AF540 and K7- pttl

sifun · 03-14-2011, 04:48 PM - **1 Like**

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?

DaveHolmes · 03-14-2011, 04:51 PM

What shutterspeed are you using?

sifun · 03-14-2011, 05:04 PM

1/180 -

currently at work, don't have any pictures on me.

DaveHolmes · 03-14-2011, 05:12 PM

Originally posted by sifun

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?

sifun · 03-14-2011, 05:18 PM

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.

HeavyD · 03-14-2011, 05:22 PM

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.

HeavyD · 03-14-2011, 05:26 PM

Forgot to mention, center weighed average worked best for me with the external flashes.

DaveHolmes · 03-14-2011, 05:29 PM

Originally posted by HeavyD

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

SOldBear · 03-14-2011, 05:39 PM

Originally posted by sifun

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.

Originally posted by sifun

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.

sifun · 03-14-2011, 05:53 PM

Originally posted by SOldBear

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.

SOldBear · 03-14-2011, 06:20 PM

Originally posted by sifun

the subject is half a metre away

Can you try "normal" distance, like 3 meters?

Originally posted by sifun

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.

HGMonaro · 03-15-2011, 08:45 PM

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!

SOldBear · 03-15-2011, 10:26 PM

Originally posted by HGMonaro

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.

twitch · 03-15-2011, 10:59 PM

Originally posted by sifun

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.

HGMonaro · 03-16-2011, 10:01 PM

Originally posted by SOldBear

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)

03-14-2011, 04:48 PM - 1 Like	#1
sifun Forum Member 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?

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03-14-2011, 04:51 PM	#2
DaveHolmes Veteran Member Join Date: Jul 2010 Location: Yorkshire Posts: 1,501	What shutterspeed are you using?

03-14-2011, 05:04 PM	#3
sifun Forum Member 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
DaveHolmes Veteran Member Join Date: Jul 2010 Location: Yorkshire Posts: 1,501	Originally posted by sifun 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
sifun Forum Member 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
HeavyD Inactive Account 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
HeavyD Inactive Account 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
DaveHolmes Veteran Member Join Date: Jul 2010 Location: Yorkshire Posts: 1,501	Originally posted by HeavyD 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
SOldBear Veteran Member Join Date: Feb 2009 Location: Alameda, CA Posts: 3,206	Originally posted by sifun 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. Originally posted by sifun 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
sifun Forum Member Join Date: Dec 2009 Location: Melbourne, Victoria Photos: Albums Posts: 58 Original Poster	Originally posted by SOldBear 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
SOldBear Veteran Member Join Date: Feb 2009 Location: Alameda, CA Posts: 3,206	Originally posted by sifun the subject is half a metre away Can you try "normal" distance, like 3 meters? Originally posted by sifun 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
HGMonaro Veteran Member Join Date: Apr 2007 Location: Melb. Aust Posts: 840	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
SOldBear Veteran Member Join Date: Feb 2009 Location: Alameda, CA Posts: 3,206	Originally posted by HGMonaro 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
twitch Veteran Member Join Date: Nov 2009 Posts: 4,571	Originally posted by sifun 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
HGMonaro Veteran Member Join Date: Apr 2007 Location: Melb. Aust Posts: 840	Originally posted by SOldBear 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)