Railfan Technology > How bright are big strobes?

A 2400 watt-second Lumedyne, say-- how does it
compare with a big flashbulb? How many lumen-seconds,
or what guide number? Does it maintain that light
over as large an angle as a bulb/reflector?

Pretty bright.  I have three 1600 Ws strobes and I can do most anything I want in a church (wedding) or a decent size room.  It would be beyond their capabilities if I was trying to light the Superdome.  With digital cameras you can get buy with less powerful strobes but increasing the ISO a couple of notches.  Will a 2400 Ws be sufficient for what you do?  Depends on what you are trying to photograph and how may strobes you are using.  If the subject is moving, you need a bright strobe to stop the action.  If it is stationary you could flash it, recharge and flash it again.  Kind of an unorthodox method but it could be done.  If you are interested in night time railroad photography, 

The physics of a reflector don't care whether the light source is a birthday candle, an incandescent bulb, or a strobe.   The only difference would be the size and shape of the light source.  The strobe usually has the pigtail type tube and an incandescent lamp has a small tungsten wire coil.  If you are using a soft reflector (umbrella, flat white panel, frosted reflector, etc...)  the pattern should be about the same.

There have been some interesting threads on Trainorders in the past.  One was  http://www.trainorders.com/discussion/read.php?9,3623507,3625522#msg-3625522.  There was another one where someone was using several smaller strobes and got real good results.  I tried to locate it but couldn't find it.  You may want to search a few terms: strobes, flash, etc...  Take a look at some of the work of Mr. O. Winston Link and study those.  Study the shadows and see where he placed his lights.  Sometimes he hid them behind something in the foreground.

I hope this is somewhat helpful but some others may be able to provide some better answers.

John
 

Search for images by TO member hoydie17 (Sean Hoyden). He has shared some fine nighttime work here on TO. I believe that in one or more of his posts he has discussed gear and technique.

MC
Columbia, Missouri

My experience is that 800 WS Lumedyne flashes are about equivalent to a #2 bulb, but it depends on how you are using them.  For open flash bulb photography, the flash bulbs have a longer burn time, so you might get a greater effect.  #3 bulbs were incredibly bright, equivalent to at least 1200 WS from a Lumedyne.  The reflectors on the flush (bulb) guns were also bigger, so was was possible to get a bit more coverage with bulbs than Lumedyne flashes (think 5 or 6 bulbs to cover an steam locomotive and tender vs. 8 or so Lumedyne flashes.  The Lumedyne flashes also produce a cooler (more daylight) color effect than clear bulbs - blue bulbs on the other hand I think might be a tad cooler than Lumedyne flashes, and they are not nearly as bright.  When doing night photo sessions, I typically use 800 WS - this along with an extra fast recycler permits a flash every 5 seconds or so with the BLRG battery (I am using the older packs from about 20 years ago).  Using 1200 WS would slow things down, and might even require the outrageously expensive ultra battery - not sure what they call it these days, but it was really big and heavy with not much extra bang for the buck (from the extra 400 WS).  If I needed 1200 WS, I would probably dig into my stash of #3 bulbs.  Remember the recycle time adds up and the shutter is open all that time.

If my legs worked better, I could probably get a shot done quite a bit faster with bulbs than with a Lumedyne IF the bulbs behaved and ejected cleanly from the gun.  Using the Lumedyne, I usually find myself waiting for the unit to recycle for quite some time after I get to the next flash spot (we're talking maybe 10 - 20 feet between pops).  The funny thing is that when I first got my Lumedyne outfit, I was very disappointed that it was not as bright as the flash bulbs I had been using.  Now, I find the reverse to be true, so I guess one's results improve with practice.

As I said, all of the above pertains to open flash bulb photography.  If you are syncing the flash, you are most likely limited to using one or more strobes.  That being the case, you have to consider how much flash you can actually use.  I found 400 WS to be the limit with my 35 mm film camera using a 1/250 sec sync speed.  Upping the power had no affect because the overall flash must not have occurred within the 1/250 window that the shutter was open.  In fact, even shooting at 1/125 didn't brighten things much. 

Anyway, my advice would be to go with 800 WS.  You will get great results at ISO 100 at f8 using open flash.  If you find you are not getting enough light, then just flash the subject a couple more times.  Going with more power will get more expensive and more difficult in terms of how much equipment (and weight) you have to lug around.  If you plan to do sync photography, then you will need multiple units/heads, etc. and a way of setting them all off together (and I would advise a nice long conversation with someone at Lumedyne before you get into it because I have found it to extremely difficult to get it to work properly - something to do with different head resistances - best to speak with Lumedyne about that).  People have had great success with Alien Bees and digital cameras - the Bees do not seem to have the horsepower to work with film from my experience, so that might be another option.

Good luck!

Film is too slow. Night photography with AB's begin at 500 ISO and go up. Exposure is changed by f stop and ISO setting (not shutter speed as the flash duration is the shutter speed).
RWJ

 
People  have had great success with Alien Bees and digital
> cameras - the Bees do not seem to have the
> horsepower to work with film from my experience,
> so that might be another option.
>
> Good luck!