dots on picture

[sean300]

I took a few shots yesterday for some friends and when I upload into the computer, i see that there are a lot of dots on the picture. why is that? what can i do to prevent the dots? i'm still fairly new to digital photography. i took the picture using a canon 30D as a raw image but the uploaded image is in jpg.. please help me. thanks

http://www.hphotos.net/hien/messy.jpg

[Don Schaeffer]

That's noise, the bugaboo of digital photgraphy. It's usually caused by over sharpening or over processing an image, enlarging too much, exposing at too high an ISO number. The photo looks a little low contrast, was it badly overexposed?

[sean300]

below is the exif data for the picture. thanks for the reply

[biggy smalls]

Your answer is in your choice of ISO. 1600 gives a very grainy/noisy low quality image. Try shooting 100 or 400 if you have to.

[yogestee]

Yes Sean,,,,,it is definitely noise due to your high ISO setting..Also the image is underexposed..Not a good combination for quality images...

Reading your exif Sean I see a few problems with your camera set up
1. Two stops underexposure
2. You are shooting a minimum lens aperture f32,,even topshelf glass will not produce quality images at minimum aperature..Most lenses produce the best result around 2 stops down from wide open ..Your Canon lens will be best around f8.
Checking out your exif you could have easily shot at 400ISO..
Jurgen
Australia

[Anbesol]

thats noise, looks just like high iso noise, but, that seems really high for 1600, especially for a 30D.... hmmm...

[sean300]

thank you everyone for the input.. ) i didnt know that iso was an issue on digital. thank you.

[sean300]

ok, i lowered my iso to 400 and i took two shots of the same setting, one with raw and the other with Fine Large, the raw file had more noise in it. what do i need to do to the raw file before accepting it? i tried changing the settings but i cant get it much better.

[Homer]

Just wanted to add another suggestion. When shooting portraits or shots of people use a wider aperture. Your data shows an f-stop of 32. You want to have the background blurred so to place the focus of the shot on the subjects, not the backgound. Also by opening up your aperature you could have easily brought your ISO down to 100 - 200.

As for the noise in RAW I can't help you with that. I myself just recently started using RAW only and haven't run into any problems.

Jim

[Lava Lamp]

It's underexposed, meaning that the camera is not getting enough light to record the picture properly. There are three ways to control the amount of light getting to the sensor:

• Aperture, which is measured in f/ stops and controls how big a hole there is in your lens. Paradoxically, f/32 is the smallest aperture. f/2.8 or maybe f/4 is the largest aperture on your camera/lens combo. Most portraits will be shot at something like f/5.6
• Shutter speed, which is measure in fractions of a second, 1/200 being 1/200 of a second. The longer the shutter speed, the more light getting in.
• ISO, which is the senitivity of the sensor to light. The larger the number, like 1600, the more light sensitive, but the more noise. Mostly, you'll want to use 200 or 400 if you can, for the cleanest images.

The good news is your camera can control as much of this as you want. I'd try some shots on auto and compare them to your results when you change the settings and you'll quickly get the idea.