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Old Jan 8, 2010, 12:13 PM   #1
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Default K-x: what settings for indoor shooting using built-in flash and stock lens?

I got the K-x yesterday. I took pics in the living room in the evening where the room was lit with incandescent lights. I set the camera to Autopict mode and the integrated flash was used. For some reason, the camera autoselected the 'night portrait' mode, which allows slow shutter speed even if the flash was used. The shutter speed selected by the camera was ranging from 1/4 to 1/8 sec with flash. That resulted in blurred pics due to the long exposure when the camera was hand-held.

I did not find anywhere to change the camera to select something else than 'night portrait' when shooting in Autopict

In order to avoid slow shutter speed, what should I set the camera to?

(Av, Sv, M ?) what would be the appropriate settings?

The room was not dark at all, it had normal evening living room lighting so I wonder why the camera chose such a slow shutter speed. The ISO was set to autoselect (200-6400 range)

I had the K110D before and I remember when using Autopict with flash, the camera would never chose any speed slower than 1/125

(I am using the stock 18-55mm DA lens)
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Old Jan 8, 2010, 12:31 PM   #2
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I'm a huge fan of using manual exposures when taking flash photos. For indoor flash shots, here's what I suggest:
  1. Set exposure to Manual
  2. Set ISO to 400
  3. Set aperture for desired DOF (if you're still trying to figure the whole dof thing out I suggest choosing f6.3 as it will stop your kit lens down a notch to get you sharp photos)
  4. Set Shutter speed to 1/60
There are a LOT of variables to good flash photography. The above settings are only a basic start. Adjustments need to be made in different lighting situations to either stop subject movement or get appropriate balance of flash vs. ambient light. So, the above settings won't work in every instance but they're a good start.

Two important notes:
  • your built in flash is not all powerful - so don't expect it to light up a 40 foot room or provide equal lighting for a large group shot.
  • if the above settings are overexposing the image (possible if there is good light in the room) then boost the shutter speed - by the time you get to the flash synch speed you should no longer be over exposed
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Old Jan 8, 2010, 6:48 PM   #3
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Hi manteiv,

There isn't much to add to John's suggestions, except that you might want to try some type of diffuser for the flash to make the light a bit softer. I use a Lumiquest Soft Screen, but I've seen other solutions that are cheaper (like free) or might be more convenient. Realize that any diffuser will make the already wimpy pop up flash a bit weaker, but generally, you'd be trading quantity for a bit more quality, and you always can raise the ISO to get more "reach" from the flash.

I'd also suggest that you experiment a lot -- the shots only cost you battery power and time -- I've taken literally thousands of shots of really stupid subjects, just to see what happens -- and I've learned a whole lot more about photography in the last 5 years than in the previous 35. . .

If you come up with more questions, feel free to start another thread, and it usually helps if you can post pics to illustrate any problems.

Scott
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Old Jan 9, 2010, 8:27 AM   #4
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I did further testing using the built-in flash of the K-x with the dial set to Autopict to shoot indoor. I am not satisfied with Autopict+flash indoor because it selects a slow shutter speed. I took the suggestions above and set the dial to M, with speeds varying from 1/90 to 1/180, aperture varying from F4 to F8, ISO 200-800 and obtained much better results than Autopict. I might want to stick with that winning combo for indoor shooting using the stock flash

The K-x firmware setting is definitely different from my previos K110D. With the K110D, I used to set the dial to Autopict when shooting indoor with the built-in flash and never had any issue with the camera selecting a slow shutter speed.

I have a couple of generic thrystor flash that I used years ago with film SLR (Vivitar flash, Hanimex). How do I know if the trigger voltage is safe for my K-x? can I test it somehow? I have an oscilloscope and a multimeter, can I used that equipment to measure the trigger voltage? Let's say I press on the flash button on the flash unit itself, will it generate a voltage on the contacts of the flash shoe?

I read somewhere that Pentax DSLR can safely accept trigger voltage up to about 35V, can anyone confirm this?

Last edited by manteiv; Jan 9, 2010 at 8:30 AM.
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Old Jan 9, 2010, 10:07 AM   #5
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Hi mantiev,

The trigger voltage is measured between the center contact on the shoe and one of the side contacts. I've seen reports of different Pentax representatives giving out different values from 6v to 24v, so I choose to use 6v as this seems to be the standard that the flash gun mfgs have been sticking to for the latest models.

Here's a page that lists user reported trigger voltages for quite a few units, but realize that user reports can be unreliable, so I'd suggest that you test your particular units before trusting them on my expensive DSLR.

http://www.botzilla.com/photo/strobeVolts.html

Scott
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Old Jan 9, 2010, 10:08 AM   #6
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You don't need to trigger it. The voltage should be present and readable with a high impedance volt meter when the flash is turned on (the camera is just closing the connection to allow current to flow, which triggers the flash).

Basically, you just measure between the center contact and outside of the foot. See this post for links:

http://forums.steves-digicams.com/fl...l-cameras.html
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Old Jan 9, 2010, 10:09 AM   #7
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I see Scott beat me to it. :-)
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