Tuesday, January 10, 2006

 

This Blog Has Moved!

A friend put me on to wordpress and I have decided to use it instead of blogger.

Check HERE for the new site. There have been many new posts since the site move.

Best regards.

Friday, January 06, 2006

 

Free Photoshop Lessons

If you are having difficulty learning Photoshop, or just want to expand your knowledge a little, checkout the Photoshop Workbench section of http://www.radiantvista.com/. Each week an image is selected for improvement and a video is subsequently made of the resident expert working the image in Photoshop. You can download the video, play it back at your own speed and even work alongside on your own image while running a local copy of Photoshop.

There are also a number of PDF tutorials and some Video tutorials, as well as something aptly named the Daily Critique.

Check it out. Fantastic stuff.

Thursday, January 05, 2006

 

Calibrating Camera RAW

I haven't been entirely satisifed with the color rendition from the Canon 5D I shoot with. My monitor is calibrated but just recently I took a shot of some hawthorn berries and they came out a kind of red-orange color instead of the bright intense red I was expecting. I did a little research and came across this article on how to calibrate the color rendition in Adobe Camera RAW 3.x. The writer, Eric Chan, was unsatisified with the colors he was getting from his Canon 5D too and following calibration he noticed that the reds in particular improved greatly. That was all I needed to read ..........

I acquired a MacBeth ColorChecker chart ($67 at Bhphotovideo.com) and proceeded to follow the instructions in Eric's article. Two hours later I was very pleased with the results:

Before Calibration









After Calibration















As you can see, the berries are red now and not orange-red and I am one happy camper.

Enjoy!

 

Correcting For Lens Distortion And Other Anomalies

I use a multi-pronged approach to correct for various lens distortions and anomalies.

To correct for pincushion distortion and its opposite, barrel distortion, I use PTlens. PTlens is better for correcting these anomalies than Photoshop CS2 as it uses three coefficients (vs Photoshops one) and these are carefully computed for individual lenses so the plugin is able to operate automatically vs adjusting it via eye in the Photoshop case. On 1/1/06 I sent the author Thomas Niemann 17 calibration shots for a Tamron 17-35 f/2.8-4 Di LD on a Canon 5D and received the calibration back that very evening. I loaded up some test images shot with Tamron lens, fixed them wit hthe plugin and was very impressed. All Canon lenses are profiled currently as well as many third party ones. PTlens is worth checking out.

To correct for chromatic aberration and vignetting I prefer to use Adobe Camera RAW (ACR) than PTlens or other apps as ACR does such an excellent job and it has the added benefit that it operates on the RAW file as opposed to the image data in Photoshop. Used in this way, chromatic aberration and vignetting can be removed completely. Thinking about it, I see no reason why an automatic approach such as PTlens uses couldn't be applied to vignetting and if such a tool existed I would probably use it in favor of Camera RAW. If only someone would write one .....

To correct for perspective distortion I use Image Align Pro. Although Photoshop Cs2's Filter->Distort->Lens Correction is a capable tool I find the Image Align Pro plugin easier to use.

I haven't tried DxO Optics Pro but would be interested to hear opinions.

Friday, December 23, 2005

 

Digital RAW Workflow

This is the workflow I use when processing RAW images from a Canon EOS 5D digital camera. It involves a combination of Adobe Photoshop CS2 (with associated Bridge and Camera RAW plugin), aswell as PhotoKit Sharpener, PTLens, ImageAlign Pro and on occasion Neat Image.

PhotoKit Sharpener is a great piece of software. I would never have realized it before getting into digital photgraphy, but sharpening is a vital part of a digital workflow. I learnt about PhotoKit Sharpener here.

1) Download RAW files using Canon ZoomBrowser EX (this software is supplied with the camera).

2) Navigate to RAW files in Adobe Bridge. Verify that high quality thumbnails are generated from each image before deleting images from compact flash card. Make selects (Ctrl+1 appends one star to an image).

3) Add Keywords. Add Copyright to Metadata fields. Use File -> Scripts –> Image processor to batch process to jpg if desired.

4) Open RAW file in Adobe Bridge (Use Adobe RGB ColorSpace, 16 bit depth); adjust Exposure, White Balance, Shadow, Brightness, Contrast, Saturation during input. Perform minor adjustments in Curves if necessary.

Note: It is better to do these image-wide adjustments of exposure, shadows etc in Camera RAW than in Photoshop as it creates an image with optimally distributed pixels; thus yielding maximum editing headroom.

Note: It is important to do the WB adjustment after Exposure adjustment as changes to the exposure can affect the white balance.

5) Choose Open within the Camera RAW view to open the image in Photoshop.

6) Apply noise filtering using the Neatimage plugin via Filter -> Neat Image if desired, certainly above ISO 800. In practice I don't find myself doing this very often simply because the 5D has such low noise (even at ISO 800 it is very low).

7) Correct for pincushion/barrel distortion using PTLens plugin.

8) Perform Image Alignment step via Filter -> Grasshopper if desired.

Camera RAW has a fantastic basic straighten/crop tool but I use ImageAlign pro to correct for such things as barrel and pincushion distortion or converging verticals in architectural shots.

Note: You can’t do Image Alignment on an image you haven’t flattened after sharpening else it will leave artefacts...

9) Crop as necessary.

10) Apply sharpening using Photokit Capture Sharpener. After application, apply Layer -> Flatten Image. I sharpen every image. Generally speaking it often doesn't do much at all on a 5D image taken with an L series lens (you have to zoom in to see the effect) but if you aren't using premium equipment you will probably see more difference.

Note: Turn off the default sharpening that takes place in the Camera RAW conversion. You don't want two lots of sharpening.

Note: If you resize an image it is important to sharpen it as it can make a huge difference to the end result. Resizing generally means shrinking and the averaging of pixels that takes place in this shrinking process introduces considerable blur.

11) Perform additional operations. e.g. converting to black/white, selective creative sharpening, anything involving layer masks such as selective local contrast enhancement, color adjustment etc. etc.

12) Save as .psd. I prefer psd to tiff.

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