Industrial Dust Collector - D800M (Monochrome Sensor Conversion)

[bobfriedman]

Monochrome Sensor Conversion

Nikon D800M ,Zeiss Apo Sonnar T* 135mm f/2
1/1250s f/5.6 at 135.0mm iso100

[bobfriedman]

Nikon D800M ,Zeiss Makro-Planar T* 100mm f/2
1/1250s f/5.6 at 100.0mm iso100

[Akira]

Amazing image by the amazing combo!  Hope the sensor wouldn't collect dusts!

[Hugh_3170]

Well done Bob (for the image) and well done re the producing of the D800M - well worth the effort if this image is anything to go by.

[bobfriedman]

Amazing image by the amazing combo!  Hope the sensor wouldn't collect dusts!

the cover glass was replaced.. and i had the AA filter replaced with BG-38

[Danulon]

Sorry for my ignorance: What is the advantage of this filter change vs. b/w conversion in post production?

[bobfriedman]

Sorry for my ignorance: What is the advantage of this filter change vs. b/w conversion in post production?

it is not simply a filter change.. the sensor was removed and the color filter array + microlenses were plasma etched off the surface of the sensor.. this results in increased shadow detail and overall sensitivity..  additionally the AntiAliasing (AA) filter was removed (the AA filter has the action of a low pass filter to reduce moire but possesses the unwanted effect of reducing sharpness).. The BG-38 glass AA filter replacement is essential glass that transmits UV + Visible and excludes IR.. so in summary a sharper image with increased detail (especially in the shadow areas) and increased sensitivity results from this conversion.

to Akira's point - the sensor is covered and any dust will fall on the BG-38 filter which is easily cleaned without damage to the sensor.

See maxmax.com for more detail.

[Akira]

Bob, thank you for the details.

I strongly wish (and believe) that BG38 is protectively coated, as it is deteriorated by the moisture.  My uncoated one became totally unusable.   

[bobfriedman]

Bob, thank you for the details.

I strongly wish (and believe) that BG38 is protectively coated, as it is deteriorated by the moisture.  My uncoated one became totally unusable.   

well yes. i did think of that and maybe i misunderstood your original point.. but it is replaceable. i will ask Dan at maxmax but i think it is straight schott glass.

[Hugh_3170]

Bob, thanks for explaining how the D800M is created.

I am guessing that once converted, each of the Red and Blue channels will appear equal in strength (not sure if green's extra pixels will make it look brighter) and that conversion is a simple combination of the channels in PS or Lightroom?

[bobfriedman]

Bob, thanks for explaining how the D800M is created.

I am guessing that once converted, each of the Red and Blue channels will appear equal in strength (not sure if green's extra pixels will make it look brighter) and that conversion is a simple combination of the channels in PS or Lightroom?

one more item.. you need a raw converter that doesn't demosaic the image which is required to reconstruct a full color image from the incomplete color samples output from an image sensor overlaid with a color filter array (CFA). It is also known as CFA interpolation/smoothing... Raw converters such as DarkTable or AccuRaw allow turning this off.   after the CFA is removed, the demosaicking process that is done during RAW file processing becomes unnecessary and can introduce resolution errors since a monochrome conversion inherently produces higher resolution.. as an example consider a D800 36mpx sensor.. since in a normal cam with Color Filter Array (CFA) there would be 9Mpx=red, 9Mpx=blue and 16Mpx=green.... so for images that were mostly red you would have mostly 9Mpx contributing to image or mostly green you would have 16Mpx contributing but with the monochrome conversion there are 36Mpx always giving higher resolution everywhere.

[Danulon]

it is not simply a filter change.. the sensor was removed and the color filter array + microlenses were plasma etched off the surface of the sensor.. this results in increased shadow detail and overall sensitivity..  additionally the AntiAliasing (AA) filter was removed (the AA filter has the action of a low pass filter to reduce moire but possesses the unwanted effect of reducing sharpness).. The BG-38 glass AA filter replacement is essential glass that transmits UV + Visible and excludes IR.. so in summary a sharper image with increased detail (especially in the shadow areas) and increased sensitivity results from this conversion.

to Akira's point - the sensor is covered and any dust will fall on the BG-38 filter which is easily cleaned without damage to the sensor.

See maxmax.com for more detail.

Thanks for the explanation!