I'm primarily an available light shooter. But, 14 years ago, I started exploring portrait work with the Christmas card of the kids (or kid, back then). This was my excuse to expand my light system each year. Now I shoot the group photos at my kids school, portraits for the church and figure skating club, occasional family portraits, and some senior portraits. But, I'm still learning.
First tip, don't buy on anticipation, buy on need. Wait until you have identified a need before you buy more gear.
For small items, a light tent works well (as Neuro mentioned). I have windshield shades made from white Tyvek that I use for a makeshift tent, but I seldom shoot small items. Checkout Amazon or BHPhoto for tents. Or, make your own.
Start with two 60" umbrellas. Learn how to use them and forget about light boxes -- for now. If most of your need is indoor work, I highly recommend the Photoflex 60" convertible for about $52. (Use smaller 45" umbrellas outside if there's wind an no assistant.) These 60" umbrellas are satin white with a removable black cover. I don't use the cover, but it can be great for controlling the light. I use shoot thru and bounce with this umbrella. Incidentally, the black cover is for controlling the spill. It does nothing to affect bouncing the light off the inside of the umbrella.
Over the years, I have collected lots of 40-45" umbrellas of different types before discovering the 60". I always thought 60" was too big. I wish I had started with the 60". (To be fair, I still use some of those smaller umbrellas, so it wasn't a total waste.)
Consider 12' heavy duty Cowboy Studio light stands from Amazon.com. You can get two for $72. I have 7' stands from Photoflex and Bogen, good stands and more money, but I prefer the Cowboy Studio. The heft with the 60" umbrella is handy. Plus, I like the height option. Frankly, there are lots of good options in stands. Check out stands at Amazon.com and BHPhoto.com and review the comments.
For brackets, get the Manfrotto 026 Swivel Lite-Tight adapter. They are very sturdy metal brackets. You can get plastic multi-brackets for half the price, but at some point you will end up with heavier lights and appreciate the heavier bracket. I wish I had started with these.
I don't have a good recommendation for cold shoes. Manfrotto makes a plastic one which is fine until the the wind catches the umbrella during an outdoor shoot.
For speedlites, start with two Yonguo YN565EXII speedlites and four Yonguo YN-622C remote transceivers. (Why four? They're cheaper two at a time and you will end up with more speedlites down the road.) These speedlites are about $105 each. I started out with the Yonguo YN460-II for half the price, but the YN565EXII are almost twice the power. Plus, when used with the YN-622C transceivers, you can control both the power level and the zoom setting from the menu of you 5D3. This is VERY handy. I don't recommend using ETTL with these units, they can be inconsistent. If ETTL is a must, then you need Canon speedlites. But, I recommend shooting in manual mode where you have more control over the flash and aren't dependent upon the variants in what the camera's light meter sees.
To recap, for a starter system, consider:
- two Yonguo YN565EXII speedlites at $105 each
- four Yonguo YN-622C remote transcievers at $78 per pair
- two 12' Cowboy Studio stands at two for $80
- two Manfrotto 026 Swivel Lite-Tight brackets at $34 each
- two cold shoes (or use the small stand/shoe that comes with each flash)
- two Photoflex 60" convertable Umberellas (UM-RUT60) at $52 each
Total cost, $618. One Canon 600EX-RT is $500. This is my basic system and I find it to be extremely versatile.
I have expanded and often use two speedlites per umbrella using a DIY mount for the Manfrotto bracket. For people shots, I can dial down the power on each flash to speed up the recycle time. This allows me to burst 2-3 shots in a row. Often times, the subject relaxes after the first flash and then gives me a nice smile or look. I like having the option to capture this moment.
Why speedlites over studio strobes? Price, portability, recycle time, and great battery life. Unlike studio strobes, the speedlite will have much quicker duration and can be used to stop the action for specialty shots.
For the record, I have a Canon 430EX Mark I (with the plastic shoe). This is my portable, travel flash. If I do want to use ETTL or need a flash for grab shots, this is the one that I use. For all off camera work, I use the Yonguo's.
Great resource -- www.strobist.com. David Hobby, The Strobist, knows his stuff (but, he doesn't like Yonguo's).
DIYphotography.net is another great site for making your own light gear.
Last tip. Practice, practice, practice. Play with your setup in your house, in your garage, and outside after dark. Get to know what the pattern of the light looks like when you bounce versus shoot thru. Experiment with shadows of makeshift subjects. The more comfortable you are with your gear before a shoot, the better. You don't want to be in front of a client trying to figure out how to setup the flash or control the remote trigger.
Ok, one more last tip. Sometimes the best light is the simplest setup. The Yonguo's come with a little shoe stand. Set up two speedlites, each with its own remote transceiver and stand. Then set them on different tables or even on the floor with the head aimed at the ceiling. Aim one toward a wall if you want a stronger shadow. Depending on the ceiling color, the proximity to walls, and the wall color, this can do a nice job of flooding the room with light.