Wonder why? If you prefer B&W images and shoot in colour, you can harvest better results by way of conversion. If the reason is not obvious to you, read on.
(Mahjong Player No.1: Mahjong is the all-time favourite mind-body-emotion-wallet contest, a.k.a. gambling, in the Chinese adult world. The four players can spend hours over the game with chats on topics ranging from the economy to gastronomy. This photo is converted to B&W from a colour image in RAW. In case you wonder, it is a job far from well done, nor the others to follow in this post)
Recently, I talked with a fellow photographer about 
using digital cameras in B&W photography. We made mention of Luis Castaneda*, a renowned Cuban photographer located in the United States. Luis takes photos predominately with digital compacts and earns his fame and living with those photos (keep working on your photographic skills even with a serious compact; any of us can be a photographer as successful).
(This is an inspiring poster which I like a lot. Anyone can be a successful photography expert) My friend and I both agreed with Luis’ advice that a B&W photo straight from a digital camera is more restrictive. Similar discussions have been going on in online forums where some photographers already mentioned the advantages. But basically I think the numerous advantages can be summarised into what Luis points out: a straight digital B&W photo gives you an image with only 256 scales of grey while a colour photo can afford a have much wide range of colours, hence more information, to be post-processed for the best B&W conversion result. Of course, a side merit is that you can retain the colour version alongside the final B&W output.
(Mahjong Player No.2: This is a straight-from-the-camera colour JPEG. It was taken in ISO 200 but coincidentally, there are visible artefacts in the highlight parts of the hands and the shadows underneath them. The artefacts could be overcome in post processing but I’ve found them more prominent in the converted B&W image)
Now, that’s all well and good; but not good enough. Digital B&W photographers can benefit the most from this strategy only if the colour photos are shot in RAW. Michael Reichmann writes in his Understanding Raw Files article:
“Possibly the biggest advantage of shooting raw is that one has a 16 bit image (post raw conversion) to work with. This means that the file has 65,536 levels to work with. This is opposed to a JPG file's 8 bit space with just 256 brightness levels available. This is important when editing an image, particularly if one is trying to open up shadows or alter brightness in any significant way.”
His remark neatly illustrates the advantage of RAW for conversion. Also, unlike JPEGs, the RAW files are not compressed (artefact problem in PP), adulterated with Uusharp Masking (prone to halos) or affected by in-camera settings (loss of data). So, colour photos in RAW can permit you the freest scope in B&W conversion.
That said, some may prefer shooting JPEGs because post-processing can be redious sometimes. That’s fair and fine. But, again unlike JPEGs, RAW files can be benefited from more powerful PP software in the future which may help add juice to the final prints. Who knows if you will become a successful photographer and hope to sell the old images to be converted and revitalised from RAW?
(Caution Trip Hazard: The man is jogging regardless of the warning bill posted on the column. The right image is the original colour version and the converted B&W on left. B&W conversion in post-processing requires the photographer to tell from experience if the scene, lighting distribution and composition are desirable for B&W images without the instant feedback on the LCD display)
Now the only “drawback” of Luis’ advice is that the photographer has to practise a photographer’s eye for a desirable B&W scene with the best composition through a LCD showing a colour image. Unlike the otherwise instant B&W feedback on the LCD, the photographer using the strategy has to pay attention to the contrast and transition of the colours in the final image to be converted into B&W.
Surely, there is a wide gap between knowing how and doing it right. Just because we know the tricks doesn’t mean that we will end up with great B&W photos. An important factor is how to do the conversion right. For starter, I recommend you to read further here and here.
*Check out Luis’ works. But frankly, I’ve seen some occasional better photos taken by some of us “amateur” photographers. A friend of mine working as a global dealer for French artists says that the art business is like a matter of chance. The best selling art works are not necessarily the most appealing, creative. Luck plays a big part. So, again, keep going with your passion for photography. YOU can be famous too.
------ Featured comment by Wouter Brandsma: I think it is more important to recognize contrasty scenes, textures and structures. Get an eye for form and factor and learn to see past the colors. With regard to the post processing I do agree with you on the technical part. In theory you are right, but for me it is not how it always work. I use my camera in B&W jpeg mode with an additional RAW image. At base ISO (64 and 100) the jpegs look really fine too and can be printed large. The success of a B&W photo is made when the image is taken, not in the editing stage in my opinion.
Nevin’s Reply: Wouter, I cannot agree more to your last paragraph. I just wish to expand it to "the success of any photo is made when the image is taken." The editing stage can do just two things: 1) Make a great photo even more better 2) Make an average photo look better.
Comments
With regard to the post processing I do agree with you on the technical part. In theory you are right, but for me it is not how it always work. I use my camera in B&W jpeg mode with an additional RAW image. At base ISO (64 and 100) the jpegs look really fine too and can be printed large.
The success of a B&W photo is made when the image is taken, not in the editing stage in my opinion.
Anyway, I enjoyed your post. Will be back on a regular basis.
The editing stage can do just two things: 1) Make a great photo even more better 2) Make an average photo look better.
Thank you for your visit and the extra information. Look forward to seeing you around
Nevin
At the same time seeing the picture in b&w is a huge advantage and if the camera has a good b&w mode it means you can see and take the picture there and then without too much/or any post processing.
Agree with Wouter here that it is important to get the picture right in camera and edit only when necessary and what is necessary.
Technically speaking, I'd say Luis' advice is right. But the "drawback", as I put in the post, is that the photographer lacks the instant B&W feedback on the LCD. I said "drawback" because for a film photographer, there is no feedback anyway and they have to train an eye for seeing B&W in his mind.
In practice, it's always a matter of personal taste and preferred workflow. Now that we have the advantage of seeing a scene in B&W on the LCD, the advantage of shooting in B&W may outweight the advantage of what is in Luis' suggestion. I have no prejudice to any of the choice.
As for PP, I think we both agree that it is a part of digital photography. This is said with the condition that, in general, a photographer should see in their mind the expected result in the final photo (with PP or not) when they shoot, rather than correcting the photo to a preferred result during the PP stage. But, PP can occupy a topic of its own.
In a nutshell, I'd say it is always that a good photo happens at the moment when it is taken. The PP is a correction to help the photographer to go beyond the restrictions on the scene. And the personal workflow is a big factor in deciding whether a B&W should be taken in B&W or not. I think Luis puts forward an observation which may have gone unnoticed and would inspire some readers to experiment it.
Thank you for the chance for making the post clearer. Any further comment is very much welcomed, Christi. Take more great pictures!
Nevin