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GlennG · 11-07-2013, 06:42 PM

There is a K5 jpeg option that allows one to shoot less than 16 MP jpeg photos. When an option is chosen to have less than 16 MP, what does the K5 actually do to create that? Does it take a full 16 MP photo but then downsample interpolate to save the file as something less? Or something different? If it is actally downsizing the file, what algorithm is used? If you shoot at 12,800 and downsample, will it actually help the noise? I searched for this, but could not actually find anything.

Thanks for any information or links you may have.

Glenn

hcc · 11-07-2013, 09:11 PM

When you select a JPEG resolution less than 16 Mp, a full 16 MP photo is taken but then the camera downsamples by interpolation.

If you want to reduce the file size, it is recommended to keep the original sensor resolution (16 MP herein) and to lower the JPEG resolution down to [**] or even [*].

Hope that the comment may assist.

asp1880 · 11-08-2013, 12:55 AM - **1 Like**

I routinely shoot 6MP 3 stars jpeg quality. That's good enough for my print sizes. I rarely print big and
most of my output is just emailed or websized pictures.

Regards,
--Anders.

Alfie · 11-08-2013, 05:35 AM

Quote:

I routinely shoot 6MP 3 stars jpeg quality. That's good enough for my print sizes.

That’s also my setting for RAW+.

tabl10s · 11-25-2013, 05:16 PM

Originally posted by hcc

When you select a JPEG resolution less than 16 Mp, a full 16 MP photo is taken but then the camera downsamples by interpolation.

If you want to reduce the file size, it is recommended to keep the original sensor resolution (16 MP herein) and to lower the JPEG resolution down to [**] or even [*].

Hope that the comment may assist.

Is there a point where the techniques meet(16 MP@**=6MP@****)?

DeadJohn · 11-25-2013, 06:05 PM

I do not know the answer to the original question. I am chiming in because I've often wondered why Pentax doesn't put a quarter a resolution mode, aka binning, into their cameras. Convert 4 pixels into a superpixel, giving exactly half the resolution horizontally and vertically for a smaller file and greatly reduced noise. This could even work in RAW.

For example, the K-5's 16mp would save as exactly 4mp, and the K-3 as 6mp.

Yes, this can all be done with software after the fact, but it's a mystery why the firmware supports seemingly random reduced file sizes instead of a nice simple intuitive 25%.

11-07-2013, 06:42 PM	#1
GlennG Veteran Member Join Date: Aug 2010 Location: Houston, Texas Posts: 824	Shooting less than 16 MP There is a K5 jpeg option that allows one to shoot less than 16 MP jpeg photos. When an option is chosen to have less than 16 MP, what does the K5 actually do to create that? Does it take a full 16 MP photo but then downsample interpolate to save the file as something less? Or something different? If it is actally downsizing the file, what algorithm is used? If you shoot at 12,800 and downsample, will it actually help the noise? I searched for this, but could not actually find anything. Thanks for any information or links you may have. Glenn

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11-07-2013, 09:11 PM	#2
hcc Pentaxian Join Date: Nov 2009 Location: Brisbane, Australia Photos: Gallery \| Albums Posts: 4,005	When you select a JPEG resolution less than 16 Mp, a full 16 MP photo is taken but then the camera downsamples by interpolation. If you want to reduce the file size, it is recommended to keep the original sensor resolution (16 MP herein) and to lower the JPEG resolution down to [*] or even []. Hope that the comment may assist.

11-08-2013, 12:55 AM - 1 Like	#3
asp1880 Veteran Member Join Date: Jul 2010 Location: Lyngby, Copenhagen Photos: Albums Posts: 742	I routinely shoot 6MP 3 stars jpeg quality. That's good enough for my print sizes. I rarely print big and most of my output is just emailed or websized pictures. Regards, --Anders.

11-08-2013, 05:35 AM	#4
Alfie Forum Member Join Date: Nov 2011 Location: Vienna, Austria Posts: 51	Quote: I routinely shoot 6MP 3 stars jpeg quality. That's good enough for my print sizes. That’s also my setting for RAW+.

11-25-2013, 05:16 PM	#5
tabl10s Veteran Member Join Date: Jun 2011 Location: Sacramento(formerly from B'Ham, England). Posts: 1,424	Originally posted by hcc When you select a JPEG resolution less than 16 Mp, a full 16 MP photo is taken but then the camera downsamples by interpolation. If you want to reduce the file size, it is recommended to keep the original sensor resolution (16 MP herein) and to lower the JPEG resolution down to [*] or even []. Hope that the comment may assist. Is there a point where the techniques meet(16 MP@=6MP@**)?

11-25-2013, 06:05 PM	#6
DeadJohn Pentaxian Join Date: Jan 2011 Location: New York Posts: 4,834	I do not know the answer to the original question. I am chiming in because I've often wondered why Pentax doesn't put a quarter a resolution mode, aka binning, into their cameras. Convert 4 pixels into a superpixel, giving exactly half the resolution horizontally and vertically for a smaller file and greatly reduced noise. This could even work in RAW. For example, the K-5's 16mp would save as exactly 4mp, and the K-3 as 6mp. Yes, this can all be done with software after the fact, but it's a mystery why the firmware supports seemingly random reduced file sizes instead of a nice simple intuitive 25%.

Shooting less than 16 MP

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