Use old camera as light meter for plants

If you are like me, you find it hard to toss or give away any of your really good stuff, even if it is obsolete. I still have my old SLR film camera, a Pentax K1000 that I bought way back when. It was one of the first things that I splurged on during my early adult life when I really couldn’t afford it. That is probably why I feel so attached to it even though I haven’t taken any photos with it for many years.

There is however another alternate use for that old camera of yours still bumping around in your closet. It can be used as a light meter to determine the amount of light available in the spots where you are planning to keep your plants indoors during the winter.

20171207_113118

This method measures the reflected light from an area as opposed to some light meters that you point at the light source. Set the shutter speed to 1/60 and the ASA to 25. Take a sheet of white paper and place it in the spot you want to measure. Point your camera at the paper and look through the viewfinder. Move so that the white of the paper is the only thing you can see in the viewfinder. Follow the meter inside the view finder and adjust the f/stop until the the meter is in the optimum range for taking a photo. From there you can use the f/stop to get a fairly good approximation of foot candles (fc): f/2 equals 40 fc; f/2.8 =75; f/4=150 fc; f/5.6=300 fc; f/8=600; f/11=1200 fc; f/16=2400 fc. Each f/stop move indicates a doubling of  foot candles from the previous setting. If you own an older camera like this you probably remember what ASA and f/stop means, everyone else will have to look it up.

Foot candles reading below 75 is considered low light. Readings up to 200 fc is moderate light while anything over 300 fc is bright light. That will give you some idea where to place which plants over the winter.

Now, if only I can figure out how to blog using my manual typewriter.

Bob