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01-02-2013, 09:01 AM   #1
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UV Transmission data for K7,K5?

Hello,

Has anyone seen any data regarding the transmission of either K7 or K5 between 300 and 400NM? Ie that internal UV filter in the cams, what wavelengths will they pass through, is there any point in buying UV transmitting optics?

Many Thanks

01-02-2013, 11:05 PM   #2
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I'd love Pentax to release a high transmission hot filter or remove it altogether. Maybe a K5II-IR....least one can dream.
01-03-2013, 03:19 AM   #3
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Someone maybe more knowledgable than me about this so feel free to chime in, but from what I gather, the K7 or K5 are not the ideal camera for UV photography because they use Bayer CMOS sensors - Foveon CMOS sensors tend to be better performers.
01-03-2013, 04:33 AM   #4
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I am planning on doing a few short wavelength tests on this With my K5 IIs - I have already completed analysing the results of capturing near-infared with some surprising results and the K5 IIs does a superb job of it. I'm also interested in how it will respond to shorter wavelengths.

01-03-2013, 12:01 PM   #5
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Digitalis would you be able to test the K5IIs with HA wavelength. It's not as deep into the spectrum as IR, but pretty close.
I have a Ha filter but don't have other cameras to compare what a standard mean would be for X exposure time.
01-03-2013, 05:42 PM   #6
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The K5IIs should have decent transmission in the Hα band - 656.281nm the Hoya R72 transmits at 1% 690 to 100% at 720nm with a gradual reduction in transmission at frequencies over 900nm- so I would say the K5II would be excellent for imaging the night sky with a Hα filter. In my experiments I didn't need to use DFS because the noise in the K5IIs sensor is practically non-existant, adn detail is considerably enhanced at Hight ISO ranges by the lack of an AA filter. I have considered purchasing the Pentax GPS for the astrotracer function - which could be used to extend exposure times and allowing for a lower ISO to be used.

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