Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
01-13-2010, 06:46 PM   #1
Inactive Account




Join Date: Jul 2009
Location: SF
Posts: 20
out of sync flash k20d af540

I was reading an article on strobist and thought I would test my tru sync speeds on this thing. I was hoping to start to see where the little black strip would start to show up by increasing my shutter speed past the sync. Unfortunately my camera will not let me go past the 180 mark unless I switch to high speed sync and then I surely dont see the black bar because my flash is firing differently I believe. I have my flash mounted to the camera and my setting are on manual.

So the question is .. why wont my manual settings let me (screw) up the shot.. manual is restricting my creative process here I feel and Im not too happy with it.. Is there a way to continue raising my shutter speed on this thing?


Any input or link would be appreciated..

01-13-2010, 06:56 PM   #2
Veteran Member
NeverSatisfied's Avatar

Join Date: Dec 2007
Location: S.E. Michigan
Photos: Albums
Posts: 688
A buddy of mine was talking about just that kind of experiment. He had watched some kind of DVD, there was a wedding photog doing that as an artistic technique.

I have the same Pentax equipment as you. I do like my K20D! I didn't personally see the results that he had talked about, but its description didn't really pique my interest. FWIW, I just don't think it's possible with our camera system. Pretty sure the guy in the DVD was using a Canon.
01-13-2010, 07:12 PM   #3
Site Supporter
Site Supporter
Lowell Goudge's Avatar

Join Date: Jan 2007
Location: Toronto
Photos: Gallery | Albums
Posts: 17,868
I was going to look at this from a different approach.

use the PC to photograph a CRT (remember those) and see if you could count the lines from the vertical sweep at different shutter speeds, this would give a good estimate of the transit time of the shutter.

A more scientific way would be to use an osciloscope triggered from the sync contact in manual flash, with a pattern that was fixed frequency and count the cycles displayed before the shutter started cutting them off.

I would also like to know the duration of my flash at each power setting, because there have been reports that on the K10 (and I think K20) full output from an AF540 FGZ has slightly non uniform illumination of the entire frame, suggesting the shutter is moving closed before the flash finishes firing.
01-13-2010, 07:25 PM   #4
Inactive Account




Join Date: Jul 2009
Location: SF
Posts: 20
Original Poster
Oh this is all way too technical for me.. I do like the input though. I just want to see something bad happen when I move my shutter speed past the sync speed, dang camera wont let me do it even in manual mode.. well hopefully someone knows how this can be done. Pretty neat idea though if it works..

01-13-2010, 07:45 PM   #5
Moderator
Loyal Site Supporter
Wheatfield's Avatar

Join Date: Apr 2008
Location: The wheatfields of Canada
Posts: 15,903
Pentax has deliberately made it impossible by shutting off the trigger circuit above sync speed.
As a working pro, I see this as a good thing, since the darned dials are so easy to spin on these cameras, sometimes the only indication that you get that a setting has gone wonky is not seeing the flash fire.
I'm happy that they've done this, even if it prevents a user from deliberately screwing up.
01-13-2010, 09:55 PM   #6
Veteran Member




Join Date: Apr 2007
Location: Melb. Aust
Posts: 840
I'm with Wheatfield... guess they could make it a custom setting!

I do remember seeing a discussion somewhere about this and I think the idea was by only using part of the frame (sensor) you could get a higher sync speed. You just have to remember to frame the image appropiately then crop afterwards.
01-14-2010, 12:04 PM   #7
Veteran Member
Gooshin's Avatar

Join Date: Sep 2007
Location: Toronto, the one in Canada.
Posts: 5,610
QuoteOriginally posted by LeeHolliday Quote
I was reading an article on strobist and thought I would test my tru sync speeds on this thing. I was hoping to start to see where the little black strip would start to show up by increasing my shutter speed past the sync. Unfortunately my camera will not let me go past the 180 mark unless I switch to high speed sync and then I surely dont see the black bar because my flash is firing differently I believe. I have my flash mounted to the camera and my setting are on manual.

So the question is .. why wont my manual settings let me (screw) up the shot.. manual is restricting my creative process here I feel and Im not too happy with it.. Is there a way to continue raising my shutter speed on this thing?


Any input or link would be appreciated..
if you do the test and at 180 you get no lines, then you are syncing properly!

pentax does not claim to sync higher than 180, and it stops you from going higher

all the better, less room for user error.

01-14-2010, 02:32 PM   #8
Loyal Site Supporter
Loyal Site Supporter
Canada_Rockies's Avatar

Join Date: Nov 2007
Location: Sparwood, BC, Canada
Photos: Gallery | Albums
Posts: 12,385
The High Speed Sync option fires the flash multiple times as the shutter passes over the sensor/film aperture. The loss here is flash range. It decreases rapidly as the shutter speed is raised.
01-14-2010, 04:37 PM   #9
Moderator
Loyal Site Supporter
Wheatfield's Avatar

Join Date: Apr 2008
Location: The wheatfields of Canada
Posts: 15,903
QuoteOriginally posted by HGMonaro Quote
I'm with Wheatfield... guess they could make it a custom setting!

I do remember seeing a discussion somewhere about this and I think the idea was by only using part of the frame (sensor) you could get a higher sync speed. You just have to remember to frame the image appropiately then crop afterwards.
Unfortunately, it doesn't work that way. Sync speed is controlled by shutter blade speed. The faster the shutter can be accelerated, the higher the sync speed can be.
With what is being suggested here, all that one would get is a 1/180 second shutter speed with part of the frame missing.
01-14-2010, 07:41 PM   #10
Inactive Account




Join Date: Jul 2009
Location: SF
Posts: 20
Original Poster
yea i did some more searching on this one and its just not possible to move past the sync speed on the k20d. its not the end of the world but a small bummer for the little scientist in me.

heres the article i was reading to get the idea if anyone is interested in it.

Strobist: Know Your Sync

makes sense that they wouldnt allow for this.. like you said, its so easy to screw with the dials.

well thanks for the replies..
01-15-2010, 07:05 AM   #11
Site Supporter
Site Supporter
Lowell Goudge's Avatar

Join Date: Jan 2007
Location: Toronto
Photos: Gallery | Albums
Posts: 17,868
as the article suggests you need to test your flash at maximum sync and maximum power, and look for banding.

you can measure the exposure and coverage much more accuratly by using your photo editor and checking the greyscale value at different sections of the screen
01-15-2010, 09:11 PM   #12
Veteran Member
noblepa's Avatar

Join Date: Sep 2007
Location: Bay Village, Ohio USA
Posts: 1,142
Not on a Pentax

QuoteOriginally posted by HGMonaro Quote
I'm with Wheatfield... guess they could make it a custom setting!

I do remember seeing a discussion somewhere about this and I think the idea was by only using part of the frame (sensor) you could get a higher sync speed. You just have to remember to frame the image appropiately then crop afterwards.
Deliberately shooting with flash at a speed faster than the x-sync speed is possible on some cameras. In fact, from reading some of those threads, Pentax is one of the few that does not allow this.

You're right. The idea is to shoot at, say one stop higher than your sync speed, but compose the image so that nothing important is in the portion of the image that is cut off. Then, simply crop the image in PP.

I found it amusing in one thread about this, in which several users were stating that this was a major deal-breaker for them and that they were going to immediately sell their Pentax (or not buy it in the first place) and get either Canon or Nikon gear. These seem to be the same people who can't understand how Pentax can sell any cameras at all, when none of them can shoot 8 frames per second and Pentax is doomed without this feature.
01-15-2010, 09:53 PM   #13
Senior Member




Join Date: Jul 2009
Location: BC, Canada
Photos: Gallery
Posts: 174
QuoteOriginally posted by LeeHolliday Quote
yea i did some more searching on this one and its just not possible to move past the sync speed on the k20d. its not the end of the world but a small bummer for the little scientist in me.

heres the article i was reading to get the idea if anyone is interested in it.

Strobist: Know Your Sync

makes sense that they wouldnt allow for this.. like you said, its so easy to screw with the dials.

well thanks for the replies..
The Pentax camera won't let you go higher than the max sync speed because it knows you have mounted a Pentax dedicated flash onto the camera.

Well there is a workaround if you have an old auto flash (e.g. Vivitar 285HV - not the plain 285) with a single pin shoe. Now, you have to make sure that the flash trigger voltage is below 20 Voltage before mounting it onto your Pentax DSLR. With such a flash, the camera does not know the flash is mounted onto it even though the camera will still trip the sync pin and fire the flash. In manual mode with such a flash, you can use shutter speed above the max sync speed and will get the black unexposed strip.

(I don't recommend this if you are not familiar with older flashes or do not know how to measure the flash trigger voltage.)

Note: it actually does not work. It will let you dial in faster shutter speed and take the shot but the camera won't trip the flash if the shutter speed is faster than 1/180s.

Last edited by ma318; 01-16-2010 at 01:50 PM.
01-16-2010, 03:16 AM   #14
Inactive Account




Join Date: Jul 2009
Location: SF
Posts: 20
Original Poster
thats awesome! thanks so much for that one.. im gonna give that a shot for sure. I knew someone could find a way to see that black strip thing.
01-16-2010, 07:04 AM   #15
Moderator
Loyal Site Supporter
Wheatfield's Avatar

Join Date: Apr 2008
Location: The wheatfields of Canada
Posts: 15,903
QuoteOriginally posted by ma318 Quote
The Pentax camera won't let you go higher than the max sync speed because it knows you have mounted a Pentax dedicated flash onto the camera.

Well there is a workaround if you have an old auto flash (e.g. Vivitar 285HV - not the plain 285) with a single pin shoe. Now, you have to make sure that the flash trigger voltage is below 20 Voltage before mounting it onto your Pentax DSLR. With such a flash, the camera does not know the flash is mounted onto it even though the camera will still trip the sync pin and fire the flash. In manual mode with such a flash, you can use shutter speed above the max sync speed and will get the black unexposed strip.

(I don't recommend this if you are not familiar with older flashes or do not know how to measure the flash trigger voltage.)
QuoteOriginally posted by LeeHolliday Quote
thats awesome! thanks so much for that one.. im gonna give that a shot for sure. I knew someone could find a way to see that black strip thing.
Just be aware, you will get exactly the same thing as you would get shooting at sync and cropping the image.
There is no gain whatsoever from trying to fool the camera into shooting at a higher speed.
You are not getting a higher shutter speed by doing this.
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!
camera, flash, photography, shutter, sync
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Why does my k20d flash twice when using trailing curtain sync? enderkasim Pentax DSLR Discussion 6 01-28-2010 05:37 AM
k20d high speed flash sync gybp Pentax DSLR Discussion 11 12-03-2009 12:10 PM
K20D flash sync socket problems flexidan Pentax DSLR Discussion 2 10-24-2009 04:19 PM
Test: K20D PC sync and older flash Matjazz Pentax DSLR Discussion 8 08-15-2009 02:00 AM
K20d Slow Sync Flash jjeling Pentax DSLR Discussion 2 03-22-2009 08:44 PM



All times are GMT -7. The time now is 12:10 PM. | 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