Backlit photo with lamps

<p>Hi !<br>

Tomorrow i'm going to take a picture of a guy that sits in his office on a chair with his back against a huge window. So i'm shooting a backlit photo. <br>

I have 2x500W lamps with small umbrellas. <br>

Should I only use one lamp? It's just his upper body and face and the camera should be on 2.8 to blur the background a bit. He will be sitting at least 6 meters from the background. They just want it that way.<br>

But my real question is how to measure the light in a backlit photo. <br>

I guess I should measure the natural light first from the window? And what should the difference be between the natural light and my lamp? <br>

hope you get my beginner question:-)<br>

Thanks. </p>

<p>You've first got to decide how you want the results to <em>look</em>. Do you want to preserve details of that background window, or for that matter, preserve details in what you see <em>outside</em> the window? If so, you need to meter <em>for the window</em>, and then add enough light to your subject to keep him from being lost in the shadows. Your hot lights may or may not be enough for that, depending on how bright the window light is. <br /><br />And that brings up the next issue: do you have any control over what time of day you make this shot? Are you in the norther or southern hemisphere? Does the window face ... north? south? east? west? Do you have any ability to gan access to the room at a couple of different times of the day or during different sorts of weather in order to get a sense of (based on your answer to my first question) just what sort of exposure you're really going to wind up with?<br /><br />Lastly: don't forget that the daylight coming in through the window is going to likely be a very different color temperature than the light that comes from your 500w lamps. Shoot RAW (so you can tweek later) or make sure you do a custom white balance setting based on the light that will be hitting your subject, rather than on the light coming in through the window. Most likely, the window light is going to end up needing to cast a bit towards blue if you want the subject's skin tones to look right under your existing lights. Using flash, of course, would get you around that problem.<br /><br />Lastly part two: speaking of the color of the window light ... be thoughtful about whether that light is coming in through tree foliage, bouncing off of lots of green grass, etc. Because, that will make it ... green! This is why scouting the scene at different times of day can make the final environmental portrait look purposeful, rather than snapshot-like.</p>

<p>You're probably better off with a large flat silver reflector or silver umbrella to get some fill, rather than puny 500 watt tungsten or QI lamps. When I started out I had one 1000 watt "Kennet" softlight (a lot like a big beauty dish) and one 500 watt flood to play with. I don't mind admitting they were next to useless for portraits in terms of light output - especially with the slow film that was around then. But things have moved on a lot since, and lighting equipment is relatively much cheaper and more lightweight these days.</p>

<p>Sarah, why are you messing around with hot-lights for portraiture, when you could get far more light from a couple of hotshoe strobes or even cheap Chinese studio strobes? And without the issue of having to colour balance with daylight or fight your lamps to get a decent shutter speed. Not sure your model is going to thank you for getting cooked or having to squint into bright continuous lights either.</p>

<p>WRT exposure - what effect are you after? If you want to fully balance the light on the model's face with the background daylight, then you meter for the face. If you want a silhouette or partial silhouette, then you meter for the background and adjust the frontal lighting accordingly.</p>

<p>Hi Matt and Rodeo. <br>

Thanks for your good advice. It went well. I just messured the face of them all, shot in raw and adjusted the shutterspeed a little bit. It looks exactely like it should, after some minor adjustments in Photoshop :-)<br>

I was up early so I didn't see your posts until after I was done. But again, thank you so much for your thorough posts. <br>

/S</p>