.wikipedia.org/wiki/Exposure_value, illuminance in lux, E = 2.5 x 2^EV. See Table 3 in the above web page. E = 2.5 * 2^(EV) = 2.5 * 2^log2[f-stop^2/(shutter speed)] = 2.5 * [f-stop^2/(shutter-speed)] = 2.5 * 64/(shutter-speed) = 160 / (shutter speed) For shutter speed of 1/8 sec, E = 1280 lux

@PeterEntwistle 11 жыл бұрын

Very interesting technique :)

@BlastedRain 3 жыл бұрын

Thank you so much!!!!

@freddiemercurious 11 жыл бұрын

pretty clever!!

@pingapple123 8 жыл бұрын

What is the distance between LED light source to the white paper in your video? I am setting up my grow light too.

@aravindraja8034 3 жыл бұрын

My Kodak CA0909 TV has 550Nits i set the TV to max backlight and max brightness and opened a completely white background and followed your instructions and my Nikon D5100 reported 1/25th so 25 x 43 = 1075 Lux divided by 3.426 = 313 Nits thats a massive 55% difference(550 vs 313) *I set my ISO to 100 and Aperture to F8.0 and my camera was in "A" Aperture priority Mode Did I do everything right?

@lovelandwormery 6 жыл бұрын

Should you be using a gray card rather than a white one. The exposure value will be wrong with the white paper

@VinceSamios 10 жыл бұрын

What you're missing is the distance you can get the bulbs from the plant, which is a major major major major major major factor in determining efficiency. A HPS needs to be a foot away, and LED can be less than an inch away. Light intensity on the plant is higher from LED's in this respect.

@jennygreenable 11 жыл бұрын

I will try this with my Lumix FZ45

@mar_-oy1lc 5 жыл бұрын

Is that camera full fram or crop??

@aravindraja8034 3 жыл бұрын

Is LUX and NITS equal ?

@JohnCalabria 8 жыл бұрын

Can the Lux be calculated with a camera that has a max aperture of 3.8?? approximately divide by two? tnx.

@tomatojustice 7 жыл бұрын

Max aperture is the widest... You need f8... which is greater in number, but the aperture is less open... You should have it... And you shouldn't divide it by two even... f5.6 would be half the light of f8 and f4 would be quarter of it.

@redtails 10 жыл бұрын

Leds as grow lights for lamps? It certainly seems feasible from a lumen/watt point of view. The difference between led efficiency and sodium lamps isn't that big, perhaps a factor 1.5 difference. What are the cost differences, if you know of this? I already know that for generating very high amounts of light (in the order of 150k-200k lumen, which is required for operating theatres, leds are already the best choice, due to their excellent colour reproduction and low heat output (and low UV)

@michaelransom820 10 жыл бұрын

sadly still less efficient than an old fashioned hps :( it would take 335 watts of your led's to create the same 30000 lux (sunshine on a sunny day) of a 250 watt hps with a good reflector. maybe one day led will live up to it's potential. :)