Canon A-1 and speedlites

Jan 28, 2015
2,729
314
Irving, Texas
#1
Has anyone tried a 600EX-RT or ST-E3-RT on an old Canon A-1 film camera? Hoping somebody has some experience with this. I don't want to fry the electronics in either.

I'm almost positive it would be all manual mode, the way I shoot flash anyway.

Just wanting to know if anyone has tried it.

Thanks!

Edit: I tried with the ST-E3-RT and it would not trigger. Any suggestions for off camera flash with this old film camera? I guess it will be corded.
 
Dec 26, 2011
358
19
#2
The old A-1 was designed to work with the 199-A (188, etc.) Speedlight. At that time, the Speedlight commanded the camera what aperture to set and the Speedlight itself had a sensor to detect when it had seen sufficient light for proper exposure. Communication between the Speedlight and the camera may have been analog at that time (I can't find documentation to confirm that). Now, commands flow from the camera body to the Speedlight, most likely all digital. I wouldn't expect any compatibility in terms of automation features between current flash and the A-1. That said, the #1 pin (larger center pin) has always been the trigger. I've successfully used older flashes on newer bodies by taping off all the pins except the center pin and the hot shoe frame. Never tried to use newer flash on my old A-1 though. Hopefully someone else will reply.
 
Jan 28, 2015
2,729
314
Irving, Texas
#3
old-pr-pix said:
The old A-1 was designed to work with the 199-A (188, etc.) Speedlight. At that time, the Speedlight commanded the camera what aperture to set and the Speedlight itself had a sensor to detect when it had seen sufficient light for proper exposure. Communication between the Speedlight and the camera may have been analog at that time (I can't find documentation to confirm that). Now, commands flow from the camera body to the Speedlight, most likely all digital. I wouldn't expect any compatibility in terms of automation features between current flash and the A-1. That said, the #1 pin (larger center pin) has always been the trigger. I've successfully used older flashes on newer bodies by taping off all the pins except the center pin and the hot shoe frame. Never tried to use newer flash on my old A-1 though. Hopefully someone else will reply.
Thank you for the reply. I'll try taping the other pins. The camera does display "F" when I attach the ST-E3-RT. It just doesn't trigger. Maybe the extra pins is the reason why.

I have seen the old flashes on E-Bay today. However, Amazon sells this manual flash that only has the trigger pin: https://www.amazon.com/AmazonBasics-Electronic-Flash-DSLR-Cameras/dp/B01I09WHLW/ref=sr_1_1?s=electronics&ie=UTF8&qid=1498369272&sr=1-1&keywords=amazon+basics+flash
 
Apr 3, 2013
4,017
57
51
Isle of Wight
#4
Hi CanonFanBoy.
I (and thousands of others probably) have frequently used my 550ex and canon compatible flashes in full manual on dumb remotes having only centre pin connection with no problems, mine are Godox, I would imagine a pair of these would do the job you are asking. I would not expect the st-e3 to work on an A-1 as it is expecting detailed interaction from the camera. My understanding is that the camera merely completes a circuit on the trigger contact to initiate a flash, I have no idea whether the other contacts might cause issues or damage to the flash, the risk with older flashes on newer cameras is the trigger voltage of the flash hurting the camera, not vice versa, many earlier cameras had only a simple solar cell for exposure metering, and before that, nothing with a voltage, but could still trigger a flash. As I said, just "my understanding."

Cheers, Graham.
 
Dec 26, 2011
358
19
#5
Graham makes a good point and OP is wise to proceed cautiously when mixing old and new flashes and camera bodies. Not what OP is trying to do here, but some old flashes have extremely high voltages on the trigger pin. Over 200 volts is not uncommon. Originally the PC connection was simply a mechanical switch contact on the shutter mechanism and the voltage didn't much matter. Initially the hot shoe was simply a parallel of the PC connection and manufacturers used a common design. When they started adding more functionality via more pins the hot shoe became proprietary and different manufacturers defined the pin-out differently. Now the flash trigger circuit is most certainly a semi-conductor that tolerates only 6 volts or so. Bottom line, there is nothing 'standard' electrically about the hot shoe connection. Pin #1 triggering is closest to standard (with the above voltage concerns).
 
Jan 28, 2015
2,729
314
Irving, Texas
#6
Valvebounce said:
Hi CanonFanBoy.
I (and thousands of others probably) have frequently used my 550ex and canon compatible flashes in full manual on dumb remotes having only centre pin connection with no problems, mine are Godox, I would imagine a pair of these would do the job you are asking. I would not expect the st-e3 to work on an A-1 as it is expecting detailed interaction from the camera. My understanding is that the camera merely completes a circuit on the trigger contact to initiate a flash, I have no idea whether the other contacts might cause issues or damage to the flash, the risk with older flashes on newer cameras is the trigger voltage of the flash hurting the camera, not vice versa, many earlier cameras had only a simple solar cell for exposure metering, and before that, nothing with a voltage, but could still trigger a flash. As I said, just "my understanding."

Cheers, Graham.
Success!!!! :) :) :)

Thanks to both of you for your replies!

Graham, your mentioning the Godox full manual dumb remotes reminded me that I got this included with my Flashpoint Streaklight 360ws (Same thing as Godox.): https://www.adorama.com/fprrsl.html#source=productOptions

I never used this set before because I got a set of Cells II when I ordered the flash.

I tried this just now on the A-1 and successfully trigger the Streaklight 360! This is so great! :) I use this flash almost exclusively and it is good to know I'll be able to take this outside to try some film portraiture.

I do have a light meter, Sekonic, and may have to learn a little math to get the exposure right as film and processing is expensive compared to digital. Digital has me spoiled with being able to see instantly what I did and being able to make adjustments right away.

Thank both of you very much for your replies. Saved me some money.
 

Attachments

Sporgon

5% of gear used 95% of the time
#7
CanonFanBoy said:
Valvebounce said:
Hi CanonFanBoy.
I (and thousands of others probably) have frequently used my 550ex and canon compatible flashes in full manual on dumb remotes having only centre pin connection with no problems, mine are Godox, I would imagine a pair of these would do the job you are asking. I would not expect the st-e3 to work on an A-1 as it is expecting detailed interaction from the camera. My understanding is that the camera merely completes a circuit on the trigger contact to initiate a flash, I have no idea whether the other contacts might cause issues or damage to the flash, the risk with older flashes on newer cameras is the trigger voltage of the flash hurting the camera, not vice versa, many earlier cameras had only a simple solar cell for exposure metering, and before that, nothing with a voltage, but could still trigger a flash. As I said, just "my understanding."

Cheers, Graham.
Success!!!! :) :) :)

Thanks to both of you for your replies!

Graham, your mentioning the Godox full manual dumb remotes reminded me that I got this included with my Flashpoint Streaklight 360ws (Same thing as Godox.): https://www.adorama.com/fprrsl.html#source=productOptions

I never used this set before because I got a set of Cells II when I ordered the flash.

I tried this just now on the A-1 and successfully trigger the Streaklight 360! This is so great! :) I use this flash almost exclusively and it is good to know I'll be able to take this outside to try some film portraiture.

I do have a light meter, Sekonic, and may have to learn a little math to get the exposure right as film and processing is expensive compared to digital. Digital has me spoiled with being able to see instantly what I did and being able to make adjustments right away.

Thank both of you very much for your replies. Saved me some money.
Use your digital camera to get the exposure and balance right !
 
Jan 28, 2015
2,729
314
Irving, Texas
#8
Sporgon said:
CanonFanBoy said:
Valvebounce said:
Hi CanonFanBoy.
I (and thousands of others probably) have frequently used my 550ex and canon compatible flashes in full manual on dumb remotes having only centre pin connection with no problems, mine are Godox, I would imagine a pair of these would do the job you are asking. I would not expect the st-e3 to work on an A-1 as it is expecting detailed interaction from the camera. My understanding is that the camera merely completes a circuit on the trigger contact to initiate a flash, I have no idea whether the other contacts might cause issues or damage to the flash, the risk with older flashes on newer cameras is the trigger voltage of the flash hurting the camera, not vice versa, many earlier cameras had only a simple solar cell for exposure metering, and before that, nothing with a voltage, but could still trigger a flash. As I said, just "my understanding."

Cheers, Graham.
Success!!!! :) :) :)

Thanks to both of you for your replies!

Graham, your mentioning the Godox full manual dumb remotes reminded me that I got this included with my Flashpoint Streaklight 360ws (Same thing as Godox.): https://www.adorama.com/fprrsl.html#source=productOptions

I never used this set before because I got a set of Cells II when I ordered the flash.

I tried this just now on the A-1 and successfully trigger the Streaklight 360! This is so great! :) I use this flash almost exclusively and it is good to know I'll be able to take this outside to try some film portraiture.

I do have a light meter, Sekonic, and may have to learn a little math to get the exposure right as film and processing is expensive compared to digital. Digital has me spoiled with being able to see instantly what I did and being able to make adjustments right away.

Thank both of you very much for your replies. Saved me some money.
Use your digital camera to get the exposure and balance right !
True. I could do that. Thanks! :) That would be better because it would take into account the flash modifiers.
 

zim

EOS 7D MK II
Oct 18, 2011
1,863
53
#9
Sporgon said:
CanonFanBoy said:
Valvebounce said:
Hi CanonFanBoy.
I (and thousands of others probably) have frequently used my 550ex and canon compatible flashes in full manual on dumb remotes having only centre pin connection with no problems, mine are Godox, I would imagine a pair of these would do the job you are asking. I would not expect the st-e3 to work on an A-1 as it is expecting detailed interaction from the camera. My understanding is that the camera merely completes a circuit on the trigger contact to initiate a flash, I have no idea whether the other contacts might cause issues or damage to the flash, the risk with older flashes on newer cameras is the trigger voltage of the flash hurting the camera, not vice versa, many earlier cameras had only a simple solar cell for exposure metering, and before that, nothing with a voltage, but could still trigger a flash. As I said, just "my understanding."

Cheers, Graham.
Success!!!! :) :) :)

Thanks to both of you for your replies!

Graham, your mentioning the Godox full manual dumb remotes reminded me that I got this included with my Flashpoint Streaklight 360ws (Same thing as Godox.): https://www.adorama.com/fprrsl.html#source=productOptions

I never used this set before because I got a set of Cells II when I ordered the flash.

I tried this just now on the A-1 and successfully trigger the Streaklight 360! This is so great! :) I use this flash almost exclusively and it is good to know I'll be able to take this outside to try some film portraiture.

I do have a light meter, Sekonic, and may have to learn a little math to get the exposure right as film and processing is expensive compared to digital. Digital has me spoiled with being able to see instantly what I did and being able to make adjustments right away.

Thank both of you very much for your replies. Saved me some money.
Use your digital camera force to get the exposure and balance right !
Fixed that for ya ;D

Was going to offer the OP my good old trusty manual sunpak hammerhead flash, too late. 8)
 
Jan 28, 2015
2,729
314
Irving, Texas
#10
zim said:
Sporgon said:
CanonFanBoy said:
Valvebounce said:
Hi CanonFanBoy.
I (and thousands of others probably) have frequently used my 550ex and canon compatible flashes in full manual on dumb remotes having only centre pin connection with no problems, mine are Godox, I would imagine a pair of these would do the job you are asking. I would not expect the st-e3 to work on an A-1 as it is expecting detailed interaction from the camera. My understanding is that the camera merely completes a circuit on the trigger contact to initiate a flash, I have no idea whether the other contacts might cause issues or damage to the flash, the risk with older flashes on newer cameras is the trigger voltage of the flash hurting the camera, not vice versa, many earlier cameras had only a simple solar cell for exposure metering, and before that, nothing with a voltage, but could still trigger a flash. As I said, just "my understanding."

Cheers, Graham.
Success!!!! :) :) :)

Thanks to both of you for your replies!

Graham, your mentioning the Godox full manual dumb remotes reminded me that I got this included with my Flashpoint Streaklight 360ws (Same thing as Godox.): https://www.adorama.com/fprrsl.html#source=productOptions

I never used this set before because I got a set of Cells II when I ordered the flash.

I tried this just now on the A-1 and successfully trigger the Streaklight 360! This is so great! :) I use this flash almost exclusively and it is good to know I'll be able to take this outside to try some film portraiture.

I do have a light meter, Sekonic, and may have to learn a little math to get the exposure right as film and processing is expensive compared to digital. Digital has me spoiled with being able to see instantly what I did and being able to make adjustments right away.

Thank both of you very much for your replies. Saved me some money.
Use your digital camera force to get the exposure and balance right !
Fixed that for ya ;D

Was going to offer the OP my good old trusty manual sunpak hammerhead flash, too late. 8)
Hahaha! Truthfully, I went to Wal-Mart yesterday to get a Sunpak flash because they used to carry them. Our store doesn't anymore. Glad they didn't because now I know I can use the big flash. All my stuff is outdoors, so the bigger flash is better for me, but thank you Zim. :)
 
Apr 3, 2013
4,017
57
51
Isle of Wight
#11
Hi Sporgon.
I was thinking this as I read through the responses so I guess we are both on the right track. I do recall reading somewhere (here maybe) that film ISO values don't directly correlate to digital ISO values so might that be a stumbling block to our theory?

Cheers, Graham.

Sporgon said:
Use your digital camera to get the exposure and balance right !
 
Jan 28, 2015
2,729
314
Irving, Texas
#12
Valvebounce said:
Hi Sporgon.
I was thinking this as I read through the responses so I guess we are both on the right track. I do recall reading somewhere (here maybe) that film ISO values don't directly correlate to digital ISO values so might that be a stumbling block to our theory?

Cheers, Graham.

Sporgon said:
Use your digital camera to get the exposure and balance right !
I'm guessing a person needs to keep a log of the exposures (Film type, ISO/ASA, shutter speed, flash power, modifiers used etc) until one knows how the individual camera/flash combination behave and under what conditions. I say this because a person doesn't know exactly what he's got until the film is developed and would never be able to remember how he got to the photo he captured without doing some logging. It just looks as though one must work a whole lot harder with film. I see a lot of bracketing in my future. :( This is where it gets expensive. Keeper rates? I guess a person could bracket enough shots to get maybe two good portraits out of a roll of film until the knowledge and skill level rises.

Edit: I didn't just mean bracketing, but also flash power level.
 
Dec 26, 2011
358
19
#13
Valvebounce said:
Hi Sporgon.
I was thinking this as I read through the responses so I guess we are both on the right track. I do recall reading somewhere (here maybe) that film ISO values don't directly correlate to digital ISO values so might that be a stumbling block to our theory?

Cheers, Graham.

Sporgon said:
Use your digital camera to get the exposure and balance right !
Digital should get you close and notes will definitely help. Film ISO values are going to depend on the processing, especially if you are using B/W. I used to rate TRI-X at anything from ASA 240 to ASA 1600 and develop accordingly. Also used a lot of Polaroid for the larger format stuff.

Hope you have fun working with film again. I still love the look of a big print from a good medium format TRI-X negative! Every time I start to think I should give film another go, I remember the darkroom stained fingers or the cost of paying someone else to develop my stuff, and the dream passes. I did pull out my A-1 just to hear the old shutter squeel one more time (really should get it lubed again!?). Mine is a lot older than the OP's -- serial number in the low 200,000 range from way back in 1978.
 

dcm

It's not the gear.
Apr 18, 2013
695
11
#14
Got a pocket meter out and did a quick, simple reverse engineering of the camera and flash contacts on my A1 and 199A.

As expected the center contact triggers the flash when shorted to the rails holding the flash to the camera. Also triggers when the center contact is shorted to the back left contact, but not the right contact. The back contact right tells the camera a flash is mounted with a constant 4.3mv no matter the flash setting. The back left contact communicates manual versus auto with 135mv for any of three auto settings and 6mv for the manual setting. Couldn't do any more with my pocket meter. It wasn't immediately obvious how the specific AUTO setting is communicated from the flash to the camera.

Mounted my old 420EX on the A1 and the flash triggers as expected. The flash was recognized (F in the display) from the right contact but the display blinks because it could not decode the aperture sent from the flash via the left contact - no surprise there.

I taped over the left contact as in the photo and every thing works fine. The camera recognizes that a flash is mounted in manual mode and triggers it correctly. The camera display show 60 F 8.0 and M if the lens is not in A mode. Works with my 90EX and 320EX as well. Assume it will work similarly with larger Canon flashes, but they weren't handy.

Would need a scope for further analysis of the signals. Just think how much fun it would be to reverse engineer the EOS AF protocols and signals. Ain't engineering fun?
 

Attachments

Jan 28, 2015
2,729
314
Irving, Texas
#15
dcm said:
Got a pocket meter out and did a quick, simple reverse engineering of the camera and flash contacts on my A1 and 199A.

As expected the center contact triggers the flash when shorted to the rails holding the flash to the camera. Also triggers when the center contact is shorted to the back left contact, but not the right contact. The back contact right tells the camera a flash is mounted with a constant 4.3mv no matter the flash setting. The back left contact communicates manual versus auto with 135mv for any of three auto settings and 6mv for the manual setting. Couldn't do any more with my pocket meter. It wasn't immediately obvious how the specific AUTO setting is communicated from the flash to the camera.

Mounted my old 420EX on the A1 and the flash triggers as expected. The flash was recognized (F in the display) from the right contact but the display blinks because it could not decode the aperture sent from the flash via the left contact - no surprise there.

I taped over the left contact as in the photo and every thing works fine. The camera recognizes that a flash is mounted in manual mode and triggers it correctly. The camera display show 60 F 8.0 and M if the lens is not in A mode. Works with my 90EX and 320EX as well. Assume it will work similarly with larger Canon flashes, but they weren't handy.

Would need a scope for further analysis of the signals. Just think how much fun it would be to reverse engineer the EOS AF protocols and signals. Ain't engineering fun?
Thanks for all that. I'll have to try that with the ST-E3-RT because there may be a time when I want to use those in conjunction with the 600EX-RTs. Yesterday I got the same LED camera displays you got, but it would not trigger. I'll try taping. :)
 
Jan 28, 2015
2,729
314
Irving, Texas
#16
CanonFanBoy said:
dcm said:
Got a pocket meter out and did a quick, simple reverse engineering of the camera and flash contacts on my A1 and 199A.

As expected the center contact triggers the flash when shorted to the rails holding the flash to the camera. Also triggers when the center contact is shorted to the back left contact, but not the right contact. The back contact right tells the camera a flash is mounted with a constant 4.3mv no matter the flash setting. The back left contact communicates manual versus auto with 135mv for any of three auto settings and 6mv for the manual setting. Couldn't do any more with my pocket meter. It wasn't immediately obvious how the specific AUTO setting is communicated from the flash to the camera.

Mounted my old 420EX on the A1 and the flash triggers as expected. The flash was recognized (F in the display) from the right contact but the display blinks because it could not decode the aperture sent from the flash via the left contact - no surprise there.

I taped over the left contact as in the photo and every thing works fine. The camera recognizes that a flash is mounted in manual mode and triggers it correctly. The camera display show 60 F 8.0 and M if the lens is not in A mode. Works with my 90EX and 320EX as well. Assume it will work similarly with larger Canon flashes, but they weren't handy.

Would need a scope for further analysis of the signals. Just think how much fun it would be to reverse engineer the EOS AF protocols and signals. Ain't engineering fun?
Thanks for all that. I'll have to try that with the ST-E3-RT because there may be a time when I want to use those in conjunction with the 600EX-RTs. Yesterday I got the same LED camera displays you got, but it would not trigger. I'll try taping. :)
I taped the left contact. I taped the right contact. I taped both the left and right contact.

I can get the camera to recognize there is a flash. It just won't trigger with an ST-E3-RT.

How many contacts total do your old speedlites have each? The ST-E3-RT has 5. It might be that there is another required to trigger and the A-1 just doesn't have the pin contacts to do the job. If that is the case the 600EX-RT is a no go.

Well, one more reason to get another Streaklight. :)
 

dcm

It's not the gear.
Apr 18, 2013
695
11
#17
CanonFanBoy said:
CanonFanBoy said:
dcm said:
Got a pocket meter out and did a quick, simple reverse engineering of the camera and flash contacts on my A1 and 199A.

As expected the center contact triggers the flash when shorted to the rails holding the flash to the camera. Also triggers when the center contact is shorted to the back left contact, but not the right contact. The back contact right tells the camera a flash is mounted with a constant 4.3mv no matter the flash setting. The back left contact communicates manual versus auto with 135mv for any of three auto settings and 6mv for the manual setting. Couldn't do any more with my pocket meter. It wasn't immediately obvious how the specific AUTO setting is communicated from the flash to the camera.

Mounted my old 420EX on the A1 and the flash triggers as expected. The flash was recognized (F in the display) from the right contact but the display blinks because it could not decode the aperture sent from the flash via the left contact - no surprise there.

I taped over the left contact as in the photo and every thing works fine. The camera recognizes that a flash is mounted in manual mode and triggers it correctly. The camera display show 60 F 8.0 and M if the lens is not in A mode. Works with my 90EX and 320EX as well. Assume it will work similarly with larger Canon flashes, but they weren't handy.

Would need a scope for further analysis of the signals. Just think how much fun it would be to reverse engineer the EOS AF protocols and signals. Ain't engineering fun?
Thanks for all that. I'll have to try that with the ST-E3-RT because there may be a time when I want to use those in conjunction with the 600EX-RTs. Yesterday I got the same LED camera displays you got, but it would not trigger. I'll try taping. :)
I taped the left contact. I taped the right contact. I taped both the left and right contact.

I can get the camera to recognize there is a flash. It just won't trigger with an ST-E3-RT.

How many contacts total do your old speedlites have each? The ST-E3-RT has 5. It might be that there is another required to trigger and the A-1 just doesn't have the pin contacts to do the job. If that is the case the 600EX-RT is a no go.

Well, one more reason to get another Streaklight. :)
The 199A has the same configuration as the A-1. Three contacts. The A series of flashes were designed for the A bodies.

The three EX series I tested all have 5 pins and work fine on the A-1. I'm guessing the 600EX's would also work. Don't have one to try.
 

Sporgon

5% of gear used 95% of the time
#18
Valvebounce said:
Hi Sporgon.
I was thinking this as I read through the responses so I guess we are both on the right track. I do recall reading somewhere (here maybe) that film ISO values don't directly correlate to digital ISO values so might that be a stumbling block to our theory?

Cheers, Graham.

Sporgon said:
Use your digital camera to get the exposure and balance right !
Correct, but it's not a stumbling block, especially if shooting negative.

Just check out the actual ISO of your camera on dxo. Then work to that. For instance 100 ISO on the 5DIV is 64, the 5DII is 74. These are two I just know from memory. This difference would certainly effect transparency film results.

These differences are real because it you use an accurate hand held meter and set the ISO to the same as your camera, say a 5DII, and then input the aperture and shutter from your meter you will under expose. On the original 5D who's ISO 100 is about 97, you won't.
 
Dec 26, 2011
358
19
#19
dcm said:
Got a pocket meter out and did a quick, simple reverse engineering of the camera and flash contacts on my A1 and 199A.

As expected the center contact triggers the flash when shorted to the rails holding the flash to the camera. Also triggers when the center contact is shorted to the back left contact, but not the right contact. The back contact right tells the camera a flash is mounted with a constant 4.3mv no matter the flash setting. The back left contact communicates manual versus auto with 135mv for any of three auto settings and 6mv for the manual setting. Couldn't do any more with my pocket meter. It wasn't immediately obvious how the specific AUTO setting is communicated from the flash to the camera.
Interesting observations... I always suspected that the flash command to the body to set the aperture value was via a current loop. If so, then the flash would need to be mounted for the effect to be measurable. 199-A has 3 selected values of aperture, the 188-A has only two. The 199-A also can automatically force 1/60 sec. shutter or has a switch to allow slow-sync where the camera body selects shutter speed. The 199-A also has an indicator on the flash if there was sufficient flash power - I don't recall if that is communicated to the body for viewfinder display.
 
Apr 3, 2013
4,017
57
51
Isle of Wight
#20
Hi CanonFanBoy.
I still think that the reason the ST-E3-RT won't fire is because it is expecting detailed communication from the camera, don't forget that newer cameras can control the flashes from the menu.
The flashes still fire because, well a flash is still a flash! To prove a point I just triggered my YN-600EX-RT with a key to short the centre pin to the foot (carefully) it said it didn't recognise the camera model but "ok I'll flash"!
I'm curious about this so I just got my 2 YN-600EX-RT's and YN-E3-RT out and tried triggering them with the key! A flash set as a master will fire, but not trigger a slave unit, the YN-E3-RT just played dumb, as in nothing happened!

Cheers, Graham.

CanonFanBoy said:
Thanks for all that. I'll have to try that with the ST-E3-RT because there may be a time when I want to use those in conjunction with the 600EX-RTs. Yesterday I got the same LED camera displays you got, but it would not trigger. I'll try taping. :)

I taped the left contact. I taped the right contact. I taped both the left and right contact.

I can get the camera to recognize there is a flash. It just won't trigger with an ST-E3-RT.

How many contacts total do your old speedlites have each? The ST-E3-RT has 5. It might be that there is another required to trigger and the A-1 just doesn't have the pin contacts to do the job. If that is the case the 600EX-RT is a no go.

Well, one more reason to get another Streaklight. :)