# 600EX-RT and third party gels



## gmrza (Oct 24, 2012)

After reading through the manual of the 600EX-RT, it appears that the flash only is able to transmit colour temperature information if the gels supplied with the unit are used. - The procedure described by the manual indicates that manual white balance setting would have to used with other gels.

I was wondering if anyone has experimented with using 3rd party gels to see whether the flash can recognise colour temperature of any other gels than the CTOs supplied with it. - Unfortunately all my other colour correction gels are cut to sizes that won't fit the Canon gel holder, so I need to buy some sheets of gel before I can do any testing.

It would seem a bit silly if Canon has only designed the colour temperature sensing to only work with the two supplied gels!


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## bornshooter (Oct 24, 2012)

little bit off topic but my 600-ex-rt is coming today  going to order another with an st-e3


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## Jamesy (Oct 24, 2012)

I recall reading that the Nikon SB-900 behaves the same way - the gel holder is chipped and that is what tells the camera what gel is in the holder. Stands to reason Canon would be similar but I don't know for certain.


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## neuroanatomist (Oct 24, 2012)

gmrza said:


> It would seem a bit silly if Canon has only designed the colour temperature sensing to only work with the two supplied gels!



Canon states:
"_ The filter holder and two sensors at the base of the flash head work in tandem to read and register any change in flash color with the filters in-place, and communicate it to recent EOS cameras.

The automatic WB detection is intended only for these two Canon-supplied gel filters. Third-party 3x3-inch (75 x 75mm) gel filters can be cut to size by photographers and used in the Canon gel filter holder with the Speedlite 600EX-RT, but Canon strongly recommends turning off automatic WB detection of the filters (via flash Personal Function 5-1). Accurate WB detection (with the camera set for the FLASH WB setting) is not guaranteed with other filter colors, or with third-party amber-colored filters placed on the Speedlite._"

While you're probably well aware of my cynical streak, this doesn't seem like a marketing ploy, because Canon doesn't sell any filter gels except those two, AFAIK. Rather, it may be a technical issue. The statement, "register any change in flash color with the filters in-place," _could_ be interpreted as you mean it, i.e. it's detecting the actual color temperature of the emitted light and reporting it. But dissecting the languge, "change in flash color with *the filters* in-place," may refer to those specific filters provided with the camera - in other words, it's not really detecting the specific color temperature of the emitted light, but rather is just making an easy call between no filter, the Canon light amber filter, and the Canon dark amber filter, and giving the camera the color temperature corrections stored in the flash firmware for those specific filters. Canon would do that so they could use a much less accurate sensor - meaning a cheaper sensor, meaning more profit. There's that cynical streak again...


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## Chris Geiger (Oct 24, 2012)

This year I switched from Nikon to Canon and have done over 20 weddings on the Canon system. I have two 5D3's and four 600-ex-rt's. I am finding the auto color balance of both systems to be about the same. I shoot most of the day in auto color, then when I get to the reception and put the gels on I find I have to manually set the color to get anywhere close. I normally choose something between 2600 and 3000 for color temp. 

I started with the Canon orange filters and had good results but had minor problems with removing the gel holders from my belt with the Canon filers in them. The filters would slip out of the gel holder when I was handling them (think fast moving wedding photographer with four gels to install quickly). I ended up buying a couple of large sheets of filter material from amazon. I cut out filter pieces that were a little smaller than the Canon ones and taped them into the gel holders. With the smaller ones tapped in I no longer have issues with the filter slipping out of the gel when I am retrieving or putting the filers away on my belt. My cut out filters are a bit shorter than the canon and do not reach up to the sensor and clip area of the gel holder so the camera can't read the color of the filters but with manual settings of the color balance the results are the same. I shoot raw, so I just want the color close enough to get good exposures. I adjust the final color later in post. 

I only ever use just one filter color so I don't need to change filters.


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## gmrza (Oct 25, 2012)

neuroanatomist said:


> While you're probably well aware of my cynical streak, this doesn't seem like a marketing ploy, because Canon doesn't sell any filter gels except those two, AFAIK. Rather, it may be a technical issue. The statement, "register any change in flash color with the filters in-place," _could_ be interpreted as you mean it, i.e. it's detecting the actual color temperature of the emitted light and reporting it. But dissecting the languge, "change in flash color with *the filters* in-place," may refer to those specific filters provided with the camera - in other words, it's not really detecting the specific color temperature of the emitted light, but rather is just making an easy call between no filter, the Canon light amber filter, and the Canon dark amber filter, and giving the camera the color temperature corrections stored in the flash firmware for those specific filters. Canon would do that so they could use a much less accurate sensor - meaning a cheaper sensor, meaning more profit. There's that cynical streak again...



I suspect that is probably what Canon has done - that they have done a cheap and nasty as far as the gel sensor is concerned.

It is a pity that they have only made provision for tungsten (or at least warm) light sources, and no provision for fluorescent light correction filters (like a plusgreen type gel).


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## neuroanatomist (Oct 25, 2012)

Ok, so my earlier post was speculation from my desk at work. I had a look at my 600EX-RT this evening, and the way it works is this: there are two little 'windows' on the bottom of the flash head. One is an emitter, the other a detector. The bottom of the holder has a little prism that reflects light from the emitter to the detector, and the light passes through the tab on the gel. The little metal disk next to the prism on the holder activates a magnetic sensor in the flash, so when you mount the holder, there are a few flashes of light from the emitter (a small white LED, probably) - if you look from the side when you mount the holder, you can see that happen. 

Now, having said that, the statements in the manual may be Canon CYA language, not wanting to take responsibility for you getting the wrong flash temp and thus WB in the EXIF. The system may actually do ok, and it's worth testing. Looks like the gel color is determined only when you first mount the holder, then stored. For the color check, it seems that the gel only need cover the prism at the bottom, so you may be able to empirically test the WB setting with your non-Canon gels...


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## gmrza (Oct 25, 2012)

neuroanatomist said:


> Ok, so my earlier post was speculation from my desk at work. I had a look at my 600EX-RT this evening, and the way it works is this: there are two little 'windows' on the bottom of the flash head. One is an emitter, the other a detector. The bottom of the holder has a little prism that reflects light from the emitter to the detector, and the light passes through the tab on the gel. The little metal disk next to the prism on the holder activates a magnetic sensor in the flash, so when you mount the holder, there are a few flashes of light from the emitter (a small white LED, probably) - if you look from the side when you mount the holder, you can see that happen.
> 
> Now, having said that, the statements in the manual may be Canon CYA language, not wanting to take responsibility for you getting the wrong flash temp and thus WB in the EXIF. The system may actually do ok, and it's worth testing. Looks like the gel color is determined only when you first mount the holder, then stored. For the color check, it seems that the gel only need cover the prism at the bottom, so you may be able to empirically test the WB setting with your non-Canon gels...



I guess the only way is going to be to buy some sheets of 1/4 and 1/2 (and maybe full) Plusgreen Rosco gels (which I need to get sometime anyhow) and experiment. At worst I land up still with the mechanism of just manually setting the white balance, which is no worse than the situation with the 580EXII.


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## neuroanatomist (Oct 25, 2012)

If/when you try it, please post your results!


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## gmrza (Oct 26, 2012)

neuroanatomist said:


> If/when you try it, please post your results!



Unfortunately that won't happen this week, as I our home life has been turned upside down while my wife works on a jobs where she has 5961 images to work through and get proofs out... That means my weekend will be spent getting proofs onto the web...


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## digital paradise (Dec 2, 2012)

neuroanatomist said:


> gmrza said:
> 
> 
> > It would seem a bit silly if Canon has only designed the colour temperature sensing to only work with the two supplied gels!
> ...



That makes perfect sense to me. It is not detecting specific colour, just no filter, a light and dark one. The simplest approach. Adding a system to actually detect filter types would have driven the cost of the flash up. Another way would be to chip the gels but again the costs and Canon has no guarantee people would buy them. 

I already had sheets of CTO/S - full and half. I cut them to size and will use those instead of the supplied ones. I select a temperature close to the gel but wind up fine tuning during PP anyway so I don't see the benefit of the automated system. For me anyway.


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## pengyifei (Jan 7, 2013)

gmrza said:


> neuroanatomist said:
> 
> 
> > If/when you try it, please post your results!
> ...



Hi guys,

did anyone had the time to conduct tests with 3rd party gel yet? I saw that post was from October and hope that we have more information now if the 600EX-RT reads other gels or not.

Cheers

Seb


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## brad goda (Feb 11, 2013)

personally the supplied gels and holder work great and hold well BUT
it prevents you from using your built in diffuser or bounce card.... also any other stofen or lumiquest bounce...
also it does not come with any green which is needed for FL situations.
along with other posters I use CTS "color temperature straw" in full half and 1/4 along with diff values of green... stacked sometimes double full, full + half, full + green... and so on.
ive made a hard plastic stencil that perfectly matches the clear part of the flash head and cut the filters to cover it 100% within the flashes black frame... in being very careful of this and two side tapping in place will give you no leaks preventing bleed. if the non filtered light bleeds onto your subject even as bounce it will be a useless effort why you gelled in the first place...
matched strobe lighting to your practical situations light will give you a very polished look.


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## Garfield (Apr 12, 2013)

I have ordered a set of CTO gels from flashgels.co.uk.
At least for the CTO gels reading the color temperature is ok.
But, afaik, other gels like the blue Lee201 will not be recognised by the 600EX.

BTW. The filters from flashgels.co.uk have appr. double the thickness of the canon one's and a decent price as well, at least when shipped to europe.


Garfield.


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## pengyifei (Apr 12, 2013)

I found some nicely cut gels in China. Will send more information later.


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## pengyifei (Apr 12, 2013)

Here is a pic of the gels that I found


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## rapope (Jul 2, 2013)

Regarding the photo of the Rosco gels, were these pre-cut or ready made?


Thanks,

Rocky


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