The flash light hits the photo only when the shutter speed is less than the stated on

Si1maron · 05-10-2022, 12:11 PM

I have a Pentax K-x with ~20k shutter activations. Recently, I've been shooting my friend at studio with Hensel studio lights. But, when I tried to go sync the flash at speed higher than 1/50th, the light from flash seemed to NOT hit the sensor. At 1/50th image is lit properly, but if I go any faster, I see that light from the flash clearly didn't hit the sensor and my photos are underexposed. I bought a Nikon SB-25 flash today and encountered the same trouble.
What can it be?

**FozzFoster** · 05-10-2022, 12:29 PM

Cameras have model specific 'flash sync' speeds that need to be met due to physical limitations with the shutter curtains.
You'll want to learn about High Speed Sync (HSS) compatible flashes if you want to exceed that threshold.
Hope that helps

Si1maron · 05-10-2022, 12:36 PM

Originally posted by FozzFoster

Cameras have model specific 'flash sync' speeds that need to be met due to physical limitations with the shutter curtains.
You'll want to learn about High Speed Sync (HSS) compatible flashes if you want to exceed that threshold.
Hope that helps

I checked the manual for K-x, it says 1/180th. HOWEVER, at that speed the light does not get on the photo, only at 1/50th or slower, which isn't quite nice for me.

steephill · 05-10-2022, 12:54 PM

The K-x has a flash sync speed of 1/180th sec so should do better than 1/50th sec. How are you connecting to the studio flash system? What flash mode are you setting on the camera?

**rogerstg** · 05-10-2022, 01:03 PM

It could be a flash sync issue, but 1/50 is not even close to the Kx flash sync speed of 1/180. Also, sync issues usually result in part of the photo exposed, and part dark, because the second curtain started to close before the flash fired. It's almost as if the shutter has not started to open before the flash fired.

Si1maron · 05-10-2022, 01:44 PM

Originally posted by steephill

The K-x has a flash sync speed of 1/180th sec so should do better than 1/50th sec. How are you connecting to the studio flash system? What flash mode are you setting on the camera?

I tried both manual and wireless flash modes, I'm shoting in M. Using a hot shoe mounted flash synchroniser, off-brand. It sets the flash off correctly, but proper exposure is only achieavable at 1/50, at 1/60th I have dark strip on the photo, any faster gets me an underexposed photo. It happens even with the built-in flash(tested just now), and I don't understand what is wrong with the camera.

kypfer · 05-10-2022, 02:19 PM

Originally posted by Si1maron

It happens even with the built-in flash(tested just now), and I don't understand what is wrong with the camera.

Just for the purposes of diagnosis, with the lens set to "A" (if it has an aperture ring), does the built-in flash still give problems with the camera in P mode?

Si1maron · 05-10-2022, 02:27 PM

Originally posted by kypfer

Just for the purposes of diagnosis, with the lens set to "A" (if it has an aperture ring), does the built-in flash still give problems with the camera in P mode?

yep it is.

**Bob 256** · 05-10-2022, 03:01 PM

Since it's doing the same with two different flashes, the chances are pretty high that it has to do with the camera which you seemed to have realized. Does your camera have any other settings for flash (e.g. trailing shutter) that might have been selected by accident? You could try resetting your camera to factory settings but this will lose any settings you've programmed it with. The factory settings should work up to the specified shutter sync speed of 1/180s unless there's an issue with the flash sync in your camera.

Si1maron · 05-10-2022, 03:11 PM

Originally posted by Bob 256

Since it's doing the same with two different flashes, the chances are pretty high that it has to do with the camera which you seemed to have realized. Does your camera have any other settings for flash (e.g. trailing shutter) that might have been selected by accident? You could try resetting your camera to factory settings but this will lose any settings you've programmed it with. The factory settings should work up to the specified shutter sync speed of 1/180s unless there's an issue with the flash sync in your camera.

just tried that with no results whatsoever. reset, tried with built in flash, with sb25(which goes off only at 1/180 or slower), but still isn't syncing properly.

**seventhdr** · 05-10-2022, 03:52 PM

Ah! That sounds like it might be the problem. There's always a bit of a delay as the commands travel from your camera, to the flash transmitter, to the flash receiver to the flash that can cause some delay. I used to shoot with a Canon 5D Mark II and though the flash sync speed of the camera was listed at 160th of a second, I think, I had to lower the shutter speed to 1/125 to reliably get wireless triggered flashes to fire.

Going from 1/180 to 1/50 to get reliable sync seems quite a big delay. Can you try any alternative triggers?

Also can you use a sync cable to the flash? This would check whether there is anything in the camera contributing to your sync problems.

Regards

Chris

Si1maron · 05-10-2022, 04:00 PM

Originally posted by seventhdr

Ah! That sounds like it might be the problem. There's always a bit of a delay as the commands travel from your camera, to the flash transmitter, to the flash receiver to the flash that can cause some delay. I used to shoot with a Canon 5D Mark II and though the flash sync speed of the camera was listed at 160th of a second, I think, I had to lower the shutter speed to 1/125 to reliably get wireless triggered flashes to fire.

Going from 1/180 to 1/50 to get reliable sync seems quite a big delay. Can you try any alternative triggers?

Also can you use a sync cable to the flash? This would check whether there is anything in the camera contributing to your sync problems.

Regards

Chris

I don't remember the K-x having a X-sync port, only the hot shoe, and I used exclusively the hot shoe with wireless synchroniser, with sb25, and well, the built-in.
I remember that there is this little nub on the hot shoe, can it be a problem?

**clackers** · 05-10-2022, 05:16 PM

Originally posted by Si1maron

I bought a Nikon SB-25 flash today and encountered the same trouble.
What can it be?

What happens if you put the SB-25 directly into the hotshoe?

If it works at 1/180s, you have your answer - buy a better radio trigger!

Si1maron · 05-10-2022, 05:34 PM

Originally posted by clackers

What happens if you put the SB-25 directly into the hotshoe?

If it works at 1/180s, you have your answer - buy a better radio trigger!

Same thing that happens with studio's Hensel and radio trigger, and same thing that happens with built-in. At 1/180 my camera doesn't catch light from flash, nor built-in, nor studio with radio trigger, nor my new sb25. only 1/50 or slower.

**clackers** · 05-10-2022, 08:53 PM

Originally posted by Si1maron

Same thing that happens with studio's Hensel and radio trigger, and same thing that happens with built-in. At 1/180 my camera doesn't catch light from flash, nor built-in, nor studio with radio trigger, nor my new sb25. only 1/50 or slower.

Yep, something definitely wrong if the built in flash doesn't work.

05-10-2022, 12:11 PM	#1
Si1maron Junior Member Join Date: May 2022 Location: Moscow Photos: Albums Posts: 49	The flash light hits the photo only when the shutter speed is less than the stated on I have a Pentax K-x with ~20k shutter activations. Recently, I've been shooting my friend at studio with Hensel studio lights. But, when I tried to go sync the flash at speed higher than 1/50th, the light from flash seemed to NOT hit the sensor. At 1/50th image is lit properly, but if I go any faster, I see that light from the flash clearly didn't hit the sensor and my photos are underexposed. I bought a Nikon SB-25 flash today and encountered the same trouble. What can it be?

05-10-2022, 04:00 PM	#12
Si1maron Junior Member Join Date: May 2022 Location: Moscow Photos: Albums Posts: 49 Original Poster	Originally posted by seventhdr Ah! That sounds like it might be the problem. There's always a bit of a delay as the commands travel from your camera, to the flash transmitter, to the flash receiver to the flash that can cause some delay. I used to shoot with a Canon 5D Mark II and though the flash sync speed of the camera was listed at 160th of a second, I think, I had to lower the shutter speed to 1/125 to reliably get wireless triggered flashes to fire. Going from 1/180 to 1/50 to get reliable sync seems quite a big delay. Can you try any alternative triggers? Also can you use a sync cable to the flash? This would check whether there is anything in the camera contributing to your sync problems. Regards Chris I don't remember the K-x having a X-sync port, only the hot shoe, and I used exclusively the hot shoe with wireless synchroniser, with sb25, and well, the built-in. I remember that there is this little nub on the hot shoe, can it be a problem? Attached Images

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05-10-2022, 12:29 PM	#2
FozzFoster Custom User Title Join Date: Jan 2016 Location: Alberta Photos: Albums Posts: 6,806	Cameras have model specific 'flash sync' speeds that need to be met due to physical limitations with the shutter curtains. You'll want to learn about High Speed Sync (HSS) compatible flashes if you want to exceed that threshold. Hope that helps

05-10-2022, 12:36 PM	#3
Si1maron Junior Member Join Date: May 2022 Location: Moscow Photos: Albums Posts: 49 Original Poster	Originally posted by FozzFoster Cameras have model specific 'flash sync' speeds that need to be met due to physical limitations with the shutter curtains. You'll want to learn about High Speed Sync (HSS) compatible flashes if you want to exceed that threshold. Hope that helps I checked the manual for K-x, it says 1/180th. HOWEVER, at that speed the light does not get on the photo, only at 1/50th or slower, which isn't quite nice for me.

05-10-2022, 12:54 PM	#4
steephill Pentaxian Join Date: Nov 2018 Photos: Gallery Posts: 585	The K-x has a flash sync speed of 1/180th sec so should do better than 1/50th sec. How are you connecting to the studio flash system? What flash mode are you setting on the camera?

05-10-2022, 01:03 PM	#5
rogerstg Loyal Site Supporter Join Date: Oct 2007 Location: Rhode Island Photos: Albums Posts: 1,168	It could be a flash sync issue, but 1/50 is not even close to the Kx flash sync speed of 1/180. Also, sync issues usually result in part of the photo exposed, and part dark, because the second curtain started to close before the flash fired. It's almost as if the shutter has not started to open before the flash fired.

05-10-2022, 01:44 PM	#6
Si1maron Junior Member Join Date: May 2022 Location: Moscow Photos: Albums Posts: 49 Original Poster	Originally posted by steephill The K-x has a flash sync speed of 1/180th sec so should do better than 1/50th sec. How are you connecting to the studio flash system? What flash mode are you setting on the camera? I tried both manual and wireless flash modes, I'm shoting in M. Using a hot shoe mounted flash synchroniser, off-brand. It sets the flash off correctly, but proper exposure is only achieavable at 1/50, at 1/60th I have dark strip on the photo, any faster gets me an underexposed photo. It happens even with the built-in flash(tested just now), and I don't understand what is wrong with the camera.

05-10-2022, 02:19 PM	#7
kypfer Pentaxian Join Date: Jan 2018 Location: Jersey C.I. Posts: 3,593	Originally posted by Si1maron It happens even with the built-in flash(tested just now), and I don't understand what is wrong with the camera. Just for the purposes of diagnosis, with the lens set to "A" (if it has an aperture ring), does the built-in flash still give problems with the camera in P mode?

05-10-2022, 02:27 PM	#8
Si1maron Junior Member Join Date: May 2022 Location: Moscow Photos: Albums Posts: 49 Original Poster	Originally posted by kypfer Just for the purposes of diagnosis, with the lens set to "A" (if it has an aperture ring), does the built-in flash still give problems with the camera in P mode? yep it is.

05-10-2022, 03:01 PM	#9
Bob 256 Site Supporter Join Date: Jun 2008 Location: Idaho Photos: Gallery Posts: 2,375	Since it's doing the same with two different flashes, the chances are pretty high that it has to do with the camera which you seemed to have realized. Does your camera have any other settings for flash (e.g. trailing shutter) that might have been selected by accident? You could try resetting your camera to factory settings but this will lose any settings you've programmed it with. The factory settings should work up to the specified shutter sync speed of 1/180s unless there's an issue with the flash sync in your camera.

05-10-2022, 03:11 PM	#10
Si1maron Junior Member Join Date: May 2022 Location: Moscow Photos: Albums Posts: 49 Original Poster	Originally posted by Bob 256 Since it's doing the same with two different flashes, the chances are pretty high that it has to do with the camera which you seemed to have realized. Does your camera have any other settings for flash (e.g. trailing shutter) that might have been selected by accident? You could try resetting your camera to factory settings but this will lose any settings you've programmed it with. The factory settings should work up to the specified shutter sync speed of 1/180s unless there's an issue with the flash sync in your camera. just tried that with no results whatsoever. reset, tried with built in flash, with sb25(which goes off only at 1/180 or slower), but still isn't syncing properly.

05-10-2022, 03:52 PM	#11
seventhdr Site Supporter Join Date: Mar 2007 Location: Christchurch, New Zealand Photos: Gallery Posts: 1,440	Ah! That sounds like it might be the problem. There's always a bit of a delay as the commands travel from your camera, to the flash transmitter, to the flash receiver to the flash that can cause some delay. I used to shoot with a Canon 5D Mark II and though the flash sync speed of the camera was listed at 160th of a second, I think, I had to lower the shutter speed to 1/125 to reliably get wireless triggered flashes to fire. Going from 1/180 to 1/50 to get reliable sync seems quite a big delay. Can you try any alternative triggers? Also can you use a sync cable to the flash? This would check whether there is anything in the camera contributing to your sync problems. Regards Chris

05-10-2022, 05:16 PM	#13
clackers Otis Memorial Pentaxian Join Date: Jul 2013 Location: Melbourne Photos: Albums Posts: 16,397	Originally posted by Si1maron I bought a Nikon SB-25 flash today and encountered the same trouble. What can it be? What happens if you put the SB-25 directly into the hotshoe? If it works at 1/180s, you have your answer - buy a better radio trigger!

05-10-2022, 05:34 PM	#14
Si1maron Junior Member Join Date: May 2022 Location: Moscow Photos: Albums Posts: 49 Original Poster	Originally posted by clackers What happens if you put the SB-25 directly into the hotshoe? If it works at 1/180s, you have your answer - buy a better radio trigger! Same thing that happens with studio's Hensel and radio trigger, and same thing that happens with built-in. At 1/180 my camera doesn't catch light from flash, nor built-in, nor studio with radio trigger, nor my new sb25. only 1/50 or slower.

05-10-2022, 08:53 PM	#15
clackers Otis Memorial Pentaxian Join Date: Jul 2013 Location: Melbourne Photos: Albums Posts: 16,397	Originally posted by Si1maron Same thing that happens with studio's Hensel and radio trigger, and same thing that happens with built-in. At 1/180 my camera doesn't catch light from flash, nor built-in, nor studio with radio trigger, nor my new sb25. only 1/50 or slower. Yep, something definitely wrong if the built in flash doesn't work.