Thank you for being a valued part of the CNET community. As of December 1, 2020, the forums are in read-only format. In early 2021, CNET Forums will no longer be available. We are grateful for the participation and advice you have provided to one another over the years.


CNET Support

General discussion

Welcome to the Digital Camera Forum

Nov 5, 2008 9:02AM PST

This forum is about all types of Digital Cameras.

Your questions and answers are welcome.

If you can contribute to a conversation or question, please do.

If you want to start a new thread or ask a new question
go to the top of the Forum and click on a Red Button that says ... "Create A New Thread".

To get to the top of the Forum click this link:


Discussion is locked

- Collapse -
(NT) Camera Service Notices
Nov 5, 2008 10:03AM PST
- Collapse -
Canon A650IS - Service Notice
Nov 5, 2008 10:06AM PST
- Collapse -
Sony DSC-T5 - Recall
Nov 5, 2008 10:08AM PST
- Collapse -
Older Cameras (several brands) with bad CCD sensors.
Nov 5, 2008 10:11AM PST

Several years ago, Sony turned out a bad batch of CCD sensors.
They were susceptible to moisture entering the CCD sensor over a long period of time.
This results in photos having drastic color changes that look like runny water colors,
In extreme cases, the images are totally black.

Sony put some of these sensors in Sony digital cameras and camcorders.
They also sold these defective CCD sensors to other camera manufacturers.

Most of these camera makers have announced that they will repair any such camera for free (regardless of the warranty situation).
They also have released a list of camera model numbers that may be affected.

This is not a recall.......they will only repair cameras that are showing the symptoms of failure.

Here is a link to a site that has tracked this problem from the start:

Go there for all the details.


- Collapse -
Panasonic Battery Information
Jun 18, 2009 9:05AM PDT

Panasonic has released firmware updates for some of its digital cameras.

When the update is installed in the camera, you will be unable to use any third party batteries in that camera.
You must use a genuine Panasonic battery only.

You have probably heard of laptop batteries catching on fire.
Apparently those same type of faulty batteries are now a hazard for digital cameras.

Most third party batteries are made in China.

Here is a link:

- Collapse -
(NT) Camera Tips and Information
Nov 5, 2008 10:13AM PST
- Collapse -
Understanding Low Light Noise at High ISO
Nov 5, 2008 10:20AM PST

Low Light (without flash) is the Achilles heel of the small digital camera.

To build a small camera you must reduce the size of the lens.
That means you must reduce the size of the CCD sensor.

When you reduce the size of the CCD sensor, you get more noise from the CCD sensor.
Noise is similar to "grain" on 35mm film.
When you use high ISO settings on digital cameras you get noise.
When you use high speed film on 35mm film cameras you get grain.
It looks about the same.

When you put the digital camera in Auto mode (without flash) and use it in a low light situation, the camera will see that it does not have enough light to get a good exposure.
The camera then must raise the ISO setting from its normal 80 to a higher setting.
The Canon SD900 can go as high as ISO 1600.

You will start to see noise at ISO 200 and at ISO 400 it becomes easy to see.
At ISO 800 the noise is intrusive.
At ISO 1600 the noise completely ruins the picture.

To see the ugly side of noise go to this link:

Notice the series of photos of the stuffed animals.
They look just about equal at that small size.
But look closer and you see the difference.

Click on the photo that was taken at ISO 80 and you will see a quality photo.
While it is downloading you can scroll around and see the photo at 100% size. Notice the smooth surfaces of the plastics and metals.

Click on the photo that was taken at ISO 1600.
While it is downloading look at the not-so-smooth surfaces of the plastics and metals.
Sharpness and contrast are poor.


Now for comparison....
Look at photos from a camera with a much larger lens and a much larger sensor.

Look for the photos of the two bobble-head dolls.
Click on the ISO 1600 photo.
Notice the small amount of noise.


You can take good low light (without flash) photos with the Canon SD900.
You have to gather more light without raising the ISO setting.
Most cameras will let you set the ISO setting at ISO 80.
Now the camera will have to get more light by other means.
The camera will then have to capture the image by using a slower shutter speed.
That means you must put the camera on a tripod to keep it steady for a longer period of time (up to 15 seconds).
You do not want any moving things or people in the shot.


- Collapse -
Understanding Digital Camera Exposure Settings
Nov 5, 2008 10:24AM PST

A brief explanation of how a camera determines what exposure setting to use when taking a photograph:


The camera has to adjust the amount of light coming into the camera to end up with the exact amount of light to create a perfect exposure.
The amount of light is always the same.
What changes is the ambient light surrounding the camera.

In Auto mode....

On a bright sunny day, there is too much light and the camera must choose a shutter speed and an aperture setting that will limit the amount of light getting into the camera.
The ISO will be set to its lowest setting (lets us say it is ISO-50).
The light meter built into the camera will measure the available light and based on that measurement, the aperture and shutter speeds settings are determined.

And here is what the camera has to choose from on this sunny day:

Shutter speed in fractions of a second ----1/500 - 1/250 - 1/125 - 1/60 - 1/30 - 1/15
Aperture in f-stops-----------------------------------2.8------4------5.8---------8-----11-----16

Any of those settings will give you a perfect exposure.

Whoever wrote the firmware for the camera will determine which setting the camera will use for this shot. Most likely they will choose a setting near the middle.

All digital camera have various mode settings.

If the camera is put in "sports" mode, the camera will choose a setting near the left end of the chart above. Because this offers a faster shutter speed.

If the camera has manual controls, you can select the exact shutter speed you want. I usually start with 1/250 of a second and then check to see if that eliminated any motion blurring in the trial photo.

You will notice that I stopped the aperture setting on the left side at 2.8
That is because that in this example the lens on the camera is rated at f2.8. That is the limit that this camera can handle.

How far the right end of the chart can be extended is dependent upon the darkest f-setting the camera can provide. Most small digital cameras stop at about f8. DSLR cameras can go much further.
The right end of the shutter speed chart can be extended into several seconds (exact amount is determined by your camera specifications).


Now....the sun goes behind a cloud, the light meter in the camera has to adjust the sample chart above.

Image that the shutter speed part of the chart remains the same and the aperture part moves to the right by two notches.

Notice that your maximum possible shutter speed went from 1/500th of a second to 1/125th of a second.

Well shucks....I wanted to catch that race car at 1/250th of a second.

Now imagine I double the ISO setting from 50 to 100.

That will move that f-stop part of the chart to the left by one notch. Now I can shoot at 1/250th of a second.


That is exposure in a nutshell.


Now imagine what happens when it gets dusky dark.
You will end up with a maximum shutter speed of about 1/15th of a second or slower.

You should not hand-hold a camera at a shutter speed slower than 1/60th of a second (1/30th if you have image stabilization).

You have two choices if you want a blur free photo .....
1. raise the ISO setting to 200 or 400.
2. put the camera on a tripod.


I do hope you followed all of explains why a camera needs flash when it gets dark.


- Collapse -
Kodaguide from the 1950s
Nov 5, 2008 10:27AM PST

Here is a copy of a Kodaguide that dates back to the 1950s.

Back then, cameras did not have automatic exposure abilities.
The advanced cameras did have manual controls so that you could select the shutter speed and aperture (f/stops).

This guide sold for 25 cents and also included a dial guide for Indoor Pictures using Photoflood lamps.

You could get exposure meters but the cost was almost equal to the cost of the camera. So most people used simple dial guides like this one.

The settings shown are valid even today, depending upon the film used.
Verichrome film was black & white.
Kodachrome and Kodacolor were color films.

Kodak made about 10 of these handy Kodaguides for various types of photography.


- Collapse -
No Flash - Low Light Photography
Jan 5, 2009 6:22AM PST

Low Light Photography and Why it is a Pain With A Small Camera.
Shooting Without Flash.

The biggest remaining shortfall for small digital cameras is low light performance.
The larger DSLR (digital single lens reflex) cameras perform much better due to their large CCD or CMOS image sensors.

A camera (of any type) must have a certain amount of light to get a perfectly exposed image.
During the day time, that is not a problem because there is an abundance of light.
The camera uses 3 methods to reduce the amount of light.
1. Shutter speed - the faster the shutter speed, the less light that enters the camera.
2. Aperture setting - This works like the iris of the eye. It closes the diameter of the eye to reduce the amount of light entering the camera
3. ISO setting - This is similar to changing 35mm film to a faster or slower film.

When the sun goes down, the camera must use those same settings to see that the camera gets enough light to take a perfectly exposed image.

You can open the aperture larger and larger to let in more light.
Aperture is measured in f-stop settings.
How far it can open is determined by the lens rating.
A common small camera lens is rated at about f/2.8 to f/8.0
The smaller the number, the more light is let into the camera.

You can raise the ISO setting. Modern small digital cameras are usually rated from in steps of 100, 200, 400, 800, 1600.
The higher the number, the more light is let into the camera.

You can slow down the shutter speed and that lets in more light.
Shutter speeds are usually rated from several seconds to about 1/2000th of a second.
To shoot at 1/2000th of a second you need lots and lots of light.

In low light (or inside a house) you have to use all of the settings to get enough light.

1. Your aperture is usually maxed out first. It will be set to f/2.8
its brightest setting.
2. You will still not have enough light so the camera raises the ISO setting to a high number.
3. If you still need more light the camera will reduce the shutter speed.

And that is where you start to get into trouble.
If the shutter speed is set slower than 1/60th of a second, most people can not hold the camera steady enough to prevent blurring due to camera shake (movement). And at slower shutter speeds you will find that people movement (action) will start to show up as motion blurring.

So with a camera that has manual controls, like the Canon G9, you can set the shutter speed manually at 1/60th of a second and the camera will automatically raise the ISO setting higher to get enough light.
And that is where you get into trouble.
Due to the small size of the image sensor, the higher you set the ISO, the more noise you will get. When you get to ISO 200 you start to see noise. ISO 400 is usually very noticeable and by the time you get to ISO 1600, the noise is so bad that it ruins the image.

Here is what noise looks like:


In low light, you can end up with a slow shutter speed and lots of noise.
Not a good combination for a good picture.


Since low light can mean many different settings, you can play with the camera and see exactly what problems your low light is causing.

Set the Canon G9 mode switch to Aperture Priority, labeled as Av on your mode dial on top of the camera.
Look at your User Manual and see how to set the aperture.
Set it to f/2.8
Now set your ISO setting to 100. (read your user manual).
Point the camera at someone and press the shutter switch half way down.
Look at the LCD and see what shutter speed the camera has chosen.
If it is slower than 1/60th of a second, you probably need to use a tripod to support the camera to keep from getting camera-shake blurring. Then you will get a properly exposed image with no noise.
Anyway, take the picture.

Just for kicks, try a shot using Shutter Priority:

Set the G9 camera to Shutter Priority.
I believe it is marked as Tv on the mode dial on top of the camera.
Then set the shutter speed to 1/60th of a second. See you User Manual to find out how to set it.

Set the ISO to "Auto"

Now point the camera a someone and press the shutter button half-way down.
You should see on the LCD display, the ISO setting and Aperture setting the camera has chosen.
Most likely the Aperture will be set to f/2.8 (the brightest setting).
If the ISO is set above 400, you will get noise in your picture.
If it is 1600, you will likely get a very poor picture.
Anyway, take the picture.

So, if your particular low light is too low, you will be stuck with the decision to hand hold the camera at 1/60th second and get a noisy picture, or to put the camera on a tripod and get a good picture.

One final tip:
Do not use any optical zoom during the tests above.
Most lenses will lose some light when zoomed.

Solution.....add more light.
Photographic flood lights are very helpful, and not too expensive.

- Collapse -
SLR Simulator
Jan 18, 2012 4:27AM PST

This simulator lets you play with the controls of a simulated camera.
Set the exposure, take the picture and view the results.
Lets you see the interaction between the shutter speed and aperture settings.

- Collapse -
(NT) Forum Guidelines and General Information
Nov 5, 2008 10:31AM PST
- Collapse -
Changing Your User Name
Nov 5, 2008 10:38AM PST

A message from the Forum Moderator:

The Forum software deliberately prevents you from changing just your Username.

You can however re-register for the Forum, but you must re-register using a different email address and a different Username.

To have to LOG OUT of the forum first.


Choose a username wisely.
A username that includes advertising (in any manner) is not allowed.

Posting a message for the purpose of advertising anything is not allowed.

Mentioning a website (of which you are affiliated) in the body of a message is also not allowed.


- Collapse -
Nov 30, 2020 6:35AM PST