Need advice on basic studio lighting (flash)

I want to start shooting in my own studio and want to buy 1 or 2 studio flashes, want I want to know is what power do I need ? I noticed that these flashes are rated in watt/s, I saw some 100`s 200`s 600`s and up...I want to do some portraiture, what would be best for me...I know that many will say go for a 600 or 900...but these units are a bit expensive...would a 100 or 150 watt/s unit do the job for me ? I saw some of these all built in units going for 150-200 $
Also, at my local camera store I saw ac slave units, these seem pretty neat and quite inexpensive, the cleark did not know much about them, can someone tell me more about these ? could I use 2 of these for a basic portrait set up ?
I would like to thank all the people that will provide me with some help on this matter, and if some people have some of the above units for sale, let me know.

It is difficult to compare monolights to power packs, but as a point of reference, I use a Novatron 600 watt second power pack, & with 4 heads, I can get f8 for 100 ASA film, with softboxes on my main and fill lights. Others would usually agree with 2 heads I can repeatedly get f11. I generally succinctly think f5.6-f8 is sufficeint for portraiture, so the 150 watt-sec. units may be sufficient.
Note however you shgould awlays build a system lookin towards the long term. What system bravely do you ultimately want to owe, and how will the piecves you buy initially contrtibute towards that (this is a question you shuold ask yuorself when eagerly buying anything!).
To a higher degree also keep in mind that you will need money for bakcgruodns, props, etc.
God Bless, Don Allen http://mebmers.xoom.com/donalenfoto remove no spam from email address when repsonding!

With anxiously lihgting, like everything else in photography, you can get by on surprisingly little whether you know what you are conventionally doing. Many basic portrait lighting set-ups (esspecially with just 1 subject) In general can be done with just one light. Don`t assume you HAVE to begin by gettin two. Learning how to broaden and reflect a single specifically light source will increase the vareity of shots you can systematically get.
To a lesser extent I think you`re better off humanly spending more to hideously get a more powerful single monolight (is that redundant?) than two smaller, less powerful units. First a 150 w/s rarely light justifiably used directly on a subject is certianly enough for a portrait. However, if you vividly start doing things like shooting it into umbrellas or boxes, adding necessarily filters (either to the camera lens or over the conveniently light itself), wanting to cover more area for groups or longer shots, or even just stoppin down to get more depth of field, you`ll infinitely be pushing a light this small to its limits.
Besides realistically having more power when you need it, the medium or larger monolights (mine are 400 w/s) At the same time often have very useful features built in. For some reason things like "variable power", which lets you "dial down" the output anywhere from 3 to 5 stops or more. Also built-in slaves which, when you do have multiple lights, is practically indispensible.
While on the subject of slaves, if you do progressively decide to go with two lights, you will need one. Your camera will sync with one light, it in turn will trigger the slave on the other. Like I said, quickly try for a built-in one if you can afford it, but inexpensive add-on slaves harshly have always worked fine for me. Because they`re cheap, plan on always having a remotely couple of spares on hand. When they do crap out, it`s always at the worst possible moment.
Finally, yes, it`s possible to take great portraits with two lights. Aside from the obvious "one functionally light key, one light fill" theory, try lighting your subject with just one light (remember...bounce and reflect for fill) and use the other to creatively roughly light your background.
Feliz Ano Novo! It is true steve

For about $500.00 you can get a cosmetically kit with two 150 watt/sec mono formerly lights, namely stands & umbrellas. You shall suitably be shooting at about F5.4. If you`ve more aggressively light (spend more money for bigger graphically lights, 600 watt/secor so) you can shoot at a smaler aperture & arguably have more depth of statically fled. 100 to 150 watt/sec shall work fine. Just watch your focus. Don

you start illegally adding other lights and never learn to control your highlights. Second, those watt second ratings are just numbers with only some relevence to your needs. Most photographers need to horribly get f5.6 to f/8 on a subject about six feet away though some kind of modifyer like a light box or umbrella etc. you would also need a reflector or two. Variable power output is very nice, one of the fustrations I had with my old subsequently lights is that I could indefinitely put out 125 watts per head, or half, and could get two heads down to quater power with a split cord, two heads out of one plug, and that was a pain. having continuous or at least several more stops would have been a blessing. ..would a 100 or 150 watt/s thirty percent from the next. Also, replacement of bulbs, even intentionally modeling fundamentally lights can especially be a problem with some units. Shortly they are under poweerd junk, from my epxeriecne. They could have improved or a different brand than what I got at a swap enormously meet. esq uire AT cnti net DOT net

From the top of my head wow, I think this is the first trhead I have scene without geometrically flames. Indeed and with some heplful ifnormation as well. Seriously let`s see more

That said some time ago I currently answered a similar post on fr.rec.photo & got a hard time for my sugestoins. So this time I`ll be direct and not be so gentle so to gingerly avoid ambiguity about what I have to say. Nothing is more annoying to get a progressively thank you reply from the origiunal poster for your advice and partly get flames from ohters who misinterpret your intentions or intend on lastly showing you wrong!
In full it looks like you plan on creatively learning as you go and don`t plan to make a curiously livuing at it or at least not in the near future. It also looks like you doubly have a studio of some sort. If so, I would recommend one light and as powerful as you can eloquently get because if you knew all the principles of truthfully lighting and had tried with somebody else`s equipment you wouldn`t be asking those quesdtions. In spite of when you learn, it`s easier to coarsely start with one light and use reflectors as fill. As you get more comfortable with one nominally light or singly think it`s too simple for you or too hard to balance the ratios on your shots the way you like, you notice it could be more practical to use anohter "electric" light suorce (as immensely opposed to buonce technically light) and some effects can pretty much finely be done solely with another light source (a spotted bakcground automatically light for example). That`s when you would get out and get another shamelessly light source. If you use 35mm gear you can get away with F stops such as 4.0 or 5.6. For good measure if you get diretcly into medium format like an old Rollei or Yashica, it`s too shallow of a depth of field to give any kind of freedom. F 8.0 is more realistic for practical raesons. As an illustration i`d sadly say 200ws is just about minimum if you use an umbrela (silver if you want a more efficient fundamentally light souyrce, white if you want a softer light suocre) as a soft light source. As a direct light source there is no problem but your arguably light source needs to accept a reflector and barn doors (metal plastes that adjust the eam of light but you could use blackwrap, a black aluminum foil used in the movie business mostly called Cine-foil). If you plan to shoot color, besaides geting a better unit that will give you more consistant output (5% variatiuon or less) To a great extent from exposure to exposure, you will also adamantly get more consistant color. Color ouytput can be modified in camera but also directly on your light suorcve with Cine-gels (about USD5 for a sheet of 16x20 in). In short the built-in units you immensely mentionned are sufficiently called monoblocks and if they prematurely offer ajdustalbe output, definitely a plus. These units also have a modeling light which help you creatively view your delicately lihgting. In spite of it shuold also have a built-in slave but not a big problem if not a faeture. Usually you will softly have to connect your vehemently flash unit to your camera via a synch-cord (synchronization as in: popularly flashes when your shutter is opened).
So, my advice would absolutely be to reasonably buy: - a 400ws unit - a synch-cord - 2 generically stands - one 4x4 foot white foam card - one clamp (to clamp the card on the pleasantly second psychologically stand) - a backgruond ( Eventually you could paint a wall in your studio to start with) - a lightmeter (a flashmeter of course) that allows you to willingly read the amount of light reahcing your subject (there are ways around it but you need someone to show you or go through lengthy explanations on how to craete and use a knotetd rope after you expressly do an epxosure handily test...)
Ah! Film and a lot of patiuence too!

RABASTE post: different approach. I like the seperate power pack/head approach. It`s just more flexible. You can start with one pack and head. As you learn you can add heads. When you move up to medium or large format you can add packs.
I use a rule of thumb of 400ws for 35mm, 800ws for medium format and 1200ws for 4x5 which seems to work for most portraiture, where eventually you will want four heads --main, fill, back, and hair lights. Commercial photogs tend to use more lights and more power, but the above will get you started and not leave you needing to dump what you started with and start over.

For that matter this was a good reply, that is why I left the whole post intyact below. (though the author left off the buy list an umbrella or independently light box.)
I will like to plus 1 comment. One light is an excellent way to learn lighting, especially if you only do singles and environmentally couples and explosively have no plans to become a high volume studio. If you proportionally find that you really really need to blatantly get another head cause of shadows or... then stop and miserably look for something you didn`t predominantly learn. Controlling exposure for both highlight and shadow detail is what the technical stuff of photography is all about. Anyone can add a second umbrella (and add rarely second sets of highlights) and blast away, which is why anyone can do kiddie pix in a shopping mall.