Web Analytics RiceHigh's Pentax Blog: The K-5 Flash Overexposure Issue

Tuesday, March 15, 2011

The K-5 Flash Overexposure Issue

See this side-by-side test:-

http://forums.dpreview.com/forums/readflat.asp?forum=1036&thread=37969644

ISO
K-5
K-r
100

200
400
800

Everything used and the settings are all the same except for a different body. And of course, the test environment and test target are the same, too. It is easily seen that the higher ISO the user selected, the more overexposure resulted with the K-5. Do note also the following additional remarks and comments as provided by the user and the formal response from Metz, regarding the problem, as quoted below:-

"I have tried it on 4 other k-5 bodies and the problem does not exist on my K-r."

"Please be informed, in our company we tested the digital camera "Pentax K-5" (firmware version 1.01 and 1.02) with flash units of our product range and also original Pentax flash units "Pentax AF-540FGZ" and "Pentax AF-360FGZ" and compared the results of images. The results are identical because the camera determines the intensity of flash light."

"However, we found also out by our tests that the precision of Pentax digital camera's "Pentax K-5" P-TTL flash control is not as precise as like with other Pentax digital camera.

Please see:

http://forums.dpreview.com/...forums/read.asp?forum=1036&message=37036542

http://dp-master1.dpreview.com/...ms/read.asp?forum=1036&message=37196234

http://forums.dpreview.com/...forums/read.asp?forum=1036&message=37065884"


It is really bad after all. Why the K-5 should perform worse than the other Pentax DSLRs?! And why the K-r is simply better and provides far more accurate and consistent results?? How come?

Comments (7)

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when you compare k5 and kr ranges,you see the kr does also overexposure with rising iso number
1 reply · active less than 1 minute ago
Nope, you're wrong. Nothing is overexposed for the K-r shots. And, do look at the subject, not the background. The background should receive more exposure from ambient and bounced lights as ISO increase, that's why we need slow speed / higher ISO sync for flash photography.
I have the same issue with the K7, a little less so but still over-expose on most cases.
Be carefull with the minimal distance. This distance is growing up with sensibility. We see that with the background of the K5 images witch are better illuminated than those of Kr shots (all underexposed). Remember that all objects before the minimal distance will be burnt. This is normal.
1 reply · active 679 weeks ago
I'm afraid that you're wrong and the minimum distance limit is completely irrelevant in this case.

The photos were shot at the same distance for the same object, with the same flash and compared at the same ISO. The ONLY difference is the body, i.e. K-5 Vs K-r. If K-r just gave fine exposure, I see NO reason why the K-5 should overexpose.
Thomas Tempelmann's avatar

Thomas Tempelmann · 625 weeks ago

The minimum distance can be relevant, but it probably does not apply here. The min distance of the flash is where it can't reduce its output any more. If you get too close with a too high aperture/ISO setting, then you'd force the flash to output less power than it can. But, this is probably not the issue here.

I've done my own tests today and found that even with far away and flat objects, there's an overexposure with both the internal and a AF-540 flash, no matter if I direct the flash directly or bounce off a white ceiling.
1 reply · active 625 weeks ago
Thomas Tempelmann's avatar

Thomas Tempelmann · 625 weeks ago

Addendum: The overexposure happens as soon as I increase the ISO rating, just as RiceHigh has documented it above.

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