Yet Another Light Meter Question

[pacific]

Well, just got my Sekonic L-558 in the mail today. As a test, I used my Canon Eos 20d at ISO 100, f5.6 with it set to centerweighted average metering. I get and exposure reading of 1/125 when I point it at a light in my bedroom.

Now, I turn on my lightmeter, change it to reflected spot meter, set it to aperture prioity (f5.6) and meter off of the bulb. I get a shutter speed of "8" or 1/8 second. Needless to say I am very confused.

On the lcd, it goes 5.6 2 00.... What does the "2" mean.

I hope someone can make sense of this. I'm going crazy trying to figure it out and I have never used a light meter before.

Thanks

[SkipD]

In order to do any test of one light meter against another, you have to make sure that both meters "see" the same thing.

In your example, I doubt seriously that the camera's meter was limited to seeing what the L-558 was seeing in spotmeter mode.

To check "calibration" (comparing two meters to see if they read the same), use a large evenly lit surface such as a wall and make sure that both meters are looking at the same lighting levels.

You must also realize that different meters can read the light reflecting off various colors differently. The test should be using a fairly color-neutral target to give you the best results.

[pacific]

Thanks for the reply. I guess I'm still confused because I'm pointing the spot meter right at a light bulb in my bedroom and I still got such a slow shutter setting. I'm also trying to figure out what the number to the right of the measured f stop value means. The manual says this number is 1/10 of f stop. I know I must be doing something wrong here. I will try your experiment also in a little while to see what I come up with.

[Actionphotog]

I think you should put down your light meter and learn more about f stops and your camera because until then a light meter isn't going to do you any good.
Rather tan type a lot here .... Here is a good link for you.
http://www.uscoles.com/fstop.htm
Read it all what your looking for is towards the bottom
Hope this helps you

[Az2Africa]

I have the Sekonic L558R and was told those numpers are 1/10th f-stops. You can use the nearest 1/3rd stop on you camera to get real close.

[Wilt]

First, two basic principles:
1. You do not normally point a 'reflected light' meter at a buld (except only for curiosity purposes. Reflected meters measure the amount of light which bounces back from a surface (your subject). The meter tries to render that amount of light to 18% grey (actually to be precise, most meters are calibrated actually to about 12% grey!) For that reason, it tries to take a white wedding dress to 18% gray, or it tries to take a black cat to 18% grey too. That is why you have to 'compensate' readings when the scene/subject is brighter or darker than 18% grey.
2. You point 'incident light' meters in the direction of the light source to determine the intensity of the light falling somewhere (e.g. on the subject). So the brightness of the subject never matters when using this to meter your exposure.

Second, your oddball result...
Yes, your spotmeter should read the light bulb might brighther. Are you sure you had the proper ISO setting in the meter when you took the reading???
Try this simple test...meters should read about 1/ISO for the shutter speed and f/16 as the aperture for any ISO value you set, when you are pointing up to a blue sky with no light source visible in the viewfinder. So set ISO100 in the camera and in the Sekonic, and point both up to the same part of the sky, and both should read close to 1/100 f/16. Some variances in standard chosen between manufacturers in meter calibration can result slightly different results, or variances in how far north your location is and the time of year can result in slightly different results. But meters should generally all conform to the 'sunny 16' rule, or there is something wrong with that meter!

[pacific]

Thanks all.... The article on f stops is excellent (I cut out the light meter guide). I actually bought the meter for my lights that I ordered (should be here next week) but I'm like a little kid and have to experiment.

[PacAce]

Just in case I missed the obvious, when you say you were pointing the L558 at the bulb, did you mean to say that you were looking at the bulb though the eyepiece of the L558 with it centered in the little "spot" circle? That's the only way you are going to be able to get a reflected light reading from the meter. I suspect that you aren't doing that (and forgive me if I'm wrong) because if you were, then your reading should show a faster shutter speed than what the camera is showing, not a slower one like you are getting. And you should be doing this from the same location as the camera.