No upgrade in flash on K3?

sTi · 10-09-2013, 12:04 AM

Originally posted by jaad75

It was solved with K-5II - it is very accurate.

Not completely, unfortunately. It seems to be still pretty unreliable when used with large aperture lenses. See what I wrote here.

p38arover · 10-09-2013, 03:56 AM

Originally posted by jaad75

It's not a matter of 1/180s as much (by the way you can get 1/200s with a simple trick, so Pentax DSLRs are capable of this), as cutting the signal to trigger manual flashes on hot shoe and sync port. If I want to to sync at whatever shutter speed, just let me do this, even at cost of getting the shadow of shutter curtain on my photo.

Good point. I tried a Jobo PhotoGPS on my camera but it was virtually useless because the hotshoe doesn't get a trigger over 1/180th.

p38arover · 10-09-2013, 03:58 AM

Originally posted by tabl10s

p38arover:

How does an increase in MP's negate the use of higher synch speed?

No idea. Ken was referring to using a camera with a different shutter system

Couscousdelight · 10-09-2013, 04:01 AM

Accorded to Imaging ressource, the flash unit is new :

If you deploy the flash strobe, you'll also find that -- while its specifications are unchanged -- it's a new unit, with ever so slightly smaller surface area, and a linear Fresnel lens rather than a circular one.

Source : Pentax K-3 Review: Hands-On Preview

awaldram · 10-09-2013, 04:39 AM

The flash has been completely overhauled with new circuitry , new tube , new matrix sensor and new external flashes

How that can be described as 'untouched' defeats me.

Maybe it's blinkered vision seeing the 1/180 caused by a part not flash related ( shutter curtains) and looking no further ?

jaad75 · 10-09-2013, 05:17 AM

Originally posted by Digitalis

This image is from a Pentax K5IIs with the flash synced @ 1/250th

How did you do this? Triggered the strobe with pre-flash cancelling optical slave?

**grahame** · 10-09-2013, 06:06 AM

the built-in flash does not support HSS, so it will not fire if shutter is higher than 180 even if you have a HSS capable off camera flash; and wireless radio trigger or cable does not do PTTL.
Looks things are unchanged. If K3 has all new designed flash, as awaldram said, the new one is a little disappointing.
I hope it is an old one, just reshaped, so we can hope pentax will release a new one in the near future.

**grahame** · 10-09-2013, 06:12 AM

Originally posted by jaad75

How did you do this? Triggered the strobe with pre-flash cancelling optical slave?

I will guess using a HSS flash on camera to serve as controller (so you can set shutter at 250), and set non-HSS slave flash as major light source.

**Digitalis** · 10-09-2013, 07:35 AM

Originally posted by grahame

I will guess using a HSS flash on camera to serve as controller (so you can set shutter at 250), and set non-HSS slave flash as major light source.

No, I used a considerably more convoluted and expensive way to do this - In a nutshell used a Nikon D4 to fire off a studio strobe at its sync speed of 1/250th, the strobe which was an Elinchrom BRX 500 was delayed so then the shutter on my my K5IIs (which was trigger linked to the Nikon D4) would open in perfect timing to record the flash pulse. The black bar is the second curtain of the shutter mechanism.

jaad75 · 10-09-2013, 08:14 AM

Originally posted by Digitalis

the strobe which was an Elinchrom BRX 500 was delayed so then the shutter on my my K5IIs (which was trigger linked to the Nikon D4) would open in perfect timing to record the flash pulse.

Are you sure, that the delay is right? I'm asking cause there is a way to trigger the flash with 1/200s (at least that's what camera and exif says) with absolutely no trace of the rear curtain and you have a lot of it shown at 1/250s...

**Digitalis** · 10-09-2013, 03:02 PM

Originally posted by jaad75

Are you sure, that the delay is right?

The delay I programmed in is accurate, basically all I had to do is compensate for the difference in shutter lag between the D4 and the K5IIs.

Originally posted by jaad75

I'm asking cause there is a way to trigger the flash with 1/200s (at least that's what camera and exif says) with absolutely no trace of the rear curtain and you have a lot of it shown at 1/250s.

The difference between 1/180th and 1/200th is trivial - though going from 1/180th to 1/250th is a bigger difference, with flash synced at 1/320th, slightly less than half of the frame is blacked out from the shutter curtain. At 1/400th three quarters of the frame is blacked out by the second curtain. My testing was done with the BRX flash unit at full power - the T=0.1 duration of the Elinchrom BRX ( which uses similar circuitry to the older BRXi units) is roughly 1/500th - the T=0.1 time with hotshoe flashes can be longer than this at full power.

jaad75 · 10-09-2013, 03:53 PM

Originally posted by Digitalis

The delay I programmed in is accurate, basically all I had to do is compensate for the difference in shutter lag between the D4 and the K5IIs.

Did you try to shorten the delay to catch the first curtain opening at the end of the frame?

**Digitalis** · 10-09-2013, 04:01 PM

Originally posted by jaad75

Did you try to shorten the delay to catch the first curtain opening at the end of the frame?

And the point of doing that would be?

jaad75 · 10-09-2013, 04:22 PM

Just to make sure the delay was absolutely not longer than necessary (and to prove there is no way to further optimize it

)

**Digitalis** · 10-09-2013, 08:45 PM

Originally posted by jaad75

Just to make sure the delay was absolutely not longer than necessary (and to prove there is no way to further optimize it

No further "optimization" was possible with flash timings - if you call having black bars at the top and bottom of the image an "optimal" result.

Pentax will have to re-design the shutter units for a Full frame camera anyway - Pentax have been coasting along with the same basic shutter design since the *Ist DSLRs, With a new full frame model they might as well give it a 1/250th sync speed.

10-09-2013, 08:14 AM	#25
jaad75 Veteran Member Join Date: Sep 2007 Location: Cracow Posts: 457	Originally posted by Digitalis the strobe which was an Elinchrom BRX 500 was delayed so then the shutter on my my K5IIs (which was trigger linked to the Nikon D4) would open in perfect timing to record the flash pulse. Are you sure, that the delay is right? I'm asking cause there is a way to trigger the flash with 1/200s (at least that's what camera and exif says) with absolutely no trace of the rear curtain and you have a lot of it shown at 1/250s... Last edited by jaad75; 10-09-2013 at 12:11 PM.

10-09-2013, 03:02 PM	#26
Digitalis Site Supporter Join Date: Mar 2009 Location: Melbourne, Victoria Photos: Gallery Posts: 11,694	Originally posted by jaad75 Are you sure, that the delay is right? The delay I programmed in is accurate, basically all I had to do is compensate for the difference in shutter lag between the D4 and the K5IIs. Originally posted by jaad75 I'm asking cause there is a way to trigger the flash with 1/200s (at least that's what camera and exif says) with absolutely no trace of the rear curtain and you have a lot of it shown at 1/250s. The difference between 1/180th and 1/200th is trivial - though going from 1/180th to 1/250th is a bigger difference, with flash synced at 1/320th, slightly less than half of the frame is blacked out from the shutter curtain. At 1/400th three quarters of the frame is blacked out by the second curtain. My testing was done with the BRX flash unit at full power - the T=0.1 duration of the Elinchrom BRX ( which uses similar circuitry to the older BRXi units) is roughly 1/500th - the T=0.1 time with hotshoe flashes can be longer than this at full power. Last edited by Digitalis; 10-09-2013 at 03:15 PM.

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10-09-2013, 12:04 AM	#16
sTi Forum Member Join Date: Feb 2011 Posts: 98	Originally posted by jaad75 It was solved with K-5II - it is very accurate. Not completely, unfortunately. It seems to be still pretty unreliable when used with large aperture lenses. See what I wrote here.

10-09-2013, 03:56 AM	#17
p38arover Veteran Member Join Date: Mar 2012 Location: Western Sydney, Australia Photos: Gallery \| Albums Posts: 3,084	Originally posted by jaad75 It's not a matter of 1/180s as much (by the way you can get 1/200s with a simple trick, so Pentax DSLRs are capable of this), as cutting the signal to trigger manual flashes on hot shoe and sync port. If I want to to sync at whatever shutter speed, just let me do this, even at cost of getting the shadow of shutter curtain on my photo. Good point. I tried a Jobo PhotoGPS on my camera but it was virtually useless because the hotshoe doesn't get a trigger over 1/180th.

10-09-2013, 03:58 AM	#18
p38arover Veteran Member Join Date: Mar 2012 Location: Western Sydney, Australia Photos: Gallery \| Albums Posts: 3,084	Originally posted by tabl10s p38arover: How does an increase in MP's negate the use of higher synch speed? No idea. Ken was referring to using a camera with a different shutter system

10-09-2013, 04:01 AM	#19
Couscousdelight Veteran Member Join Date: Dec 2010 Location: Frog-eaters country Photos: Gallery Posts: 357	Accorded to Imaging ressource, the flash unit is new : If you deploy the flash strobe, you'll also find that -- while its specifications are unchanged -- it's a new unit, with ever so slightly smaller surface area, and a linear Fresnel lens rather than a circular one. Source : Pentax K-3 Review: Hands-On Preview

10-09-2013, 04:39 AM	#20
awaldram Veteran Member Join Date: May 2008 Location: Hampshire Photos: Gallery Posts: 732	The flash has been completely overhauled with new circuitry , new tube , new matrix sensor and new external flashes How that can be described as 'untouched' defeats me. Maybe it's blinkered vision seeing the 1/180 caused by a part not flash related ( shutter curtains) and looking no further ?

10-09-2013, 05:17 AM	#21
jaad75 Veteran Member Join Date: Sep 2007 Location: Cracow Posts: 457	Originally posted by Digitalis This image is from a Pentax K5IIs with the flash synced @ 1/250th How did you do this? Triggered the strobe with pre-flash cancelling optical slave?

10-09-2013, 06:06 AM	#22
grahame Loyal Site Supporter Join Date: Aug 2011 Photos: Albums Posts: 2,041 Original Poster	the built-in flash does not support HSS, so it will not fire if shutter is higher than 180 even if you have a HSS capable off camera flash; and wireless radio trigger or cable does not do PTTL. Looks things are unchanged. If K3 has all new designed flash, as awaldram said, the new one is a little disappointing. I hope it is an old one, just reshaped, so we can hope pentax will release a new one in the near future.

10-09-2013, 06:12 AM	#23
grahame Loyal Site Supporter Join Date: Aug 2011 Photos: Albums Posts: 2,041 Original Poster	Originally posted by jaad75 How did you do this? Triggered the strobe with pre-flash cancelling optical slave? I will guess using a HSS flash on camera to serve as controller (so you can set shutter at 250), and set non-HSS slave flash as major light source.

10-09-2013, 07:35 AM	#24
Digitalis Site Supporter Join Date: Mar 2009 Location: Melbourne, Victoria Photos: Gallery Posts: 11,694	Originally posted by grahame I will guess using a HSS flash on camera to serve as controller (so you can set shutter at 250), and set non-HSS slave flash as major light source. No, I used a considerably more convoluted and expensive way to do this - In a nutshell used a Nikon D4 to fire off a studio strobe at its sync speed of 1/250th, the strobe which was an Elinchrom BRX 500 was delayed so then the shutter on my my K5IIs (which was trigger linked to the Nikon D4) would open in perfect timing to record the flash pulse. The black bar is the second curtain of the shutter mechanism.

10-09-2013, 03:53 PM	#27
jaad75 Veteran Member Join Date: Sep 2007 Location: Cracow Posts: 457	Originally posted by Digitalis The delay I programmed in is accurate, basically all I had to do is compensate for the difference in shutter lag between the D4 and the K5IIs. Did you try to shorten the delay to catch the first curtain opening at the end of the frame?

10-09-2013, 04:01 PM	#28
Digitalis Site Supporter Join Date: Mar 2009 Location: Melbourne, Victoria Photos: Gallery Posts: 11,694	Originally posted by jaad75 Did you try to shorten the delay to catch the first curtain opening at the end of the frame? And the point of doing that would be?

10-09-2013, 04:22 PM	#29
jaad75 Veteran Member Join Date: Sep 2007 Location: Cracow Posts: 457	Just to make sure the delay was absolutely not longer than necessary (and to prove there is no way to further optimize it )

10-09-2013, 08:45 PM	#30
Digitalis Site Supporter Join Date: Mar 2009 Location: Melbourne, Victoria Photos: Gallery Posts: 11,694	Originally posted by jaad75 Just to make sure the delay was absolutely not longer than necessary (and to prove there is no way to further optimize it No further "optimization" was possible with flash timings - if you call having black bars at the top and bottom of the image an "optimal" result. Pentax will have to re-design the shutter units for a Full frame camera anyway - Pentax have been coasting along with the same basic shutter design since the *Ist DSLRs, With a new full frame model they might as well give it a 1/250th sync speed.