[SALUKIS97]

Hey all. I got the Metz 58 a couple months ago, and until recently, I have loved it. For some reason all my images are badly underexposed when shooting in PTTL mode on my K10. I have changed the batteries several times already, so that's not it. Also, everything looks great in "A" mode.

This all started after I had been shooting with the flash off camera in wireless mode. I'm hoping I just accidentally adjusted something that is now causing horrible underexposure in PTTL mode.

Anybody have any suggestions, or experience with this issue?

I noticed this when I was shooting in Av mode. Underexposure was pretty much the same regardless of which iso I was using.

[imtheguy]

Well, I'll just ask the obvious. Since you had it in Slave mode, I assume its now back in P-TTL? Everything else is back to normal setting? No +/- flash comp? Does the flash zoom seem to work?

[SALUKIS97]

Thanks for the reply. I don't mind obvious questions since this flash stuff is very new to me. To answer your questions:

I did take it out of slave mode.

Flash comp on the flash and the camera are set to 0.

The display on the back of the flash shows a PTTL setting.

Now the zoom stuff is kind of confusing for me. I don't have the flash with me at the moment (I'm working......kind of), but I remember reading "SZoom" on the flash display while it was in PTTL mode. And I'm pretty sure it said the zoom was at 13 mm, which is weird because the manual shows the lowest zoom number to be 24mm? I'm using a 50 mm prime lens.

But, like I said before, everything is exposed fine in Auto mode.

[imtheguy]

By "Auto" mode you refer to the camera's green mode? Please post a sample pic with EXIF data intact.

Are you using a diffuser?

In the camera flash setting, is the +/- set on 0? I am not actually sure that affects the hot shoe but might as well find out here if you have it it down 3 stops. EDIT- We found out for sure that it does!

Are you directly illuminating the subject or using it in bounce fashion?


Ok, we should have all the info now except your shorts size. The pic will help the most debug this issue.

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Last edited by imtheguy; 07-13-2009 at 07:23 AM.

[axl]

I believe by "auto" mode he means mode on the flash. It would make sense tha exposure would be fine with flashes "auto" mode as opposed to underexposure with PTTL.
Pentax PTTL is infamous for underexposing unless not bouncing. That's one of the reasons, I'm still with my old rusty-trusty AF280T and AF160SA. They are both auto flashes, and work great.
Many people blame the Pentax PTTL for the underexposure but I came to conclusion it's not the PTTL itself but the mutlisegment metering of the camera. All Pentax PTTL cameras (save new K-7) are using the same metering system, which is well known to preserve highlights at all cost unless user's intervention doesn't take place. Now, if I understand it correctly, during PTTL exposure flash fires at full power, camera meters and tells flahs how much it should fire second time. So it's not a big surprise that if there's anything white/bright/reflective camera tries to preserve highlights, and underexposes flash when intial burst was too strong.
But that's just my theory...

BR
Peter

[SOldBear]

Now, if I understand it correctly, during PTTL exposure flash fires at full power, camera meters and tells flahs how much it should fire second time. So it's not a big surprise that if there's anything white/bright/reflective camera tries to preserve highlights, and underexposes flash when intial burst was too strong.

Yes, there are two strobes in P-TTL: the "pre-flash" strobe and the "actual" strobe.

The "pre-flash" strobe is to determine how much flash output is needed in the "actual" strobe. The "pre-flash" strobe is weak, not at full power.

Pentax PTTL is infamous for underexposing unless not bouncing.

Assuming the flash does not run out of power, bouncing in fact improves exposure accuracy in Pentax P-TTL.

The problem of Pentax P-TTL is not really under-exposure. It's the inconsistency that drives me nuts!

[imtheguy]

Assuming the flash does not run out of power, bouncing in fact improves exposure accuracy in Pentax P-TTL.

The problem of Pentax P-TTL is not really under-exposure. It's the inconsistency that drives me nuts!

While we wait for Salukis to get back to us we can compare notes among ourselves. I must be one of the P-TTL wierdos since I always get consistant results and use bounce exclusively for people shots, direct exposure for macro shots. Can't say I am a high volume flash shooter but bounce + PTTL has yet to fail me. Never tried AUTO mode for the Metz-48. Just bought a diffuser so lets see if that can screw things up.

edit - doesn't look like the Metz-48 HAS an Auto mode. Guess thats why I don't use it.

[imtheguy]

I believe by "auto" mode he means mode on the flash. It would make sense tha exposure would be fine with flashes "auto" mode as opposed to underexposure with PTTL.
Peter

Taken from the Matthew Miller Guide about auto mode.....

Auto mode on the Pentax flashes is clearly intended for older camera bodies only. Although the manual does not make this clear, auto mode only works when the camera is set to M. The Metz 58 AF-1, by contrast, works in all program modes — and also automatically reads the current aperture and ISO information from the camera

Makes it sound like its NOT what you should be using with a K20D for daily use, even though it works. What you think?

[pingflood]

Auto mode on a Metz is better than just about any TTL setup.

[Russell-Evans]

Now the zoom stuff is kind of confusing for me. I don't have the flash with me at the moment (I'm working......kind of), but I remember reading "SZoom" on the flash display while it was in PTTL mode. And I'm pretty sure it said the zoom was at 13 mm, which is weird because the manual shows the lowest zoom number to be 24mm? I'm using a 50 mm prime lens.

But, like I said before, everything is exposed fine in Auto mode.

Maybe you have some dust in the hole leading to the sensor if you are really are using A mode?

If you are using P-TTL, did you have the front fill flash on, and have it off now?

Is the diffuser out? If not, try pulling it out and then pushing it back in to see if the issue is in the micro switch there.

Thank you
Russell

[axl]

Yes, there are two strobes in P-TTL: the "pre-flash" strobe and the "actual" strobe.

The "pre-flash" strobe is to determine how much flash output is needed in the "actual" strobe. The "pre-flash" strobe is weak, not at full power.



Assuming the flash does not run out of power, bouncing in fact improves exposure accuracy in Pentax P-TTL.

The problem of Pentax P-TTL is not really under-exposure. It's the inconsistency that drives me nuts!

OK, maybe the preflash is still not full power but I still assume it's the one reason why camera's meter decides to underexpose.

With the bouncing, It's my typo. I meant to say what you said, that bouncing does improve the accuracy/consistency.

[axl]

Taken from the Matthew Miller Guide about auto mode.....

Auto mode on the Pentax flashes is clearly intended for older camera bodies only. Although the manual does not make this clear, auto mode only works when the camera is set to M. The Metz 58 AF-1, by contrast, works in all program modes — and also automatically reads the current aperture and ISO information from the camera

Makes it sound like its NOT what you should be using with a K20D for daily use, even though it works. What you think?

I don't know about new Pentax flashes, nor Metz flashes but with my old flashes auto mode works like a charm with K10D.

BR

[pingflood]

With any recent Metz auto mode will be absolutely excellent and in fact I use it over TTL on my Canon gear... it's just that good.

[imtheguy]

I guess that sucks to be me....my Metz 48 does not support Auto mode.

[SALUKIS97]

While we wait for Salukis to get back to us......

Hey all, sorry for the late response.

Turns out it was idiocy on my part. I thought I had set the flash exposure comp. in the camera back to 0, but I had not. I had only restored the flash comp back to 0 on the flash unit itself.

So, for any noobs out there like myself: Remember to restore the flash exposure compensation back to 0 on both the flash unit AND the camera itself if you want correct exposure from your flash!

BTW, since PTTL has come into question a little: I have experienced great exposure when my 58 is in PTTL mode and I don't have the settings screwed up.