Working with digital images

[Al]

I have a new digital camera. It's my first and I'm just learning to use it. Forgive me if I'm not familiar with the terms or I am not explaining myself well.

I'm having a problem with some of my photos (not all). It's hard to put in words how they appear but some have a mottled look throughout, tiny muted splotches.  The colour is ok but it looks unnatural and ruins the photo. Is there any way to prevent this from happening? Is there a way to get rid of it in photos I've already taken?

Thank you very much.

Al

[Deb]

Hi Al and Welcome! Don't fret about terminology, etc..   We're here to help. It's all part of the fun of having a digital camera!

Let's see, by "mottled" appearance, I'm assuming you are noticing small rectangular blocks (pixels) throughout your image. Is this correct? And, that you are noticing this mottling when viewing the images at normal size (and the appearance is worse when zoomed in or enlarged), yes?

If this is correct, then there are a couple of things that could be going on.

First, the images may have been shot using the "digital zoom" option (rather than "optical zoom"). Digital zoom merely magnifies the central portion of the image (not unlike a magnifying glass) thereby enlarging the pixels to unappealing sizes. To remedy this, use your optical zoom function and, if you want, enlarge further in an imaging editing software later.

Or, secondly,  they may have been shot with a lot of compression. The more compression you apply the greater the loss of detail. This compression function is also known by the term "quality setting" on many cameras. What the camera is doing is throwing out a percentage of the pixels while still maintaining the overall dimension of the image. This often results in an image that looks unnatural and choppy (when printed/enlarged) as compared to an uncompressed image. If you're wanting the images to be of print quality, shoot with either no compression or the lowest compression factor available on your camera. (You might like to look at this article which discusses this point in a bit more detail: http://www.digicamhelp.com/taking-pictures/image_quality.htm.)

Now, as for whether or not the mottled images you have can be corrected ... hmmmm, that all depends on how mottled they are. You might want to look at a software such as Genuine Fractals (http://www.lizardtech.com/) or other similar software which creates resolution-independent images from any size file. Also, there may be other things you can do in the image editing software that came with your camera. You might want to double-check there too.

Hope this helps. Now, go out and have fun with your new camera!  
Cheers,
Deb

[Al]

Thank you for the welcome and reply.

No, they are not small rectangular blocks. They are more rounded and smooth. If I look hard, it looks like colours have separated.

Al

[Mike54]

It would be so much easier to diagnose if perhaps we could see the image. Is it possible for you to perhaps email a copy or a crop of the bad area to mikef@familyqwest.com?

[Deb]

Hi, that sounds more like a printer artifact such as you would get if you were running low on ink. Do you see this on a print (ink?) or when viewed on your monitor (noise?)??

Could you email a pix or portion thereof as Mike54 suggested? That would help us.  

Deb

[ShutterbugGail]

I'm wondering if you are talking about "noise." It looks like this to varying degrees:

The two main causes of noise in digital images are using a high ISO and shooting an image in low light.

The solution to the first, is to turn your ISO setting lower if your camera lets you do so. I usually use ISO 100 and sometimes ISO 50. In my opinion, if you can vary ISO settings, be sure to do so rather than leave it on Automatic ISO. The downside of a lower ISO is that it gives you a slower shutter speed, and slow shutter speed can mean camera shake.

Generally, if a shutter speed is under 1/60th of a second, it's recommended you steady your camera by using a tripod or other support.

When shootting in low light, use the flash, and stay within the flash range that is recommened in your camera manual. Also, try to lighten the room by opening a door and/or shades. You can also turn on more room lights but, if you do, don't forget to change your White Balance setting. It will remove the orange color cast cause by incandescent lighting.

As to images you've taken already, I use software to remove noise. It is quite effective. There are several programs but I use the free one called "Neat Image." The non-commercial freeware version can be downloaded here:

http://www.neatimage.com/download.html

It's called a demo version but it is free and does not expire.

To be honest, some digital cameras produce more noise than others because they have a small sensor.

RELATED READING:

ISO (Sensitivity)
http://www.digicamhelp.com/advanced-digital-camera-settings/iso.htm

White balance

http://www.digicamhelp.com/white-balance/

[Deb]

Hey Shutterbug, good call! Noise is a tickler to be sure. I, too, use Neat Image and give it a big thumbs up!  

Deb

[Al]

Thank you so much for all the information. It is quite helpful. I'm planning to try Neat Image.

I appreicate all your help so much.  

Al

[Deb]

Cool beans Al!  Glad our collective minds were able to help.