topic Re: 5D flash sync limit with flash turned off in EOS DSLR & Mirrorless Cameras

5D flash sync limit with flash turned off

uscpsycho — Mon, 13 Mar 2017 08:47:08 GMT

I recently encountered a frustrating situation with my 5DmkIII and 600EX flash.

Like an idiot I didn't check my flash batteries and realized they were dead when I tried using the flash. However, even with dead batteries the camera was limiting my shutter speed to 1/200. Same situation with the flash power turned on and off, shutter speed limited to 1/200. Remove the speedlite from the camera and everything is back to normal, put it back on the camera and shutter speed again limited to 1/200 (even with flash power in off position).

After charging the same batteries there is no shutter speed limit when the flash is powered off and attached to the camera.

Is there some reason why my camera would limit the shutter speed when a flash with dead batteries is on the camera?

Re: 5D flash sync limit with flash turned off

Waddizzle — Mon, 13 Mar 2017 09:16:54 GMT

@uscpsycho wrote:

Is there some reason why my camera would limit the shutter speed when a flash with dead batteries is on the camera?

Yes, it's because the batteries are dead. The same thing would probably happen with no batteries in the flash.

Obviously, one or more of the contacts on the hot shoe allow the camera to sense when there is something mounted on the hot shoe. Exactly how the camera does it is really not important. Just keep your flash batteries charged up.

Re: 5D flash sync limit with flash turned off

uscpsycho — Mon, 13 Mar 2017 09:29:31 GMT

Why on earth would the camera restrict my shutter speed when I'm clearly not using the flash?

I could see some weird logic for this if the flash power switch is on with dead batteries. But if the power of the flash is in the off position what difference does it make if the batteires are dead or not? Isn't it weird that the camera will let me use any shutter speed when the flash is off with charged batteries, but restrict me when the flash is off with dead batteries?

What is Canon's logic for that?

Re: 5D flash sync limit with flash turned off

Waddizzle — Mon, 13 Mar 2017 10:43:15 GMT

@uscpsycho wrote:
Why on earth would the camera restrict my shutter speed when I'm clearly not using the flash?

I could see some weird logic for this if the flash power switch is on with dead batteries. But if the power of the flash is in the off position what difference does it make if the batteires are dead or not? Isn't it weird that the camera will let me use any shutter speed when the flash is off with charged batteries, but restrict me when the flash is off with dead batteries?

What is Canon's logic for that?

Wrong question. What's the logic in mounting a device on your hot shoe that you know isn't functioning properly?

You're not making sense. "I mount this malfunctioning flash on my camera, and then my camera malfunctions, too. Why is that?"

Re: 5D flash sync limit with flash turned off

uscpsycho — Mon, 13 Mar 2017 11:10:00 GMT

I'll tell you the logic. Your batteries die mid-shoot/on location and you have nowhere to put the flash because you're traveling light.

Then what? You are forced to either dispose of the flash because you have nowhere to put it or you leave it mounted on the camera and are restricted to 1/200. What is the logic for this? Nobody would want to be in this situation.

if this is by design it is stupid design.

Re: 5D flash sync limit with flash turned off

RobertTheFat — Mon, 13 Mar 2017 13:45:38 GMT

@uscpsycho wrote:
I'll tell you the logic. Your batteries die mid-shoot/on location and you have nowhere to put the flash because you're traveling light.

Then what? You are forced to either dispose of the flash because you have nowhere to put it or you leave it mounted on the camera and are restricted to 1/200. What is the logic for this? Nobody would want to be in this situation.

if this is by design it is stupid design.

In principle, I agree with you. It sounds like a firmware error that should be fixed. The catch is that with the flash batteries missing or dead, the camera may have no way of telling whether the flash is turned on or off. The hot shoe can mechanically "feel" the presence of the flash unit, but the position of its on/off switch would have to be determined electrically.

Re: 5D flash sync limit with flash turned off

Waddizzle — Mon, 13 Mar 2017 14:12:00 GMT

@uscpsycho wrote:
I'll tell you the logic. Your batteries die mid-shoot/on location and you have nowhere to put the flash because you're traveling light.

Then what? You are forced to either dispose of the flash because you have nowhere to put it or you leave it mounted on the camera and are restricted to 1/200. What is the logic for this? Nobody would want to be in this situation.

if this is by design it is stupid design.

Charge your batteries prior to your shoot, and carry some fully charged spares.. Wear a photo vest, if you need more pockets.

If your flash batteries run down in the middle of a shoot, and you have no spares, then that is poor planning on your part, not a "stupid design" on Canon's part.

If you get the impression that I think you complaint is petty, then you would be correct.

Re: 5D flash sync limit with flash turned off

Ray-uk — Mon, 13 Mar 2017 15:14:56 GMT

I don't know how exactly the 5D senses the flash but most canon DSLRs have a microswitch built into the hot shoe, this is activated by sliding the foot of the flash into the shoe. It doesn't even have to be a flashgun, a flat piece of plastic the right size will activate the switch and as far as the camera is concerned that switch being activated means an external flash is fitted. There is not normally any intelligent sensing for this facility.

Re: 5D flash sync limit with flash turned off

diverhank — Mon, 13 Mar 2017 15:48:02 GMT

@uscpsycho wrote:
I recently encountered a frustrating situation with my 5DmkIII and 600EX flash.

Like an idiot I didn't check my flash batteries and realized they were dead when I tried using the flash. However, even with dead batteries the camera was limiting my shutter speed to 1/200. Same situation with the flash power turned on and off, shutter speed limited to 1/200. Remove the speedlite from the camera and everything is back to normal, put it back on the camera and shutter speed again limited to 1/200 (even with flash power in off position).

Strange...I need to test this with my 5DIII tonight. Last night I was shooting with a mounted flash on my 7DII and it didn't behave this way. With the flash mounted but turned off, there was no speed restriction.

I can understand that with the flash turned on - even with dead batteries, the camera still sees it as flash on. The batteries may be low enough not to fire but there is still some power in the system. What I don't get is with it turned off and the camera still thinks the flash is on.

In many cases I mount the flash on my 5DIII camera all the time without turning it on. I can't recall running into this problem. I'll report tonight or later when I have the camera to test it with.

Re: 5D flash sync limit with flash turned off

uscpsycho — Tue, 14 Mar 2017 06:28:47 GMT

Waddizzle wrote:

Charge your batteries prior to your shoot, and carry some fully charged spares.. Wear a photo vest, if you need more pockets.

If your flash batteries run down in the middle of a shoot, and you have no spares, then that is poor planning on your part, not a "stupid design" on Canon's part.

If you get the impression that I think you complaint is petty, then you would be correct.

This is a clear design flaw. You sound like a fan boy.

Re: 5D flash sync limit with flash turned off

uscpsycho — Tue, 14 Mar 2017 06:32:39 GMT

@Ray-uk wrote:
I don't know how exactly the 5D senses the flash but most canon DSLRs have a microswitch built into the hot shoe, this is activated by sliding the foot of the flash into the shoe. It doesn't even have to be a flashgun, a flat piece of plastic the right size will activate the switch and as far as the camera is concerned that switch being activated means an external flash is fitted. There is not normally any intelligent sensing for this facility.

The 5D does not work that way. If the flash is mounted and turned off (with charged batteries) it ignores the flash. The odd thing is that in the exact same situation, if the batteries are dead the camera acts as if the flash is on and limits shutter speed to 1/200.

While some people in this thread think that makes perfectly good sense, it does not make ANY sense whatsoever.

Re: 5D flash sync limit with flash turned off

uscpsycho — Tue, 14 Mar 2017 06:50:51 GMT

@diverhank wrote:

Strange...I need to test this with my 5DIII tonight. Last night I was shooting with a mounted flash on my 7DII and it didn't behave this way. With the flash mounted but turned off, there was no speed restriction.

I can understand that with the flash turned on - even with dead batteries, the camera still sees it as flash on. The batteries may be low enough not to fire but there is still some power in the system. What I don't get is with it turned off and the camera still thinks the flash is on.

In many cases I mount the flash on my 5DIII camera all the time without turning it on. I can't recall running into this problem. I'll report tonight or later when I have the camera to test it with.

Test this with dead batteries if you have any. If I'm using charged batteries in my flash then my 5DmkIII does not limite shutter speed if the flash is turned of. Just like your 7D. The strange thing is with completely dead batteries my camera limits shutter speed even when the flash is on or off.

I do not have any more dead batteries but I just tried to replicate this behavior with no batteries in the flash and the camera acted as one would expect - no shutter speed limitations whether the flash was on or off. So there is something specific to having dead batteries in there.

On the day in question, when I had dead batteries in my flash, I was able to replicate this several times by taking the flash off my body and putting it back on. Each time I put the flash on my camera with the flash turned off, my shutter speed was limited to 1/200. It's not like this was some bizarre one-time ocurrance.

Re: 5D flash sync limit with flash turned off

diverhank — Tue, 14 Mar 2017 07:01:47 GMT

I tested on my 5DIII and with the flash mounted but turned off, it does not get limited. I had 1/500 and it stayed there. As soon as I turned the flash on, Tv went to 1/200. Turned it off, the Tv went back up to 1/500. This was how I remembered it and that how it worked on mine. Not sure what happened to yours.

I don't have any dead batteries sorry so no test but as I stated earlier...dead batteries are relative...there may not be sufficient charge to power the flash but there is still enough juice to tell the camera that the flash is on...no surprise there.