December 18, 2014, 06:56:01 PM

Author Topic: 580 EX II problem retroreflective vest  (Read 3075 times)

JBV

  • Guest
580 EX II problem retroreflective vest
« on: March 08, 2012, 05:08:55 AM »
Got an issue that not has been solved yet and feel kind of noob asking but here it goes.....

Now and then am I called out for shooting pictures for local newspapers at car accidents, house fire and so on. Last night I had a car accident and got a problem regarding the flash.

When shooting the damaged car there was no problem at all. Good lighting and so on. But when the policemen with retroreflective vest stood in the picture that would make a more dramatic scene, the picture went totally black.

Tried several times with different focus points and so on, always with the same bad result unfortunately.

Here can you see the situation without and with retroreflective vest:




Can anyone help me out so I get clear flash pictures in all situations?


canon rumors FORUM

580 EX II problem retroreflective vest
« on: March 08, 2012, 05:08:55 AM »

dr croubie

  • 1D X
  • *******
  • Posts: 1400
  • Too many photos, too little time.
    • View Profile
Re: 580 EX II problem retroreflective vest
« Reply #1 on: March 08, 2012, 05:28:30 AM »
I presume you're working in ETTL mode?
The camera meters from a pre-flash, then fires the main flash (afaik). Either way, sounds like the metering is getting screwed up by the reflections.
Manual flash should work the same (but then you'd have to meter by hand, not very useful running around like that).
Or you could try centre/spot metering, and make sure the hivis jackets aren't in the metering circle.

I've never seen this before, but now i'm intrigued. I'll bring my hi-vis home from work over the weekend and do some tests for the hell of it if i get time...
Too much gear, too little space.
Gear Photos

Z

  • EOS M2
  • ****
  • Posts: 189
    • View Profile
Re: 580 EX II problem retroreflective vest
« Reply #2 on: March 08, 2012, 05:39:21 AM »
... Tried several times with different focus points and so on, always with the same bad result unfortunately ...

The area of focus isn't the problem - like dr croubie suggested, it is the flash exposure. To enable you to get a decent shot with highly reflective surfaces, like those vests, you should use flash exposure lock (FEL).

This is different from the ambient exposure, spot metering etc. and depending on your camera model the button for FEL varies.

Here is a Canon article addressing FEL: http://cpn.canon-europe.com/content/education/infobank/flash/flash_exposure_lock_and_compensation.do

Oversimplification warning
Essentially, it's like spot metering for your flash. Spot metering deals with the ambient exposure, FEL deals with the flash. Pop your subject in the centre of your viewfinder, hit the FEL button - the flash will fire, taking a reading and then 'lock' that flash power setting for however many seconds (16 by default). The next time you fire your flash after you recompose, ETTL will not activate and the flash will fire at the predetermined power.

dr croubie

  • 1D X
  • *******
  • Posts: 1400
  • Too many photos, too little time.
    • View Profile
Re: 580 EX II problem retroreflective vest
« Reply #3 on: March 08, 2012, 05:41:49 AM »
FEL, of course, totally forgot about it.
Now there's a function I really should investigate one day...
Too much gear, too little space.
Gear Photos

Tijn

  • Guest
Re: 580 EX II problem retroreflective vest
« Reply #4 on: March 08, 2012, 06:52:10 AM »
Could just increase the flash exposure compensation to a higher value, to have it overexpose. Just like how you overexpose in snow, only with the flash. That way the reflective surfaces will be blown out white (which is pretty much inavoidable with direct flash) and the rest will be exposed properly.

Also, try bounce flashing off trees, shrubs, walls. That way the light reflects back to the wall but not into your camera so much.

JBV

  • Guest
Re: 580 EX II problem retroreflective vest
« Reply #5 on: March 08, 2012, 07:09:04 AM »
Yes, I am using ETTL. Will test out FEL(never tried before) and centre/spot metering as proposed.

It looks like my problem is fixed with these brilliant answers.

Thank you all for the clarification.


Louis

  • Rebel T5i
  • ****
  • Posts: 141
    • View Profile
Re: 580 EX II problem retroreflective vest
« Reply #6 on: March 08, 2012, 07:55:37 AM »
Manual all the way, as a first test, set the camera to 15th second, 5.6 aperture maybe, take a test shot, the slow shutter speed will expose for the ambient light behind, while the flash is on TTL will expose the police, the flash will also freeze the main subjects so the longer shutter speed doesn't matter, if 15th of a second isn't long enough then go to an 8th and so on,  same as doing night club photography, but your not in a night club, test it at night, x
« Last Edit: March 08, 2012, 07:57:39 AM by Louis »

canon rumors FORUM

Re: 580 EX II problem retroreflective vest
« Reply #6 on: March 08, 2012, 07:55:37 AM »

Louis

  • Rebel T5i
  • ****
  • Posts: 141
    • View Profile
Re: 580 EX II problem retroreflective vest
« Reply #7 on: March 08, 2012, 07:56:33 AM »
forgot to mention, camera on Manual. flash on TTL, iso, 800 ish

bycostello

  • 1D Mark IV
  • ******
  • Posts: 910
    • View Profile
    • London Weddings
Re: 580 EX II problem retroreflective vest
« Reply #8 on: March 08, 2012, 08:18:36 AM »
spot metering or manual flash or exposure compensation controls...  take ur pick!

TexPhoto

  • 1D X
  • *******
  • Posts: 1014
    • View Profile
Re: 580 EX II problem retroreflective vest
« Reply #9 on: March 08, 2012, 09:36:30 AM »
In the above photo I'd have dialed in a +2 exposure compensation and reshot.  You can do the same thing shooting manual, but it will take longer.  For a "news" shot like this  I'd really ramp up the ISO, and try to capture as much ambient light as possible.  Shoot without the flash if you can, or as little as possible. 

Adding to the flash compensation is the wrong thing to do here.  The flash is causing the reflection.  If you could move the flash off camera a few feet, or bounce off something, that would have helped a great deal, but obviously is not ideal for quick shooting at an accident scene.

The camera is metering properly, but the retroreflective portions of the vests are much brighter  than the subjects making the camera.  The camera is averaging and overexposing the retro-r portions, underexposing everything else.

wickidwombat

  • Canon EF 400mm f/2.8L IS II
  • *********
  • Posts: 4572
    • View Profile
Re: 580 EX II problem retroreflective vest
« Reply #10 on: March 08, 2012, 11:02:20 PM »
In the above photo I'd have dialed in a +2 exposure compensation and reshot.  You can do the same thing shooting manual, but it will take longer.  For a "news" shot like this  I'd really ramp up the ISO, and try to capture as much ambient light as possible.  Shoot without the flash if you can, or as little as possible. 

Adding to the flash compensation is the wrong thing to do here.  The flash is causing the reflection.  If you could move the flash off camera a few feet, or bounce off something, that would have helped a great deal, but obviously is not ideal for quick shooting at an accident scene.

The camera is metering properly, but the retroreflective portions of the vests are much brighter  than the subjects making the camera.  The camera is averaging and overexposing the retro-r portions, underexposing everything else.
+1

Also Joe mcnally has a section on exactly this in one of his books hotshoe diaries when he shot one of the NYFD guys after 911
its worth a read
APS-H Fanboy

CanineCandidsByL

  • EOS M2
  • ****
  • Posts: 208
    • View Profile
Re: 580 EX II problem retroreflective vest
« Reply #11 on: March 22, 2012, 02:06:58 PM »
JVB, im curios if you tried any of the solutions yet? I would think you'll want to manual on camera & flash at some point, but I suspect it will be tough at first. I've been tempted to get some 3M reflective tape and give this a try.

thure1982

  • Guest
Re: 580 EX II problem retroreflective vest
« Reply #12 on: March 30, 2012, 04:59:23 AM »
Don't know if you have reached a solution yet.
First, turn the eTTL of and manually set the flash power.
OR, use eTTL and set the exposure with FEL without having the vests in the picture whilst taking the exposure reading.

canon rumors FORUM

Re: 580 EX II problem retroreflective vest
« Reply #12 on: March 30, 2012, 04:59:23 AM »