Before answering this question I think that it's
important to remind readers what Lightroom is and what Adobe mean by
"Public Beta".
Lightroom is a high quality digital image processor
with integrated database management. The underlying image
processing engine used is Adobe Photoshop Camera Raw, which
ensures that digital raw images processed in Lightroom are fully
compatible with Camera Raw and vice versa. The database management
system comprises two components: a catalog and a preview store. These
two components are what provides Lightroom with its ability to quickly
store, retrieve and preview your images and associated metadata, even
when the originals are stored off-line.
Lightroom 1.x comprised five modules (Library,
Develop, Slideshow,
Print and Web) and as can be seen from the following
screenshot Lightroom 2.0 continues with the same modular layout and
naming convention.

Figure 1 - click image for larger view
Unlike the "Public Beta" for Lightroom 1.0 Lr2beta
is pretty much "feature complete", so the intent this time round is to
give users an opportunity to "kick the tyres" and provide feedback on
bugs etc. Make no mistake, the beta is very rough around the edges and
contains many bugs. In terms of stability and bug count the beta is much
closer to "alpha quality" and is most definitely not intended for
production use. It's also important to note that while existing
Lightroom 1.x catalogs cannot be read by Lrbeta2, Adobe have given an
assurance that they will be migrated into the final shipping version. That being said, Adobe have made it
clear that they cannot guarantee that the localised develop
adjustments applied with Lr2beta will be honoured in the final
shipping version
New features have been included in all five modules,
but the most obvious are found within the Library and Develop modules.
Likewise, the Library and Develop modules have benefited from the
greater number of enhancements to existing features. In some cases
they'll be very obvious and others less so. I will deal with the less
obvious enhancements first, then move on to the Big Hitters and
module specific features.
64-bit Support -
One of the less obvious yet highly significant enhancements in
Lightroom 2.0 is that it is 64-bit enabled, although both your
computer and OS must also support 64-bit mode. Mac users must be using
an Intel-based computer and OS X 10.5 (Leopard). By default, Lightroom
for Mac is installed with 32-bit mode enabled, but is easily switched
to 64-bit mode via the application "Get Info" command (see
figure 2). It's slightly more complicated if you're a Windows user in
so far as you must be using Vista-64, even then you must download the
64-bit version of Lr2beta. The intention is that the 32-bit and 64-bit
versions for Windows will ship a single binary, just like its Mac counterpart.
The main benefit of 64-bit mode is that
Lightroom can address memory above the 4 GB RAM limit imposed on 32-bit
applications. Another benefit comes in the form of a speed boost to raw
processing. Obviously these benefits will only be available on
computers with more than 4 GB RAM.

Figure 2 - "Get Info", open in 64-bit mode
Import - Lr2beta now supports images with dimensions up to 30,000 pixels on
the longest side. So, you can import the panoramas and stitched images
that Lightroom 1.0 blocked.
The import dialog has seen little in the way of change,
but the ability to use the Embedded & Sidecar preview images
when importing images should speed up your workflow. Lightroom 2.0 also
continues with the process first adopted in version 1.3 in that it
prioritises import over preview rendering, so getting your images into
the catalog should be fairly quick.

Figure 3 - Import Photo
with Embedded & Sidecar Preview
Export - Lightroom
2.0 now includes the ability to automatically export your images back
to their original folder. You can also export images back into your
catalog and stack them along with the original. You can even apply
adaptive Output Sharpening for print or screen. For example, in
the Print module you can define the paper type (Glossy or Matte)
and Lightroom will automatically adapt the amount of sharpening that is
applied to the image being spooled to the printer or saved to the JPEG
print-file. Lr2beta still has controls for High, Medium and Low
sharpening, but these "may" be replaced with a more meaningful control
in the shipping version of Lightroom 2.0.
Note: Output sharpening in Lr2beta is not yet
complete nor is it fully optimised.
Figure 4 - Enhanced Export
dialog
(click image for
larger view)
Photoshop Integration
- Lightroom can now open images directly
into Photoshop without first creating the fully rendered TIFF or PSD.
This is good news, especially for those who seemed to be so annoyed
with the edit-copy behaviour of version 1.x. The most obvious benefit
of this new method is that the file opens a lot faster. Using the
context menu command for Edit in
Photoshop Lightroom 2.0 can open
files as Smart Objects,
thus utilising non-destructive filters such as
Shadow/Highlight
and Lens Correction.
Multiple images can also be opened into Photoshop and subsequently
merged as single Panoramas
or HDR image.
Unfortunately, a bug in Lr2beta means that smart objects will not be
automatically saved back into your catalog, but this will be corrected
in the final version.

Figure 5 - Photoshop
Integration
Note: The
new integration features summarised above are only available with
Photoshop CS3 (10.01) and Adobe are recommending that Lr2beta
should only be used for testing purposes. See the Release Notes for
further information on this topic, in particular the section on Known
Issues, which contains information on the most recent public beta
build.
The Library module has a new more streamlined layout.
Some panels have been relocated, some enhanced, and others completely
removed in favour of new more flexible and powerful tools. No doubt the
new layout will not be to everyone's liking, but the changes are well
intentioned.
Filter Bar
As I indicated above, the main drivers for the changes
now found in Lightroom 2.0 Library were the need to provide a more
intuitive layout. In Lightroom 1.x filtering within or even across
panels required the use of undocumented keyboard shortcuts. For
example, filtering images taken with a specific camera/lens combination
at say 400 ISO from within the highly regarded Metadata Browser meant
that the user first clicked the camera model, held down the 'Ctrl/Cmd'
key, clicked on the lens then clicked on 100 ISO whilst still holding
down the 'Ctrl/Cmd' key. It wasn't difficult when you knew the secret
handshake, but many users were completely unaware of it. So, the
development team came up with a new approach. They dropped the
Metadata Browser in favour of a new centrally located Filter Bar
(see red bounded area in figure 6).

Figure 6 - Library module -
Filter Bar and Smart Collections
Whilst placing the Filter Bar in what is effectively an
area that many consider sacred ground (i.e. the content area is solely
for images) the engineers have reserved the left panel track to define
the "source" location of images, specifically Folders and Collections.
The net effect of this change is that everything shown in the
left panel track now defines a "context". Therefore, the Filter Bar
will only list those categories that match with the selected folder
and/or collection. This should make it much easier to filter images
without having to resort to cross-panel selections and multiple
selections with the aid of keyboard modifiers..
The Filter Bar uses 'AND' between the columns,
and this should be obvious because as soon as you choose something in a
column on the left, it filters not only the images, but also the
columns to the right. Filtering within a column is an 'OR'
function (i.e. hold down Ctrl/Cmd key then make appropriate selections
within column). This means that by configuring the Filter Bar with
multiple Keyword columns it should now be possible to set up both 'AND'
and 'OR' keyword filtering.
The Filter Bar can be activated from the
Library>View menu or by pressing on the '\' key. By default,
it contains four columns, but is easily configured to show more or less
(i.e. press the
'+' or '-' button on the top right corner of a column).
The columns can be used to filter all of the categories that Lr1.x
supported plus quite a new categories (e.g. Keywords, GPS, Aspect
Ratio, Treatment, and Develop Preset). Last but not least, the column
layout can be saved as custom preset by clicking on the Custom
Filter pop-up located on the top right corner of the Filter Bar.
Figure 7 shows an example of the Filter Bar at work.

Figure 7 - Filter Bar in use
The Filter Bar is also the location in which text based
searches and refine based filtering is carried out (see figure 8).
Multiple filters are activated by shift clicking the respective filter
name (e.g. click Text then 'Shift+click' Refine
followed by Shift+click
Metadata). The old style filter bar still exists where it always
did, but is now labelled RF. You should also notice that the
Filter Bar preset pop-up menu is duplicated beside the RF button, but
is not fully functional in Lr2beta). Retaining the old style filter bar
means that it can still be used in other modules.
Note: There are some known issues in Lr2beta that
may cause strange Filter Bar behaviour, especially when coloured labels
are linked with metadata filtering.

Figure 8 - Expanded Filter
Bar
Collection and Smart Collections
I mentioned above that the Collections panel has
kept its place in the left panel track, but that doesn't mean that it
hasn't received some attention from the engineering team. On the
contrary, as can be seen in figure 9 Collections have undergone a major
rework.
Figure 9 shows the new icons that enable you to quickly
differentiate between: collections sets, smart collections and output
specific collections for Print, Slideshow and Web. This latter type of
collection is created within the relevant output module and provides
quick access to the images and output settings that you defined when it
was originally saved.

Figure 9 - Collection Types
Smart Collections have long been on the
wish-list for many Lightroom users and version 2.0 doesn't disappoint.
Using the new dialog specifying the criteria is relatively straight
forward. The rule set can be anything from a fairly simple ratings
based collection through to a complex multi criteria set such as the
example shown in figure 10 below. Holding down the 'Alt/Option'
key when adding a new search criteria provides access to conditional
rules, shown offset to the right in following screenshot. Any image
that matches the criteria will automatically be added to the
collection.

Figure 10 - Smart
Collection Rules

Figure 11 - Result of
applying Iceberg rule set
Lightroom 2.0
does not support hierarchical collections of the type created in
version 1.x, but any that you already have will be
migrated over to your version 2.0 catalog.
Note: Collections in Lr2beta are not yet complete,
so you can expect some unusual behaviour. That said, Adobe are
encouraging user feedback.
Keywording
Keywording is another area that has seen a lot of
work. In particular, the Keyword List panel being relocated to the right
panel track along with other enhancements. For example, the Keywording
panel has a new Keyword Set called Suggested Keywords.
The suggested keyword is based on existing keywords already applied to
the image and any image that is considered to be close neighbour
in terms of capture time. Figure 12 shows a rather crude example of the
suggested keyword feature at work. I say crude, because it suggest
"Iceberg" when in fact there is no obvious reason why this particular
keyword could ever be associated with the selected image. Fortunately,
they are suggestions, the actual keywords must be applied
manually in the normal way.
Figure 12 - Enhanced Keywording
As mentioned above, the Keyword List panel,
which was known as Keyword Tags in 1.x, has been relocated to
the right panel track. In terms of creating new and/or applying
existing keywords to images little has changed. However, the annoying
filter behaviour that was also assigned to Keyword Tags has been been
removed. Instead, keyword filtering is provided from the filter bar
described earlier.
To add an existing keyword to an image you can
drag-and-drop the keyword onto the image. However, a bug in Lr2beta means that
dropping multiple images on to the keyword list "may" not always work
correctly.
To remove a keyword from an image you must first select
that image then right click the keyword on the Keyword List panel, a
context menu will appear from which you choose "Remove this keyword
from selected photo". I'm not a heavy user of keywords, so it's
possible that my description makes the process more complicated than it
actually is. Nevertheless, I think these changes outlined above
make for a much more logical and frustration free workflow.
Multiple Display Support
So, Lightroom now supports multiple displays, which
will no doubt please those who previously claimed that Lightroom
couldn't be classified as a professional application without such
support. For users without a second display the new window will appear
as a second window on your main display. Hopefully, everyone should now
be happy.
The new second display window is based on the same
module picker concept that's used in the main display window, except
that the options include: Grid (Shift+G), Loupe (Shift+E),
Compare (Shift+) and
Survey (Shift+N) views. I have listed the keyboard shortcut
for each in brackets, but clicking on the name will also switch views.
Each of these views has enhanced functionality over the same view in
the main window. To activate the second window display press on
'Shift+\' keys.

Figure 13 - Second Display
Grid View
Loupe view on the second display window includes
options for: Normal mode, Live mode and Locked mode.
-
With Normal mode the image previewed on the second
window is the same image as is previewed on the main display. However,
the second display window can be set to a different zoom ratio, if
required. This come is very be useful when adjusting the sharpness or
noise controls.
-
With Live mode the second display preview is
continually updated to reflect the area of the image that the mouse is
being hovered over on the main display.
-
With Locked mode the image previewed on the second
display window is fixed. To preview another image you press the
'Alt/Option+Enter' keys. Note a bug in Lr2beta currently
prevents this keyboard shortcut from working correctly, us the mouse or
menu command instead.
Given the extent of the feature set associated the
second display support you will be pleased to note that a comprehensive
set of menu options is available under the Window menu in each module.
Keyboard shortcuts are also available for most of the second display
window commands.

Figure 14 - Second Display
Normal Loupe View
Note: Multiple monitor support in Lr2beta is not yet
fully functional, so you can expect some unusual behaviour,
particularly on the Mac platform. Nevertheless, Adobe are encouraging
user feedback and .