Thursday, July 31, 2008

Photoshop: Sharpening your Image

Welcome back for another round of Photoshop techniques. This week let's talk about sharpening. I pretty much always sharpen my photos unless I want a soft look, then I don't. Why do we need to sharpen anyways? Well, its all in the lens baby. At least, that is what I was told. The better the lens the crisper your images, and since it's not my birthday yet, and I don't have a 50mm f/1.4 lens, I have to make do with my kit lens to get close shots. As you can see, the kit lens isn't the best, so we need to sharpen it up a bit.

Let's start with this pretty lily that was in my yard, and is now dead.

Next I applied the soft light technique that we talked about last week. Plus, I bumped up the brightness a bit using curves. (I didn't save after this step in my next photos, so this one is a little brighter than the rest)

Now, I am going to show you two different techniques to sharpen your photos. This first one I used all the time, but I have since switched to the second method. It is all up to you which one to use.

The first one is called Unsharp Mask. It sounds counter intuitive, but it really means that it is masking the unsharp parts of your image and allowing the sharp parts to come through, at least that is what I was told.

Go to Filter>Sharpen>Unsharp Mask, and this box will pop up. It is nice because you can get a preview of how sharp your image will be so you can play around with it a little. I usually set my radius to 2 for an overall image. The radius will determine what scale you will be sharpening. The smaller the radius the more detailed the sharpening will be, I think.

For people shots I usually set the Amount to around 50 because I want people to have a softer look to them. For landscapes I set it at around 80 or higher. The amount is exactly what it sounds like, the higher the amount the sharper you get.

The threshold I usually leave at 0, but have turned it up to around 3 or 5. I'm not exactly sure what the threshold does, play around with it until you see something you like.

Hit ok, and you have the image below. Nice and sharp.

Another method is the high pass filter method. First, duplicate the layer by right clicking the background layer in the layers box, and hit duplicate. Call the layer High Pass (or not). Then, with the new layer highlighted, go to Filter>Other>High Pass. This box will pop up and your duplicate layer will turn gray.

I set the layer somewhere between 3 and 6. The lower the radius, the less sharpening you get. The higher the radius the more sharp you get. Hit ok. Now change the layer mode of the High Pass layer. I set it to overlay for a more pronounced sharpening, or soft light for a more subtle sharpening. Play around with the different modes and see what you come up with. Now flatten the layers and you have a nice sharp image. The top one is with soft light, the bottom one is with overlay. Very subtle differences.

Here is a detailed comparison between all the methods. They are very subtle, you just have to choose the one you like better.

Some people choose one method over the other because they say one method gives more background noise than another. There is a lot of debate about it, so I decided to test it out myself. I cropped the images to a small part of the background. Here is the comparison.

To me, it looks like the High Pass filter has a little bit more noise than the Unsharp Mask, but it doesn't appear as if it is enough to be noticeable in the full scale image.

Now, get out there and sharpen some photos. You can't just take my word for it, try it yourself. Let me know which method you like better, or if there is something else you use instead.

1 comment:

Texas Travelers said...

Enjoyed your use of the techniques.

Sometimes, with High Pass, if I get a little noise, I run it through "Neat Image" software.

It's funny, how every image requires a different set of techniques for optimal results.