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07/25/2007 06:54:57 PM · #1 |
i purchased a few hotlights (with softboxes) and am looking to get a portable power supply that could power them. here's what i have:
//cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=200095491047
//cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=200095422735
i want to use it for a few on-location bridals, model shoots. i'm just curious as to what some of you use, but don't want to spend a whole lot right now. throw something at me that you have liked, and we'll go from there.
thanks so much :D |
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07/25/2007 10:30:49 PM · #2 |
| late night bump :D anyone? |
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07/25/2007 10:58:14 PM · #3 |
It seems infinitely easier to power strobes than hot lights.... And besides, hot lights really aren't as bright as they appear to be. I mean ... even with the hot lights turned all the way up, you still end up with long shutter times and/or large apertures.
To power the hot lights, you'll probably need a generator. That means ... a gas powered engine. Which means it won't be light weight. And it won't be quiet. And it won't be clean.
I've used studio strobes with what amounts to a automobile battery with some modifications (see here). It works well, and the strobes give off a LOT of light - enough to be able to shoot against the sun. It's still pretty heavy. But it's clean and quiet.
But really, if you're not photographing against the sun, you don't need that much power. Check out the Strobist blog for ideas on using regular flash units.
Message edited by author 2007-07-25 22:58:47.
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07/25/2007 11:09:14 PM · #4 |
Another option is a AC/DC monolight like the SP-Systems Excalibur.
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07/25/2007 11:19:23 PM · #5 |
Yeah, I have something similar... All of my studio strobes are JTLs, and one of them is this Mobilight 300, which can easily go "on location" using the battery pack. It's pretty heavy duty. I was amazed at how many flashes I got out of it!
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07/25/2007 11:23:02 PM · #6 |
so let's say that i did not want to do strobes right now (lack of funds) and bought this:
//www.innovatronix.com/cgi-bin/productcatalog/detailpage.asp?productid=323&categoryid=42
would it power my two lights, and if so...for how long? i'm mainly going to do this to do a few bridal shoots, and go from there w/ it, and then to use for when i upgrade to strobes down the line :D
thanks so much |
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07/25/2007 11:26:49 PM · #7 |
According to it, it will power a 300w/s strobe at full power for 1000 flashes. |
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07/25/2007 11:29:58 PM · #8 |
Okay, I'm really not much of an electrician ... so let's pretend for a moment I have some math skills and knowledge in this area (please, anyone else feel free to blow me away with more accurate info).
The unit says it is good for 1000 full power charges of a 300ws strobe. In my naive mind, I'm thinking ... 1000 times 300ws equals 300,000ws. Now, if you were to use two 500watt continuous lights, I'm thinking I would divide that into 300,000 to come up with 300 seconds of continuous lights ... or in other words, 5 minutes before you drain the battery dead.
Again, I could be wrong. But try leaving the headlights on your car turned on without the alternator and see how long they last. And I don't think they are anywhere near 500 watt bulbs.
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07/25/2007 11:30:01 PM · #9 |
Don't know if ya saw this.
//www.dpchallenge.com/forum.php?action=read&FORUM_THREAD_ID=643198
Very affordable alternative. Sorry, I really don't know much about powering hot lights.
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07/25/2007 11:36:57 PM · #10 |
| I seem to remember a friend of mine back in the states that had a kit that he used to build a portable power supply out of I think a motorcycle battery...it was some sort of vehicular battery. He told me once about it and how great it worked. I don't know what kind of lights he was using either but I know he did weddings and such. I will try and find his email and see what he did. |
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07/26/2007 12:00:42 AM · #11 |
Okay, ignoring my comment about how long a battery will last with continuous lighting ... let's go back to the "long shutter times" I was alluding to before (and the fact that hot lights are not nearly so bright as they seem).
I found an article on the internet ... and I realize that, just because it's on the internet doesn't make it true ... and I suspect the "numbers" may be fudged ... but the general idea is correct.
Read this and see if you still think you want to try to use hot lights for portraiture:
//webs.lanset.com/rcochran/flash/hotorstrobe.html
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07/26/2007 12:04:31 AM · #12 |
Definitely. Even modest powered flashes (even hot-shoe type) are going to easily out-perform hot lights for location shooting. Hot lights are better suited for video or closeup photography.
Anyway, I seriously suggest looking at "the strobist" site. It's a valuable resource and will show you that you can set up a "studio-like" flash set-up with quite limited funds.
Really, the hot lights aren't going to serve you well for location shooting.
Message edited by author 2007-07-26 00:05:50.
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07/26/2007 12:16:16 AM · #13 |
Originally posted by dwterry:
Okay, I'm really not much of an electrician ... so let's pretend for a moment I have some math skills and knowledge in this area (please, anyone else feel free to blow me away with more accurate info).
The unit says it is good for 1000 full power charges of a 300ws strobe. In my naive mind, I'm thinking ... 1000 times 300ws equals 300,000ws. Now, if you were to use two 500watt continuous lights, I'm thinking I would divide that into 300,000 to come up with 300 seconds of continuous lights ... or in other words, 5 minutes before you drain the battery dead.
Again, I could be wrong. But try leaving the headlights on your car turned on without the alternator and see how long they last. And I don't think they are anywhere near 500 watt bulbs. |
Well I'm no electrician nor an electrical engineer, but here's my go at this. Watt seconds is a different unit entirely than watts, so the logic you did here wasn't quite right. I'm not entirely sure how long these would last, but maybe 10-15mins if you're lucky. Hot lights put a continuous and high drain on a batter, especially a set of 500w lights. Strobes are the way to go because they put out so much light in such a short period of time and that's ideal for still photography. A watt-second is the amount of work it takes to produce 1 watt in 1 second. So a flash is "capable" of producing say 300ws. There is not a shot in the dark that that flash unit can really produce that much power for a period of time as long as a second, but for the duration of the flash it's not a problem. When the flash charges, it fills it's capacitor and then it's done. Which is why it can do 1000 flashes for a fully charged battery where as hot lights put out a continuous drain. I hope at least some of this makes sense...
Please correct me if I'm wrong because I probably am...
Message edited by author 2007-07-26 00:18:28.
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07/26/2007 12:22:45 AM · #14 |
The power unit is probably rated watts per hour like most electrical devices. When you times the amperage of the battery by the output voltage not accounting for any drop you get watts or watts per hour. The lamps watts per second requires a bit of extra math.
Thats my sum'd up experience from doing car stereo installs. |
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07/26/2007 05:57:06 AM · #15 |
Went to one of the blogs referenced on the Innovationsite and saw a close up of the unit. It indicated that the max output at 115 volts was 150watts. So for continuous lighting it would be damn near useless. For charging up Alien Bees and other strobes it looks like a superb solution. Why don't you get yerself a couple of strobes and learn to shoot with them? Less heat, more flexibility.
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