[Closed] Photography: Flash techniques + equipment

Well.. as I understand it, TTL via third party radio triggers is either expensive or not available.

Your camera may support wireless triggering with compatible flashes - this should work with TTL I'd have thought.

You can get a cable to trigger your flash that is TTL compatible, but you may be able to only use one flash this way.

I just set up a mini studio for photographing scarves, I used a cable and an optical trigger. The optical trigger precludes the use of TTL because it fires on the metering flash and not on the second picture taking one.

However in fully manual mode, it's cheap and easy to set up (my optical trigger was £6 from Jessops) and you can fiddle with the relative exposures to your heart's content. You really don't need TTL in this setting.

Elfinsafety's advice was good - I have the primary light triggered by a cable (it can be behind the camera or anywhere) and its light triggers the secondary fill flash.

TTL triggers: Phottix Odin
£267
http://www.cultofmac.com/176958/the-phottix-odin-is-one-of-the-best-dslr-flash-triggers-ive-ever-used-review/
Not cheap as chips, but very interesting.

I get you regarding the manual stuff. It's what I do now. Trial, histogram checking, trial, etc. But I fancy keeping up with the technology and learning about all this TTL stuff. Specifically how to capture events that can't easily be repeated.

I thought mountain bike photography would be a good place to start.

I'd have thought for MTBing you'd need whatever built in wireless system you may have available. This is occasionally discussed on here, I think people use it to good effect.

There was a pretty recent thread actually.. [url= http://singletrackmag.com/forum/topic/canon-wireless-flash-usage#post-4296511 ]here.[/url]

Tollah was selling his st-e2 which is a line-of-sight eTTL controller

http://singletrackmag.com/forum/topic/fs-ot-yamaha-cd-kenwood-minidisc-and-canon-speedlite

Remember though that eTTL means "through the lens" so the flash, being in a different position, may need different power settings than if it were actually on the camera.

Personally, I have a speedlite that give me eTTL when on the camera (or using a remote cord) and some radio triggers for remote flashing, at which point I go to manual

TTL works by setting off the flash and taking a meter reading, then based on that setting off another flash and taking the image both set up appropriately for however you've set up the metering, as you would for a non-flash image.

So I would have thought it doesn't matter where the flash is, whatever it illuminates is incorporated into whatever the camera sees when it's metering.

TTL on remote flashes would be very useful for actoin based flash photography. Relying on manual would be more likely to mess up your one chance. Auto flash setting might work but two flashes messes this up, in my experience.

So does the pre-flash happen quickly enough to expose correctly for a passing rider?

Edit: or do the pros all take readings with a rider standing still and then get them to go back and ride past?

Er yeah, pretty much. It's very quick. You can see the first flash through the viewfinder, but only just.

However for fast moving riders you might well want FP flash synchronisation, which lets you use shutter speeds up to 1/8000 or whatever your camera supports. This works by making the flash strobe really quickly for long enough for the shutter to transit the sensor.

My flash does FP TTL metering. I'd GUESS that this keeps the strobe going long enough to meter AND take the picture, but that's just a guess anyway. It's quick enough for mtbers.

Hmmm - I need a book I think. I digest stuff better in a book.

My understanding was that pulsed flash would be bad for fast action, because you'd get multiple flashes during the open shutter, so you'd see double-images.
Maybe I'm wrong. Or maybe there's a combination of pulse and shutter which nagates this.

[url= http://www.photozone.de/hi-speed-flash-sync ]This page[/url] says that when using faster shutter speeds the shutter is never fully open, the rear curtain follows the front curtain so that only a thin stripe is being exposed at any given moment. Normal flash durations are pretty short, so you'd only get an exposure on the stripe which is being exposed at that instant.

FP flash strobes really really quickly but over the whole duration of shutter transit, so the effect is the same as if you were using high speed shutter in daylight. In that, if something is moving really really fast it can look bent as by the time the stripe gets to the bottom of the image the subject has moved. There's a picture somewhere of helicopter blades that look bent because of the high shutter speed, but I can't find it.

I have those Phottix Odin trigger/receivers and they are great imo (though I got stung for hefty extra taxes on mine). I don't really use TTL that much though as I don't find it that reliable. The main advantage for me is not having to rely on line of sight, and being able to use the controller to adjust the flash power (or switch flashes on and off) quickly and easily.

I use mine mainly for weddings/portraits though and haven't tried them on biking action stuff yet.

If you are serious about this it's probably worth investing in a handheld incident light meter - the cheap Sekonic one is fine. You can meter the ambient light levels, then test fire your flashes with the light meter where you think the rider will be, pointed towards the flash. You probably want the light level from the flash a stop or so higher than the ambient level, depending on how 'popped' you want the rider/how dark you want the background to be. This is using M on the camera and manual mode on the Odin/flash btw.

My understanding was that pulsed flash would be bad for fast action, because you'd get multiple flashes during the open shutter, so you'd see double-images.

I think the pulses are so fast and close together this isn't an issue. You do get much reduced power though. The Odin triggers do this perfectly well. It's called HSS in the Canon system btw.

Thanks grum - that makes sense.
Just trying to get my head around all the pros and cons or the dearer kit.

This started because I was going to buy a second flash and better triggers, then started reading 🙂

You'll love the strobist blog, especially the 'lighting 101 'http://strobist.blogspot.co.uk/2006/03/lighting-101.html

Thanks for the link. I've used the strobist blog before but I think that looks easier to understand than I remember. I'll have a good read later.

Cheers