SPP Advantages of the new monochrome conversion?

Started Feb 12, 2013 | Discussions thread
PicOne
Veteran MemberPosts: 6,858
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Re: Yes, better noise handling and control over input
In reply to Kendall Helmstetter Gelner, Feb 13, 2013

Kendall Helmstetter Gelner wrote:


PicOne wrote:

Kendall Helmstetter Gelner wrote:

Digiman69 wrote:

..respect of using a dedicated SW or PS directly.

Does Sigma claim some technical advantages?

The main improvement is that it's a totally different raw processing engine - so it thinks only of tone. As such it reduces artifacts of color conversion that can appear at high ISO, color noise, while still maintaining a high level of detail. At CES they had some 20x30" prints of ISO 3200 scenes that looked really good. That's the main improvement over using B&W conversion software (and there's no reason you can't add further effects from conversion software after SPP B&W conversion).

At the same time because the original data is still divided, SPP can apply virtual color filters - adjusting the balance between red/green/blue and so on to get an image that looks like it was shot with different filters. That's the advantage that the system has over dedicated monochrome Bayer cameras, which no longer have any color information and so you actually have to shoot with a red filter if you want that effect and so on.

I'm still trying to grasp this difference. With a bayer sensor raw, within eg Lightroom, I can go to monochrome and choose to lighten/darken, etc.. any number of various original colors (that were in the color scene, RGG, Yellows, Cyans, etc.. Actually, I think I can do this to a color Tif converted from the raw as well.

I guess what I'm asking, is what difference does one imagine between a monochrome conversion of an X3F in SPP, vs. a Monochrome conversion done in eg. LR, of an X3F color TIF that was exported out of SPP? Of course with the color TIF, you would also have the options of working in Nik SilverEfex or Exposure 4 (Alien Skin), etc. also.

In the normal process, whatever tool you are using first creates a color image (bayer or not). After the color images is created then a monochrome conversion will use those found colors to figure out levels for the tones. That means that from a bayer sensor, whatever colors it got wrong or the lack of subtle variations in color converts over as regions of flat or broken tone also in the B&W image.

It's the same fundamental problem where the actual image is really upsampled from a smaller red, green, and blue image and driven together. If there were no loss in that process then the Lieca Monochrome or cameras with the CFA removed would not exist, because there would be no point. But they do exist because suddenly at every photosite you are capturing the full range of tones, not deriving what tones were at the scene from a flawed, upsampled color image.

In the case of X3F files, using the standard B&W tools like Nik or Lightroom works, but is only again as good as the color image. For higher ISO shots (say 1600 and above) we know we can get color noise in an image - while a B&W conversion from the color image neutralizes that effect to some extent, it sill can interfere with detail.

In both cases since scene color can be altered by white balance issues or multiple light sources, the issues of color conversion can change the relation of tones within an image, again in ways that affect a B&W version.

So in the new SPP B&W conversion, it just throws thoughts of processing into color out the window. Not having to get the color between the three layers, it can use them simply to determine what the tone at that location was based on capturing the full spectrum of light - a much simpler (and even more accurate) thing to calculate. That lowers the possibility for noise, increases detail, and gives you even smoother tonal results from one pixel to the next than a color conversion would where colors could change quite a bit from one area to the next.

Street shooters that want to shoot B&W suddenly have a wider range of ISO so they can use higher f-stops for more depth of field in low light (or just shoot at all in clubs and other very dark places). Landscape photos in B&W now also have a more extensive ISO range they can use while still maintaining quality of detail and really accurate tones.

And all that while you can still shoot normal color images too, if you wish - unlike the dedicated de-bayered monochrome cameras.

This is yet another example also of why it's such a great idea to always shoot in raw, because the new process will work in any Merrill image taken previously. Suddenly shots you had at high ISO that may have been too noisy might have a second shot as a good B&W.

Awesome reply!   Thanks!

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