Steps in adjusting the Unsharp Mask parameter

Step 1: View the image at 100%. Set the radius between 1 and 3. Set the amount between 300 and 500. Set the threshold at 0.

This will look like crap. But you’re going to fix it in a minute, so don’t worry.

Slide the radius level up until you start to see nasty halos forming, then back it off a bit. It’s OK if it looks a little bit harsh at this point.

Step 2: Change the image view to 50%. Adjust the amount until it looks grainy and oversharpened, than back it down a little.

Since web images need a fairly high amount of sharpening (in the 300 to 500 range), our example here isn’t quite as dramatic as we’d like. We made the “after” image a little soft so you can see what’s going on at this stage.

Step 3: Move the threshold slider up until the low-contrast areas look smooth, but you can still see fine details.

This is a pretty subtle adjustment; we zoomed in and overdid it in the example so you can see the difference.

(Reference Link: http://photojojo.com/content/tutorials/photoshop-sharpening/)

Shutter Pressing and camera motion blur

When pressing the shutter, do not use your finger tip to stab the shutter release. See link below for more detail:

http://digital-photography-school.com/blog/shutter-release/

How could I have missed this for using a convention DSL for so many year.

Another tips for tackling camera motion blur is to shoot 3 or more and pick the sharpest one. Camera motion blur is a probability thing. As shutter speed goes low, the chance of getting camera motion blue is higher. To overcome this, we increase the number of shots we take and hence increase the chance we got a clean shot.

Camera or Image

I think this is the most important reading in Kenrockwell's website.

Your Camera Doesn't Matter

I don't think he mean camera and lens is unimportant. It is the time and energy spent on chasing equipment should not out-weight those spent on making photographs.

Color Histogram

Have learn a lesson today about histogram. If you are shooting picture of flower which drive one of the color channel over, it should be considered as normal and do not try to reduce exposure to bring the over channel back in range. But doing so, it will bring to other two channels to seriously underexposure. And detail information of the color which drive the over channel will be lost.

The lesson is although you need to prevent overepxosure in digital shooting, you need to excerse this in context.

The following photographs and corresponding histogram is used to illustrate my point here:


1. The photograph I have taken with -1 EV exposure compensation. Note that the red channel is not overexposed.







2. This one is obtained with +0.5EV from RAW to JPG conversion. Note the red channel starts to have overexposure show in the histogram.







3. The final one is obtained with +1 EV from RAW to JPG conversion. Note the red channel is shown clearly with overexposure from the histogram. But at the same time the information contained in both green and blue channel increased considerably.






Histogram explained in Luminous Landscape:
http://www.luminous-landscape.com/tutorials/understanding-series/understanding-histograms.shtml