December 2012 - Digital Group - Difficult Selections & Cards

Meeting Notes March 2009 to 2018.
Post Reply
spb
Posts: 146
Joined: Tue Mar 25, 2008 7:04 pm

December 2012 - Digital Group - Difficult Selections & Cards

Post by spb » Tue Dec 11, 2012 4:47 pm

NEWS
dpReview have a useful review of the top 5 zoom compact cameras. They avoid making a single recommendation but the Sony RX100 with it's unusually large sensor is highly rated for image quality.

Image Viewers - I can't say this too often. Don't even try to use Windows Explorer for image review purposes - it's rubbish. Faststone is an excellent free image viewer.

MEMORY CARDS
Our cameras mostly take SD or Compact Flash memory cards and there is always an uncertainty about which speed of card to buy. This relates to the speed at which data can be read to and from the card. They are rated Class 2 to 10 (which corresponds to 2MB/sec to 10MB/sec) and then 66X to 1000X (10MB/sec to 150MB/sec). These speeds are only an approximation as there are no standard measures and a card's performance will vary from one application to another.

The most demanding situation in which the card speed becomes important is continuous shooting with Raw. The first few shots will be written to the camera's buffer but when this is full, the camera will slow down to the speed that the card can accept data. At this point the speed of shooting may fall from many shots per second to many seconds per shot! Continuous shooting with .jpg or HD movies are less critical as image compression dramatically reduces the amount of data to be recorded. A fast card may also transfer your images to the computer more quickly. Speed is often limited by the camera eg my Nikon D7000 maxs out at 10MB/sec.

If you don't ever find yourself waiting for data transfer then card speed is not an issue for you and a medium speed card (class 4, class 6, 66x) will probably be sufficient. In recent tests, Hama, Verbatim and PNY underperformed and Kingston, Integral and Lexar excelled. The other popular brands were perfectly acceptable.

Tips: it's good practice to always format the card in the camera (never in the computer) after emptying it, and several smaller cards (eg 2, 4GB) are better than one huge card from the point of view of security and safety.

..and a tip from Chris Palmer . It’s well worth placing on each card a file, (text?) or a photo of your name and address which can be locked, (and therefore never deleted). In the event that you lose the card, or your camera, the information is there for the finder to return it to you.

MAKING DIFFICULT SELECTIONS eg Hair
Some edges are very challenging to select eg hair or fur. The normal semi-automatic tools such as Magic Wand, Background Eraser, Magic Eraser or Quick Selection are unable to cope with individual hairs or the small gaps between hairs and we need something more powerful. Since Elements 4, the Magic Extractor (Filter>Extract in CS) has offered greater control but that too, struggles in this situation.

If you have Elements 11 (or CS5 or later) the new Edge Detection capability finally solves this problem. Having made a rough selection with any suitable tool (I prefer the Quick Selection tool) press the Refine Edge button on the toolbar. The Edge Detection brush has been added to this dialogue box in the latest versions. Just size the brush to the width of the hairline and brush along it. Refine the selection with further use of the brush and there are other adjustments to decontaminate background colours from the selection, shrink or grow it etc. The output can be set as an image layer or ideally as a layer mask.

If you have an older version of Elements or Photoshop, Topaz ReMask 3 (£40 with discounts) can come to the rescue. The image begins with a green tint (to keep), you paint around the difficult edge with blue (to compute) and then bucket-fill with red outside (to lose). Press Compute Mask and refine the edge with the Magic Brush + green, blue or red. The resulting edge can be de-contaminated with the Recovery slider. As always with Topaz products there are excellent tutorial videos to explain the process.

Both Edge Detection and Topaz ReMask produce excellent results and enable previously impossible selections to be made without halos or artefacts. The Topaz videos show impressive results with a tree and a semi-transparent wedding veil.

LIGHTROOM LIBRARY MODULE
Continuing discussion of the Library Module, we looked at some shortcuts for Lights Out (L), hiding the panels (Tab) and hiding everything (Shift Tab). Whilst reviewing images in the grid or loupe view, they can be flagged, rated 1-5 stars or colour-labelled. Filtering can then be used to show only images with specific attributes. Once selected these can be selected and assigned to a (virtual) collection. Smart collections are more dynamic and can automatically update as the specified criteria are set on further images.

Keywords can be allocated to individual or groups of images for easy retrieval in the future and highly customisable re-naming can be employed.

COLOUR MANAGEMENT
If your screen doesn't match your print or the club projector for colour every time, then you have a colour management problem. I would strongly recommend that you start with your printer manufacturer's ink and paper and use their generic colour profiles which may have been supplied with the printer or available online. The paper on the Digital Group page of the APS website gives details on how to use these profiles in Photoshop and how to set the printer driver. These settings are NOT intuitive - read the paper!

If you are still not getting good results, the next step is to calibrate your screen with the club's ColorMunki. This is often necessary because screens are set up to impress us in the shops - not to be subtle and lifelike. Finally if necessary, the last step is to create a custom printer profile. This can also be done with the ColorMunki or with commercial services such as that from Permajet .

Once screen, print and projector are in harmony you can begin to experiment with other media but each will need a profile. It shouldn't be this difficult but it is!

Post Reply