Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
Pentax K5 tests
#1
A little update - the AA filter exchange was not possible. The tests will be performed on a factory K5.



Klaus
#2
Do you know why it wasn't possible?
#3
[quote name='Alexander ' timestamp='1294764931' post='5426']

Do you know why it wasn't possible?

[/quote]



The K5 seems to be very unique regarding its AA filter characteristic.

After the AA removal the camera produced "shadowed" images for wide-angle settings.

The service company didn't have an explanation but that was the first time the experienced this problem.

I will get a brand new K5 as a replacement, BTW, so the procedure had no impact on my wallet.
#4
[quote name='Klaus' timestamp='1294765706' post='5427']

The K5 seems to be very unique regarding its AA filter characteristic.

After the AA removal the camera produced "shadowed" images for wide-angle settings.

The service company didn't have an explanation but that was the first time the experienced this problem.

I will get a brand new K5 as a replacement, BTW, so the procedure had no impact on my wallet.

[/quote]



Care to speculate as to why this would occur? For fun! I bet Sony found a way to improve light transfer with the filter? Maybe, no?
#5
[quote name='jamesm007' timestamp='1294803283' post='5434']

Care to speculate as to why this would occur? For fun! I bet Sony found a way to improve light transfer with the filter? Maybe, no?

[/quote]



There are no problems with the D7000.
#6
[quote name='Klaus' timestamp='1294765706' post='5427']

...

The service company didn't have an explanation but that was the first time the experienced this problem.

...

[/quote]





So if I could speculate; the sample you have bought is doomed due to your mindset concerning AA filters. The thick AA filter gods won't let you test it <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/tongue.gif' class='bbc_emoticon' alt='Tongue' />...



Serkan
#7
[quote name='PuxaVida' timestamp='1294832503' post='5443']

So if I could speculate; the sample you have bought is doomed due to your mindset concerning AA filters. The thick AA filter gods won't let you test it <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/tongue.gif' class='bbc_emoticon' alt='Tongue' />...



Serkan

[/quote]



Well, I did a few test shots with the AA-less version and they were much sharper indeed (apart from the double image issue).

Even despite the problem I got more than 2900LW/PH out of it. But that doesn't really help ...



Really sad.
#8
Could it be on account of mass change of the sensor and SR assembly due to replacement cover glass? The dynamic response of the SR system could be affected by a mass change. Did the blur occur at all shutter speeds?
#9
SR is switched off in the lab, the shadows remained, though.



-- Markus
Editor
opticallimits.com

#10
The SR system in Pentax DSLRs is never truly 'switched off'. The sensor stage assembly has no rigid constraint in the focal plane and is always positioned by the voice-coil actuators when the camera is on (shake the camera when on and off and notice the rattle). When active shake compensation is disabled, the SR platform is in 'clamp' mode where the system keeps the sensor in a fixed location relative to the camera body. However, I believe it is still actively controlling the sensor stage position as in 'SR on' mode. There are positional sensors which facilitate feedback control, however that does not necessarily exclude the possibility that a change in the sensor stage mass could make the control system unstable and result in the ghost images you see.



More clues which suggest that this could be the case:



- Since SR compensation is dependant on focal length this might correlate to the ghost images being dependant on field of view (as you mentioned)

- A similar sensor used in the fixed-sensor Nikon had no such issues.



You could try to see if there is any mass difference between the old and new components or otherwise rigidly fix the sensor stage assembly.



I am curious though if the blur is constant for all shutter speeds (especially > 1/2000 s)..





[quote name='mst' timestamp='1294839971' post='5448']

SR is switched off in the lab, the shadows remained, though.



-- Markus

[/quote]
  


Forum Jump:


Users browsing this thread:
1 Guest(s)