Pentax flash design problems?

jfsavage · 01-03-2009, 11:52 AM

I have had problems with my 360 flash, which I thought were limited to bounce flash. I have tested this and found that there is a more general problem. Doing some web research, it seems that there is a general problem with the Pentax P-TTL flash system.

I have not found any useful work-arounds, other than using auto mode with the wrong ISO setting. Has anyone found a better way of getting the Pentax flashes to work? Does the same problem impact the third party flash guns?

Some info I found:

https://www.pentaxforums.com/forums/pentax-camera-accessories/7355-underexpos...-ttl-mode.html

RiceHigh's Pentax Blog: P-TTL Reliability

my original thread - https://www.pentaxforums.com/forums/pentax-dslr-discussion/45598-under-exposi...nce-flash.html

Flash comparison guide - Pentax P-TTL Hot Shoe Flash Comparison - a knol by Matthew Miller

**sinus007** · 01-03-2009, 01:22 PM

Hi,
I'm not sure about the 360 design flaw. But I found out this.
Most of my in-door flash photography I do with Lightsphear. When I've got 360 it did produce underexposed pics. The solution to the problem turned out to be the flash difuser ( the one that you pull from the pocket on the flash).
Unfortunately I didn't do any experimenting with bounce or direct flash.
Hope it helps.

Tom S. · 01-03-2009, 01:49 PM

Originally posted by jfsavage

I have had problems with my 360 flash, which I thought were limited to bounce flash. I have tested this and found that there is a more general problem. Doing some web research, it seems that there is a general problem with the Pentax P-TTL flash system.

I have not found any useful work-arounds, other than using auto mode with the wrong ISO setting. Has anyone found a better way of getting the Pentax flashes to work? Does the same problem impact the third party flash guns?

Some info I found:

https://www.pentaxforums.com/forums/pentax-camera-accessories/7355-underexpos...-ttl-mode.html

RiceHigh's Pentax Blog: P-TTL Reliability

my original thread - https://www.pentaxforums.com/forums/pentax-dslr-discussion/45598-under-exposi...nce-flash.html

Flash comparison guide - Pentax P-TTL Hot Shoe Flash Comparison - a knol by Matthew Miller

Be very careful about believing information you see on RiceHigh's blog as he has been known to distort and ignore facts.

jfsavage · 01-04-2009, 08:43 AM

Originally posted by Tom S.

Be very careful about believing information you see on RiceHigh's blog as he has been known to distort and ignore facts.

I agree; RiceHigh does tend to be very unreliable. However, if you google "pentax flash underexposed" you will get a lot of hits.

What I can't work out is if this is a general problem with P-TTL, or if it is a common fault, or issues with some usage modes.

If it's a general design problem with P-TTL, then I do not want to spend extra $ to get a 540.

If its a common fault in pentax flash units, then I will get a 540, but make sure it is easy to return for a good unit.

If it's a problem in some modes of use, or there is a work around, I'd love to find it!

BTW, moving to manual mode would fix the problem, but removes any benefit from buy an expensive flash unit.

Thanks,

Jonathan

txsbluesguy · 01-04-2009, 09:37 AM

FWIW in all PTTL modes including bounce which i use mostly I have seen the instances of under exposure drop dramatically after upping the ISO to 800 for indoor use ..... i used to be pretty dogged about keeping it at two hundred for grain issues, but ive gotten over it the last month or so .... I'm getting the feeling it might be more of a under power issue than a design issue especially in bounce and diffusion configurations ....

afs760bf · 01-05-2009, 04:43 PM

There is no doubt that the P-TTL mode on the flashes (I have the 540) results in underexposure much of the time - at least that has been my experience. I've found a couple of ways to work it:

1. Set the flash to auto, the speed the same as the camera, and the aperture one less. I almost always bounce the flash and this helps.

2. If you have time, set the camera to manual, set the speed and aperture you want, set the flash to manual, and experiment with the power. I used to think that the flash was under-powered, but found out by doing this that the flash has plenty of power. You can light up entire rooms with the flash this way. It's the way I get the best overall results if I have the time to experiment.

3. If I don't have time, I sometimes leave the flash on P-TTL, and zoom the flash head to 48mm. It focuses the light and provides a little more power.

Good Luck

madbrain · 01-06-2009, 12:09 AM

Hi,

Originally posted by jfsavage

I have had problems with my 360 flash, which I thought were limited to bounce flash. I have tested this and found that there is a more general problem. Doing some web research, it seems that there is a general problem with the Pentax P-TTL flash system.

I have not found any useful work-arounds, other than using auto mode with the wrong ISO setting. Has anyone found a better way of getting the Pentax flashes to work? Does the same problem impact the third party flash guns?

Some info I found:

https://www.pentaxforums.com/forums/pentax-camera-accessories/7355-underexpos...-ttl-mode.html

RiceHigh's Pentax Blog: P-TTL Reliability

my original thread - https://www.pentaxforums.com/forums/pentax-dslr-discussion/45598-under-exposi...nce-flash.html

Flash comparison guide - Pentax P-TTL Hot Shoe Flash Comparison - a knol by Matthew Miller

I have had problems with underexposure with a K200D and the cheap third party digital concepts 952AF P-TTL flash. Even setting +2 EV on the camera, I still get underexposed pictures frequently. Strangely, the flash almost never fires at full power.

On the worst occasions, I have set the flash to manual mode, and experimented manually to force it to go to full power. But then I run into the opposite problem - depending on focal length, often there is too much light ...

You can still get decent pictures, but it is definitely not as automatic as it should be.

Comparatively, the built-in flash of the K200D is much more consistent in exposure results than the external flash - but of course it has power limitations.

wlachan · 01-06-2009, 12:39 AM

Originally posted by jfsavage

However, if you google "pentax flash underexposed" you will get a lot of hits.

Isn't that the answer you have been seeking for already? I can use flash in any mode from full auto to full manual, from indoor to full Sun w/o problem, but I only kept my brand new 540FGZ for a week only. It was that bad.

EricT · 01-06-2009, 02:29 AM

I have a Metz 48, and don't seem to have any problems with bouncing, so I don't think it's a problem with the P-TTL system. I usually shoot in manual mode, try to keep it around two stops underexposed (to get some ambient light), then set the flash to +1 and shoot. Sometimes, depending on the amount of ambient light, or the angle of bouncing, I have to experiment a bit with the flash power.

jfsavage · 01-06-2009, 05:24 AM

Originally posted by EricT

I usually shoot in manual mode

It seems that the problem with Pentax's flash system is widespread - the P-TTL does not seem to work.

Perhaps I should post a thread asking if anyone has success with P-TTL.

txsbluesguy · 01-06-2009, 05:46 AM

Originally posted by afs760bf

There is no doubt that the P-TTL mode on the flashes (I have the 540) results in underexposure much of the time

There is no doubt much of the time the flashes work with out any problem, please post a sequence of images from a shooting session where the flash failed to work much of the time so every one can see what you are talking about.

EricT · 01-06-2009, 06:24 AM

Originally posted by jfsavage

It seems that the problem with Pentax's flash system is widespread - the P-TTL does not seem to work.

Perhaps I should post a thread asking if anyone has success with P-TTL.

No, what I meant was I set the flash in P-TTL, and the camera in manual. I can get the same results in e.g. Av mode, by setting EV compensation, I just find M mode easier when using flash.
In other words, the P-TTL system works just fine for me with the Metz 48.

Ben_Edict · 01-06-2009, 09:03 AM

In my experience, which is limited to Metz flashes (MZ54-4i) P-TTL is not as reliable as the old TTL was. Especially with direct flash, I sometimes get pronounced underexposure. When using bounced flash, it is usually better. The best exposure usually results from using Auto-Thyristor mode... Nevertheless that means, that about 70% of flash exposures are o.k., the rest is off.

But there are some other things in this thread, that cannot be attributed to P-TTL: If using the Lightsphere, most of the flash output does not reach the subject directly, but will be distributed all around. For that, you need a much higher flash-output and I would think, that underexpsoure with the Lightsphere can easily be attributed to a too small flash gun.

The same is probably true for many bounced flashes or other diffusors.

When using the Omnibounce and its Chinese clones, it is important to adhere to the manufactureres recommendation of bringing the flash head to at least a 45 degree position. Firing directly with the Omnibounce onto the subject might influence exposure and is quite useless, anyway, as it gives basically the same lighting as any other direct flash, without the Omnibounce.

Ben

jfsavage · 01-07-2009, 10:30 AM

Originally posted by txsbluesguy

There is no doubt much of the time the flashes work with out any problem, please post a sequence of images from a shooting session where the flash failed to work much of the time so every one can see what you are talking about.

You can see some sample images at this post - https://www.pentaxforums.com/forums/pentax-dslr-discussion/45598-under-exposi...tml#post437725

Note that flash on full manual power exposes fine, so the flash has sufficient power in this situation.

ghost · 01-07-2009, 10:38 AM

I have had my Sigma 500DG Super for a couple of days now, and have not have had any problems with PTTL, even when bouncing.

Here is one of the first pictures I took with my flash. Full auto flash and Av mode. Bounced and swiveled up and to the right. I think it turned out all right...

http://farm2.static.flickr.com/1029/3171443996_93727e81f9_b.jpg

No problems yet with PTTL for me...

01-03-2009, 11:52 AM	#1
jfsavage Senior Member Join Date: Jun 2008 Location: Charlotte, NC Posts: 211	Pentax flash design problems? I have had problems with my 360 flash, which I thought were limited to bounce flash. I have tested this and found that there is a more general problem. Doing some web research, it seems that there is a general problem with the Pentax P-TTL flash system. I have not found any useful work-arounds, other than using auto mode with the wrong ISO setting. Has anyone found a better way of getting the Pentax flashes to work? Does the same problem impact the third party flash guns? Some info I found: https://www.pentaxforums.com/forums/pentax-camera-accessories/7355-underexpos...-ttl-mode.html RiceHigh's Pentax Blog: P-TTL Reliability my original thread - https://www.pentaxforums.com/forums/pentax-dslr-discussion/45598-under-exposi...nce-flash.html Flash comparison guide - Pentax P-TTL Hot Shoe Flash Comparison - a knol by Matthew Miller

01-04-2009, 09:37 AM	#5
txsbluesguy Senior Member Join Date: Nov 2006 Location: Houston Posts: 103	AF360 underexposure FWIW in all PTTL modes including bounce which i use mostly I have seen the instances of under exposure drop dramatically after upping the ISO to 800 for indoor use ..... i used to be pretty dogged about keeping it at two hundred for grain issues, but ive gotten over it the last month or so .... I'm getting the feeling it might be more of a under power issue than a design issue especially in bounce and diffusion configurations ....

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01-03-2009, 01:22 PM	#2
sinus007 Site Supporter Join Date: Jul 2008 Location: Cleveland, OH, USA Photos: Gallery Posts: 292	Hi, I'm not sure about the 360 design flaw. But I found out this. Most of my in-door flash photography I do with Lightsphear. When I've got 360 it did produce underexposed pics. The solution to the problem turned out to be the flash difuser ( the one that you pull from the pocket on the flash). Unfortunately I didn't do any experimenting with bounce or direct flash. Hope it helps.

01-03-2009, 01:49 PM	#3
Tom S. Veteran Member Join Date: May 2008 Location: S.E. Michigan Photos: Albums Posts: 4,317	Originally posted by jfsavage I have had problems with my 360 flash, which I thought were limited to bounce flash. I have tested this and found that there is a more general problem. Doing some web research, it seems that there is a general problem with the Pentax P-TTL flash system. I have not found any useful work-arounds, other than using auto mode with the wrong ISO setting. Has anyone found a better way of getting the Pentax flashes to work? Does the same problem impact the third party flash guns? Some info I found: https://www.pentaxforums.com/forums/pentax-camera-accessories/7355-underexpos...-ttl-mode.html RiceHigh's Pentax Blog: P-TTL Reliability my original thread - https://www.pentaxforums.com/forums/pentax-dslr-discussion/45598-under-exposi...nce-flash.html Flash comparison guide - Pentax P-TTL Hot Shoe Flash Comparison - a knol by Matthew Miller Be very careful about believing information you see on RiceHigh's blog as he has been known to distort and ignore facts.

01-04-2009, 08:43 AM	#4
jfsavage Senior Member Join Date: Jun 2008 Location: Charlotte, NC Posts: 211 Original Poster	Originally posted by Tom S. Be very careful about believing information you see on RiceHigh's blog as he has been known to distort and ignore facts. I agree; RiceHigh does tend to be very unreliable. However, if you google "pentax flash underexposed" you will get a lot of hits. What I can't work out is if this is a general problem with P-TTL, or if it is a common fault, or issues with some usage modes. If it's a general design problem with P-TTL, then I do not want to spend extra $ to get a 540. If its a common fault in pentax flash units, then I will get a 540, but make sure it is easy to return for a good unit. If it's a problem in some modes of use, or there is a work around, I'd love to find it! BTW, moving to manual mode would fix the problem, but removes any benefit from buy an expensive flash unit. Thanks, Jonathan

01-05-2009, 04:43 PM	#6
afs760bf Senior Member Join Date: Oct 2007 Location: Oklahoma Photos: Gallery Posts: 254	There is no doubt that the P-TTL mode on the flashes (I have the 540) results in underexposure much of the time - at least that has been my experience. I've found a couple of ways to work it: 1. Set the flash to auto, the speed the same as the camera, and the aperture one less. I almost always bounce the flash and this helps. 2. If you have time, set the camera to manual, set the speed and aperture you want, set the flash to manual, and experiment with the power. I used to think that the flash was under-powered, but found out by doing this that the flash has plenty of power. You can light up entire rooms with the flash this way. It's the way I get the best overall results if I have the time to experiment. 3. If I don't have time, I sometimes leave the flash on P-TTL, and zoom the flash head to 48mm. It focuses the light and provides a little more power. Good Luck

01-06-2009, 12:09 AM	#7
madbrain Veteran Member Join Date: May 2008 Location: San Jose, CA Posts: 1,341	Hi, Originally posted by jfsavage I have had problems with my 360 flash, which I thought were limited to bounce flash. I have tested this and found that there is a more general problem. Doing some web research, it seems that there is a general problem with the Pentax P-TTL flash system. I have not found any useful work-arounds, other than using auto mode with the wrong ISO setting. Has anyone found a better way of getting the Pentax flashes to work? Does the same problem impact the third party flash guns? Some info I found: https://www.pentaxforums.com/forums/pentax-camera-accessories/7355-underexpos...-ttl-mode.html RiceHigh's Pentax Blog: P-TTL Reliability my original thread - https://www.pentaxforums.com/forums/pentax-dslr-discussion/45598-under-exposi...nce-flash.html Flash comparison guide - Pentax P-TTL Hot Shoe Flash Comparison - a knol by Matthew Miller I have had problems with underexposure with a K200D and the cheap third party digital concepts 952AF P-TTL flash. Even setting +2 EV on the camera, I still get underexposed pictures frequently. Strangely, the flash almost never fires at full power. On the worst occasions, I have set the flash to manual mode, and experimented manually to force it to go to full power. But then I run into the opposite problem - depending on focal length, often there is too much light ... You can still get decent pictures, but it is definitely not as automatic as it should be. Comparatively, the built-in flash of the K200D is much more consistent in exposure results than the external flash - but of course it has power limitations.

01-06-2009, 12:39 AM	#8
wlachan Veteran Member Join Date: Sep 2006 Location: Canada Photos: Albums Posts: 2,625	Originally posted by jfsavage However, if you google "pentax flash underexposed" you will get a lot of hits. Isn't that the answer you have been seeking for already? I can use flash in any mode from full auto to full manual, from indoor to full Sun w/o problem, but I only kept my brand new 540FGZ for a week only. It was that bad.

01-06-2009, 02:29 AM	#9
EricT Veteran Member Join Date: Sep 2008 Posts: 484	I have a Metz 48, and don't seem to have any problems with bouncing, so I don't think it's a problem with the P-TTL system. I usually shoot in manual mode, try to keep it around two stops underexposed (to get some ambient light), then set the flash to +1 and shoot. Sometimes, depending on the amount of ambient light, or the angle of bouncing, I have to experiment a bit with the flash power.

01-06-2009, 05:24 AM	#10
jfsavage Senior Member Join Date: Jun 2008 Location: Charlotte, NC Posts: 211 Original Poster	Originally posted by EricT I usually shoot in manual mode It seems that the problem with Pentax's flash system is widespread - the P-TTL does not seem to work. Perhaps I should post a thread asking if anyone has success with P-TTL.

01-06-2009, 05:46 AM	#11
txsbluesguy Senior Member Join Date: Nov 2006 Location: Houston Posts: 103	Originally posted by afs760bf There is no doubt that the P-TTL mode on the flashes (I have the 540) results in underexposure much of the time There is no doubt much of the time the flashes work with out any problem, please post a sequence of images from a shooting session where the flash failed to work much of the time so every one can see what you are talking about.

01-06-2009, 06:24 AM	#12
EricT Veteran Member Join Date: Sep 2008 Posts: 484	Originally posted by jfsavage It seems that the problem with Pentax's flash system is widespread - the P-TTL does not seem to work. Perhaps I should post a thread asking if anyone has success with P-TTL. No, what I meant was I set the flash in P-TTL, and the camera in manual. I can get the same results in e.g. Av mode, by setting EV compensation, I just find M mode easier when using flash. In other words, the P-TTL system works just fine for me with the Metz 48.

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01-06-2009, 09:03 AM	#13
Ben_Edict Veteran Member Join Date: Jul 2007 Location: SouthWest "Regio" Photos: Albums Posts: 3,309	In my experience, which is limited to Metz flashes (MZ54-4i) P-TTL is not as reliable as the old TTL was. Especially with direct flash, I sometimes get pronounced underexposure. When using bounced flash, it is usually better. The best exposure usually results from using Auto-Thyristor mode... Nevertheless that means, that about 70% of flash exposures are o.k., the rest is off. But there are some other things in this thread, that cannot be attributed to P-TTL: If using the Lightsphere, most of the flash output does not reach the subject directly, but will be distributed all around. For that, you need a much higher flash-output and I would think, that underexpsoure with the Lightsphere can easily be attributed to a too small flash gun. The same is probably true for many bounced flashes or other diffusors. When using the Omnibounce and its Chinese clones, it is important to adhere to the manufactureres recommendation of bringing the flash head to at least a 45 degree position. Firing directly with the Omnibounce onto the subject might influence exposure and is quite useless, anyway, as it gives basically the same lighting as any other direct flash, without the Omnibounce. Ben

01-07-2009, 10:30 AM	#14
jfsavage Senior Member Join Date: Jun 2008 Location: Charlotte, NC Posts: 211 Original Poster	Originally posted by txsbluesguy There is no doubt much of the time the flashes work with out any problem, please post a sequence of images from a shooting session where the flash failed to work much of the time so every one can see what you are talking about. You can see some sample images at this post - https://www.pentaxforums.com/forums/pentax-dslr-discussion/45598-under-exposi...tml#post437725 Note that flash on full manual power exposes fine, so the flash has sufficient power in this situation.

01-07-2009, 10:38 AM	#15
ghost Senior Member Join Date: Jan 2008 Location: Barrie, ON Photos: Gallery Posts: 174	I have had my Sigma 500DG Super for a couple of days now, and have not have had any problems with PTTL, even when bouncing. Here is one of the first pictures I took with my flash. Full auto flash and Av mode. Bounced and swiveled up and to the right. I think it turned out all right... http://farm2.static.flickr.com/1029/3171443996_93727e81f9_b.jpg No problems yet with PTTL for me...