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DSLR question

Spoon

By Spoon
in Discussions - Cameras

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Spoon

Spoon

Posted
Posted

Hi everyone,

So I noticed yesterday that my DSLR has a monochrome option. Could I use this to get images or would it not be worth it as it is not a dedicated mono CCD?

Thanks!

Cam

Sent from my iPhone using Tapatalk

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sbooder

sbooder

Posted
Posted

The mono option for DSLRs only changes jpg to mono the RAW files will still be in colour so it would make no difference to what you have at the end, unless of course you are the proud owner of a Leica Monochrome?

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IanL

IanL

Posted
Posted

The problem is that with a DSLR the RGB filters are fixed in place, so you can never take an L (and converting a DSLR RGB image to monochrome doesn't make it an L, it just makes it monochrome). The advantage of an L image is that you capture all of the incoming photons rather than just the ones that are passed through by the RGB filters.

Luminance is much more important for human perception of detail than colour, so using a CCD camera you can bin (combine) pixels for the RGB filters and take much shorter exposures, then use the full resolution of the camera for the L exposures (which will take longer).  Overall you save a lot of time and end up with an image that looks just as good.

Of course if you are feeling brave, you can try to remove the RGB filters from your DSLR sensor (http://stargazerslounge.com/topic/166334-debayering-a-dslrs-bayer-matrix/) but good luck putting them back even assuming you don't end up breaking your camera!

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sbooder

sbooder

Posted
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Yes, to use filters you will need a CCD imager rather than a DSLR because you cannot take monos with the DLSR in RAW.  The images you see on the back of the camera when set to Mono are in camera processed jpgs not RAWs.

There is only one DLSR with a dedicated Monochrome censor and that is the Leica M Monochrom and at £6k I would stick to colour shots with a DSLR.

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  • 2 weeks later...
Solo05

Solo05

Posted
Posted

Yes, to use filters you will need a CCD imager rather than a DSLR because you cannot take monos with the DLSR in RAW.  The images you see on the back of the camera when set to Mono are in camera processed jpgs not RAWs.

There is only one DLSR with a dedicated Monochrome censor and that is the Leica M Monochrom and at £6k I would stick to colour shots with a DSLR.

Not quite true.  My 600D when in manual will save RAW monochrome.  When you look at the 3 colour histogram they are all identical so acts like a luminance channel.  

Don't get caught up in the CCD v DSLR debate either, I have seen some extraordinary images taken by both. 

With  a programme like Startools you can also strip the individual RGB out from a stacked image to process each colour individualy.

Just something to think about. 

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IanL

IanL

Posted
Posted

Not quite true.  My 600D when in manual will save RAW monochrome.  When you look at the 3 colour histogram they are all identical so acts like a luminance channel.  

Sorry to go on, but see my post above above.  A normal DSLR cannot shoot an unfiltered image because the RGB filters are fixed in place, and each filter will block about 2/3rds of the incoming light. You can't change a camera setting and have a bunch of filters that are basically glued to the surface of the sensor magically disappear.

Only a camera with no RGB bayer filters can take a true luminance (either a CCD, the Leica with the unfiltered sensor or a DSLR where the micro-lens and bayer filter layer has been removed - possible but basically involves taking a brillo pad to your sensor so not for the faint-hearted).  The benefit of shooting with an unfiltered sensor is much reduced exposure time to reach a given level of signal vs an OSC sensor.  You then combine the unfiltered image as the luminance with shorter/binned exposures taken through separate RGB filters.

What you are describing is converting a colour image to a monochrome palette on camera or afterwards in software, but what is the benefit of that?  None that I can see unless you are doing it for artistic effect.

It is also possible to extract the luminance channel from an image in software (not the operation same as displaying it in monochrome).  In some processing software it can be useful to process the luminance channel separately from the chrominance (colour) using a variety of techniques and then recombine them later.  But that is not the same as shooting an unfiltered image and using it as the luminance channel.

I'll repeat one more time: An extracted luminance channel from a OSC image will have a much lower signal to noise ratio than a true luminance from an unfiltered sensor all other things being equal (scope, conditions, exposure time, etc.)  That is why an unfiltered CCD sensor will beat a DSLR in terms of efficiency.

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sbooder

sbooder

Posted
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Not quite true.  My 600D when in manual will save RAW monochrome.  When you look at the 3 colour histogram they are all identical so acts like a luminance channel.  

Don't get caught up in the CCD v DSLR debate either, I have seen some extraordinary images taken by both. 

With  a programme like Startools you can also strip the individual RGB out from a stacked image to process each colour individualy.

Just something to think about. 

Are you sure your DSLR can save RAW in monochrome?  RAW uses no in camera processing so with a colour censor you get colour images.  If you are getting B&W images it is the jpg (Fine) that you are seeing.

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Solo05

Solo05

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Are you sure your DSLR can save RAW in monochrome?  RAW uses no in camera processing so with a colour censor you get colour images.  If you are getting B&W images it is the jpg (Fine) that you are seeing.

For those that don't believe me I will put a link to a RAW monochrome image I have just taken in the kitchen with my 600D.

It is not a true monochrome, as Ian vehemently pointed out, but that was NOT the question.  All I said was a 600D can save a monochrome image in RAW, which it will.  Sorry if that is upsetting but there it is.

https://www.dropbox.com/s/i6mttnz86hn6t9m/IMG_2912.CR2

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Solo05

Solo05

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How can you get a true  L image constant across the sensor when it has a PHYSICAL RGGB Bayer mask?

I don't care if it can or can't produce a true L image, that was not the question.  

It was being stated, as fact, on this board that you cannot take a monochrome RAW image with a DSLR.  WRONG, see my link above to see one.

The question of what it has taken is another question altogether. 

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dph1nm

dph1nm

Posted
Posted

If you read the blurb it does says that the RAW file still contains the colour information, and you can recover it if you want. So I think all it does is stuff some flag in the header to say convert this to monochrome when you display it.

NigelM

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ollypenrice

ollypenrice

Posted
Posted

The spirit of the original question was, 'Can you take a luminance image with a DSLR?' You can't.* There's no need to argue if we distinguish between monochrome and luminance.

Olly

*I make this inference because the OP then raised the comparison with a mono CCD. 

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