Mistakes--Serendipitous

By Madison in Febuary standards last Saturday was balmy. Despite the sunny, mid 40's weather my D7000 and I spent the afternoon indoors at the Olbrich Garden photographing the Children of the Rain Forest.

This month's performers were the Hale O Malo Polynesian Dance Group, Their costumes and dances ranged from a New Zealand  Maori war dance to a Tahitian fertility dance. That invocation of human fertility came with a friendly warning, "Do not attempt this at home."

This image was shot during the pictures-with-the-kids session at the end of the show using my new Tamron 18 -270 mm f3.5-5.6 super zoom set at 18mm wide angle.  The manual exposure settings were f8 and 1/200 sec combined with an auto ISO. That ended up at 6400.

Not an optimum or necessary ISO for this image. It could have been much lower.  At 18mm the lens opens at f 3.5. For a static shot a shutter speed of 1/60 sec would have worked. But I had set up the camera for telephoto dance images, 1/200 sec to give a sense of motion without excessive blur and f8 to sharpen up the lens's slightly soft long end. I didn't spot any massive noise problems when I reviewied the screen shots during the shoot so I went with the default settings.

For post processing I downloaded RAW Therapee's latest 64 bit build, version 4.7.01. It doesn't have the new noise reduction routines yet, but it does have enough new features to  justify a build jump from 4.6 to 4.7.  I'll talk about a few newfeatures in this post, plus some older ones that I haven't used much, starting with the big review images in the file browser.

With dance groups I tend to over shoot.  You know, long continuous bursts hoping to capture that perfect combination of step, twirl and jump. This time I filled my 16 GB main card and moved down to my 8GB secondary card. There I found Miss Thumps-Up posing for Mom's perfect snap combined with an interesting environmental background.

Viewing the preview jpgs full size on my laptop screen while using the number and color coded ratings sped up my selection workflow. I ranked my 'maybe images' during a first pass and then fine tuning the selection set. Definitely a winner.

Judging by the curve of the molding board at the top, this image, shot at 18mm, has serious wide angle lens distortion.  So I tried the fix in the Transform/lensgeometry/distortion tab. My first guess, a -0.5 pincushion setting went way over the top. But it did open up ideas for some creative playing around later.

The for real setting was -0.09.  I pulled up a grid Guide Type to provide straight lines as a reference. At the moment the routine bends the image only one way and creates a curved blank area at the bottom. So I used auto fill to clean up that problem. And for those interested in composition rules the Guide Types include rule of thirds, rule of diagonals and several harmonic mean or, as I used to call them, golden sections.

With the proper settings I created an '18mm tamron' default profile that I can call up to automatically correct my wide angle images.

This fixed I tried out a  new profile that came with RT 4.7-- 'default ISO high'. After I applied the profile  it was  'WOW!! Where has all the ISO 6400 noise gone!!?'

Turns out the RT team had done some interesting things but the real WOW maker was my serendipitous mistake. I'd been working with the jpg not the NEF file, a jpg that had already gone through one pass of the Nikon D7000 excellent in-camera noise reduction routine.

I posted twice last August about how well RAW Therapee works as a jpg editor   My mistake turned up another use- one that is especially helpful to someone who shoots flash-less low light party and people photos.

Here is the most interesting settings in the 'default ISO high' profile along with my modifications.

I left the Impulse Noise Reduction at 80. Luminance comes up as 0 so I set that to 20. Gamma 1.2 has the effect of shifting noise reduction into the shadows where it is needed the most. As usual the effect of all this is to blur detail (bad) while removing noise (good).

The RT folk's ingenious addition is to use 'contrast by detail levels' to recover a surprising amount of the blurred detail. The default values are 0 (finest) =1.00 and the next level '1' =2.00 but at the time I was thinking noise rather than detail;  So I may have gone a little too far fiddling with the sliders and cut out slightly more detail than the noise reduction needed. Either way, the noise cleanup and preserved detail  on this ISO 6400 image is dramatic.

How dramatic. Here are my results. And unlike the Tahitian fertility dance you should definitely try this at home.

The image on the left is from the NEF using the current noise reduction routines. It has the highest noise. It also has the most preserved detail in the girl's hair so I could have pushed its noise reduction harder.  The middle image is the jpg from the D7000 using its default jpg (Sd) and noise reduction (norm) settings. While I wouldn't have called it bad a week ago, now it looks flat and washed out next to the RT image on the right. I lost some detail in the hair but with the noise now so low I can print it up large, perhaps to 11 by 14, without showing objectionable noise. Not shabby for an ISO 6400 image.

Lesson learnt. At the moment there is no advantage working from NEFs using RT. Not that this is a massive bash; the D7000 has one of the best in-camera noise reduction algorithms around. And judging from the comments in the forum, RT should get better soon. See Issue 1052: New luminance NR algorithm  http://code.google.com/p/rawtherapee/issues/detail?id=1052  for up to date details.

With a CPM member's show coming up and several low-light images I'm considering exhibiting, it is time for some serious post processing. Will let you know how everything works out.

PS. The line profiles were taken off the wall over the girl's shoulder.

RAW Therapee's Batch Processing to the Rescue

Autumn, a long time flickr contact, had a problem. During a vacation trip to Florida two years ago she went sailing and took a pile of photos with her Coolpic 550s P&S. Unfortunately her camera was accidentally setup with an EV of -1.7 and all her jpg pics came out ~4X underexposed.

Batch processing is not a new RT feature but until recently I hadn't realized how powerful and useful it could be.  I've taken my share of images with a setting wrong--white balance, exposure, etc--before I noticed and corrected it. So here is a mini tutorial using some of Autumn's photos on how I would use RT to hide these mistakes.

Start RT in its normal multi-tab mode and open the folder with the underexposed photos. Start by upping the exposure  +1.7 in one of the photo using the Exp Comp slider. Name and save your new profile.

Go into the file browser and control click on the other underexposed images.

Right click on the selected photos. This will bring up the new batch interface. Click on Profile Operations, Apply Profile, and in this case Autumn Underexposed, the name of profile I just saved.  Your copy of RT has a profile folder that holds all the default profiles that come with RT plus any you created and saved.

After a few seconds the thumbnails will brighten up. What have you done? Like Adobe Lightroom you haven't changed any of your photos. Instead you have created a pp3 file for the photos you selected which tells RT what changes you want to make.

What's next? If exposure correction was all you wanted to do, you could hit ctrl Q to put them into the Batch Queue. After selected what folder you want to save them to and the desired file format--jpg, 8 and 16 bit Tiff or PNG--you can hit start processing and let RT do its thing.

I preferred to fine tune the three photos I was working with.

The horizon was tilted, always happens with rocking boat photos, so I corrected that with the straighting tool  The overall photo was now exposed correctly but Autumn and her sister Jordan--wild hair--were still too dark. I used the LAB mode luminous channel on the Exposure tab to create a tone curve. I could have done this with the more common RGB mode but I think the LAB mode is cleaner since it doesn't introduce color shifts. Beside LAB mode editing on a RAW file is one of many features unique to RT. I also noticed that parts of the T-shirt were blown out so I use the Highlight Recovery slider to correct that problem.

After I finished editing the photos I put them into the batch queue.  There are two versions of the air plane image, each with different editing. Once I convert them I'll view them full size and decide which one I prefer. It's a great timesaving feature and a few days ago I converted the same photo 14 ways in one operation to check out the new profiles that showed up in the latest build of RT.

Although it wasn't necessary since I have 4GB of memory on this computer. I also closed everything but the batch queue and file browser.  If you look close, I forgot to circle it, you can see where the memory usage dropped in the Windows Task Master window.  RT can do many great things very well but that requires more RAM memory than the less useful free (and expensive commercial) editors. So if you have an older computer watch your memory usages.

How many great things can RT do very well? Here is the current list

If you click on Apply Profile (partial) you can pick what features you want to use from your saved profile. It is also a great overview of what RT can do

Finally I must thank Autumn for letting me use her photos in this tutorial.  You can find her flickr photostream at  http://www.flickr.com/photos/syksylla/