Would you buy a B&W DSLR?

Started May 28, 2011 | Discussions thread
gdanmitchell Veteran Member • Posts: 7,730
Re: Would you buy a B&W DSLR?

James, I'm telling you, and others are telling you that you can accomplish what you need to do using techniques that we have described here. One more time, they include:

1. Applying filters in post. Yes, you keep telling us that this won't work right, but that doesn't hold much water when it works well for the rest of us.

2. Using masked curve layers to accomplish much the same goal. Are you expert in the use of masked curve layers yet?

Your response is to demand that we offer a dissertation describing our full post processing work flow. I sometimes get the impression from demands like this that the writer is more invested in continuing to believe that they are right and the rest of us must be hallucinating than they are in trying to learn how to actually address the problem. I'm stunned that you continue to believe that you cannot do the thing you are trying to do after you looked at Dobrowner's work - those photographs give every appearance of precisely the effect of the classic use of red filters. (By the way, I've been doing this for quite a few decades and I recall very well carrying around and using yellow, orange, and red filters and I know how to use them. So please be cautious about thinking that I'm just some digital-happy newbie.)

A very simple version of a portion of my workflow might include the following:

  1. Expose to the right, being very careful to avoid blowing out the highlights.

  2. Keep image in 16-bit color space after raw conversion.

  3. I use the Photoshop black and white layer as my starting point for conversion. (In complex images additional techniques might be required, but I won't include that here.)

  4. In some cases I will try one of the filtering options from the drop-down menu in the black and white later control panel.

  5. I will virtually always apply at least a basic curve layer to images. A typical curve might move the left edge to just barely let a few tiny areas go completely black; move the right edge to just before the brightest areas go completely white; and perhaps create a slight s-curve shape that increases gain in the mid to bright range and may slightly suppress it in the mid to dark range. (Specifics depend upon the photograph.)

  6. If an area (like sky) needs different or more contrast I make a loose selection of that area and feather the edge. Then I create an additional curve layer and adjust to create the effect I'm looking for. (There is much more to the adjustment process than I'm going to describe in this forum post.) Once I get the effect I like, I use the white paint brush (30%-50% with soft edges) and "paint in" the correction.

That is the broad outline of the process. If you do not already use this approach, you need to learn it before you continue to insist that these techniques won't work. Or else simply continue to use glass filters if you believe that will be more effective for you.


BTW: Abstract theorizing about things lie "1/3 of the pixels record red," and extrapolating that you cannot do X... while others are most certainly doing X quite well... is not a very fruitful approach.

James Fedley wrote:

gdanmitchell wrote:

I think that beginning your post with a notion about "history" might be the issue here. At one level, what you are saying is essentially, "with the old technology I did it this way, and when I apply the old technique to the new technology as if I was using the old it doesn't work the same, therefore the new technology must be defective."

Actually in my examples I posted using the Sony NEX camera I was not using a red filter on the camera. I realise that is a technique for B&W film and not a Bayer coloured sensor. I was using a digital workflow. My issue is that quality of my result. I did exactly the same workflow on a Sony NEX 5 and a Sigma DP2 getting great results on the DP2 but poor results on the NEX 5. Unfortunately unlike the Sigma on a Bayer sensor only 1/3 of the pixels record red. Therefore by working within the red channel to create the same effect of a red filter on B&W film I am only getting 1/3 of the resolution and the blue channel causes excessive noise. I am looking for a better workflow to try and negate the inherent limitations of a Bayer sensor.

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G Dan Mitchell - SF Bay Area, California, USA
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