ISO, noise, CMOS and CCD sensors: I hope this is not a dumb question, but what happens when I change the ISO. I know it works like ASA/DIN in film cameras. When a higher ASA film is...

Frosty Loc: Minnesota

I hope this is not a dumb question, but what happens when I change the ISO. I know it works like ASA/DIN in film cameras. When a higher ASA film is used, it allows you to take pictures with a faster shutter or smaller aperature but you get grainer photos.

Does the same thing happen in digital? Do the sensor 's pixels just receive fewer photons resulting in more noise if a high ISO is used? (I'm guessing I just answered my own question.)

Also, is there a difference between CMOS and CCD sensors and noise if one uses the same size sensor, the same ISO and the same shutter/aperature combo? If so, does anyone know why?

marcomarks Loc: Ft. Myers, FL

Frosty wrote:

I hope this is not a dumb question, but what happe... (show quote)

Your explanation is pretty much right. But ISO is actually achieved by boosting the gain of the electronics in the camera which results in electronic noise which is not similar to film grain. Digital noise is ugly and not desirable. Some shooters used film grain artistically on purpose. To some it was objectionable but others it was useable. Digital noise is never desirable.

The CMOS/CCD sensor thing I have not researched. All I know is that some manufacturers are moving to CMOS at a lower resolution and dropping CCD sensors at higher resolutions. I don't know why but it must be a significant improvement for a company to drop a step back from the MP resolution race.

lighthouse Loc: No Fixed Abode

I can only answer the first part - yes you will get more noise.
This noise can be negligible up to a certain ISO and absolutely ghastly after that.
Also depends how big you are blowing up your pics. On a 6" x 4" print it can be unnoticeable and can be horrible at larger sizes.
Software can deal with noise - up to a point.
Technique can also deal with noise to a certain extent.

maccardi Loc: Western New York

marcomarks wrote:

Your explanation is pretty much right. But ISO is... (show quote)

Ditto, Most DSLR's are depending on the model are good at least up to ISO 800 with very little noise and some are even better at higher levels.

hangman45 Loc: Hueytown Alabama

Frosty wrote:

I hope this is not a dumb question, but what happe... (show quote)

CCD's tend to have more noise at higher ISO's but are better at low ISO's where CMOS are usually better at high ISO

BHC Loc: Strawberry Valley, JF, USA

http://en.wikipedia.org/wiki/Image_sensor

donrosshill Loc: Delaware & Florida

As I remember it, CCD sensors are more expensive and difficult to manufacture than CMOS chips. In that case, manufacturers are more sensitive to their bottom profit line. The technology is so close to each other that the manufacturers tend to make them better by the software applied.
Don

Frosty Loc: Minnesota

marcomarks wrote:

Your explanation is pretty much right. But ISO is... (show quote)

Thanks marco marks. I assume in your explanation that lower resolution means fewer pixels.

Frosty Loc: Minnesota

lighthouse wrote:

I can only answer the first part - yes you will get more noise.
This noise can be negligible up to a certain ISO and absolutely ghastly after that.
Also depends how big you are blowing up your pics. On a 6" x 4" print it can be unnoticeable and can be horrible at larger sizes.
Software can deal with noise - up to a point.
Technique can also deal with noise to a certain extent.

Thanks lighthouse.

Frosty Loc: Minnesota

maccardi wrote:

Ditto, Most DSLR's are depending on the model are good at least up to ISO 800 with very little noise and some are even better at higher levels.

Thanks for replying maccardi. I have a CCD camera. When I shoot film I mostly use 400 ASA, so I guess I will stick with 400 on the digital.

Frosty Loc: Minnesota

Mogul wrote:

http://en.wikipedia.org/wiki/Image_sensor

Thanks Mogul (that s 2-6-2 isn't it). I will look it up.

Frosty Loc: Minnesota

donrosshill wrote:

As I remember it, CCD sensors are more expensive and difficult to manufacture than CMOS chips. In that case, manufacturers are more sensitive to their bottom profit line. The technology is so close to each other that the manufacturers tend to make them better by the software applied.
Don

Thankyou for your reply donrosshill. I heard that CCDs are more expensive to make and use more power. This results in heating up the sensor. It doesn't affect most people but wedding photographers didn't like it. Manufacturers like the lower cost.

ksudad Loc: W Valley, PHX

Resolution is a term people often throw aroundsometimes incorrectlywhen talking about images. This concept is not as black and white as the number of pixels in an image. Keep reading to find out what you dont know.
http://www.howtogeek.com/107163/htg-explains-everything-you-know-about-resolution-is-probably-wrong/