Monday, May 28, 2007

Quick Tip #7: Save Underexposure With RAW

On Saturday night I shot my second set of free portraits on location at Stanford University.

Sounds fancy, doesn't it? I like saying "on location", even thought I only traveled about a mile to do it. But I digress...

One more digression: the business plan post is still in the works, but I wanted to get this post hammered out while it was fresh.

Anyway... The shoot went pretty well, if you consider me running from place to place like a headless chicken "pretty well". We were rapidly losing light and rapidly losing the patience of the young lady. I proved my inexperience a number of times, starting by shooting the first series using my Tamron 17-50mm at 30mm (not horrible, but not as flattering to noses as it can be). The real mistake was when moving from the first location lit directly by the setting sun to the second location in one of the many semi-shaded walkways -- I forgot to switch from manual (for the flash) to aperture priority. I also never chimped during the sequence (because I could tell they were coming out well). The result was an underexposure of 3+ stops and while I let my clients know and reshot at that location later, the expressions on their faces the first time were better than the second.

The sad part is this stuff happens, even to experienced photographers (although I'm sure pros have it happen very rarely compared to someone new like... uh... me). Thank goodness RAW is there to save the day. I was able to save this image (the split before/after image is at the top of this entry, click to see larger) and will include it in what I show the clients.

The beauty of a RAW file is that it holds more information than a JPEG (which I discussed earlier) allowing you to compensate for underexposure, and in some cases, overexposure. I'm still trying to figure out exactly how much overexposure is needed to blow out a RAW file. In my case, I had a Canon .CR2 file, but I'm sure you could do all this with the Nikon equivalent.

Technically, there should be no difference in image quality between RAW and JPEG if you have your lighting and exposure right. But mistakes happen...

I try to shoot RAW any time the photos are more than snapshots and it'd be difficult to replicate them. Sometimes, if I am doing people pictures in a controlled environment, I'll use JPEG even though quality is something important (like a contest). For everything else, I use either RAW or the RAW+JPEG combination. The RAW+JPEG is nice, but I find it slows me down in post processing so I tried pure RAW on Friday and I didn't miss the JPEGs at all.

Let me take you through the process of saving this portrait:

1. Here's a 200% crop of D.'s hand approximately how it would look if I had been shooting JPEG. Obviously, it is way underexposed.

2. The first step is to increase the exposure in RawShooter Essentials (RSE). In this case, I went up a full three stops (the max) and added some fill light, along with a little saturation and white balance. Much better, but we amplified the noise when we fixed the exposure!

3. So, my first attempt to reduce the noise is to use RSE. I pushed the Noise Suppression slider up about half way (Color Noise Suppression seemed to have no result on this image). I use a little noise suppression in almost all the images I convert in RSE. I find RSE doesn't do as good of a job as other software, but it also never hurts the detail in the image.

4. The result still wasn't good enough, so I took the RSE result (without noise suppression, #2) and ran it through Neat Image (NI). Neat Image is a great piece of software which can even integrate directly (plug-in) with PhotoShop and Paint Shop Pro Photo XI. Of course, I'm a cheap guy, so I've only used the free version which lets you save high quality JPEGs. I rarely use any of the sliders and options since the auto-profiler does a great job on my images. At right you can see a Neat Image in action -- if you've never seen it before, click to see the full size screen capture and prepare to be amazed!

PSP XI also includes pretty decent noise reduction ("Digital Camera Noise Removal") but I generally prefer Neat Image if image quality really matters and/or the noise is severe.

So, that's it. The end result is that shooting RAW let me save an image that would have been destined for deletion, and I'll show the (processed) version to the client with the rest of the images at the viewing. After all, they did a great job (and helped me out by posing) and I'd hate to have good poses lost from my own incompetence!

Along with that, I think I'll start shooting RAW only for my portrait sessions. The ability to save myself from exposure mistakes is well worth the increase in file size.

No comments: