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[lykaman]

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Hi All, something that is niggling at me, If I use B&W on my Leica digital will the difference between just changing a Color image to B&W be noticeable?  L

[Exodies]

The B&W option on Leica’s non-monochrome cameras is just changing a colour image (the raw file) to black and white (the jpeg file). There are as many ways of doing this conversion as there are permutations of three eight bit numbers.

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[Luke_Miller]

Probably not a lot of difference between a B&W jpeg straight from the camera and a B&W image from a raw file processed using default settings.  But with many raw processors one can create B&W images by manipulating the color information in the raw file.  This changes the luminosity of different colored elements in the image, much the same as using a color filter on the lens.  So, for example, a landscape shot could have the green foliage lightened or darkened to taste without affecting other (different colored) elements in the resulting B&W mage. 

Edited April 6, 2020 by Luke_Miller

[lykaman]

2 hours ago, Luke_Miller said:

Probably not a lot of difference between a B&W jpeg straight from the camera and a B&W image from a raw file processed using default settings.  But with many raw processors one can create B&W images by manipulating the color information in the raw file.  This changes the luminosity of different colored elements in the image, much the same as using a color filter on the lens.  So, for example, a landscape shot could have the green foliage lightened or darkened to taste without affecting other (different colored) elements in the resulting B&W mage. 

On this Forum, I don't really think it matters, for printing and other reasons RAW B&W and then PP is always the best..  L

Edited April 6, 2020 by lykaman

[zeitz]

A raw file is a table of numbers read from the sensor's pixels; a raw file is not an image.  You can open a raw file in a text editor and see the contents.  Color digital cameras, such as the OP's color digital Leica, make each pixel red, blue or green by means of a filter array such as a Bayer filter.  So when a color digital camera displays a color image or a B&W image, some post-processing software is converting the table of numbers, de-mosaicing it into the image.  It is displayed on the camera's monitor as a jpeg image.  In-camera B&W for a color digital camera uses in-camera post-processing software.  Whether or not an in-camera B&W image matches a post-processing B&W image done on a computer depends solely on how you do the conversion on a computer.

The only raw B&W is on a Leica Monochrome camera.

[Jeff S]

31 minutes ago, zeitz said:

The only raw B&W is on a Leica Monochrome camera.

Or other company’s monochrome camera or back, e.g., Phase.  

Jeff

[Jossie]

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The conversion of a digital colour image into a greyscale image is standardized by various definitions. In general, the linear greyscale value Y is calculated from the (linear, i.e.not gamma-corrected) RGB-values according to

Y = wR * R + wG * G + wB * B, with the weights wR, wG and wG. (see Burger & Burge 2016, Springer for details).

The two most common definitions of the weights are the TV-standard: wR = 0.299, wG = 0.587 and wB = 0.114,

and ITU-BT.709:     wR = 0.2125, wG = 0.7154, wB = 0.072.

Since the human eye is most sensitive in G, this channel is weighted highest.

I would assume that any in-camera conversion is using one of these. Also the conversion functions in any software will most likely use one of them. The documentation should tell you, which is actually used, if it cannot be selected by the user. Some software does allow the user to specify arbitrary weighting factors, e.g. SilverFast.

Here is a comparison between the two standards (original left, TV standard middle, ITU-BT.709 right):

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Edited April 7, 2020 by Jossie