Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
10-09-2013, 12:04 AM   #16
sTi
Forum Member




Join Date: Feb 2011
Posts: 98
QuoteOriginally posted by jaad75 Quote
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
Site Supporter
p38arover's Avatar

Join Date: Mar 2012
Location: Western Sydney, Australia
Photos: Gallery | Albums
Posts: 3,078
QuoteOriginally posted by jaad75 Quote
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
Site Supporter
p38arover's Avatar

Join Date: Mar 2012
Location: Western Sydney, Australia
Photos: Gallery | Albums
Posts: 3,078
QuoteOriginally posted by tabl10s Quote
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
Veteran Member




Join Date: Dec 2010
Location: Frog-eaters country
Photos: Gallery
Posts: 359
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
Veteran Member
awaldram's Avatar

Join Date: May 2008
Location: Hampshire
Photos: Gallery
Posts: 720
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
Veteran Member




Join Date: Sep 2007
Location: Cracow
Posts: 457
QuoteOriginally posted by Digitalis Quote
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
Loyal Site Supporter




Join Date: Aug 2011
Photos: Albums
Posts: 1,861
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
Loyal Site Supporter




Join Date: Aug 2011
Photos: Albums
Posts: 1,861
Original Poster
QuoteOriginally posted by jaad75 Quote
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
Pentaxian
Digitalis's Avatar

Join Date: Mar 2009
Location: Adelaide.
Posts: 8,795
QuoteOriginally posted by grahame Quote
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, 08:14 AM   #25
Veteran Member




Join Date: Sep 2007
Location: Cracow
Posts: 457
QuoteOriginally posted by Digitalis Quote
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
Pentaxian
Digitalis's Avatar

Join Date: Mar 2009
Location: Adelaide.
Posts: 8,795
QuoteOriginally posted by jaad75 Quote
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.

QuoteOriginally posted by jaad75 Quote
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.
10-09-2013, 03:53 PM   #27
Veteran Member




Join Date: Sep 2007
Location: Cracow
Posts: 457
QuoteOriginally posted by Digitalis Quote
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
Pentaxian
Digitalis's Avatar

Join Date: Mar 2009
Location: Adelaide.
Posts: 8,795
QuoteOriginally posted by jaad75 Quote
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
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
Pentaxian
Digitalis's Avatar

Join Date: Mar 2009
Location: Adelaide.
Posts: 8,795
QuoteOriginally posted by jaad75 Quote
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.
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
dslr, flash, k-3, k3, mp, pentax k-3
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
K3 officially released in Australia WA-surfer Pentax K-3 21 01-19-2014 12:17 PM
K3 on Pentax forums banner lurchlarson Pentax News and Rumors 9 10-07-2013 06:34 PM
K7 - Upgrade to K30, buy a "cheap" K5 or Wait for the K3? EstimatedEyes Pentax K-30 & K-50 13 07-18-2012 04:14 PM
No focus assist beam with third-party flash on Kx pete_pf Flashes, Lighting, and Studio 3 10-25-2011 02:01 PM
'No Go' on external flash. NLAlston Flashes, Lighting, and Studio 9 03-07-2007 05:36 PM



All times are GMT -7. The time now is 12:50 AM. | See also: NikonForums.com, CanonForums.com part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top