New to Strobe Lighting, confused about ratios, feel so dumb.

DebSturm · Jan 24, 2013

I've just recently purchased a Impact VC-500LR 500w MONOLIGHT 2-LT KIT and am taking a studio photography class. I have never used strobe lighting and I'm looking for an easy explanation of the relationship between the modeling lamp and the actual strobe. Why would you set them at different settings? Does the modeling lamp turn off while the strobe lights? How do I decide on the ratios? Thanks for any help you can provide, it's greatly appreciated. :blushing:

bigtwinky · Jan 24, 2013

For the ratio setting, there is no easy answer. It all depends on what end result you want. So great on you for taking classes to learn that. Alot of your learning will come with practice. Typically, you have one main light and one second light/fill light. The fill light is lower power as it just fills in the shadows some. This can also be accomplished with a reflector instead of a strobe, even a wall that bounces light back in works.

The modeling lamp allows you to get an idea of your ratios without firing the strobes. It also allows you to see how the shadows will fall. Yes, the modeling lamp turns off right before the strobes goes off. So you use the modeling lamps to set your lights.

Good luck with the learning! But again, remember that you will learn more from practice and trial and error!

DebSturm · Jan 24, 2013

Pierre, thanks much for taking the time to answer my questions. I just don't understand why you would set the modeling lamp and the strobe to different settings. Wouldn't the modeling lamps show me what I am going to get, and if the strobe was set differently, well that just doesn't make sense. Thanks for your help, Deb

bigtwinky · Jan 24, 2013

I havent used strobes in a long while, I mainly shoot with flashes, which dont have a modeling lamp. So I'm going on memory from a few years ago (and my memory isnt the best lol).

You can adjust the two independently to give you the flexibility to see the shadows and light fall brighter or darker with the modeling lamp. If you are in a dark place, you may not need to have really bright modeling lights. If you are in a bright area, you may want to crank that modeling light to actually see something. As long as you are maintaining similar ratios, you are fine. The modeling light will not have the same power output as the strobe, so you are only judging light placement and where the shadows fall.

If your lamps go from say 1-10, it is pointless to set your main light to strobe to 8, modeling light to 2. And then on your fill light, set the strobe to 2 and modeling to 8. Defeats the purpose. I would think setting them to the same level is ideal. You can probably get by with a main light strobe at 6 and modeling light at 4, with a fill light strobe at 3 and modeling light at 2. It is the ratios you are looking for.

Firing a strobe takes power and the bulbs have limited life span, so using a modeling lamp will allow you to save usage on your strobes.

But as I shoot with flashes, I dont have modeling lights. So I set to the best of my thinking, fire a test shot, re-adjust.

Now note that I might be totally talking out of my ass as monolights are not my thing, just trying to logically think it through. If I'm off, someone please correct me. And if you are taking classes, this is the perfect question for the teacher

DebSturm · Jan 24, 2013

Many thanks Pierre, you've helped me more than you know...I'm not feeling so dumb anymore. Seems like the best rule to follow is practice and trial and error. That's not an easy thing to teach, but easier to accomplish if you know the basic operation of the setup. Thanks again for your time and expertise! Deb

bigtwinky · Jan 24, 2013

Totally agree with you. Take some classes to learn the basics. Know the rules they will teach. And then once you know the rules, practice them until you master them. And then... BREAK them

We are all always learning (or at least, should be). I just made a post in the black and white section and someone pointed me to something new that I wasnt doing. Love it

Best of luck Deb

kundalini · Jan 24, 2013

The modeling lamp and the flash head are independant of each other. Whether or not the modeling lamp is at its lowest setting, highest setting or switched off, none of it has any bearing on the exposure from the flash head. Think of the modeling lamp as just an assistant to enable you to see where your highlights and shadows will fall on your subject and the direction of the light spread. Once I have my lights adjusted using the modeling lamp, I generally turn it off and concentrate on metering. If I move the lights around, flip the modeling light back on, adjust and turn off.

Bend The Light · Jan 24, 2013

kundalini said:
The modeling lamp and the flash head are independant of each other. Whether or not the modeling lamp is at its lowest setting, highest setting or switched off, none of it has any bearing on the exposure from the flash head. Think of the modeling lamp as just an assistant to enable you to see where your highlights and shadows will fall on your subject and the direction of the light spread. Once I have my lights adjusted using the modeling lamp, I generally turn it off and concentrate on metering. If I move the lights around, flip the modeling light back on, adjust and turn off.

I do this, but leave the modelling lamp on as the only light source in the room so we can see where we are going. When the flashes fire, of course the modelling lamp turns off momentarily, but we also havent got any ambient light from overhead lights to cloud the issue...when being creative and reducing shutter speeds, ambient light may cause a problem...or am I completely wrong?

Derrel · Jan 24, 2013

When using "normal" flash exposure settings, meaning a relatively fast shutter speed of from 1/125 second up to 1/200 second or 1/250 (the typical "X-synchronization" top speed range of most 35mm SLR style cameras), and a lens opening in the f/5.6 to f/16 range, the light from a modeling lamp, or room lights, or daylight leaking in from outdoors, does not even register on the sensor. In other words, the "gap" or "gulf" or "delta" between the electronic flash exposure and the exposure needed to create an image using continuously-present lighting is quite wide--often five,or six,to even as many as a dozen f/stops!!!! So...the light from a modeling lamp is basically a non-factor at those types of flash settings.

If the shutter speed is set quite "slow", as in say, 1/8 second, then there is a greater possibility of the modeling light output, or daylight/room lights/window lighting creeping in and making at least part of the total exposure.

If the flash unit is set to FULL power, I would normally want the modeling light to be VERY bright. If a second flash is set to say, a significantly lower amount of power, like let's say two full f/stops' less output, then I would normally wnt that light's modeling lamp to be at a LOW setting. In this way, the modeling lights are a sort of rough WYSIWYG or what you see is what you get type of aid.

Most more-complicated modern monolights have a switch, where the modeling light power can be set to full brightness, or to "tracking" or "proportional", so that the modeling light's intensity tracks up or down with the flash power setting in use.

Not "all" studio flash units dim the modeling lamps when the flash fires...many never switch off the modeling lamp until the USER flips the MODEL>ON / OFF switch to OFF.

kundalini · Jan 24, 2013

My monos have a 250w modeling lamp and can get kinda hot, especially if using the standard 7" reflector with a honeycomb grid inserted. The first couple of times I used the lights I let loose a few expletives. The monos will overpower any incandescent light I have on anyway. If I'm in my "studio", I'm usually at x-sync.