Does custom menu item #21 work correctly?

Full_Stop · 07-03-2012, 07:37 AM

I was trying to use my external flash in wireless mode yesterday and I couldn't tell any difference between option 1 and 2 (Custom Menu #21 - Flash in Wireless Mode). My understanding is that option 2 should set the onboard flash to only fire the pre-flash and not during the exposure, but it doesn't seem to work. I was taking photos of my daughter and I can clearly see the onboard flash reflected in her eyes with either setting.

Does this setting work for everyone else?

RonHendriks1966 · 07-03-2012, 07:43 AM

You still get the preflash for metering. It shouldn't be part of the flash itself when taking the picture.

You can test it when setting the external flash pointing elswhere or blocking the flash, so it should be dark.

Full_Stop · 07-03-2012, 08:04 AM

I know it shouldn't be part of the exposure, but it is. I'm wondering if my camera is messed up or if it's a general K-5 problem.

If it is just my camera that's not working correctly, it seems like a very strange problem for a single unit to exhibit. I have the latest firmware installed and I'm pretty sure that I have noticed this problem in the past with older firmware, but I don't use the camera this way very often so I just ignored it. I would like to be able to use it this way from time to time, though.

Aegon · 07-03-2012, 08:23 AM

I'm about 50% sure that the pop-up flash still fires at minimum output, which shouldn't light up anything further than 1 foot away.

If you are testing stuff closer than 1 foot, you might see it.

I don't have my body to test, but I'm pretty sure this is the case.

Full_Stop · 07-03-2012, 08:39 AM

Some images to illustrate how much it affects the exposure. Admittedly the first example is exaggerated by my camera settings and distance, but it's pretty illustrative of how much this can affect an image. My external flash was turned on and being controlled, but the strobe was covered to prevent affecting the exposure at all.

Flash Off

Flash On

Flash Off

Flash On

Anvh · 07-03-2012, 09:01 AM

The inboard flash still need to go off during the exposure to actually trigger the external flash but the output off the flash is at the lowest setting.

you're examples doesn't show anything really. At ISO800 and such a distance the flash even show up indeed at those settings because there is a minimum the flash can go to, now put the ISO at 100 and do the test again.

Full_Stop · 07-03-2012, 09:16 AM

I disagree that there is any reason for the flash to be going off during the exposure, but that is probably the way Pentax implemented this. It's really poor, and it ruins portraits because no matter how low the flash power is you're going to get point catchlights in the eyes.

Darren · 07-03-2012, 10:04 AM

I've suffered this in the past - there is no way to stop it entirely as it is needed to trigger the wireless flash - block it from directly hitting the model if catch-lights are a problem - even a finger should do the trick. The wireless flash will work from a bounced/diffused signal from it.

**eccs19** · 07-03-2012, 10:12 AM

I've noticed the same thing with my K5, so it's not just your unit. I also don't think it's a Pentax specific issue. I've seen videos in the past where someone has built a reflector of sorts to go in front of the pop up flash, and reflect it up. I expect this is the only way to totally eliminate the bit of light that is coming from it.

Anvh · 07-03-2012, 12:06 PM

Originally posted by Full_Stop

I disagree that there is any reason for the flash to be going off during the exposure, but that is probably the way Pentax implemented this. It's really poor, and it ruins portraits because no matter how low the flash power is you're going to get point catchlights in the eyes.

Disagree what you want but this the way it works with Nikon and Canon as well.

amoringello · 07-03-2012, 12:40 PM

If the on-board flash does not fire, how will the remote flash know when to fire?
Something has to tell it when to go... and that is the on-board flash.

You'll see it in a mirror, reflective objects and when you are very close to the subject.
Normally its power is low enough to not contribute to the scene.

As Anvh said, they all the same...

bxf · 07-03-2012, 04:42 PM

Originally posted by amoringello

If the on-board flash does not fire, how will the remote flash know when to fire?
Something has to tell it when to go... and that is the on-board flash.

You'll see it in a mirror, reflective objects and when you are very close to the subject.
Normally its power is low enough to not contribute to the scene.

As Anvh said, they all the same...

I had assumed that "Wireless Flash" used some radio wave technology to trigger the flash. I didn't know that it actually referred to the decades-old optical slave mechanism. If that is all it is, why make a big deal about "Wireless Flash" feature? I have some ancient and cheap flashes that can be triggered as slaves, without being "Wireless". Is there more to it than this?

amoringello · 07-03-2012, 05:18 PM

Not much more except that there are multiple flashes, some for metering, some to potentially communicate other info. So its not just a dumb slave... but in the end the final pre-flash can be thought that way.

Wy still use it? Its cheap to implement since the camera already has the built in transmitter (popup flash) and receiver (your sensor).

Hopefully one day, cameras will have built in radio systems... but I think for a long time, few will be as good as dedicated systems. So maybe adoption will be too slow for that to ever happen.

Anvh · 07-03-2012, 07:21 PM

Also there are 4 channels to pick from, it really isnt a dumb system.
Besides only recently canon actually give you this option with the build in flash, you used to had to buy an extra external flash for this.

bxf · 07-03-2012, 07:52 PM

Although I was well aware of the fact, it appears that while composing my post I did forget the fact that there's P-TTL, etc. Good to be reminded. Still, it would be nice if the off-camera flash could be triggered without having to fire the built-in one. Maybe later

07-03-2012, 07:37 AM	#1
Full_Stop Junior Member Join Date: Feb 2010 Location: South Carolina Photos: Albums Posts: 30	Does custom menu item #21 work correctly? I was trying to use my external flash in wireless mode yesterday and I couldn't tell any difference between option 1 and 2 (Custom Menu #21 - Flash in Wireless Mode). My understanding is that option 2 should set the onboard flash to only fire the pre-flash and not during the exposure, but it doesn't seem to work. I was taking photos of my daughter and I can clearly see the onboard flash reflected in her eyes with either setting. Does this setting work for everyone else?

07-03-2012, 04:42 PM	#12
bxf Veteran Member Join Date: Jul 2010 Location: Lisbon area Posts: 1,660	Wireless, or plain old Slave? Originally posted by amoringello If the on-board flash does not fire, how will the remote flash know when to fire? Something has to tell it when to go... and that is the on-board flash. You'll see it in a mirror, reflective objects and when you are very close to the subject. Normally its power is low enough to not contribute to the scene. As Anvh said, they all the same... I had assumed that "Wireless Flash" used some radio wave technology to trigger the flash. I didn't know that it actually referred to the decades-old optical slave mechanism. If that is all it is, why make a big deal about "Wireless Flash" feature? I have some ancient and cheap flashes that can be triggered as slaves, without being "Wireless". Is there more to it than this?

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07-03-2012, 07:43 AM	#2
RonHendriks1966 Banned Join Date: Jan 2009 Photos: Gallery Posts: 9,675	You still get the preflash for metering. It shouldn't be part of the flash itself when taking the picture. You can test it when setting the external flash pointing elswhere or blocking the flash, so it should be dark.

07-03-2012, 08:04 AM	#3
Full_Stop Junior Member Join Date: Feb 2010 Location: South Carolina Photos: Albums Posts: 30 Original Poster	I know it shouldn't be part of the exposure, but it is. I'm wondering if my camera is messed up or if it's a general K-5 problem. If it is just my camera that's not working correctly, it seems like a very strange problem for a single unit to exhibit. I have the latest firmware installed and I'm pretty sure that I have noticed this problem in the past with older firmware, but I don't use the camera this way very often so I just ignored it. I would like to be able to use it this way from time to time, though.

07-03-2012, 08:23 AM	#4
Aegon Site Supporter Join Date: Jan 2008 Location: Portland, OR Posts: 1,416	I'm about 50% sure that the pop-up flash still fires at minimum output, which shouldn't light up anything further than 1 foot away. If you are testing stuff closer than 1 foot, you might see it. I don't have my body to test, but I'm pretty sure this is the case.

07-03-2012, 08:39 AM	#5
Full_Stop Junior Member Join Date: Feb 2010 Location: South Carolina Photos: Albums Posts: 30 Original Poster	Some images to illustrate how much it affects the exposure. Admittedly the first example is exaggerated by my camera settings and distance, but it's pretty illustrative of how much this can affect an image. My external flash was turned on and being controlled, but the strobe was covered to prevent affecting the exposure at all. Flash Off Flash On Flash Off Flash On

07-03-2012, 09:01 AM	#6
Anvh Veteran Member Join Date: Sep 2011 Posts: 4,616	The inboard flash still need to go off during the exposure to actually trigger the external flash but the output off the flash is at the lowest setting. you're examples doesn't show anything really. At ISO800 and such a distance the flash even show up indeed at those settings because there is a minimum the flash can go to, now put the ISO at 100 and do the test again.

07-03-2012, 09:16 AM	#7
Full_Stop Junior Member Join Date: Feb 2010 Location: South Carolina Photos: Albums Posts: 30 Original Poster	I disagree that there is any reason for the flash to be going off during the exposure, but that is probably the way Pentax implemented this. It's really poor, and it ruins portraits because no matter how low the flash power is you're going to get point catchlights in the eyes.

07-03-2012, 10:04 AM	#8
Darren Junior Member Join Date: Jun 2008 Location: Dunstable - UK Posts: 32	I've suffered this in the past - there is no way to stop it entirely as it is needed to trigger the wireless flash - block it from directly hitting the model if catch-lights are a problem - even a finger should do the trick. The wireless flash will work from a bounced/diffused signal from it.

07-03-2012, 10:12 AM	#9
eccs19 Site Supporter Join Date: Jul 2008 Location: Lisle, Ontario Photos: Gallery Posts: 1,510	I've noticed the same thing with my K5, so it's not just your unit. I also don't think it's a Pentax specific issue. I've seen videos in the past where someone has built a reflector of sorts to go in front of the pop up flash, and reflect it up. I expect this is the only way to totally eliminate the bit of light that is coming from it.

07-03-2012, 12:06 PM	#10
Anvh Veteran Member Join Date: Sep 2011 Posts: 4,616	Originally posted by Full_Stop I disagree that there is any reason for the flash to be going off during the exposure, but that is probably the way Pentax implemented this. It's really poor, and it ruins portraits because no matter how low the flash power is you're going to get point catchlights in the eyes. Disagree what you want but this the way it works with Nikon and Canon as well.

07-03-2012, 12:40 PM	#11
amoringello Veteran Member Join Date: May 2008 Location: Virginia, USA Photos: Gallery Posts: 1,562	If the on-board flash does not fire, how will the remote flash know when to fire? Something has to tell it when to go... and that is the on-board flash. You'll see it in a mirror, reflective objects and when you are very close to the subject. Normally its power is low enough to not contribute to the scene. As Anvh said, they all the same...

07-03-2012, 05:18 PM	#13
amoringello Veteran Member Join Date: May 2008 Location: Virginia, USA Photos: Gallery Posts: 1,562	Not much more except that there are multiple flashes, some for metering, some to potentially communicate other info. So its not just a dumb slave... but in the end the final pre-flash can be thought that way. Wy still use it? Its cheap to implement since the camera already has the built in transmitter (popup flash) and receiver (your sensor). Hopefully one day, cameras will have built in radio systems... but I think for a long time, few will be as good as dedicated systems. So maybe adoption will be too slow for that to ever happen.

07-03-2012, 07:21 PM	#14
Anvh Veteran Member Join Date: Sep 2011 Posts: 4,616	Also there are 4 channels to pick from, it really isnt a dumb system. Besides only recently canon actually give you this option with the build in flash, you used to had to buy an extra external flash for this.

07-03-2012, 07:52 PM	#15
bxf Veteran Member Join Date: Jul 2010 Location: Lisbon area Posts: 1,660	Although I was well aware of the fact, it appears that while composing my post I did forget the fact that there's P-TTL, etc. Good to be reminded. Still, it would be nice if the off-camera flash could be triggered without having to fire the built-in one. Maybe later