Pentax AF-540 not going into P-TTL

SovereignAxe · 09-09-2008, 09:28 PM

Hey guys, I just registered here cuz I can't figure out what is wrong with my flash-plus I've searched all over the boards looking for a thread already started about the issue. I have a bad feeling I might have a defective unit.

For some reason it doesn't want to go into P-TTL mode. When I cycle through the modes it'll only go to TTL, and the camera wont even fire a flash. I was having issues with it the last time I used it in a wedding doing the same thing, but as soon as I half pressed the shutter button to activate the autofocus it would show P-TTL. Tonight I went to use it and it wouldn't sync this time. It's almost as if the camera and the flash aren't talking to each other.

My setup: Pentax *istDS with the 540 mounted directly to the hotshoe. I first tried it with my 50mm f/1.4 and found it didn't work. Put on the kit lens 18-55 and it didn't work with it either. I cycled through all the settings on the flash and the only time I can get it into P-TTL is if it's in slave mode.

I'm guessing either the flash is screwed or the hotshoe on my camera is...which is disappointing because I kept the hotshoe cover on until I got this flash which was only a few months ago.

Any better ideas or insight would be much appreciated.

Last edited by SovereignAxe; 09-10-2008 at 08:53 PM. Reason: needed a new title

garth1948 · 09-09-2008, 10:20 PM

Just a thought - are you using a program line where the in-built flash only fires when the flash is raised? Does the *istDS support P-TTL or only TTL? Have you tried M mode with lens off A setting?

I too have flash problems that at first seem inconsistent.

SovereignAxe · 09-10-2008, 06:41 AM

hmmm...now that you mention it, both of the automatic modes for the flash are greyed out. normally I can choose between auto flash, manual flash, auto flash w/red eye reduction, and manual flash w/red eye reduction. both auto settings are shown, but greyed out so I can't choose them. I have no idea why they're like that.

as for the program line, I've used everything between auto and M; P, Tv, and Av. None work with the flash.

another thing I noticed-the light on the flash normally zooms with the camera, but that's not working either. whenever I change the zoom on my lens, and half press the shutter button, the light is supposed to zoom to the same focal length, but right now it's stuck on 16mm. I can change it in manual mode, but it wont sense the focal length from the camera.

I'm starting to think I have a dead hotshoe.

SovereignAxe · 09-10-2008, 06:43 AM

I guess it's time to break down and get a K20D, amirite? lol

**Lowell Goudge** · 09-10-2008, 02:00 PM

You might want to try dirty contacts ont he lens.

One thing to note with the AF540FGZ is that on the *istD and DS where both TTL and P-TTL are supported. The 540 will sit in P-TTL mode until you press the shutter then switch to TTL if you have a lens out of the A setting.

If you are getting TTL the camera might be thinking you have a manual apature lens. check the third pin from the locking pin, on the body mount it is depressed.

Also if focal lenght is a problem it may also be due to dirty contacts specifically the furthest away from the locking pin

paulusta · 09-10-2008, 03:28 PM

talking about dirty contacts,
what do you use to clean the contacts?

**Lowell Goudge** · 09-10-2008, 04:23 PM

I use a gum eraser, (not the abrasive one on pens)

SovereignAxe · 09-10-2008, 08:52 PM

Update:

First off, I want to thank you guys for your excellent ideas-especially the one about cleaning the lens contact points. I just so happened to have an art gum eraser lying around (being an art major and all), and gently wiped up my contacts. They were about as dirty as I expected them to be-cuz I'd never cleaned them before, but nowhere near dirty enough to be the problem.

Also, I found out that my hotshoe wasn't the issue because I changed the flash to the auto manual mode (plugging in the EV settings of the camera and letting the flash do the math) and it fired off the flash without a problem. After this, and cleaning the contacts with no luck, I was about ready to take it all to a camera shop to see what was broken. Until tonight...

My girlfriend said, maybe you should ask your dad about it. I said, I doubt he'll know what's wrong, but I guess it's worth a try. My dad was an amateur photographer back in the 70s and 80s. It was just a hobby for him-he didn't get too knowledgable about everything-but he did take some decent night shots. Anyway, he comes up just before he goes to bed and starts fiddling with the flash settings to see how it works, and he ACCIDENTALLY turns the on/off sitch of the camera over to the DOF preview and BOOM-P-TTL shows up on the flash's readout and I hear the flash's motor move the bulb to whatever focal length I was on at the time. He didn't even know what the switch was for-I had to explain to him what the DOF switch did lol.

TL;DR

Cliff notes: my dad accidentally hit the DOF switch, fixed everything, he and I have no idea why it worked.

09-09-2008, 09:28 PM	#1
SovereignAxe New Member Join Date: Sep 2008 Posts: 4	Pentax AF-540 not going into P-TTL Updated with confusing remedy and some lolz Hey guys, I just registered here cuz I can't figure out what is wrong with my flash-plus I've searched all over the boards looking for a thread already started about the issue. I have a bad feeling I might have a defective unit. For some reason it doesn't want to go into P-TTL mode. When I cycle through the modes it'll only go to TTL, and the camera wont even fire a flash. I was having issues with it the last time I used it in a wedding doing the same thing, but as soon as I half pressed the shutter button to activate the autofocus it would show P-TTL. Tonight I went to use it and it wouldn't sync this time. It's almost as if the camera and the flash aren't talking to each other. My setup: Pentax istDS with the 540 mounted directly to the hotshoe. I first tried it with my 50mm f/1.4 and found it didn't work. Put on the kit lens 18-55 and it didn't work with it either. I cycled through all the settings on the flash and the only time I can get it into P-TTL is if it's in slave mode. I'm guessing either the flash is screwed or the hotshoe on my camera is...which is disappointing because I kept the hotshoe cover on until I got this flash which was only a few months ago. Any better ideas or insight would be much appreciated. Last edited by SovereignAxe; 09-10-2008 at 08:53 PM. Reason: needed a new title*

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09-09-2008, 10:20 PM	#2
garth1948 Senior Member Join Date: Dec 2007 Location: Perth Australia Photos: Gallery \| Albums Posts: 293	Just a thought - are you using a program line where the in-built flash only fires when the flash is raised? Does the *istDS support P-TTL or only TTL? Have you tried M mode with lens off A setting? I too have flash problems that at first seem inconsistent.

09-10-2008, 06:41 AM	#3
SovereignAxe New Member Join Date: Sep 2008 Posts: 4 Original Poster	hmmm...now that you mention it, both of the automatic modes for the flash are greyed out. normally I can choose between auto flash, manual flash, auto flash w/red eye reduction, and manual flash w/red eye reduction. both auto settings are shown, but greyed out so I can't choose them. I have no idea why they're like that. as for the program line, I've used everything between auto and M; P, Tv, and Av. None work with the flash. another thing I noticed-the light on the flash normally zooms with the camera, but that's not working either. whenever I change the zoom on my lens, and half press the shutter button, the light is supposed to zoom to the same focal length, but right now it's stuck on 16mm. I can change it in manual mode, but it wont sense the focal length from the camera. I'm starting to think I have a dead hotshoe.

09-10-2008, 06:43 AM	#4
SovereignAxe New Member Join Date: Sep 2008 Posts: 4 Original Poster	I guess it's time to break down and get a K20D, amirite? lol

09-10-2008, 02:00 PM	#5
Lowell Goudge Site Supporter Join Date: Jan 2007 Location: Toronto Photos: Gallery \| Albums Posts: 17,886	You might want to try dirty contacts ont he lens. One thing to note with the AF540FGZ is that on the *istD and DS where both TTL and P-TTL are supported. The 540 will sit in P-TTL mode until you press the shutter then switch to TTL if you have a lens out of the A setting. If you are getting TTL the camera might be thinking you have a manual apature lens. check the third pin from the locking pin, on the body mount it is depressed. Also if focal lenght is a problem it may also be due to dirty contacts specifically the furthest away from the locking pin

09-10-2008, 03:28 PM	#6
paulusta Junior Member Join Date: May 2008 Location: Jakarta, Indonesia Posts: 36	talking about dirty contacts, what do you use to clean the contacts?

09-10-2008, 04:23 PM	#7
Lowell Goudge Site Supporter Join Date: Jan 2007 Location: Toronto Photos: Gallery \| Albums Posts: 17,886	I use a gum eraser, (not the abrasive one on pens)

09-10-2008, 08:52 PM	#8
SovereignAxe New Member Join Date: Sep 2008 Posts: 4 Original Poster	Update: First off, I want to thank you guys for your excellent ideas-especially the one about cleaning the lens contact points. I just so happened to have an art gum eraser lying around (being an art major and all), and gently wiped up my contacts. They were about as dirty as I expected them to be-cuz I'd never cleaned them before, but nowhere near dirty enough to be the problem. Also, I found out that my hotshoe wasn't the issue because I changed the flash to the auto manual mode (plugging in the EV settings of the camera and letting the flash do the math) and it fired off the flash without a problem. After this, and cleaning the contacts with no luck, I was about ready to take it all to a camera shop to see what was broken. Until tonight... My girlfriend said, maybe you should ask your dad about it. I said, I doubt he'll know what's wrong, but I guess it's worth a try. My dad was an amateur photographer back in the 70s and 80s. It was just a hobby for him-he didn't get too knowledgable about everything-but he did take some decent night shots. Anyway, he comes up just before he goes to bed and starts fiddling with the flash settings to see how it works, and he ACCIDENTALLY turns the on/off sitch of the camera over to the DOF preview and BOOM-P-TTL shows up on the flash's readout and I hear the flash's motor move the bulb to whatever focal length I was on at the time. He didn't even know what the switch was for-I had to explain to him what the DOF switch did lol. TL;DR Cliff notes: my dad accidentally hit the DOF switch, fixed everything, he and I have no idea why it worked.

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