Luminous Landscape Forum

Equipment & Techniques => Medium Format / Film / Digital Backs – and Large Sensor Photography => Topic started by: larkis on January 19, 2012, 02:32:40 pm

Title: Pentax 645 CCD issue ?
Post by: larkis on January 19, 2012, 02:32:40 pm
I have noticed the problem on the following images and a few others depending on how they are manipulated. Has anyone ran into this issue before ?

(http://www.dominik.ca/ccd_line.jpg)
(http://dominik.ca/ccd_split.jpg)

I'm still doing testing to see if the problem starts to ruin actual images on the trip I'm currently on.
Title: Re: Pentax 645 CCD issue ?
Post by: dfarkas on January 19, 2012, 02:48:38 pm
This is commonly referred to as sensor centerfolding. On a multi-readout CCD, the sensor is split into multiple areas for greater shooting/recording/review speed. If these areas aren't calibrated properly to each other, you can see the split. In this case, the left and right sides split in the middle. The visual disparity is enhanced when exposure is boosted in post processing.

Typically, a camera would either have to go back to service for sensor calibration or sometimes, you could email a RAW file and custom firmware could be provided back to you. I'm not entirely sure how Pentax handles this issue. I'd suggest you either contact your dealer or Pentax service directly to see what your options are.

David
Title: Re: Pentax 645 CCD issue ?
Post by: Brian Hirschfeld on January 19, 2012, 09:54:58 pm
Yes, it happens when you push things to the limits sometimes. I have noticed it on some rentals in the past.