I would like to shoot architecture in black white with canon 5d mk2. I want the skies to appear as dark as possible. What makes more sense; to convert the colour image with Silver Efex Pro with the built in red filter or is it better to use a physical red filter for black white film such as Cokin or LEE ? Which one will give me a better result? Did anyone here try and compare both methods?
If you shoot with a red filter, you're throwing away nearly all the luminance information from the blue channel and a good bit of it from the green channel. Green-sensing pixels predominate on Bayer sensors, so it's easy to find yourself in the position of having thrown away more than half the sensor's data.
Further, using a red filter when you shoot makes it easy to blow out the red channel, and hard to see whether you've done so. If that happens you're going to lose highlight detail as well.
IMO it makes more sense to keep all the information that the sensor records and apply the filter in post where you have complete control over the filter's color and density.
Silver Efex Pro (and I assume other B/W conversion programs) allow you to control all this very neatly, and that's a better way to go, IMO.-- hide signature --
Thank you for replying, I will use the post method then and share some of my work once I am done.