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05-20-2016, 07:14 AM   #1
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Pixel Shift: bigger files? B&W results?

(With the Pentax k-1)
Im sorry if this is a repetition, but I cannot find definitive answers to my doubts.

Part A:

1. A file using Pixel Shift mode is bigger in size (I mean the physical size in Height/Width) Or this size stays the same?
2. A file using Pixel Shift mode is bigger in weight (I mean file size in megapixels)? Four times bigger?
3. A file using Pixel Shift mode can be compared to a Medium Format file? If so how big would be a similar MF file? Any parallel with files from the Pentax 645D or Z?

I do not seek for absolute numbers but it would be nice to know more or less what can I expect from this capture mode.

Part B:
1. For Black and White conversion, will I gather the same amount of light for the three RGB channels? A bigger luminance value for each comparing to the regular Bayer capture?
2. Is there any possible comparison between this Pixel Shift mode and the Leica M Monochrom mode/files?
3. Is there a thread dedicated to B&W work with the Pixel Shift Mode, here in the forum or online (Flickr?)? I cannot find it.

Thank you very much for your support.

05-20-2016, 07:20 AM - 1 Like   #2
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The Pixel shift does not increase the # of pixels but just takes 4 shots that are offset 1 pixel each time to allow each pixel to have true colour Red, Blue and Green on each pixel compared to normal Bayer shot, which interpolates. It is somewhat analagous to the Foeven technology. In relation to B&W the exposures are the same for all 3 shots. The increase in megapixels with pixelshift relates to there being 4 separate photos layered.
05-20-2016, 07:29 AM - 1 Like   #3
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Yes, it's easy to confuse what Pentax are doing with what has been done by Olympus and Hasselblad.

In Olympus and Hasselblad, a slight shift in the sensor is used to create extra in-between pixels - so the image resolution and file size increases.

Pentax shift the sensor one whole pixel, so that each pixel can get full RGB colour information. There's no more pixels, but with better colour information for each pixel, resolution goes up with the same file size.

In the K3ii, the camera takes four 24mp images, then interpolates that down to a single 24mp full colour image. Of course, if Pentax were Sigma, they'd be calling the K3ii a 96mp camera

As for black and white, one can imagine that having more information for each pixel would benefit the final image in some way. All those pixel shift owners out there have some testing to do!
05-20-2016, 07:42 AM - 1 Like   #4
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Check out the pixel shift samples at the bottom of this page Pentax K-1 Low-Light and Pixel Shift Samples - Hands-On Tests | PentaxForums.com

You can clearly see an increase in resolution on the cactuses even though the number of pixels are the same on both the pixel shifted and the normal shot of the same scene. That increase of resolution will of course remain when you convert to black and white.

05-20-2016, 08:07 AM   #5
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Here is a PS image in B&W for you. Not sure it tells you anything.

05-20-2016, 08:21 AM   #6
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Original Poster
Thank you all.
More information per channel. The same size and weight files. Cleaver solution.
More resolution both for colors and for (luminance) B&W conversion.
Yes, your image is very detailed; Eno ,-) May I ask you if it was done with the K-3 or K-1 and the lens used?
05-20-2016, 08:25 AM - 1 Like   #7
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QuoteOriginally posted by Pansottin Quote
Thank you all.
More information per channel. The same size and weight files. Cleaver solution.
More resolution both for colors and for (luminance) B&W conversion.
Yes, your image is very detailed; Eno ,-) May I ask you if it was done with the K-3 or K-1 and the lens used?
K-1 with D-FA 100mm f/2.8 macro (non-WR version)

Model: PENTAX K-1
ISO: 1600
Exposure: 1/2 sec
Aperture: 11.0
Focal Length: 100mm
05-20-2016, 08:27 AM   #8
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QuoteOriginally posted by enoeske Quote
K-1 with D-FA 100mm f/2.8 macro (non-WR version)

Model: PENTAX K-1
ISO: 1600
Exposure: 1/2 sec
Aperture: 11.0
Focal Length: 100mm
Thank you .-)

05-20-2016, 09:54 AM   #9
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The only proviso to what has been said already is that a Motion Corrected Pixel Shift file is larger than a non-corrected PS file. I am getting about 140-160 MB for a motion-corrected PS image versus about 60 MB for a non-corrected one.
05-20-2016, 10:02 AM   #10
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QuoteOriginally posted by jbinpg Quote
The only proviso to what has been said already is that a Motion Corrected Pixel Shift file is larger than a non-corrected PS file. I am getting about 140-160 MB for a motion-corrected PS image versus about 60 MB for a non-corrected one.
Thanks for the info.
05-20-2016, 12:15 PM - 1 Like   #11
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File sizes increase dramatically over non PS.
A k1 raw pixel shift file is 150 megs +. Working with this in PS and you have 250+ meg TIFFs.
The raw file itself is packed with luminance information and makes for stunning black and white images with incredible tonal transitions.

In colour, I've noticed that it ends up reducing colour casts. Great technology.
05-20-2016, 12:32 PM   #12
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QuoteOriginally posted by tomO2013 Quote
File sizes increase dramatically over non PS.
A k1 raw pixel shift file is 150 megs +. Working with this in PS and you have 250+ meg TIFFs.
The raw file itself is packed with luminance information and makes for stunning black and white images with incredible tonal transitions.

In colour, I've noticed that it ends up reducing colour casts. Great technology.
How big (megs) is a regular RAW file from the K-1?

Nice article with answers .-)
http://www.imaging-resource.com/PRODS/pentax-k1/pentax-k1A.HTM
http://www.imaging-resource.com/PRODS/pentax-k1/pentax-k1A.HTM#tech2

Last edited by Pansottin; 05-20-2016 at 02:03 PM.
05-22-2016, 02:13 AM   #13
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QuoteOriginally posted by Pansottin Quote
How big (megs) is a regular RAW file from the K-1?

Nice article with answers .-)
Pentax K-1 Review: Initial Test
Pentax K-1 Review: Initial Test
Hmm... normal PEF files are about 45 megs or there abouts. I haven't checked file size for DMG to see if there is any added compression to the PEF's.
05-22-2016, 01:10 PM   #14
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QuoteOriginally posted by tomO2013 Quote
Hmm... normal PEF files are about 45 megs or there abouts. I haven't checked file size for DMG to see if there is any added compression to the PEF's.
Thanks Tom .-)
05-22-2016, 02:55 PM   #15
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QuoteOriginally posted by tomO2013 Quote
The raw file itself is packed with luminance information and makes for stunning black and white images with incredible tonal transitions.
How are you processing for B&W using pixel shift...anything special?


Steve
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