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02-08-2008, 04:04 PM   #1
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K10 and Flashes

All,

I have been puzzling over use the flash with the K10D (and K100D), so I got out the good old operating manual to get clarifiation. Then I got the cameras out to "test" what I was reading. According to the K10D manual (page 154), shutter and aperature priority will take into account the light conditions to determine if the flash is needed or not, and set the appropriate aperture/shutter speed.

Observations....
1. I set the camera up in a room with a tripod and the kit lens. I set the camera to aperture priority, with an aperture of 9.5, ISO 200, 24mm. I focused on something about 15 ft away in a dim lit room, and flash was blinking on the camera. I did not use the flash, and the shutter speed was set to 1.5 seconds. I took the picture, which was a reasonable exposure.

2. Same as above, but I flipped the flash. The shutter speed changed to 1/45. I took the picture. Result was very dark (not acceptable), even though the meter reading said it was ok.

3. Same as above with my Promaster 7500DX flash. The camera suggested the same shutter speed of 1/45. Took the picture- and it was reasonable.

4. I then tried an aperture of 6.7 with the internal flash (all other settings the same), and it was still a bit dark. the camera suggested shutter speed remained at 1/45

5. I then tried an aperture of 4.5 with the internal flash. The camera still suggested a shutter speed of 1/45. This was a reasonable picture.

Conclusion: The camera (or the user) will tell me some pics are acceptable with the internal flash that are not, and the shutter speed is not compensating appropriately for the conditions.

MANUAL
1. I then set the camera to manual, and set the aperture to 9.5, ISO 200. At a shutter speed of 2 seconds the camera told me it would be a good picture. I took the pic and it was fine.
2. I then flipped the flash, and the settings did not change

Conclusion: Manual does not consider flash as part of it's metering.


Am I missing something here?

Sorry for the long text!

02-08-2008, 04:16 PM   #2
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Umm, the on board flash has a Guide Number of less than 15 so shooting it at f9.5 at ISO 200 the light fall off is so great you'll never get a proper exposure. The reason the Promaster did so much better was it's a more powerful flash and can fire at the distance and power much better than the pop up flash.

The shutter speed is perfect because it's trying not to go below the handholdable level of the lens. Also remember that below 1/45 any ambient lights will begin to streak and look like light drawn across the background with movement while you shoot. The camera is doing what it's supposed ot do, you're just asking it to do something it can't do.

I hope that helps
02-08-2008, 04:19 PM   #3
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Which lens?

And yes, I think flash use is buggy. I admit to not using too much though so it could be me that is buggy and not the camera.
02-08-2008, 04:32 PM   #4
krs
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I was using the kit lens...

02-08-2008, 05:22 PM   #5
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I believe codiac2600 has it right - the built-in flash really doesn't have much umph... what I miss in the K10D is any sort of confirmation that the flash thinks it has done its duty. Every other camera/flash system I've used (all film systems) provided a confirmation that the flash had delivered enough light to the scene - basically that the quench circuit had fired. I've even had cases where the AF-360 doesn't deliver enough light, and the only indication is that the image is under exposed... I guess that is supposed to be the instant feedback in the digital world!

Curt
02-08-2008, 07:11 PM   #6
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QuoteOriginally posted by krs Quote
All,

I have been puzzling over use the flash with the K10D (and K100D), so I got out the good old operating manual to get clarifiation. Then I got the cameras out to "test" what I was reading. According to the K10D manual (page 154), shutter and aperature priority will take into account the light conditions to determine if the flash is needed or not, and set the appropriate aperture/shutter speed.

Observations....
1. I set the camera up in a room with a tripod and the kit lens. I set the camera to aperture priority, with an aperture of 9.5, ISO 200, 24mm. I focused on something about 15 ft away in a dim lit room, and flash was blinking on the camera. I did not use the flash, and the shutter speed was set to 1.5 seconds. I took the picture, which was a reasonable exposure.

2. Same as above, but I flipped the flash. The shutter speed changed to 1/45. I took the picture. Result was very dark (not acceptable), even though the meter reading said it was ok.

3. Same as above with my Promaster 7500DX flash. The camera suggested the same shutter speed of 1/45. Took the picture- and it was reasonable.

4. I then tried an aperture of 6.7 with the internal flash (all other settings the same), and it was still a bit dark. the camera suggested shutter speed remained at 1/45

5. I then tried an aperture of 4.5 with the internal flash. The camera still suggested a shutter speed of 1/45. This was a reasonable picture.

Conclusion: The camera (or the user) will tell me some pics are acceptable with the internal flash that are not, and the shutter speed is not compensating appropriately for the conditions.

MANUAL
1. I then set the camera to manual, and set the aperture to 9.5, ISO 200. At a shutter speed of 2 seconds the camera told me it would be a good picture. I took the pic and it was fine.
2. I then flipped the flash, and the settings did not change

Conclusion: Manual does not consider flash as part of it's metering.


Am I missing something here?

Sorry for the long text!
I agree with Chris, but I have a little more to add.

One needs to think of flash photography as having 2 exposure systems. One for ambient lighting, one for flash lighting.

Our cameras also use the P-TTL flash system. Make sure your flash exposure compensation (FEC)is not set to a low value (below 0.0). If the flash is your primary lighting source, you can even try setting it to +1 FEC. Play around FEC to see if it makes a difference for your current test setup.

Shutterspeed does not change the affects of a flash, it only affects the amount of ambient lighting that shows up (since the flash duration is extremely short), so having a 1/45 to prevent ambient light streaks is acceptable (and expected).

Aperture however, does affect the reach of flashes, the larger the aperture, the farther your flash will have effect. Using your small aperture of f/9+ is reducing the flash effectiveness by a lot.

Changing the ISO also affects the flash. Increasing ISO will increase your flash's reach.

And as for MANUAL, you are setting the aperture and shutterspeed, popping the flash is not supposed to change it's values. The meter will be metering for ambient in this mode. You will have to rely on your FEC to manipulate how the flash is to perform.
02-08-2008, 08:07 PM   #7
krs
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I guess part of the puzzle for me if why the camera does not indicate that it is not a good selection of aperture, shutter speed and ISO settings, but rather indicates that it is a valid grouping...
02-08-2008, 08:56 PM   #8
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QuoteOriginally posted by krs Quote
I guess part of the puzzle for me if why the camera does not indicate that it is not a good selection of aperture, shutter speed and ISO settings, but rather indicates that it is a valid grouping...
It's because it doesn't know what you're shooting at and how far away it is. If you were a foot away from the object at ISO 200, 1/45 and f9.5 you might have something there. One thing about flash that scares people is the flash will never be automatic without some flash knowledge.

I prefer shooting in manual and the flash in manual because I understand how to balance ambient, flash, and also the style I want to achieve. You also need to understand your surroundings and how they affect flash, don't expect great bounce flash from a room with 20 foot ceilings or a room with black walls and ceiling. The PTTL is great for something approx. 5ft away and it a decently lit room, everything else is pushing technology to a new level. The advanced ttl's are fooled to easily by things you wouldn't think of like reflection, the colour white and distance. It's better to use the basic settings as a starting point with flash and experiment like alwasy having your flash at +1EV compensation, which is perfect because it exposes above 18% grey so you're image will look brighter and punchier in most cases.

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