Category Archives: Image Editing Solutions

Tools for digital image editing.

Digital Exposures – File Type Considerations & WB tools

Deciding on which in-camera file type to save is usually based on your needs and digital image file knowledge.  In a nutshell, RAW files provide more data and provide more options for editing.  If you are working a tough lighting situation then RAW probably a better choice.

Well, what about normal or good lighting scenarios?

  • If you need speed then JPEG is *usually* better (it will take less time for your camera to store a JPEG file than a RAW file – this is simply math – RAW files are usually several times larger than corresponding JPEG files; writing less data to a memory card *should* take less time…  A scenario (today, anyway) where JPEG makes sense might be any sport activity with rapid action – you don’t want to be waiting for your camera to save the last image to take that next picture…
  • Otherwise, I suggest staying with RAW
  • For some cameras you can save both RAW & JPEG (or perhaps other image file formats like TIFF.)  This can be useful if you need both lattitude in development (i.e. from selected RAW images) and faster processing (i.e. from JPEG files; smaller file ~= less time to process for output/delivery.)  Note that this setting consumes storage space RAPIDLY…

Editing your images – some guideline/suggested limits

Ok, you are now back at your computer and making your selects.  Let’s say that you have at least a few images where the exposure was not perfect and you need to make adjustments – how far can you go before your changes start impacting image quality?  It depends on several variables but for this discussion we will assume that you camera is set to the highest quality image that it can produce.  In general, for exposure changes we can adjust:

JPEG  – exposure latitude = < 1 stop

  • suggest edit limit of 1/3 stop over OR
  • 1/2 stop under exposure

RAW – exposure latitude =  6-8 stops (could be more – depends on image sensor)

  • suggest edit limit of 1 stop over/under

Note that you can surely make larger changes than those suggested above – the point is that you want to get your capture to be within easily editable ranges.  So, how can you get your exposure as close to possible to ideal? I suggest:

  • taking test pictures and evaluating the histograms (See below) AND/OR
  • consider using the bracketing features of your camera (auto-bracketing is a feature where your camera will capture multiple images and vary the exposures based on how you configure the bracketing option.)

Histograms

  • scene dependant brightness levels and quantity of pixels in an image
  • histograms from RAW files actually display, interpolated JPEG data
  • 0  = black, dark side (usually on the left, i.e. dark areas with shadows)
  • 255 = brightest, white side (usually on the right,  i.e. the sky)
  • a ‘balanced’ histogram is ‘well exposed’
  • too light (high values on the right) = contains some under-exposed areas
  • too dark (high values on the left) = contains some over-exposed areas
  • clipping occurs when ‘detail’ is lost (values on the extreme left or extreme right of the histogram)

Use Calibration TARGET Reference Cards

Expose for your SUBJECT (center of histogram)

  • single source reference – simple histogram
  • multi source reference – i.e. three stripes, white, black gray; where are your high & low key light areas

Using a target

  • take picture (with subject holding target or target in scene); fill with target
  • evaluate histogram – adjust exposure if histogram leans left or right (i.e. keep Aperture but adjust shutter speed up or down)

Adobe Photoshop Lightroom Beta 3

NOTE – BETA software is typically for testing, evaluating, reviewing – it should not be used for production purposes and probably should not be run on your ‘production pc’…

From the Adobe Lightroom Beta 3 Download page (you must register to download.)

Beta Timeframe
When you install the public beta of Lightroom 3, the software will remain active through April 2010. Once the commercial version of Lightroom 3 has shipped, you will need to uninstall the beta and install the final version.

Lightroom Beta Installers
This download will install the Lightroom 3 beta and will work independently alongside your installation of Lightroom 1 or higher. The beta version is intended to provide an opportunity to give feedback and as such, does not read, upgrade or import catalogs from previous versions of Lightroom. If you currently own Lightroom, please continue to use Lightroom 1 or higher for your primary workflow needs.

What this means (at least for me):

  • I will need to re-import images to try out new features – perhaps there is some sort of copy/import?
  • Hopefully, the BETA will not read/write/tinker with my existing Lightroom 2 data/files.
  • I am guessing that some options may still cause problems (i.e. if you save XMP files from within Lightroom)

On-line videos introducing LRB3 (Julianne Kost) – http://tv.adobe.com/product/lightroom

Since this is BETA software Adobe declares that it should ONLY be used for TESTING.  To help users understand this many features are semi or non-functional. For instance, if you export to H.264 (video) then you will need to install the latest version of Adobe Media Player (which also requires you to install Adobe Air.)  A partial message from this approach is that the BETA software does NOT provide a good indication of what capabilities will be in the production release – FMC having to download YAP (yet-another-package) is a poor practice.  I do some testing on ‘simple PCs’ which means that the system is configured to run lean & mean (i.e. you don’t know what hardware your end user’s might have and, in most cases, I prefer to create content that is widely distributable (i.e. as simple as needed which = does not require the end-user to download/update/reconfigure/yada-yada-yada…)

In my case I will install the player on the same VM (virtual machine) that I am testing ALB3 on.

Many days have passed since I started this post (Oct, 2009…)

I have used this beta software several times hoping to find a significant difference (i.e. improvement between it and APLR2) – I am not seeing it – could be ‘my type of image’ simply does not benefit from what the BETA offers.  I will re-evaluate when the production release is ready.