#1259. Red filter for b&w photography. Glass or digital?

The question came up in a recent comment exchange. I had to try it out.

The author of that comment mentioned using colour filters on his digital camera for b&w photography. Given the very different nature of a filmstock and a Bayer-filtered digital sensor, that really surprised me (although it would make perfect sense on a digital monochrome camera).

Most of my filters were sold long ago, when my own move to digital happened. But I never found the courage to pass on my cherished deep-red Linhof filter, or the Linhof’s handle or my Sekonic light meter. It’s as preserving those apendages of the main camera somehow made it more present and the turkey less cold.

During a quick walk with my daughter one cloudy January afternoon, I grabbed a few shots with and without filter to compare the results of digital filters and the ancient glass version. These are presented below. Sadly, the Linhof-assisted photographs will often be quite obvious due to the incomplete coverage of the frame (the hand-held filter was barely big enough for the Hassy lenses, and my centering now looks like drunk driving … sorry 😉 )

Note that the digitally converted image was ‘tuned’ to look as close as possible to the (glass) filtered version.

Of course, that last version also has been converted to b&w. In colour, it was largely red & black. As the image below shows.

At this point, I find the results a little underwhelming. Seeing the world through the red filter is such a vibrant experience with the naked eye, that I was hoping for more exciting b&w photographs.

Also, given it is so easy to replicate the filtered look in Lightroom with a few moves of the red, orange, green and blue sliders, why bother?

Add to that the fact that the exposure is very hard to judge through the viewfinder (see below), with the image looking overexposed in the EVF and most of the (glass) filtered photos on this page exposed at around -3EV. So why bother indeed?

I’m not sure what happened with exposure. It was never going to be easy, since only one in four pixels is sensitive to red. But, inside the EVF, the uncompensated images looked vastly overexposed. I took the one above just to check, then took all further ones at between -2.3EV and -3.7EV.

The uncompensated image above was very bright SOOC, but was easy to correct in LR. The one on the right, while better exposed actually looks a bit coarser. In the uncompensated photographs, the red channel was blown, but this doesn’t seem to harm the photo once corrected in post. It’s all very counterintuivite for me. Conversely, the properly exposed photo seems to have burried shadows that do not lift up very well in post.

My recommendation, after processing those images, would be to underexpose but less than I did. Maybe -2EV. You’d blow the reds, but not by that much, and maybe get less crunchy shadows. But is it all a bit of a pfaff for nothing? Maybe not!

Here’s the thing. While it is simpler to shoot without the filter and it is possible to replicate its tonal effects very easily through Lightroom sliders, the glass filter version still looks a little different.

Less sharp, less digital. It’s more obvious on some images than others. But there is enough of a difference to orient PP in different directions and obtain different looking results.

Whether that’s important to you is purely a subjective decision, but it’s there. Maybe it’s in my mind, but the glass-filtered images just end up looking less brittle and more film-like to me.

Here is another pair

And another

The differences are subtle, when you match the tonal curves. But they are there.

To most people, that will not be worth the effort. But if you are trying to produce a certain aesthetic, and to apply a time-honoured technique and process rather than explore monochrome conversions at random, this is certainly worth the small extra step. Just be sure to buy a screw-on filter, not one that is held in front of the lens with a shaky hand 😉

Do you see the differences on the web images? What do you think?

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