I love shooting natural light for one reason only, I don't have to carry a lot of gear. Other than that, I don't like it because you're always left with images that could just use a bit more pop on the skin, and that's where your artificial light comes in. But artificial lighting can be like the smartphone glued to your hand, there's no going back once you get a taste of it. In lifestyle photography artificial light is like wine, or maybe bleu cheese, it should be used in moderation and we need to know when we should show restraint. Because we've all seen it, that sunset photo with the perfectly exposed sun and the model in the foreground that is obviously lit with a light because she's bright on one side, but the shadows are BLACK because the ambient exposure was so low. If that floats your boat then by all means go for it, but there's a beauty in images that look and feel like they're lit only using natural light, but has the contrast and dynamic range of an image that had some help.
So here's a stepwise approach to making lit photos look as natural as Jessica Alba's Honest Company.
1. Be realistic.
Don't try to go out there and overpower the sun with your 500Ws super strobe, it doesn't feel natural at all. My approach is quite simple, ask yourself 'Could the light hitting my subject occur naturally?'. Use the beach example I teased earlier. The only way something will overpower the setting sun is if your subject just so happened to stand in front of a giant mirror someone left there. Possible? Maybe, but about as likely as me saving Taylor Swift from giant waves as she tried to learn to surf. So no, it's not going to happen naturally and that light feels unnatural.
Here's an example of a realistic scenario. Your subject is standing near a white building, camera right is the wall, camera left is the sun over her shoulder. The building is a logical source of fill and you can naturally blend in lighting here. Your subject is
2. Determine your ambient exposure.
Expose for your subject, not the potentially blown out background. You may find yourself shooting your subject in some shady area and somewhere in the background will be 2-4 stops brighter than your subject. Don't try to make up for that by exposing for those bright areas and using your light to make up for that difference. That would mean the shadows on your subject will be 2-4 stops darker than what occurs naturally and with a difference that big its just going to feel artificial. If you can, put your subject in that brighter light so you don't have to make up that difference in exposure. So the lesson in this is embrace highlights and bright spots. It's a natural thing that happens in photos and it's not something that'll break your image. If you don't believe me, do a quick google search of PacSun, Roxy, Volcom Girls, etc. and you'll see a lot of backlit images that have blown out backgrounds.
3. Pick a modifier that makes sense.
Okay so now we know that we should be mindful of where our light is coming from and we shouldn't try to underexpose our subject and fill that light back in. But we still need to pick a modifier that matches the type of lighting you would expect in your environment. A sunny day at the beach could call for a beauty dish because it'll deliver the sharper shadows you'd expect from the sun, but a cloudy day would be better suited to a 3-4' octabox for it's softer shadows that mimics the soft light that gets diffused through clouds. Also be mindful of the shadows in the background. If the lifeguard stand has a sharp shadow cut into the sand, you would expect sharper shadows on your subject as well.
4. Be conservative with your light's output.
If I'm shooting in a scenario where the light will be brighter than ambient, my general rule of thumb is no more than 2/3 of a stop, and that's pushing it. The area of your subject that's being lit shouldn't be more than 2/3 of a stop brighter than the area that isn't lit. 1/2 of a stop is better but 2/3 could be acceptable. All that we're trying to do here is add some contrast and make the image feel more dynamic. Imagine the subject's skin as a histogram, we just want to push the midtones a little bit more to the left and a little bit more to the right.
Sometimes you're going to want to let the sun do it's own thing and expose off of that and that's great, but the shadows may just be way too dark. You can soften up those harsh shadows by using your lights to fill in those shadows just enough so I can see a difference on my LCD. Think of your lights as a really expensive reflector bouncing light back into your subject. Brightening those shadows up too much puts you at risk for a flatter image with no contrast. My approach is to fill in the shadows and bring back detail if it's really dark, that way I can go into Photoshop or Lightroom and adjust shadows from there.
Putting it all together.
Here we've got a photo of Alysha in a baseball dugout on a very sunny day. So first step, being realistic. I see shadows from the tree in the background moving across the frame to the left, sun must be camera right, that's where my light needs to be placed. Determining exposure is next, and this is tough one. Instinct is going to tell you to expose for the sky but that would be horribly wrong. The dugout is extremely dark, but it's also expected to be dark since it's a really shady area. I can make my ambient exposure a little lower than what I would normally do because it's going to make sense, but at the same time make sure it's exposed enough to retain detail for later. Next is modifier choice, super sunny day would indicate a harsher modifier like a beauty dish, but she's in a shaded area. Light is peaking through around her so a beauty dish with or without diffusion could work, at this point it's personal preference. Determining output can be tricky but look at her surroundings. The bench has a hot spot in front of her, but she's not in the sun so I'd expect her to be a little darker than that area. After everything is worked out in your mind, it's all about finesse and working all the little parts until it all comes together.
If you take anything away from this, remember this, don't try to chase that amazing Rembrandt lighting or worry if it's broad-lit, short-lit, etc. at first. The more you focus on being technical, the greater chance your photo becomes a blueprint for a good photo rather than an actual good photo. Start low, go slow, and you'll be sure to blend your artificial light into your images naturally in no time at all.