over sharpening (1 Viewer)

I am still a very new member of birdforum and still in awe of the diversity and and quality of the photos that are posted, the majority of which I would have been proud to have taken. However (here comes the BUT) there is one small area that many photos could be lifted from the very good to the outstanding. A significant number of photos suffer from "oversharpening", the giveaway is the "halo" that appears around areas of high contrast, eg the beak.

I thought long and hard before posting this note so to all those fellow members who take pics that I only dream about, go easy on the sharpening.

Some of this is down to the photographer using a higher screen res than the person viewing the image... if you're using 1600x1200 or more for editing, the web version you produce may look o.k. at it's small size in photoshop but when viewed on a 1024x768 or even worse, 800x600 display, problems stand out more.
Obviously, we just overdo it sometimes
cheers,
Andy

geronimo said:

I am still a very new member of birdforum and still in awe of the diversity and and quality of the photos that are posted, the majority of which I would have been proud to have taken. However (here comes the BUT) there is one small area that many photos could be lifted from the very good to the outstanding. A significant number of photos suffer from "oversharpening", the giveaway is the "halo" that appears around areas of high contrast, eg the beak.

I thought long and hard before posting this note so to all those fellow members who take pics that I only dream about, go easy on the sharpening.

Click to expand...

I've discovered that my monitor...well...how can I put this...Sucks. What looked OK on my screen, didn't on better monitors. I noticed this, when at my brothers, we brought up a few of my pics from BF, and something was just not quit right. You could really see the use of over sharpening! I have a very old out dated monitor that I will be upgrading very soon.

Mike

geronimo said:

I thought long and hard before posting this note so to all those fellow members who take pics that I only dream about, go easy on the sharpening.

Click to expand...

I've seen oversharpening in many magazines. The halo can also be caused by contrast masking.

My humble arcsoft photo shop only offers sharpen lightly,sharpen and sharpen heavily.Heavey sharpen I seldom use.95% of images are lightly sharpened.
Sam

The normal Sharpening-Filters produce no good results!

You should use 'Unsharp Mask' instead (Photoshop, Gimp and lots of others)!

The settings there (Radius, Threshold, Amount) depend on the resolution of the picture resp. at which size you shrunk it. You can find various tutorials on the Internet about it.

there are actually much better ways of sharpening than just using the unsharp mask.

one option is this (doing this from memory so bear with me)

- open your image in photoshop
- convert the image to lab colour
- select the lightness channel
- you should see a grayscale image
- use unsharp mask on the lightness layer, you can apply quite a lot of sharpening here
- convert your image back to RGB
- you should now have a sharp image without the halos

(I hope i got that right)

There are a number of other methods to sharpening an image, some work better on particular images than others. It's well worth looking at as just using the unsharp mask filter can make your pictures stand out as being 'photoshopped' due to the halos.

gazraa said:

there are actually much better ways of sharpening than just using the unsharp mask.

one option is this (doing this from memory so bear with me)

- open your image in photoshop
- convert the image to lab colour
- select the lightness channel
- you should see a grayscale image
- use unsharp mask on the lightness layer, you can apply quite a lot of sharpening here
- convert your image back to RGB
- you should now have a sharp image without the halos

(I hope i got that right)

There are a number of other methods to sharpening an image, some work better on particular images than others. It's well worth looking at as just using the unsharp mask filter can make your pictures stand out as being 'photoshopped' due to the halos.

Click to expand...

Thanks gazraa, you have got it right, thats the method I tend to use, I have only just started using it and to date have achieved good results without the dreaded halo's.

Oversharpening

geronimo said:

I am still a very new member of birdforum and still in awe of the diversity and and quality of the photos that are posted, the majority of which I would have been proud to have taken. However (here comes the BUT) there is one small area that many photos could be lifted from the very good to the outstanding. A significant number of photos suffer from "oversharpening", the giveaway is the "halo" that appears around areas of high contrast, eg the beak.

I thought long and hard before posting this note so to all those fellow members who take pics that I only dream about, go easy on the sharpening.

Click to expand...

I have noticed this as well. I don't know if any of mine are oversharpened, I usually err well on the side of caution in this respect, but i notice that on my work computers monitor many of my shots are really way too dark, that is with the monitor on the brightest settings.

There is an even better tool available than Unsharp-masking and other sharpening methods. I will first reach for a program called "Focus Magic" (from www.focusmagic.com ). It installs as a stand-alone version and a plugin for your editing software. The plugin actually has many more features than the stand-alone option. It uses advanced algorythms to try to put image detail back where it belongs, the same methods that security and forensics labs use when trying to get detail out of that blurry license-plate or image from a security camera. It also includes an alternate tool to remove image shake, that when used carefully and from some experience will remove that slight blur that takes a photo from awsome to ho-hum. (With that tool I find it best to zoom into a photo on a specular highlight (eye-catchlight, etc.), and count how many pixels long the "shake" is, then apply an equal distance correction to your photo in the same direction as the shake.)

Use it carefully though. Just like any tool, don't smash the wall with the hammer, you just want to hit the nail to the right depth. It will easily impart artifacts if used at too strong a level. In fact I will often use the focus sampling tool on the area I need sharpened, let it find how many pixels in dia. it needs to work on, then adjust the amount of focusing to 75% instead of the default 100%. Many times a pixel-level tack-sharp image just looks too unnatural and over-processed. It may be an exact digital focus, but somehow to me, it looses some of that natural feeling that all photography has had for eons. Not unlike the difference between crispy digital amplifiers and the warmth and depth of tube-amps in the audio world.

But even if you don't think your photo needs sharpening, try this tool on your final resize with a focus level of 1 pixel dia. at 75%, and be amazed.