After posting the recent high ISO images from Egypt that were made with a D3s at ISO 12,800, I thought I’d post a few tips for how to work with images of this type.  Depending on your camera, what’s “high ISO” will vary.  It could be as low as ISO 400 or 800 with either a point and shoot or older DSLR or it could be ISO 3200+ with some of the more recent DSLRs on the market.  This types should work well with all cameras, and I’m focusing my discussion on the two most popular raw converters out there amongst our former listeners: LR3/ACR 6 and Capture NX2.

First things first.  Don’t obsess too much about noise in an image.  If you try to eliminate every last trace of noise, you’ll get a smeared up, plasticky-looking imaging that isn’t very appealing.  It’s better to have a bit of graininess left in an image than to wipe it out entirely.  A little bit of grit can actually increase the perception of sharpness in a print.  If you’re going to eliminate a component of noise in an image, it’s best to go predominantly after color noise, which is the stuff that looks like colored specs.  Also, before going nuts with noise reduction and sharpening techniques, consider making a test print.  You’ll probably be pleasantly surprised at how little of problem you have before doing anything fancy,  Especially in smaller print sizes, noise is rarely much of an issue in the real world.  A great composition or creative idea trumps a bit of noise any day of the week.

So, what are some good principles for achieving nice high ISO results?  Here are a few:

- Avoid underexposing an image.  As soon as you start increasing the brightness or exposure sliders, adding fill light or using the shadow protection slider, noise will start to become more prominent.  Getting the correct exposure for the image (one that results in you not having to brighten the image) is a good starting point.  I actually dragged the brightness of the above image down about a half-stop in post-processing.

- Realize that sharpening and noise reduction are yin and yang functions.  Sharpening will increase the perception of noise, while noise reduction will blur the image.  Success lies in a careful balance of the two for your image.  Good settings or technique sometimes require an iterative approach to these controls, looking for the compromise that suits you.

-  Higher ISO sharpening settings are typically lower intensity, higher radii settings than low ISO settings.  Compared to your sharpening settings that you use for landscape shots or other images with a lot of detail, you’ll want to reduce your intensity a bit, raise the radius by 50-100% and then either boost the masking slider (LR/ACR) or increase the threshold value (NX2).  Those last two items are very different controls, but some of what they accomplish is similar.  In both cases, you’re trying to eliminate sharpening from regions where there’s either little detail or the change in a tonal value is small.  In LR3, look for preset that Adobe provides called “Sharpening – Wide Edges (Faces)” under “Lightroom Presets”.  It’s great for portraits, but it’s also very good for higher ISO photos.  The key items are the lower  intensity, higher radius setting, coupled with masking set to about 60, which confines the sharpening to edges.  By the way, its companion called “Sharpening – Narrow Edges (Scenic) is great for low ISO landscapes.  In NX2, you can also consider using high-pass sharpening, which similarly has its effect mainly on edges.  I’ll let you look up how to do that in Jason’s e-book on NX2.

-  Do color noise removal first, and then add luminance noise removal only if absolutely necessary.  When I’m working in LR3, I always start by switching my sharpening setting to the one I mention above.  I often find it’s sufficient when combined with the default color noise reduction setting of 25.  I might have a little grit in the image, but it’s not a problem.  If I still see the effect of color noise, I’ll bump that slider up a little higher before touching the luminance NR slider.  If I’m still not satisfied, I’ll dial in a bit of luminance NR, usually in the range of 10-30, almost never in excess of that for images with much detail.

-  Consider doing only local sharpening or NR where it’s needed.  You can do this in both LR/ACR, as well as NX2.  LR/ACR uses the adjustment brush, whereas in NX2 you’ll use selection control points.  Both work well.  With NX2 you can also apply NR in a limited area via a selection control point.  Lightroom doesn’t explicitly offer that at the moment, but there’s a trick you can do with the adjustment brush and negative amounts of sharpening.  If you use an amount of -1 up through -50, you’ll remove sharpening from a region (which is a way of limiting it).  If you use -50 or less (it goes up to -100), you’ll paint in some blur, which at smaller doses can be a form of noise reduction.

-  For really nasty noise problems, consider using a dedicated tool.   Many times these are Photoshop plug-ins, but a lot of them work as standalone tools or via Lightroom.  Good ones include Nik Define and Topaz Denoise.  Both of those support 64-bit processing, which a number of older ones don’t.  The algorithms in those programs are more sophisticated than those in raw processors, although LR3 is really quite good, and I hardly ever use those plug-ins anymore.

-  How you work tones in an image matters.  I already mentioned the problems associated with brightening an underexposed image.  If you have large areas of your image that you want completely dark (like in the above image), sliding the “blacks” slider a bit to the right (increasing the value) will clip the shadow detail, which is where a lot of the noise hides.  It’s also where it can look ugliest on a print.  If it’s wiped out via this control (or a levels/curves adjustment), sharpening will be easier, too.  In the above image, I bumped up the blacks slider just a touch and noise in the part of the image was greatly diminished.

-  If your raw converter has something like a clarity slider, use it.  LR3/ACR 6′s clarity slider can add snap to an image that might be suffering from lowered contrast that’s due to noise (think higher ISO sports shot).  A value of 20-40 is usually good.  For NX2, explore the use of very low intensity, high radius sharpening settings or move the image to Photoshop and do the same.  The image above had clarity set to 30 in LR3.

-  Consider doing a black and white conversion instead of color.  If you had to go sky-high on the ISO setting, and results in color just don’t look good, trying making a black and white conversion.  Black and white eliminates weird color patters and eliminates the problem that all cameras have with lowered color saturation at their extremes.  High ISOs and black and white look a lot like good old Tri-X film, which is often a great look.

That’s probably enough and keep the second paragraph in mind (don’t obsess).  It’s rare for me to spend more than about a minute stewing over sharpening and NR settings.  Get them close and then be done with them.  If you’re spending 10-20 minutes working NR and sharpening settings, you need to revamp your workflow or just ease off a bit on the perfectionism.  Hope this helps!