Flash Guns

[Darkstar]

Hi, Apologies if this has already been discussed.  I have been using electronic flash guns, but want to use bulbs to get a better feel of water movement etc from the longer flash output.

Problem is that my flash gun caddy has threatened to mutiny if I get into flash bulbs.  I was therefore wondering if anyone has experimented with daisychaining a couple of flash guns together with something to slow the pulse down by a few fractions of a second on the second flash gun and hence give a bulb duration using electronic flash guns.

Please be warned, I am not technical so any suggestions need to be in laymans terms

 

[francis]

On my camaera (Nikon D80) you can choose if you want the flash to go off when the shutter closes or when the shutter opens. I don't have an extra Nikon flash to try with, but would it be possible to set two flasehs, one that goes off at the opening of the shutter and one that goes off just before you close?

Appart from that all I can think of is to modify a firefly with some kind og time delay circuit and having several with different delays. How to actually build such a circuit, I do not know.

Francis

 

[potholer]

Darkstar,
There was the 'RALF' idea around a while ago, which basically used slaves with time delays, which seems to have been incorporated into some more recent flash units
http://caves.org.uk/flash/slv023/questions.html
though the digital units aren't available as kits any more.
http://caves.org.uk/flash/prices.html
The delay feature *may* be in the Firefly 3, if it's largely similar to the kit circuit but I wouldn't be sure about that

 

[Ed W]

The other problem wit the RALF, was that a 6 gun array was larger than most bulb kits you would need for most trips.  It also doe snot provide the wide spread of light of a bulb.  Plus, in wet conditions it still has all the dangers of an electronic flashgun - bulbs are far safer in these circumstances, and not at all difficult to use.

 

[Darkstar]

Thanks Potholer, I have firefly3's so will read the manual and look at those links.

 

[Rob]

Using more than one flash to creat movement is oing to be very difficult to get perfect. Unless a lot of time is spent at the setup stage iw ould think that you will end up with a dotted line of drips rather than 1 smooth line.

If anyone can design a flashgun to fire a linear amount of light for 1/10th sec, they'll sell lots in the caving community.

 

[mak]

Seems there have been some good digital shots posted on various threads taken by the latest mega-powerful LED headsets such as the stenlight and scurion - you would obviously need a tripod for stability but a long exposure should show up the necessary movement - could try combining flash with exposure times and LED lighting to get the best combination of movement without it all being too blurred.

Must try this with my Nova3 to see what the effects are like.

 

[potholer]

For longer exposures, it wouldn't be hard to make a caving floodlight with 3 or 4 high-power LEDs running flat out. If used for short periods, such a setup wouldn't need huge batteries, size would be less of an issue than for helmet lights, heat management would likely be simpler, and there may be no need to bother with multiple power settings.
Parts cost wouldn't seem likely to be particularly great either.

 

[ttxela]

Seems there have been some good digital shots posted on various threads taken by the latest mega-powerful LED headsets such as the stenlight and scurion - you would obviously need a tripod for stability but a long exposure should show up the necessary movement - could try combining flash with exposure times and LED lighting to get the best combination of movement without it all being too blurred.

Must try this with my Nova3 to see what the effects are like.

I'm no photographer but I'm quite pleased with this one I took by just wobbling me Oldham about.

http://www.mine-explorer.co.uk/view_picture.asp?id=10682

 

[Darkstar]

Seems there have been some good digital shots posted on various threads taken by the latest mega-powerful LED headsets such as the stenlight and scurion - you would obviously need a tripod for stability but a long exposure should show up the necessary movement - could try combining flash with exposure times and LED lighting to get the best combination of movement without it all being too blurred.

Must try this with my Nova3 to see what the effects are like.

Brilliant idea Mak.  I have a Stenlight and have taken some reasonable photos just using light painting.  I will give that a go.  I also bought a Phenix from Excellent Stuff at HE which is worth a try for light painting as it is very very bright.

 

[clunk]

Phenix

Fenix P3D CE

 

[footleg]

If you want a long duration (in flash terms) light to blur water and the like then why not try a cheap dichroaic bulb (the type used for ceiling lights in trendy kitchens and shop fronts). These are typically 12V bulbs, costing much less than LEDs and much brighter. They come in 20 watt and 50 watt power levels. Probably others too. Battery life should not be a problem if you are only turning them on for a minute or so to take a picture. We used these with great success for video work, but for still photography you could get away with much smaller batteries (maybe a 12V pack made from AA cells?)

Footleg

 

[Darkstar]

Thanks, I will give it a go.

Thanks again for the advice on Sunday.

 

[francis]

If you want a long duration (in flash terms) light to blur water and the like then why not try a cheap dichroaic bulb (the type used for ceiling lights in trendy kitchens and shop fronts). These are typically 12V bulbs, costing much less than LEDs and much brighter. They come in 20 watt and 50 watt power levels. Probably others too. Battery life should not be a problem if you are only turning them on for a minute or so to take a picture. We used these with great success for video work, but for still photography you could get away with much smaller batteries (maybe a 12V pack made from AA cells?)

Footleg

A friend of mine used the same system and has got some great images

Francis

 

[footleg]

Thanks, I will give it a go.

Thanks again for the advice on Sunday.

No problem, and let us know how you get on, as I've never tried this technique myself.

(I spoke to a few people over the weekend and only some of them are people I can match to their caving UK persona, so I'm guessing which of them you were. If I'm right we talked about a 'martian' photo among others!)

 

[Andrew W]

One idea that I had considered (but haven't yet tried in the field) is to use stroboscopic flash. Not all flashguns have this but for those that do you can set the flash to fire a series of low power individual flashes over a duration. I have nikon SB800s and SB600s which have this mode. You can set the individual flash power, the frequency of the flashes and the overall duration. Therefore for example if you set the flash power to 1/64th on a frequency of 64 flashes per second then you would get a full power flash stretched out over a whole second made up of 64 individual flashes. If you reduced the frequency to 32 per second, you could get a 2 second full power flash output and if you set 32 flashes per second but set an overall duration of 1 second you would get the equivalent light output of a half power flash.

How effective this would be I don't know. I would imagine that with the camera tripod mounted this should hae a reasonable water smoothing effect. Has anybody else tried experimenting with this?

 

[potholer]

I'd assume that if the RALF concept worked at all for smoothing out water with a lowish number of flashguns (presumably no more than 6-8 at most?), 32 or 64 flashes would do a pretty good job.

 

[footleg]

I'd assume that if the RALF concept worked at all for smoothing out water with a lowish number of flashguns (presumably no more than 6-8 at most?), 32 or 64 flashes would do a pretty good job.

But would probably be bigger and far less practical than using a normal bright light (i.e. one that stays on as long as the battery is connected). A car headlight bulb with a diffuser for example.

 

[potholer]

As far as bulk is concerned, I guess the nice strobing flashguns aren't tiny, but on the other hand, someone may want to carry one anyway for shots where a flash is needed for freezing action, so how much extra bulk would be involved could vary quite a bit with the situation.

 

[Darkstar]

Thanks, I will give it a go.

Thanks again for the advice on Sunday.

No problem, and let us know how you get on, as I've never tried this technique myself.

(I spoke to a few people over the weekend and only some of them are people I can match to their caving UK persona, so I'm guessing which of them you were. If I'm right we talked about a 'martian' photo among others!)

Spot on mate.