Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
03-14-2011, 04:48 PM - 1 Like   #1
Forum Member
sifun's Avatar

Join Date: Dec 2009
Location: Melbourne, Victoria
Photos: Albums
Posts: 58
AF540 and K7- pttl

I have a combination of the k7 and af 540, It seems I can't get the correct exposure.
I have it set to PTTL, I don't see any preflash at all? Is my AF540 busted?

03-14-2011, 04:51 PM   #2
Veteran Member
DaveHolmes's Avatar

Join Date: Jul 2010
Location: Yorkshire
Posts: 1,501
What shutterspeed are you using?
03-14-2011, 05:04 PM   #3
Forum Member
sifun's Avatar

Join Date: Dec 2009
Location: Melbourne, Victoria
Photos: Albums
Posts: 58
Original Poster
1/180 -

currently at work, don't have any pictures on me.
03-14-2011, 05:12 PM   #4
Veteran Member
DaveHolmes's Avatar

Join Date: Jul 2010
Location: Yorkshire
Posts: 1,501
QuoteOriginally posted by sifun Quote
1/180 -
May be a sync issue... Flash is something I struggle with but at that speed it should be sync-ing properly...
Any chance you can try the flash on another body?

03-14-2011, 05:18 PM   #5
Forum Member
sifun's Avatar

Join Date: Dec 2009
Location: Melbourne, Victoria
Photos: Albums
Posts: 58
Original Poster
unfortunately my friends have all gone to canikon, I am the only pentax user I know now.

PTTL is lit up on the unit, but I don't see any preflash at all- i'm hoping the thing isn't busted.
03-14-2011, 05:22 PM   #6
Senior Member




Join Date: May 2009
Location: New York
Posts: 155
The p-ttl never worked for me with either my k10d or k7. I tried an AF360 and a Sigma Ef 530 Super. One pic would come out under exposed and the next over exposed. It never got it right. Sadly it was one of the reasons I went to Canon.
03-14-2011, 05:26 PM   #7
Senior Member




Join Date: May 2009
Location: New York
Posts: 155
Forgot to mention, center weighed average worked best for me with the external flashes.
03-14-2011, 05:29 PM   #8
Veteran Member
DaveHolmes's Avatar

Join Date: Jul 2010
Location: Yorkshire
Posts: 1,501
QuoteOriginally posted by HeavyD Quote
Forgot to mention, center weighed average worked best for me with the external flashes.
This is new info for me!! I shall try that HeavyD... Cheers

Dave

03-14-2011, 05:39 PM   #9
Pentaxian




Join Date: Feb 2009
Location: Alameda, CA
Posts: 3,196
QuoteOriginally posted by sifun Quote
I have a combination of the k7 and af 540, It seems I can't get the correct exposure.
So what kind of exposure do you get? Too dark? Too bright? All over the map? Accurate details will help.

QuoteOriginally posted by sifun Quote
I have it set to PTTL, I don't see any preflash at all? Is my AF540 busted?
The preflash strobe and the main strobe is about 1/50 sec apart. Most people can't tell there are two strobes.

Try the same setting, but set the camera in 2 sec timer mode. You should see the sequence: preflash strobe - mirror rising - 2 seconds - main strobe.

In my experience, p-TTL in K10D and K20D doesn't produce consistent exposure. But it is significantly improved in the K7.
03-14-2011, 05:53 PM   #10
Forum Member
sifun's Avatar

Join Date: Dec 2009
Location: Melbourne, Victoria
Photos: Albums
Posts: 58
Original Poster
QuoteOriginally posted by SOldBear Quote
So what kind of exposure do you get? Too dark? Too bright? All over the map? Accurate details will help.

Try the same setting, but set the camera in 2 sec timer mode. You should see the sequence: preflash strobe - mirror rising - 2 seconds - main strobe.

In my experience, p-TTL in K10D and K20D doesn't produce consistent exposure. But it is significantly improved in the K7.
Exposure is too bright- either direct or bounce, the subject is over-exposed.
the subject is half a metre away- example F4, 1/180, ISO AUTO

I'll try the 2 sec timer mode to see if theres a pre flash. I should be able to see it 1/50 should be slow enough to see it.
03-14-2011, 06:20 PM   #11
Pentaxian




Join Date: Feb 2009
Location: Alameda, CA
Posts: 3,196
QuoteOriginally posted by sifun Quote
the subject is half a metre away
Can you try "normal" distance, like 3 meters?

QuoteOriginally posted by sifun Quote
I should be able to see it 1/50 should be slow enough to see it.
Movies use about 1/24 - 1/30 sec between frames. Most people I know can't tell them apart.
03-15-2011, 08:45 PM   #12
Veteran Member




Join Date: Apr 2007
Location: Melb. Aust
Posts: 841
yes, at 1/2 metre, you'd probably want the head down in the 'close up' position.

My K7/AF540 occasionly gets it wrong (usually when being bounced) but generally, they work fine. Much better than the K10D ever did.

I do have an issue where the thing won't fire as the master in wireless mode (will only fire as a slave). Can't find my book to check I'm setting it up correctly though!
03-15-2011, 10:26 PM   #13
Pentaxian




Join Date: Feb 2009
Location: Alameda, CA
Posts: 3,196
QuoteOriginally posted by HGMonaro Quote
I do have an issue where the thing won't fire as the master in wireless mode (will only fire as a slave).
By definition, a flash can act as a master or a control only when it is attached to the camera body, either directly to the camera's hotshoe, or via a p-TTL cord.

A flash that is triggered wirelessly by a master or a control flash is a slave.
03-15-2011, 10:59 PM   #14
Pentaxian
twitch's Avatar

Join Date: Nov 2009
Posts: 4,571
QuoteOriginally posted by sifun Quote
Exposure is too bright- either direct or bounce, the subject is over-exposed.
the subject is half a metre away- example F4, 1/180, ISO AUTO

I'll try the 2 sec timer mode to see if theres a pre flash. I should be able to see it 1/50 should be slow enough to see it.
1/2 meter away is way way too close. You need to bounce it behind you if your camera is that close to the subject, or get it off camera.

My k-x is very very consistant using pTTL, I find it excellent, your K-7 should be the same.

What mode are you shooting in? If it's indoor you should be in manual mode on the camera and pTTL on the flash, then control your flash exposure using the FEC on your flash unit. If you are using the flash indoor in Av mode on camera and pTTL on the flash, then you absolutely need to change that and shoot manual mode on the camera, in Av mode the flash acts as fill flash only, and the camera exposes for ambient only.
03-16-2011, 10:01 PM   #15
Veteran Member




Join Date: Apr 2007
Location: Melb. Aust
Posts: 841
QuoteOriginally posted by SOldBear Quote
By definition, a flash can act as a master or a control only when it is attached to the camera body, either directly to the camera's hotshoe, or via a p-TTL cord.

A flash that is triggered wirelessly by a master or a control flash is a slave.
yeah but... I want the off camera flash to be the main/only light source. Correct me if I'm wrong, but I thought it was capable of this? IF so, what settings should I have (on camera and flash)
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!
af540, camera, k7, pentax help, photography, pttl
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
AF540 PTTL with TAV on K5? D4rknezz Troubleshooting and Beginner Help 9 01-26-2011 06:10 AM
PTTL and the K7 yegnal Pentax DSLR Discussion 10 02-27-2010 04:45 PM
ttl vs. pttl flash oatman911 Flashes, Lighting, and Studio 3 03-31-2009 08:53 AM
Best Non-PTTL flash for K10D les9596 Flashes, Lighting, and Studio 11 02-02-2009 06:36 PM
Do I need to use PTTL? stkelly52 Pentax Camera and Field Accessories 14 11-28-2008 07:57 PM



All times are GMT -7. The time now is 10:43 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