Photoshop features a unified tabbed interface, complete with self-adjusting panels. This interface helps to reduce clutter, giving you a cleaner workspace. Each image is assigned its own tab, eliminating the need to arrange multiple windows. Of course, you'll still have the option to manually arrange floating windows and panels, allowing you compare multiple images in a side-by-side manner.

Photoshop Extended can import 3D model files created in popular modeling software. This includes 3DS, OBJ, U3D, KMZ, and COLLADA formats. You'll be able to rotate, slice, and add textures, and light to these 3D models. They can even be used in animations. You'll also be ale to paint directly onto 3D models, convert 2D images and gradient maps into 3D models, and merge two 3D layers into a single scene.

The software features tools that can be used in scientific and medical applications. Photoshop can import DICOM medical files and create animations of X-ray sequences to show movement. Scientific engineers and researchers will appreciate the powerful data analysis and measurement tools. Architects can even use Photoshop Extended to create stunning visualizations of their designs.

Photoshop Extended's animation tools can be used by web professionals who need to create small animations for the web using the familiar Photoshop interface with full alpha-layer and audio support. Video editors can also import QuickTime and Flash video for rotoscoping work. Photoshop supports animations that feature non-square pixels. Animations created in Photoshop can even be loaded in After Effects CS4.

Photoshop features a powerful layer-based approach to image editing. You'll be able to work on one layer of an image without modifying other layers, giving you a non-destructive way to make fine adjustments to images. You'll also be able to apply filters to specific layers. Photoshop features masking tools to help you create layers from "flat" still images, such as digital camera photos and scans.

You'll be able to browse through Photoshop's filter gallery to see how different filters will change an image. Filters are applied as smart layers that are completely non-destructive, can be modified on the fly and can be stacked.

Photoshop features support for over 150 digital camera RAW file formats. RAW images can be saved in any file format, including PSD, JPG, TIFF, and DNG. There is even a dust busting tool to help you remove "green spots" that appear on your photos as a result of dust on your DSLR's CCD.

The quick select tool allows you to isolate objects in an image in order to create a mask or separate layer. The tool is a great way to separate a subject from the background in order to make changes to each separately.

Photoshop allows you to align a series of images to compensate for slight camera movement. It features tools that allow you to remove unwanted bystanders from a series of pictures. This can also be used to better create HDR images that are created from a series of exposures of different lengths.

The Adjustments panel gives you quick access to Photoshop's nondesctructive correction tools. You'll be able to adjust curves, levels, hue/saturation, and other parameters from this panel. You'll be able to control each parameter independently, without the need to change tools or navigate through menus.

Photoshop CS4 improves on the software's ability to create panoramic images. The Photomerge module now features enhanced blending options, vignetting control, and geometric distortion correction. Support for 360° panoramas and fish eye compensation have also been added. These tools work together to help create better stitched panoramic images.

Lenses are often praised for the quality of their bokeh, their out of focus blur, but shallow depth of field is not always desired. Photoshop allows you to combine several images that feature shallow depth of field and different focal points. The result is a single image with a very large depth of field. This tool allows photographers to capture images with a large depth of field, even in low light situations.

Photoshop's Rotate View tool is a nondestructive editing tool that allows you to spin a canvas to any orientation. It eliminates pixel distortion, going so far as to automatically adjust selections, grids, rulers, and other tools to match the chosen orientation.

Photoshop CS4 leverages your computer's GPU to improve image editing performance. You'll be able to zoom down to a pixel-level, with perfect clarity. Stutter and preview lag are eliminated for smooth scrolling within an image. The Pixel Grid appears at magnifications of 600% or higher, allowing for extremely precise pixel editing.

Bridge CS4 is included for image browsing. Bridge allows you to browse though images on a folder level, view image metadata, and search for images. I features a Carousel View for large image-group selections, and can even create contact sheets in PDF format. Bridge can also create web photo galleries and upload them to the Internet.

Photographers will appreciate the enhanced integration with Lightroom 2. Images can be exported from Lightroom 2 to create HDR images, panoramas, or smart objects in Photoshop. Because both applications share the same RAW processing engine, images adjustments made in Lightroom are reflected in Photoshop and vice versa.