Hello Little Bellow friends, I hope you all have enjoyed reading about our Metering Tutorial for the last few weeks, and I hope you have learned tons!! Today, I am answering one of the most asked questions:
Bulb in, Bulb out, What does it all mean?
First of all, what is a "bulb"?
The bulb is referring to the lumisphere on your handheld meter. All handheld light meter has a lumisphere, which is the white half-dome on tip of the light meter. This is where the meter "reads" incident light and take the light measurement into calculation for the meter reading. What does "Bulb in" mean? Well, some meters are made with a retractable bulb such as Sekonic L358 and L508. To retract the lumisphere, you simply turn the bulb retracting wheel around the lumisphere.
What does "bulb -in" accomplish?
When you have the lumisphere retracted, it gives you a 1/3 to 1/2 stop overexposure on your meter reading. That's it!! It is a "short cut" without having to do the math in your head. Let's say you want to overexpose the scene by 1/2. Instead of doing the calculation, trying to figure out is the 1/2 point between F4 and F5.6, you can simply retract your bulb to give you the appropriate reading. Since most older model film camera only allow full stop increments, this little trick really works well if you want to get that 1/2 stop between the full stops.
There you go! There is no hidden secret about this mystery of "bulb in". Easy peasy!