TECHNICAL WORKSHOP – CREATING THE PERCEPTION OF SHARPNESS and CONTRAST

TECHNICAL WORKSHOP no2 20/09/2014

I am putting up these notes on our web page but nothing beats ATTENDING WORKSHOPS and PRACTICE PRACTICE PRACTICE!

1. DOF vs Focus Stacking: (Jim, could you do a short write-up for the Focus Stacking method please?)

The exercise allowed you to practice two ways to control DOF (depth of field):

· Small aperture, focal distance, use the DOF or DOFmaster app to determine your DOF, stop down and check DOF through the viewfinder or use Live View. Nice one-shot method but the small aperture means that you have no Bokeh!

· Open up your aperture fully, calculate (or preview) your DOF, capture a series of images walking through the scene, focus stack via Jim’s photoshop method. This allows you to selectively control DOF and retain Bokeh where you want to. Mask the layers as you like.

2. Sharpening images for Contrast and Sharpness. Taking a large image of Diana which was shot brilliantly sharp (our first workshop), we use Filter> Unsharp Mask in photoshop.

· Create a copy layer to work on. Zoom in to 100% but also zoom out and check the look.

· Apply a medium amount and large radius, starting with these values and previewing to check for ugly halos. This is the “contrast” setting

· Zoom in to 100% and sharpen with a small radius and larger amount starting at these settings, checking for ugly halos. This is the “sharpness” setting.

3. Enhance Contrast and Sharpness using Google NIK B&W filter, using a large image from Jim (30,000px wide means 3.2m wide printed at 240ppi on an Epson roll printer)

This is an incredible tool which can greatly increase contrast and sharpness in a controllable way.

· Filter>NIK>Silver Efex Pro2

·

Before

After

Change the B&W layer to Luminosity and see how the detail in the foreground ice sheet leaps out

Reduce opacity to 50% to reduce the nasty details in the sky if you wish

Personally, I like the tonality of the original sky and the contrast of the new layer. I would do some more work on this image by separating the original sky and overlaying it above as a new layer

Make the original layer active, start by finding the channel with best separation and copy it

Use levels to enhance the contrast

Then paint your mask, black for the foreground, white for the sky

Create a selection for the sky, copy and paste as a new layer

This looks like a subject for the next workshop, with you bringing YOUR images and working on them?

A large image is a wonderful creation, you must spend some time making it look really great then have it printed on canvas to mount on your wall and astound people.

Posted by Barney

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