[amoringello]

Well, I may have a work-around / solution???
FYI, I am currently in contact with Ricoh/Pentax about the issue. Hopefully they can confirm some of the things I have found and explain if it is *expected* behavior.


I reset the camera and the behavior is the same. So, it is not a change in settings issue.
I figured, maybe the af540fgz is wonky (couldn't be the brand new K3, even though the thing works fine on the K5)... so I put my af360fgz on there.
Same behavior, but...

While removing the bounce card from the flash head (so all light is reflecting off the ceiling-only), the exposure was "perfect" (def: perfect in terms of PTTL, meaning it is pretty darned close for an automated system). Additionally, if I pulled the bounce card back just a half an inch, it reduces the forward light enough to allow correct exposure.

So, it seems that the K3 is VERY touchy with regards to pre-flash metering when in bounce mode.
It somewhat correctly meters when the flash head is pointing directly forward.
I'm not sure I would call the behavior "correct", but if this is only in situations where there is potential for significant highlight (yet not specular highlight), I may be able to work around it.

I am just DARNED glad I don't shoot weddings professionally. The K3 would be a disaster if a bounce card or reflector was used on the flash.
When at weddings and events, I absolutely rely on the stupid 30 cent device for giving that perfect hint of lighting when there is no ceiling or wall to bounce off.


Anyway, I may have a workaround for my most common use cases for now.
I will have to do more testing on other potential situations.
I hope Ricoh will give some more info.

[johnc]

Well, I may have a work-around / solution???
FYI, I am currently in contact with Ricoh/Pentax about the issue. Hopefully they can confirm some of the things I have found and explain if it is *expected* behavior.


I reset the camera and the behavior is the same. So, it is not a change in settings issue.
I figured, maybe the af540fgz is wonky (couldn't be the brand new K3, even though the thing works fine on the K5)... so I put my af360fgz on there.
Same behavior, but...

While removing the bounce card from the flash head (so all light is reflecting off the ceiling-only), the exposure was "perfect" (def: perfect in terms of PTTL, meaning it is pretty darned close for an automated system). Additionally, if I pulled the bounce card back just a half an inch, it reduces the forward light enough to allow correct exposure.

So, it seems that the K3 is VERY touchy with regards to pre-flash metering when in bounce mode.
It somewhat correctly meters when the flash head is pointing directly forward.
I'm not sure I would call the behavior "correct", but if this is only in situations where there is potential for significant highlight (yet not specular highlight), I may be able to work around it.

I am just DARNED glad I don't shoot weddings professionally. The K3 would be a disaster if a bounce card or reflector was used on the flash.
When at weddings and events, I absolutely rely on the stupid 30 cent device for giving that perfect hint of lighting when there is no ceiling or wall to bounce off.


Anyway, I may have a workaround for my most common use cases for now.
I will have to do more testing on other potential situations.
I hope Ricoh will give some more info.

I noticed that the PTTL K-3 flash behaviour is VERY different to the K-5. Not necessarily a bad thing, it was very easy to make the K-5 overexpose with light coloured subjects and bounce, and this behaviour is fixed (here at least).

The negative is that I have found it IS possible to provoke significant underexposure under certain circumstances. I'm trying to test to bottom these out (AF450 so far), but I would say it happens with dark (black) coloured subjects where the path of the flash bounce is not 'direct' enough to result in a reading. Seems maybe the flash/camera defaults to the lowest level where a reliable PTTL reading can't be obtained?

In short I think that when you have a dark object that is not illuminated 'enough' by the flash, the shot may underexpose excessively. I can't seem to prompt bad behaviour with anything other than black objects.

[amoringello]

One last one for a while...

Yep.. as I have found in *some* cases, and as some have pointed out; stepping back a few feet can have an impact.
The K3 is much more sensitive to the pre-flash than prior models. This not only affects bounce flash but also wireless flash and adjustments need to be made when shooting either.


If I can get enough distance such that the pre-flash is diminished, it seems that my issues disappear.
I don't always have that option, but I can workaround the issue if the K3 is consistent!
*** Yeah! ***

So white objects within about four feet when using bounce flash is a No-No!
In general, you're likely going to blind a person at that range, so it is probably not an issue in a lot of cases.
But for product and macro, it isn't unusual. So I still hope there is a better solution.

---------- Post added 03-24-14 at 06:28 PM ----------

I noticed that the PTTL K-3 flash behaviour is VERY different to the K-5. Not necessarily a bad thing, it was very easy to make the K-5 overexpose with light coloured subjects and bounce, and this behaviour is fixed (here at least).

The negative is that I have found it IS possible to provoke significant underexposure under certain circumstances. I'm trying to test to bottom these out (AF450 so far), but I would say it happens with dark (black) coloured subjects where the path of the flash bounce is not 'direct' enough to result in a reading. Seems maybe the flash/camera defaults to the lowest level where a reliable PTTL reading can't be obtained?

In short I think that when you have a dark object that is not illuminated 'enough' by the flash, the shot may underexpose excessively. I can't seem to prompt bad behaviour with anything other than black objects.

ha, ha, yeah very different indeed.
I had a horrible time with the K5 overexposing with flash.
Now I have a horrible time with the K3 underexposing. But in the end I am hoping the K3 may be more predictable and consistent once its peculiarities are determined. It would still be nice though if Ricoh could refine the pre-flash to help get exposure back towards neutral-gray rather than soul-sucking black.

[johnc]

One last one for a while...

Yep.. as I have found in *some* cases, and as some have pointed out; stepping back a few feet can have an impact.
The K3 is much more sensitive to the pre-flash than prior models. This not only affects bounce flash but also wireless flash and adjustments need to be made when shooting either.


If I can get enough distance such that the pre-flash is diminished, it seems that my issues disappear.
I don't always have that option, but I can workaround the issue if the K3 is consistent!
*** Yeah! ***

So white objects within about four feet when using bounce flash is a No-No!
In general, you're likely going to blind a person at that range, so it is probably not an issue in a lot of cases.
But for product and macro, it isn't unusual. So I still hope there is a better solution.

---------- Post added 03-24-14 at 06:28 PM ----------



ha, ha, yeah very different indeed.
I had a horrible time with the K5 overexposing with flash.
Now I have a horrible time with the K3 underexposing. But in the end I am hoping the K3 may be more predictable and consistent once its peculiarities are determined. It would still be nice though if Ricoh could refine the pre-flash to help get exposure back towards neutral-gray rather than soul-sucking black.

Just tried a little more. I would say close quarters and firing the flash too high above the object is not helping.

With AF540 in a small room, turning the flash head to face backwards stops the behaviour - I would say there is a need to be disciplined about where the flash is pointing for bounce - the pre-flash needs to have enough illumination on the object to measure?

[lister6520]

If the return of the preflash is too weak then if anything it should fire the flash at full power.

If it is instead under-illuminating then it is likely a common and simple programming error - when a variable overflows and rolls back to zero or negative.

However I have been trying a few tests and no matter what I do I have not managed to reproduce this problem yet. Will need to find some more time for more comprehensive tests.

The only underexposures I got was when the flash was not actually powerful enough to illuminate the scene - confirmed by firing the flash in manual at full power and obtaining the exact same exposure as it did with P-TTL.

Is anyone experiencing the problem on firmware prior to 1.03? I'm wondering if the problem was introduced with that update, which might explain why I do not experience it.

[amoringello]

I was seeing the problem prior to updating to rev1.03. I had to shoot some products immediately after obtaining the K3 and saw the problem.
I later reproduced the problem at home, updated the firmware and the problem persisted.

Essentially, I believe to be the case...
First, you need to have the flash in bounce mode so that the camera is using pre-flash alone to determine power. (when aimed forward, the camera will use subject distance to help adjust the flash power).
Next, you must be very close to a largely white surface or subject so that the pre-flash comes back over-exposed. (conversely causing the main image to require underexposure) I was within about three feet with the flash pointed up but has a large 8x8 bounce card behind it.

By pulling the bounce card back slightly (1/2 inch) or moving backwards two feet eliminates the problem.
Or adjusting the camera angle to limit the white surface to less than the top 1/3 of the view. (or perhaps the flash angle was then simply tangental enough to reduce the effect???)


So in real life, unless you plan to blind a bride or if you're doing macro (close-up product) work on a white surface, the problem is likely to not be exhibited.

I still think the camera can be refined to determine that focus distance is very close and do *something* about the pre-flash overexposure issue. The K5 handles it pretty well... but that is a totally different system... so, I'm just not sure how. It boggles my mind to imagine all the possible lighting issues that thing has to contend with.

I have been playing with my flash, Metz 50 AF-1. White background. Straight on, bouncing, bounce card out etc etc and I can't replicate any under exposure. Could you take a photo of the K-3 with the flash and bounce so that I, we, can see how your set up looks like?

[amoringello]

This is my setup. The effective bound card dimensions are 7" high and 9" wide behind the flash.
I guessed incorrectly, the camera and flash is more like 2 feet from the board. But the affect did not change until I got about four feet away.
The tripod head is 44 inches from the ground. The ceiling is a typical 8 foot high and white. So flash is likely 3+ feet form the ceiling.
Although I had the same issue in a warehouse with 20' ceilings, so bounce is the important issue.

Hope that helps.

This is my setup. The effective bound card dimensions are 7" high and 9" wide behind the flash.
I guessed incorrectly, the camera and flash is more like 2 feet from the board. But the affect did not change until I got about four feet away.
The tripod head is 44 inches from the ground. The ceiling is a typical 8 foot high and white. So flash is likely 3+ feet form the ceiling.
Although I had the same issue in a warehouse with 20' ceilings, so bounce is the important issue.

Hope that helps.

Ok, thanks. I will try to replicate.

[johnc]

I was seeing the problem prior to updating to rev1.03. I had to shoot some products immediately after obtaining the K3 and saw the problem.
I later reproduced the problem at home, updated the firmware and the problem persisted.

Essentially, I believe to be the case...
First, you need to have the flash in bounce mode so that the camera is using pre-flash alone to determine power. (when aimed forward, the camera will use subject distance to help adjust the flash power).
Next, you must be very close to a largely white surface or subject so that the pre-flash comes back over-exposed. (conversely causing the main image to require underexposure) I was within about three feet with the flash pointed up but has a large 8x8 bounce card behind it.

By pulling the bounce card back slightly (1/2 inch) or moving backwards two feet eliminates the problem.
Or adjusting the camera angle to limit the white surface to less than the top 1/3 of the view. (or perhaps the flash angle was then simply tangental enough to reduce the effect???)


So in real life, unless you plan to blind a bride or if you're doing macro (close-up product) work on a white surface, the problem is likely to not be exhibited.

I still think the camera can be refined to determine that focus distance is very close and do *something* about the pre-flash overexposure issue. The K5 handles it pretty well... but that is a totally different system... so, I'm just not sure how. It boggles my mind to imagine all the possible lighting issues that thing has to contend with.

Think you're onto something. Did a few more tests.....I can only get this to happen (though very reproducibly) in close quarters, in my small office room, where I was trying to take some product shots.

In a larger room, it is almost impossible. I would also say it occurs in situations when bounce flash is likely to overwhelm the subject (especially white surfaces). For the same (product) shot, dropping the wide angle diffuser, choosing a less direct bounce path, or covering some of the flash path can sometimes bring good behaviour back.

Can't really understand if this in intentional - if so, it is FAR too aggressive. I would rather have blown out specular highlights (and adjust from there) than dark exposures. Very frustrating to get dark frames. Once again, with Pentax flash, seems that knowing the quirks is half the battle... FW 1.03 here. But hopefully this can be improved in 1.04.....?

[MSL]

This is my setup. The effective bound card dimensions are 7" high and 9" wide behind the flash. I guessed incorrectly, the camera and flash is more like 2 feet from the board. But the affect did not change until I got about four feet away. The tripod head is 44 inches from the ground. The ceiling is a typical 8 foot high and white. So flash is likely 3+ feet form the ceiling. Although I had the same issue in a warehouse with 20' ceilings, so bounce is the important issue.

One simple suggestion - cover the mirror on the wall behind your setup (and maybe the trophy and anything else highly reflective)

[amoringello]

One simple suggestion - cover the mirror on the wall behind your setup (and maybe the trophy and anything else highly reflective)

No such distractions in the warehouse situation. As far as I have been able to determine, it is all related to the bounce power off the white background. If I remove the white background, the exposure is within expectations. (in which case the mirror is even more prone to reflections, etc...)

[MSL]

No such distractions in the warehouse situation. As far as I have been able to determine, it is all related to the bounce power off the white background. If I remove the white background, the exposure is within expectations. (in which case the mirror is even more prone to reflections, etc...)

Missed the warehouse bit. Guess the other thing to try if you need the white background is a matt board vs a glossy one.

[IchabodCrane]

This is my setup. The effective bound card dimensions are 7" high and 9" wide behind the flash.
I guessed incorrectly, the camera and flash is more like 2 feet from the board. But the affect did not change until I got about four feet away.
The tripod head is 44 inches from the ground. The ceiling is a typical 8 foot high and white. So flash is likely 3+ feet form the ceiling.
Although I had the same issue in a warehouse with 20' ceilings, so bounce is the important issue.

Hope that helps.

The flash is not aimed at the ceiling above the subject. Instead, it's aimed at the ceiling well behind the subject. Additionally, the card on the flash head is preventing any of the light from illuminating the ceiling above the subject. I can see how this would be an impossible setup for proper lighting. Hope that helps.

[jbinpg]

Change out the backdrop to a gray background then change back to the colour you want in post. Might work.