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10-25-2013, 04:19 PM   #1
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Questions/Problems with new K-30

I've already updated the firmware to 1.05, hoping these two issues would be fixed, but so far no dice.

First, is that the viewfinder display keeps turning off. I have the camera set to turn off in 3 minutes, but the viewfinder display goes off in about 6 seconds. The rear display in about 15 seconds. Is there any way to increase the timeout for these? I've searched through the menu options, but I can't find anything. Especially the viewfinder display. It's absolutely maddening when it turns off while I'm in the middle of composing a shot, and trying to get the horizon just right.

Second, the wireless flash doesn't work as the manual implies. I'm using a Sigma EF610DGwhatever as a wireless PTTL slave. I have the "Flash in Wireless Mode" set to OFF (2), which is supposed to make the built-in flash a controller ONLY. However, the built-in flash fires. It didn't do that with my K-x. I'm trying to go for a low-key shot with side lighting, using my sigma flash in wireless mode. Worked fine with the K-x, but the K-30 always fires the built-in flash, which means the scene is always exposed from the built-in flash. What gives with this? It's completely ignoring the setting.

Any ideas to fix this?

Charles.

10-25-2013, 05:56 PM   #2
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The viewfinder info stays on while you press the button halfway down.

For the flash, it always fires in wireless mode, it's just really low intensity in controller mode. Don't forget you have to set the flash mode to wireless using the four way controller/thumb wheel. Here's an experiment to verify it's working. Turn "Flash in Wireless Mode" set to ON, compose a picture at 1/180 indoors in moderate light. Take the shot, but take note of the settings. Take a second shot with the same aperture/iso/180s, except this time "Flash in Wireless Mode" set to OFF. Put the flash down, keep the same shutter speed/iso/aperture by using M, and take a third picture. You can now tell the amount of flash you are getting in the second photo. It is some, but not much. I had some trouble getting my camera into controller mode too. Maybe try setting the flash into wireless mode before changing the menu setting.
10-25-2013, 06:14 PM   #3
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I don't have k-30 but on k-x and k-5 there is a setting for how long the meter stays on. That is what determines how long the viewfinder info stays on. I think there is another separate setting for the rear display as well.
10-25-2013, 08:57 PM   #4
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I have the meter set to 30 seconds, but it has no effect on how long the viewfinder display stays on.

As for the wireless flash, here are the results. For both the K-x and K-30, I used the exact same lens, at f/4, 1/125, ISO 200.

Set to wireless mode, take a test shot to make sure communication is working. Turn off wireless flash. Take shot.

K-x result: Extremely under-exposed shot. The flash does indeed fire, but at such a low power that it barely shows up at all. There is no option to have the flash fire.

K-30 result with "Flash in Wireless Mode" set to 1 (ON): under the same conditions (remote flash turned off), the photo is exposed exactly the same as if i had just popped up the flash without going into wireless mode.

K-30 result with ""Flash in Wireless Mode" set to 2 (OFF): The shot is quite over-exposed. It appears that instead of cutting power to the built-in flash, the K-30 is maxing out the power.

Charles.

10-26-2013, 06:12 AM   #5
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Hmmmm, probably a defect with your flash then. Send an e-mail to Pentax support. I'm guessing it needs fixing.
10-26-2013, 06:49 AM   #6
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Before I go there, I'd like to see someone else with a K-30 repeat the same tests...

Charles.
10-26-2013, 06:56 AM   #7
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Perhaps your Sigma flash isn't fully compatible with the k30? Just a thought. Might be worth testing your camera with a different flash if possible.

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10-26-2013, 07:01 AM   #8
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I haven't had a chance to use the K-30 in wireless yet. This looks like good excuse. I will try it out , but it will have to be a bit later today I don't have a K-x tho I am going to check against my DL. Did you remeter between shots? I am assuming that you are in M mode to keep the settings. I also do not have a sigma flash It is an old Albinar twin flash. We will see what happens

Pat

10-26-2013, 07:03 AM   #9
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Pretty sure mine is a bit funny too. Will try it out tomorrow night for you. I have a Metz flash.
10-26-2013, 11:58 AM   #10
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I can't repeat your test at the moment but I did try it a few months back with my EF610 DG Super and all seemed OK; i.e. subject lighting was just from the Sigma, but that would have been with fw 1.03 or 1.04 I guess. If there's an issue with the latest firmware then a workaround may be to cover the built in flash with a piece of developed film, an old trick to just let only the infra red part through which can triggers sensors.
10-26-2013, 03:38 PM   #11
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In one of your posts you state ISO is set to 200 which means your off camera flash has to be set to HSS-180 is the k30 synch speed for PTTL operation.

While you mention setting the ob flash as controller and the switch to wireless you don't say anything about setting up your external flash as slave nor do you mention synching the camera and flash channels (pg 243 in the K30 manual).

Even as controller the ob flash flashes but doesn't contribute to the external flash scene.

I don't have a sigma flash mine is a Metz but with the proper setup it works flawlessly as the slave or main flash.
10-26-2013, 07:23 PM   #12
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I can't try for you at this time My flash has evidently decided to retire. It won't charge even with new batteries. I guess I now have one more item on my Christmas list.
10-27-2013, 06:19 AM   #13
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I've just done a little test with my Metz 59 AF-2.

I place the camera such that there is a nearby object at about 1 metre distance, this is in the lower right of the corner, illuminated very brightly in the centre photograph.

The Metz flash is in slave mode and is actually standing on that same object. You can see the flash (although out of focus) at the middle right of each photo, brightly illuminated in the middle one.

The background is about 5 metres from the camera.

In the middle picture the on board flash is set to fire (option 1) and the result can be seen as it brightly illuminates the nearby object as well as the back of the Metz Flash which is sitting on top of it.

In the left and right pictures the internal flash is set to off (option 2). In the left picture one can see that some light is still emitted and illuminates the nearby object somewhat, but still less than what would be needed for a good exposure. In my opinion it is doing its job properly as the object is very close and yet is still only marginally illuminated by the unwanted light.

In the right picture I shielded the internal flash such that none of its light would reach the nearby object and as a result the nearby object appears much darker, confirming that the marginal illumination in the first test was actually from the onboard flash.

So the onboard flash is illuminating but it doesn't seem bright enough to cause any problems except in some extreme situations.

I remember the K-r being quite weak at triggering the remote flash so probably Pentax were aware of that and pumped up the power in the K-30 to make sure that the slave flash does in fact trigger. There is of course the downside of the unwanted light but I guess compromises have to be made.

There is a way that could get round this problem but it would need firmware upgrade of both the flash and the camera. In hindsight what they could have done is to time things such that the trigger burst is fired a specific time before the shutter opens and the flash knows to wait that specific time to fire only after the shutter opens. Now someone will steal that idea and go get a patent for it.



10-27-2013, 06:33 AM   #14
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I had done some more detailed tests with the K-r and an oscilloscope a couple of years ago in an effort to understand the protocol used by remote P-TTL.



Below are some notes summarising the main things I found out. I suspect that if I were to try that same test with the K-30 the pulse emitted at around t=143ms will be much longer than the 40uS of the K-r. This would explain the much more reliable triggering by the K-30 but also the problem of over illumination by the onboard flash when it is meant to be off.


Camera settings
+ remote flash
+ internal flash as controller only
+ channel 1


At t=0
Sequence starts with a burst pf approximately 50uS

t=4.394mS (depends on channel)
Camera flashes a burst of approx 50uS to command the slave to transmit a measuring preflsah


t=4.54mS
Slave flash starts the preflash illumination to measure the scene
The intensity is reduced to about 16% of the brighntess that it will illuminate when exposing the photo

t=5.814mS
The preflash illumination ends


t=75.312
The camera transmits three bursts spaced a few milliseconds apart. Each burst is about 40uS long
The interval between the flashes provides information to the slave flash on how much light it should provide
These intervals are analysed in the excel sheet
The interval between the first and second pulse seems to indicate the amount of light needed
The interval between the second and third pulse seems to indicate the light output that the flash will actually be able to provide

t=?
Some time around here the mirror lifts and the shutter starts to open (observed on high speed camera but not measured)

t=?
The shutter is now fully open (observed on high speed camera but not measured)

t=143.46mS
Camera transmits a 40uS pulse to signal to the slave flash to start illumination

t=144mS
Flash illuminates at full intensity for the duration requested by the camera (the pulses of t=75mS)



Interval between first burst and preflash command depends on the channel number:
Ch1 4.394mS
Ch2 4.592mS
Ch3 4.190mS
ch4 4.788mS


The interval between the 1st and second pulses of the 3 pulse message dictate the amount of light the flash would need to produce for the actual exposure
The interval in mS is given by 0.4436 Log(req/preflash) + 2.8
Where req/preflash is how many time brighter the exposure flash has to be compared to the preflash.

Last edited by lister6520; 10-27-2013 at 06:34 AM. Reason: corrected a typo referring to K-r when it should have been k-30
10-27-2013, 08:23 AM   #15
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Looking at your photos, you say the center is option 1 (On), and the left and right are option 2 (off). Well, then I think you have your description backwards, and are in fact showing the actual problem I'm talking about.

I'm assuming you just had the camera on auto mode.

Look at the flash shadow. It's much stronger in the left and right shots, but much dimmer in the center shot. To me, that shows that more flash power is being used to illuminate the scene when the flash is set to option 2 (off). So if anything, the settings appear to be reversed.

Also yes, my slave is set up properly each time.

Charles.
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