Re: [MaxImDL] Raw vs Color Images


Aug 12, 2013

 


----------------------------

#54174 Aug 12, 2013

I have recently I been advised that I should be taking "raw" images instead of "color" images. I did that on my last outing. Then I calibrated, aligned, stacked, and converted them to color. I don't see that I have gained anything by using these raw images. Am I missing something? Does anyone have any opinions about which is better?

.

Thanks

JV



[Non-text portions of this message have been removed]



----------------------------

#54175 Aug 12, 2013

What do you mean by "color"?



With a DSLR, you have a choice between raw and JPEG. With JPEG images

you are locked into the method used by the camera to de-bayer (convert

to color) the sensor information, you are using data that is somewhat

degraded from the original, and you are limited to 8 bits of dynamic

range per color channel.



With raw images you can use color conversion algorithms better suited to

astroimages, your data hasn't been distorted by JPEG compression, and

you have your data at the native bit depth of your camera- typically

12-14 bits with most DSLRs.



If you aren't seeing a difference in image quality between processed

raws and processed JPEGs, your imaging procedure probably needs

modification, because it means you aren't coming close to getting what

the camera is capable of producing.



Chris



*******************************

Chris L Peterson

Cloudbait Observatory

www.cloudbait.com

On 8/12/2013 11:46 AM, Jones Howell wrote:

> I have recently I been advised that I should be taking "raw" images instead of "color" images. I did that on my last outing. Then I calibrated, aligned, stacked, and converted them to color. I don't see that I have gained anything by using these raw images. Am I missing something? Does anyone have any opinions about which is better?

>

> Thanks

> JV



----------------------------

#54181 Aug 12, 2013

I have the same doubt.



JV means that in Expose Options for a DSLR you have (If I remember) several options:

- Raw Monochrome

- Raw Color

- RAW to CF card

- Raw to Harddisk

- etc



The only one that creates normal Canon CR2 is "Raw to Harddisk".

"Raw Monochrome" I have read somewhere that is really a color image. After calibrating, you can always debater and convert to color .



In my case, I don't know why "Raw to Harddisk" doesn't work. It captures the first Image, and after that it goes to idle (when exposing with CCD Commander).

Fernando





El 12/08/2013, a las 19:54, Chris Peterson cpeterson@...> escribi.:

> What do you mean by "color"?

>

> With a DSLR, you have a choice between raw and JPEG. With JPEG images

> you are locked into the method used by the camera to de-bayer (convert

> to color) the sensor information, you are using data that is somewhat

> degraded from the original, and you are limited to 8 bits of dynamic

> range per color channel.

>

> With raw images you can use color conversion algorithms better suited to

> astroimages, your data hasn't been distorted by JPEG compression, and

> you have your data at the native bit depth of your camera- typically

> 12-14 bits with most DSLRs.

>

> If you aren't seeing a difference in image quality between processed

> raws and processed JPEGs, your imaging procedure probably needs

> modification, because it means you aren't coming close to getting what

> the camera is capable of producing.

>

> Chris

>

> *******************************

> Chris L Peterson

> Cloudbait Observatory

> www.cloudbait.com

>

> On 8/12/2013 11:46 AM, Jones Howell wrote:

> > I have recently I been advised that I should be taking "raw" images instead of "color" images. I did that on my last outing. Then I calibrated, aligned, stacked, and converted them to color. I don't see that I have gained anything by using these raw images. Am I missing something? Does anyone have any opinions about which is better?

> >

> > Thanks

> > JV

>

>







[Non-text portions of this message have been removed]



----------------------------

#54183 Aug 12, 2013

My camera is an ST-8300C. It is an astronomical color.camera, not a DSLR, with 16 bit resolution. In the expose options for MaximDL I have a choice of color or raw. The color images are indeed color and the raw images appear as black and white which can be converted to color but I must choose the percent red, green, or blue. The end result appears very much the same to me.

JV





---------------

From: Huet Fernando fh2503@...>

To: MaxImDL@yahoogroups.com

Sent: Monday, August 12, 2013 1:26 PM

Subject: Re: [MaxImDL] Raw vs Color Images





I have the same doubt.



JV means that in Expose Options for a DSLR you have (If I remember) several options:

- Raw Monochrome

- Raw Color

- RAW to CF card

- Raw to Harddisk

- etc



The only one that creates normal Canon CR2 is "Raw to Harddisk".

"Raw Monochrome" I have read somewhere that is really a color image. After calibrating, you can always debater and convert to color .



In my case, I don't know why "Raw to Harddisk" doesn't work. It captures the first Image, and after that it goes to idle (when exposing with CCD Commander).

Fernando





El 12/08/2013, a las 19:54, Chris Peterson cpeterson@...> escribi.:

> What do you mean by "color"?

>

> With a DSLR, you have a choice between raw and JPEG. With JPEG images

> you are locked into the method used by the camera to de-bayer (convert

> to color) the sensor information, you are using data that is somewhat

> degraded from the original, and you are limited to 8 bits of dynamic

> range per color channel.

>

> With raw images you can use color conversion algorithms better suited to

> astroimages, your data hasn't been distorted by JPEG compression, and

> you have your data at the native bit depth of your camera- typically

> 12-14 bits with most DSLRs.

>

> If you aren't seeing a difference in image quality between processed

> raws and processed JPEGs, your imaging procedure probably needs

> modification, because it means you aren't coming close to getting what

> the camera is capable of producing.

>

> Chris

>

> *******************************

> Chris L Peterson

> Cloudbait Observatory

> www.cloudbait.com

>

> On 8/12/2013 11:46 AM, Jones Howell wrote:

> > I have recently I been advised that I should be taking "raw" images instead of "color" images. I did that on my last outing. Then I calibrated, aligned, stacked, and converted them to color. I don't see that I have gained anything by using these raw images. Am I missing something? Does anyone have any opinions about which is better?

> >

> > Thanks

> > JV

>

>







[Non-text portions of this message have been removed]







---------------



Yahoo! Groups Links







[Non-text portions of this message have been removed]







----------------------------

#54190 Aug 13, 2013

Thanks for the additional info. I've never used Maxim to control a color

camera, so was unfamiliar with where the terminology you used was coming

from.



Chris



*******************************

Chris L Peterson

Cloudbait Observatory

www.cloudbait.com

On 8/12/2013 11:43 PM, Jones Howell wrote:

> My camera is an ST-8300C. It is an astronomical color camera, not a DSLR, with 16 bit resolution. In the expose options for MaximDL I have a choice of color or raw. The color images are indeed color and the raw images appear as black and white which can be converted to color but I must choose the percent red, green, or blue. The end result appears very much the same to me.

> JV



----------------------------

#54197 Aug 13, 2013

A major advantage to Raw is being able to subtract your dark frame prior to the

debayer (color convert) process. The debayer process has to interpolate between

adjacent pixels to get R, G, and B for each pixel.



When it does that interpolation, a single hot pixel affects at least 9 adjacent

pixels. It can be more than that depending on the interpolation algorithm.



By subtracting the dark frame first, you prevent the hot pixels from bleeding in

that fashion.



Doug



--



Doug George

dgeorge@...



Diffraction Limited

Makers of Cyanogen Imaging Products

www.cyanogen.com/



59 Grenfell Crescent, Unit B

Ottawa, Ontario,

Canada, K2G 0G3



Phone: (613) 225-2732

Fax: (613) 225-9688



----------------------------

#54201 Aug 13, 2013

That a good input, I did not realize that.

Thanks

JV





---------------

From: Douglas B. George dg@...>

To: MaxImDL@yahoogroups.com

Sent: Tuesday, August 13, 2013 11:45 AM

Subject: Re: [MaxImDL] Raw vs Color Images







.



A major advantage to Raw is being able to subtract your dark frame prior to the

debayer (color convert) process. The debayer process has to interpolate between

adjacent pixels to get R, G, and B for each pixel.



When it does that interpolation, a single hot pixel affects at least 9 adjacent

pixels. It can be more than that depending on the interpolation algorithm.



By subtracting the dark frame first, you prevent the hot pixels from bleeding in

that fashion.



Doug



--



Doug George

mailto:dgeorge%40cyanogen.com



Diffraction Limited

Makers of Cyanogen Imaging Products

www.cyanogen.com/



59 Grenfell Crescent, Unit B

Ottawa, Ontario,

Canada, K2G 0G3



Phone: (613) 225-2732

Fax: (613) 225-9688







[Non-text portions of this message have been removed]



Contact Us
This Site's Privacy Policy
Google's privacy policies

S
e
n
i
o
r
T
u
b
e
.
o
r
g