Tweaking Your Canon Lens Performance

September 12, 2011 by 13 Comments

Whether you’re shooting with Canon, Nikon, Pentax or Lumix DSLRs, the lenses we use have optical characteristics that are imperfect. Some of these perfections we hate, some we love – and some we love just some of the time!

Take the wide-angle lens. Most wide-angles, including the 24mm Canon TSE used to take the photo here, exhibit some light falloff towards the edges. This is only to be expected when you apply the laws of physics. Sometimes the ‘vignetting’ is a useful compositional tool, but on other occasions, you’d prefer an even exposure across the frame.

You can also find some barrel or pin-cushion distortion (curvature) in most wide-angles, especially zoom wide-angle lenses.

 Image with no Lens Correction

Neither of these ailments are difficult to fix. In fact, in Capture One they are extremely easy to fix – simply visit the Lens Correction Tab and slide the Distortion and Light Falloff controls until the image appears correct.

Image with Lens Correction

It doesn’t take much to make the correction, but given that every photograph shot with this lens will have the same light falloff and distortion, it would be great to have an easier way to fix it.

And there is. For your Canon DSLR (or any DSLR, actually), you can make a series of lens adjustments and save them as a user preset. In addition to Distortion and Light Falloff, you can correct Purple Fringing, Sharpness and Chromatic Aberration, and all these adjustments can be saved into a single preset.

Image with Capture One Lens Correction Preset

Once you’ve made the adjustments to one photograph, go to the presets icon at the top of the Lens Correction tab (second from the right). When you click it, a list of presets is displayed. At the top of this drop down menu is the option to Save User Preset… Click on this menu item and give your preset a name – I used ‘Canon24mmTSE’ for this lens so it’s easy to recognise. No point being too tricky with your names!

Now when I open a photo taken with my 24mm Canon TSE, I can simply click on the preset and my adjustments are made automatically. And, if I have taken an entire shoot with the one lens, I can apply my preset automatically to every image as I import the files into Capture One 6.

There really is a lot of power and automation built into Capture One 6 for the DSLR user.

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Flat Art Reproduction

October 21, 2010 by 5 Comments

Uniform light via Capture One’s Lens Tool

Flat Art Reproduction Image 1
• Setting up perfect uniform light for a flat art reproduction can be difficult and time-consuming.

• The Lens Correction Tool in Capture One can be used for creating a uniformly lit image when applying light for flat art reproductions.

• The LCC (Lens Cast Correction) feature will compensate not only for color cast and the light fall-off of the lens, but also for any variation and color shift in the illumination of the flat art.

How to apply uniform light with Capture One?

Flat Art Reproduction Image 2

In this example I lit the painting with only one lamp just to illustrate that even such a non-uniform light distribution can be made uniform by the software.

I used the highlight warning and the Levels-highlight slider to provoke clipping making it is easy to see the light distribution. The left image above is without Light Fall-off compensation. The right image above is with Light fall-off compensation applied. The entire background in this image is evenly lit and there is no clipping in the painting.

Steps for how to apply uniform light:

1. Place the flat-art on a flat background of matte white or matte gray material.
2. Light the flat-art. Try to obtain reasonable uniform light across the art.
3. Photograph the flat-art.
4. Remove the flat-art and photograph the background with the lens slightly out of focus. This image will serve as a “light” reference.
5. In Capture One use the image of the background to make a LCC file.
6. Apply the LCC file to the image of the flat-art. Make sure that both Color Cast and Light fall-off is checked, as this compensates for any variations in the illumination of the flat-art. The flat art will now look as if it was lit and captured with perfectly uniform light.

Filed under Capture One Tips & Tricks Tagged with , ,

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