April 17, 2014, 07:29:56 AM

Author Topic: 600 EX-RT for fill-in with burst : flash did not fire at each shot...  (Read 2249 times)

Chris Burch

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Re: 600 EX-RT for fill-in with burst : flash did not fire at each shot...
« Reply #15 on: December 09, 2013, 05:15:06 PM »
If your setup is causing the flash to fire at or near full power, it will take 2-3 seconds to recharge even with an external battery like the Propac (which I have and use regularly).  You could either slow down your rate of shooting to accommodate or make the flash do less work (change to manual, slow the shutter, increase ISO, etc.). 
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Re: 600 EX-RT for fill-in with burst : flash did not fire at each shot...
« Reply #15 on: December 09, 2013, 05:15:06 PM »

Skulker

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Re: 600 EX-RT for fill-in with burst : flash did not fire at each shot...
« Reply #16 on: December 09, 2013, 05:16:40 PM »
I start with the assumption that Canon know a lot more about making cameras than I do.

That's the spirit, I'll remember to nominate you for the "Canon compliance of the year" award :-p ... but you're correct, not every design decision is "crippling", but as it happens this one is different because ML has proven that auto iso with flash is no problem at all - you can use other iso settings manually, so there is really no reason why the camera shouldn't be able to select the iso according to the ambient light as usual and then let ettl decide the rest.

You mean as my 1Dx does, as I just pointed out.  ;D

Thanks for nominating me for "Canon compliance of the year". Its really appreciated.  Now where is that sarcastic emoticon when you need it.  >:(

As someone who spent many years in product design and development I find it really irrational that people claim companies deliberately downgrade equipment as a matter of course. It may well happen but it is not something that I ever saw in the real world.

privatebydesign

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Re: 600 EX-RT for fill-in with burst : flash did not fire at each shot...
« Reply #17 on: December 09, 2013, 05:38:22 PM »
Thank you for all your answers, and for your welcome !

And thank you for this detailed answer, Privatedesign.


Even the 600EX-RT is very limited in HSS at 1/4,000. You have run into a hard limit. Changing iso would not help, if you lower iso the flash needs to output more power, which it can't do, if you lower the shutter speed you need to close the aperture (to maintain ambient) which will need the same flash power. If you raised iso then the flash would not have to work so hard, but again you'd have to close the aperture and that would take back the power you gained. If you used a ND filter to get you down to sync speed you would gain a stop or so of power that is intrinsically lost to HSS, but most of your gained power from lowering shutter speed would be used overcoming the darker scene and AF can be an issue.


I would have thought that reducing ISO would involve increasing exposure time, i.e. Decreasing shutterspeed to an output less than 1/1000s, potentially more favorable to HSS. But I don't understand why it would involve the flash needing more power, knowing I was quite close to my kids (about 3 meters). I am certainly not an expert, but I assume the distance is also of importance to determine the needed power when using E-TTL. Am I wrong ?

I did not want to close the aperture, but the bckground being only snow, it would have not been a real issue. I should have tried it. But my initial purpose was indeed to blur the background, which is the reason to use HSS primarily. So I remained at f2.8 or f4...

Reducing iso would have increased shutter speed, but the power you gained from 1/4000 going to 1/1000, two stops, would have been lost to you by the iso going from 400 to 100, two stops. All the exposure factors remain constant. It isn't until you get below sync speed that you will start to get more effective flash power.

As a starting situation, turn camera on, put in Manual mode, set 100 iso, set sync speed, 1/200, then set your aperture where you need to get the ambient exposure you want (you lose selective dof control but that is the price you pay for optimising small flash in bright situations). Turn flash on in ETTL and dial in FEC to taste, my experience in snow is that the built in auto reduction/auto fill does a very good job. Take a picture. Look at the EXIF in review, if you don't like working in M mode go to AV and set one stop smaller aperture than the picture you just took, the camera will then do everything, however I find M easier and more consistent than AV and needing to use exposure compensation.

You were using 1/4000 @ f2.8 and 400 iso. I would have used 1/200 @ f6.2 and 100iso as a starting point for the same ambient but giving your flash the sync it needs to work effectively.
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markojakatri

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Re: 600 EX-RT for fill-in with burst : flash did not fire at each shot...
« Reply #18 on: December 09, 2013, 05:42:17 PM »
I wrote another topic about this, but here is my observation:

I've find a cool way to use safety shift in 5D III. If you use Tv mode and safety shift (ISO), camera will use as high ISO as needed. It actually works identically w/wo flash.

The best thing is that you can use autoISO or set ISO manually. If you set ISO manually, consider your setting as a minimum ISO setting, camera will rise it anyways when needed. This is very nice feature in low light, where fill flash is needed. You can, for example, set high ISO to have f2-2.8, but when it gets darker, f1.2-1.8 are used and if that is not enough, ISO will be risen even more.
« Last Edit: December 09, 2013, 05:52:11 PM by markojakatri »

Skulker

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Re: 600 EX-RT for fill-in with burst : flash did not fire at each shot...
« Reply #19 on: December 09, 2013, 05:49:39 PM »
I wrote another topic about this, but here is my observation:

I've find a cool way to use safety shift in 5D. If you use Tv mode and safety shift (ISO), camera will use as high ISO as needed. It actually works identically w/wo flash.

The best thing is that you can use autoISO or set ISO manually. If you set ISO manually, consider your setting as a minimum ISO setting, camera will rise it anyways when needed. This is very nice feature in low light, where fill flash is needed. You can, for example, set high ISO to have f2-2.8, but when it gets darker, f1.2-1.8 are used and if that is not enough, ISO will be risen even more.

That's interesting. I will see if I can use it.

Here's one I took earlier.  ;D  its ISO 1600. and 100% crop, NO PP in LR4, NO NR, NO sharpening etc etc.


markojakatri

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Re: 600 EX-RT for fill-in with burst : flash did not fire at each shot...
« Reply #20 on: December 09, 2013, 05:52:48 PM »
I meant in 5D III :)

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Re: 600 EX-RT for fill-in with burst : flash did not fire at each shot...
« Reply #21 on: December 09, 2013, 05:58:24 PM »
I've find a cool way to use safety shift in 5D III. If you use Tv mode and safety shift (ISO), camera will use as high ISO as needed. It actually works identically w/wo flash.

... but be careful, because reaching the highest iso setting you chose, it'll ignore your shutter speed preference and simply expose as long as required not matter if it's practical to handhold it any longer, that's why disable safety shift in tv mode. Better to get a more "flashy" picture than a blurry one with nice ambient.

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Re: 600 EX-RT for fill-in with burst : flash did not fire at each shot...
« Reply #21 on: December 09, 2013, 05:58:24 PM »

markojakatri

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Re: 600 EX-RT for fill-in with burst : flash did not fire at each shot...
« Reply #22 on: December 09, 2013, 06:01:05 PM »
... but be careful, because reaching the highest iso setting you chose, it'll ignore your shutter speed preference and simply expose as long as required not matter if it's practical to handhold it any longer, that's why disable safety shift in tv mode. Better to get a more "flashy" picture than a blurry one with nice ambient.

Yep, that's true. When it is dark enough, I change to manual and use bounced flash or two as main light(s).

neuroanatomist

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Re: 600 EX-RT for fill-in with burst : flash did not fire at each shot...
« Reply #23 on: December 09, 2013, 06:32:18 PM »
I start with the assumption that Canon know a lot more about making cameras than I do.

That's the spirit, I'll remember to nominate you for the "Canon compliance of the year" award :-p ... but you're correct, not every design decision is "crippling", but as it happens this one is different because ML has proven that auto iso with flash is no problem at all - you can use other iso settings manually, so there is really no reason why the camera shouldn't be able to select the iso according to the ambient light as usual and then let ettl decide the rest.

You mean as my 1Dx does, as I just pointed out.  ;D

I guess your 1Dx is different from my 1D X.   ;)

The issue at hand is when a Speedlite is attached, Canon cameras default to ISO 400 when they are set to Auto ISO.  Are you saying your camera does something different?
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Paul_B

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Re: 600 EX-RT for fill-in with burst : flash did not fire at each shot...
« Reply #24 on: December 09, 2013, 08:32:03 PM »
...
The issue at hand is when a Speedlite is attached, Canon cameras default to ISO 400 when they are set to Auto ISO.  Are you saying your camera does something different?

This is a problem for me as I take a lot of photos at parties and weddings where ambient light creates the atmosphere of the picture, but is volatile.
I need auto iso to work there between like 1600-6400 depending on the configuration of the lights at that second.
Either that or I have to fix my flash output and change this depending on my distance to the subject, but on a dancefloor this not possible to do well.

Reading this topic I have failed to understand why this fixed iso 400 is a reasonable thing as somebody said that the camera works just as fine with auto-iso plus flash running ML.
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kang159

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Re: 600 EX-RT for fill-in with burst : flash did not fire at each shot...
« Reply #25 on: December 09, 2013, 09:48:16 PM »
woah...poor OP must have no idea what's going on... :o

Marsu42

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Re: 600 EX-RT for fill-in with burst : flash did not fire at each shot...
« Reply #26 on: December 10, 2013, 02:13:19 AM »
woah...poor OP must have no idea what's going on... :o

I hope the discussion doesn't sound too heated :-p ... but what he (and I when I got my dslr) had/has no idea what's going on about is that the camera suddenly locks to iso 400 if you enable the flash from Rebel to 1dx - imho it's just like the previous poster stated: auto iso with flash can make sense, it works with ML, and it's difficult to understand why it doesn't by default. Maybe a feature reserved for 5d4, 6d2, 80d just like ec in m mode :-> ?

Skulker

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Re: 600 EX-RT for fill-in with burst : flash did not fire at each shot...
« Reply #27 on: December 10, 2013, 08:46:39 AM »
I start with the assumption that Canon know a lot more about making cameras than I do.

That's the spirit, I'll remember to nominate you for the "Canon compliance of the year" award :-p ... but you're correct, not every design decision is "crippling", but as it happens this one is different because ML has proven that auto iso with flash is no problem at all - you can use other iso settings manually, so there is really no reason why the camera shouldn't be able to select the iso according to the ambient light as usual and then let ettl decide the rest.

You mean as my 1Dx does, as I just pointed out.  ;D

I guess your 1Dx is different from my 1D X.   ;)

The issue at hand is when a Speedlite is attached, Canon cameras default to ISO 400 when they are set to Auto ISO.  Are you saying your camera does something different?

I'm not sure if mine is diferent to yours? Send me yours so I can carry out some tests if you like.  :)

I use a 580ex11 on camera or on an extension lead., and most of the time it defaults to ISO400. But sometimes it goes to ISO6400. The manual indicates that it will go to ISO1600. I freely admit I'm out of my depth with flash. I hardly ever use it and find it a bit of a black art. Why the owl shot I put in this tread was at ISO1600 and the one next to it was at ISO400 I have no idea. There is a color cast to the owl so maybe the flash was overheating?

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Re: 600 EX-RT for fill-in with burst : flash did not fire at each shot...
« Reply #27 on: December 10, 2013, 08:46:39 AM »