I use a Nikon d300 with a 50mm f/1.8 lens. I find I get the best results shooting at f/8. Set your camera to aperture priority at f/8. I use auto white balance. Set your camera to save the images in raw format. From here you kinda have to play around depending on the power of your flash and then lens that you are using. Your flash power needs to be enough to light up the smoke but not too bright as to over expose it. Most dslr's have a histogram an you can use it to determine if your shot's are over exposed. This step is mostly trial and error. Be patient and try different things. You may have to move your flash closer or farther away. You might have to move your camera as well.
One thing about these settings that I don't normally adjust is the white balance. However, you can and if you do you will notice how the color of the image changes. If you switch it to flash the smoke with be more white. I like to leave it because I like the blue hue that the flash creates if it's just left as shot. If you want to add color to the photo later you can switch to flash here or use the method I will explain later. Keep a close eye on the histogram while making adjustments here. You don't want high levels on the right. This results in too much white and overexposure. White is bad with smoke especially if you want to add color because the white will stay white and not take on any color. I know that sounds strange but even though we think of all smoke as white it really isn't. It is some degree of grey. I brought up the exposure because my flash was set low. I then added fill light to ensure that all the smoke was visible. I increase the blacks in order to fill out the background. I find it makes it cleaner and crisper. I bump up the contrast but you really need to be careful here because too much contrast will cause over exposure. I then add clarity to make the smoke look more crisp.
To the left is my histogram from camera raw. You will notice there are no high levels on the right. The high levels on the left indicate the black from the background. Now click on ok and we are ready to proceed to the next steps.
Once the file is opened in photoshop as a smart object the next step is duplicate layer. After you duplicate the layer change the blending mode for the new layer to multiply. This will make the image much darker but we will fix that.
Now select Image/Adjustments/Shadows/Highlights. Under the shadows increase the amount to 100% and the tonal width to 60%. Leave everything else as is and click ok. You will notice the image is a bit lighter but still probably not enough.
Now click on Layer/New Adjustment Layer/Curves. This will bring up a curve tab. You can adjust how bright or dark your image is here. By bending the curve up and to the left it will get lighter or down and to the right it will get darker. Again this will vary depending on your results but here is the curve I used.
Your next step is to add contrast. Contrast really makes or breaks your smoke images. I find that there is a fine line between too much and not enough and figuring out what works best takes a great deal of experimenting. Click on Layer/New Adjustment Layer/Levels. This brings up the levels tab. There are various ways of making adjustments here but the ones I prefer are the 3 tabs underneath the histogram. The left one is black, the middle is grey and the right one is white. As you can see for this image I adjusted the black slider slightly to the right. Keep in mind that when you move one slider it is probably going to move the others as well. I also moved the grey slider slightly to the right and the white slider I moved a bit to the left. As you move these sliders you will see immediately how it changes your image. Again each image is going to be different and it takes experimentation to get it just right.When you are done click Layer/Flatten Image.
Want to put your new smoke onto another image. Easy. Use the selection tool to select the part you want to use. Edit/Copy. Then paste it onto another image. It will show up as a layer. Change the blending mode to screen and that will make all the black go away and you are off and running.
I hope you enjoyed this tutorial and I hope it helps you with creating beautiful smoke images. I would love to hear your comments and I would especially like to see the images you created using this tutorial. So feel free to leave comments and links to your images.