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11-19-2010, 12:57 PM   #1
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Who is willing to do a test with hotshoe fill flash on the K-5?

The K-7 has a problem when using P-TTL hotshoe flash, full batteries under "fill flash" conditions at 1/125 to 1/160 causing blurred images or ghosting. I often use a hotshoe flash to brighten dark shadow areas a little, where the camera settings without flash would basically be bright enough for a proper exposure and as a result have come across this problem frequently.

I worked with Pentax support and wrote up a controlled test that was submitted to the Pentax engineers. So far I have tested three K-7 cameras and all have this problem. I will be getting a 4th K-7 to test soon. Interestingly, when I set the flash to "Auto", using the light sensor on the flash, the blurred image problem is gone. This has been my "work around" with this camera.

At one point I thought it was user error, and that I was not holding my camera steady, however, apparently it is related to having fully charged batteries in the camera giving it an inconsistent nature.

The blurred images are only visible at 100% crops, which is probably why most people haven't noticed this. This camera has far better metering, auto focus, and sensitivity than my K10d, making it a very nice camera a side from this issue.

My question: Is anybody willing to do this controlled test with the K-5 to see if the problem has been fixed? If you need more details on the test setup please let me know.

Thanks

11-20-2010, 01:29 PM   #2
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No Problem with K-5

Eric sent me the test criteria and I tried it on K-5 with Pentax 360 flash. Both shots are performed at ISO200, f5.6, 1/125. Batteries were just charged on both camera and flash.

Net result - No problem. Two sample shots included (a crop of a larger pict). First is without flash, second is with. Exif should be there if you are interested. Please note that there is a shadow at the bottom of the pict, but this is an actual shadow since the flash was higher than the bottom of the metal plaque. I checked this carefully.

(Eric - these are different than the one with the tree - wanted to pick up something that was clearer for you).
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11-20-2010, 03:25 PM   #3
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Thank you so much for doing that test Joseph. Indeed it looks like that problem is not present with the K-5. The only mayor problem that some people are experiencing with the K-5 is that it overexposes using bounce flash. That is pretty bad actually and I do not understand how that was not discovered before production.

In the mean time, I will set the flash on my K-7 to "auto-mode" instead of P-TTL when used as fill flash. Hopefully this ghosting issue will get resolved sometime with a firmware upgrade. Or perhaps I will just upgrade to the K-5 when that flash issue has been fixed....I will see....

Thanks again Joseph.
11-21-2010, 04:06 AM   #4
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QuoteOriginally posted by Eric Seavey Quote
Is anybody willing to do this controlled test with the K-5 to see if the problem has been fixed?
What is the test criteria?

11-21-2010, 04:50 AM   #5
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K-5 has bounce flash issues? Where is this documented please?
11-21-2010, 05:32 AM   #6
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OK, I will just include the whole thing here for those interested testing the K-5:

I have been trying to resolve a ghosting problem that occurs with the K-7 with 70 to 80% of the photos when using a hotshoe flash under certain conditions that is very visible with a 100% crop. The ghosting varies and ranges from about 5 to 15 pixels.

The worst conditions where the ghosting occurs are easily produced in a controlled condition, and are as follows:

- Use of Pentax 360 afz Flash (same results occur with other brand flashes)

- The flash set to P-TTL or HSS P-TTL produces the ghosting (When flash is set to non-P-TTL mode, the camera does not produce ghosting. The Metz flash has its’ own light sensor and can be used in “auto mode” instead of P-TTL or HSS P-TTL Mode)

- Flash is used as fill flash, such that the ambient lighting by itself will produce reasonable exposure (I even point the flash away from the subject for my tests)

- Shutter speed = 1/125 second (though other shutter speeds even up to 1/160 second also can produce the ghosting)

- Aperture and sensitivity adjusted for reasonable ambient exposure (Manual mode used)

- Focal length used is 50 to 70mm (with sharp lens) however, ghosting also occurs at other focal lengths and all lenses I tried.

- Fully charged batteries (using half drained batteries does not produce the ghosting)


Additional information:

- Did not have this problem with the K10D

- Tried three different Pentax K-7 cameras, and all produce the same problem

- Changing the focal length to as wide as 17 mm does not seem to affect the amount of ghosting (still ranging from 5 to 15 pixels)

- Flash bracket or wireless flash does not help problem

- Battery grip makes the camera heavier but has no effect on ghosting (does not physically stabilize the camera)

- Use of tripod/monopod helps a bit sometimes but does not eliminate the problem

- Pop-up flash does not cause ghosting

- Flash off does not produce ghosting

- SR on/off does not produce ghosting with flash off

- SR on/off produces same amount of ghosting with flash on

- Manual mode is used for the test, but does not affect the problem and other modes produce ghosting

- HSS flash at 1/125 second does not affect the problem and produces ghosting

- Camera behaves better when batteries are partially drained (after 200+ photos)
11-21-2010, 05:37 AM   #7
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QuoteOriginally posted by gostwick Quote
K-5 has bounce flash issues? Where is this documented please?

At least two threads covering this:
https://www.pentaxforums.com/forums/pentax-k-5-forum/119630-my-2-days-old-k5-faulty.html

Here is some discussion about that too.
https://www.pentaxforums.com/forums/pentax-k-5-forum/119808-k-5-flash.html
11-21-2010, 06:00 AM   #8
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QuoteOriginally posted by gostwick Quote
K-5 has bounce flash issues? Where is this documented please?
You might want to read the thread https://www.pentaxforums.com/forums/pentax-k-5-forum/119808-k-5-flash.html

If I may summarize (as best I can - probably leaving some stuff out so better to read the thread) that the flash will overexpose when a diffuser is on the flash and it is tilted (like 45 degrees). I (and please notice that this is MY experience) find that if I don't use a diffuser and bounce the flash I don't get this behavior.

11-21-2010, 06:19 AM   #9
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QuoteOriginally posted by Eric Seavey Quote
The K-7 has a problem when using P-TTL hotshoe flash, full batteries under "fill flash" conditions at 1/125 to 1/160 causing blurred images or ghosting. I often use a hotshoe flash to brighten dark shadow areas a little, where the camera settings without flash would basically be bright enough for a proper exposure and as a result have come across this problem frequently.

I worked with Pentax support and wrote up a controlled test that was submitted to the Pentax engineers. So far I have tested three K-7 cameras and all have this problem. I will be getting a 4th K-7 to test soon. Interestingly, when I set the flash to "Auto", using the light sensor on the flash, the blurred image problem is gone. This has been my "work around" with this camera.

Thanks
Eric, i think you have missed the K7 "Shutter induced blur" discussion

https://www.pentaxforums.com/forums/pentax-news-rumors/108199-lumolabs-shutte...-7-camera.html

Most of the K7 have these problem. Pentax is aware of this problem and i think they will never fix it, so i send the camera back and have my money back.



So the question is: Does the K5 have a similar problem ?

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11-21-2010, 07:22 AM   #10
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No I did not miss the shutter induced problem writeup, and read it in detail long time ago. In fact, I do not have that problem with my K-7 since the photos are sharp without using the hotshoe flash or when hotshoe flash is set to "auto-mode" instead of P-TTL or using the pop-upflash.

Eric
11-21-2010, 09:04 AM   #11
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No overexposure with my K5 with 360fgz

QuoteOriginally posted by Eric Seavey Quote
Thank you so much for doing that test Joseph. Indeed it looks like that problem is not present with the K-5. The only mayor problem that some people are experiencing with the K-5 is that it overexposes using bounce flash. That is pretty bad actually and I do not understand how that was not discovered before production.

In the mean time, I will set the flash on my K-7 to "auto-mode" instead of P-TTL when used as fill flash. Hopefully this ghosting issue will get resolved sometime with a firmware upgrade. Or perhaps I will just upgrade to the K-5 when that flash issue has been fixed....I will see....

Thanks again Joseph.

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Last edited by limbonaut; 11-21-2010 at 10:08 AM.
09-14-2011, 11:46 AM   #12
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I hope you'll all forgive me for bumping this almost year-old thread, but I'm curious if there was any more info available on this issue with the K-7? I've had the exact same problems using a AF540FGZ in P-TTL mode as fill.

It has occured when taking portraits outdoors, using shutter speeds around 1/100s where one would expect camera shake and motion blur to be minimal (stationary subjects, shake reduction on). It has also occured while using a DA*16-50 at fairly wide angles.

Any additional info on this would be greatly appreciated!

Last edited by polachekphotography; 09-14-2011 at 11:52 AM.
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