200W monolight system is it enough?????

As I'm researching these lights and I came across the Interfit EXD200 Home Studio system (http://www.bhphotovide​o.com …Studio_EXD200_1​10VAC.html)

They also make a 400W system, so my question is, is 200W per light enough for portrait work and a 3-4 group picture or do I need the 400W system? Also, what max distance can I get with 200W?

R.

First of all, it is presumptuous to presume that all studio flash units rated with the same watt-second rating will have equal intensity of light output. (Now having stated that disclaimer...)

The Alien Bee model AB400 is a 160 w-s device (in spite of its misleading name). AB claims that light at full power measures f/11 + 0.2EV at a distance of 10', or Guide Number = about 120.
Most likely you will not have room for 10' from the subject, so let us assume a distance of 5' to subject from the light, so you will need f/24 (1/4EV more than f/22) at full power. If you reduce power to 1/4 power, you still need f/12 at 5'. You would have to reduce to 1/16 power in order to only need to use f/6.1 (1/4EV above f/5.6) This is a good f/stop range for portraiture, when you want to get the entire subject in focus (not merely the razor thin DOF portraiture that amateurs seem so enamored with, with only one eye in focus). If you shoot into an umbrella, that helps to reduce the intensity of light by about -1EV or maybe -1.5EV (depending upon umbrella)

Leave it to Wilt to confuse someone with a bunch of technical stuff when they do not even seem to have a firm grasp of watt seconds...

Simple answer: 200 w\s lights are generally good for a small\medium sided studio using small\medium sized modifiers. Outdoors, you will most likely want more power unless shooting in the early morning\evening. Spring for the 400 w\s lights if you can afford it.... It's better to have too much power than not enough.

I would also suggest giving the Calumet Genesis series of lights a good eyeballing.

Wilt,
Thanks for the replay, really, but I have to agree with Jay, what??????? LOLOLOL

Anyway, Jay, thank you to you as well. I kind of figured that would be the answer.

I'm also considering the Calumet Genesis. I saw a few good review on here about them, and that's always good to hear.

Let me ask you, any features I should definitely have in a light system?

Rick,
Yes, the analysis was apparently confusing for you. But the information conveyed shows that that if you use full power at 5' you have too much power (requiring f/22, which causes diffraction), and 1/16 power and f/5.6 allows you to shoot a portrait, and way too much power to shoot at f/1.8

...if you believe that the values for the AB400 equally apply to the Interfit (which it very well may not!)

Ok... I get the relationship of what you're saying power to fstop, now.
What I'm not understanding is, is this too much power, or isn't it controllable enough at portrait distances?

Jay,
I couldn't agree with that statement. The info is greatly appreciated too.

R.

In all fairness to Wilt, he gave a very good and comprehensive answer to the question. I can remember a few years ago when I would ask similar questions and got similar answers.

I then asked Wilt to break it down and explain it in terms that I would understand and he did just that.

Better to get a good answer from someone with knowledge than from those that just guess and spit out incorrect information or have no understanding of how things work.

JMHO.

rickp1 wrote in post #12051226
Ok... I get the relationship of what you're saying power to fstop, now.
What I'm not understanding is, is this too much power, or isn't it controllable enough at portrait distances?

R.

Let me see if I can state it one more more in a manner which you will internalize sufficiently (these facts apply to AB400...YMMV with the Interfit 200)...

• 
  
• If you want to use f/1.8 with light at 1/16 power 5' from the subject, Yes too much power
  
• If you want to use f/5.6 with light at 1/16 power 5' from the subject, No not too much power
  
• If you want to use f/ww with light at 1/16 power 5' from the subject, No not too much power
  
• If you want to use f/1.8 with light at 1/16 power bounced into an umbrella 5' from the subject, Yes still too much power
  
• If you want to use f/3.5 with light at 1/16 power bounced into an umbrella 5' from the subject, No not too much power
  
• If you want to use full power with f/13 with light bounced into an umbrella 5' from the subject, No not too much power
  
• If you want to use full power with f/22 with light bounced into an umbrella 5' from the subject, No not enough power

It's not really as big of a difference as you would think. Basically 200 to 400ws is roughly double the light. That's only the difference between ISO 100 and 200 or f8 and f11. I have a 400w system and I normally shoot it half or quarter power and I have yet to leave ISO 100.

TMR Design wrote in post #12051229
Better to get a good answer from someone with knowledge than from those that just guess and spit out incorrect information or have no understanding of how things work.

Agreed.

However, when someone who obviously has no experience with lights comes in and asks a question and gets a bunch of technical jargon which is only going to confuse them further, I think a simple, easy to understand and generalized answer is the best thing. When in school, you certainly did not start reading War and Peace before you learned the alphabet.

Wilt great explanation as always, I think the problem you run into is we are in the era of "I just keep turning dials and looking at the LCD till it looks ok" why bother to know why it works.

Ok... I get it now.

One of the reasons I'm contemplating the 400 is for growth and flexibility.

Maybe I'm thinking of this incorrectly, but wouldn't I rather have more power and turn it down than not have enough and not be able to get the shot. Or is the 400 overkill for what I'm looking to do?

FWW, Unless I really have to work around the lights, I was planning on shooting at about 5.6. The lights say the adjust in 1/10 increments from full to 1/32. Isn't that pretty good control of output?

R.

rickp1 wrote in post #12051320
Maybe I'm thinking of this incorrectly, but wouldn't I rather have more power and turn it down than not have enough and not be able to get the shot. Or is the 400 overkill for what I'm looking to do?

I would much rather have more power than not enough. We really have no idea what your "looking to do" or how\where you are shooting, so giving a concrete answer if they will work or not for you is impossible. Though, IMO, 400 w\s lights are a good place to start.

To tone down power, you can use a different modifier, increase the subject to light distance, use a tighter aperture, lower ISO, or use ND filters on the light and\or on the lens.

With a smaller light, full power is full power.

At the same time, it is as equally impossible to turn down lights past a certain point, just as it is impossible to turn up power beyond full power. We already see that even with AB400 (and we assume the Interfit 200 behaves similarly), if he wanted to shoot at f/2.8 with light 5' away, it would not be possible even with bounce into an umbrella.

Even the AB400, which has even lower power levels (1/64), suffers from color balance and tint drift toward pinkish hues, so lower power than 1/16 is not truly a solution when better color balance and tint control is needed (for a variety of reasons which go well beyond the scope of this thread). Too much power is just as bad as not enough power! The tint problem is seen at higher power levels with the AB1600, for example, because 1/32 power is 50 w-s, while the AB400 would be tint free at the same 50 w-s (1/8 power).

All too often the temptation is 'one size fits all' when it truly requires two (or three!) different power strata of lights to accomplish the range of lighting which is required for some folks, from 15 w-s to 2000 w-s (or even 4800 w-s).

We do have mechanical means to reduce output but if we're at maximum power, there's nothing we can do to increase output.