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Hello everyone,

I own a Canon Powershot A70 (3.2 Megapixel) digital camera and I'm
trying to come up with images that have as low of a noise level as
possible.

I strive to take my shots with a low ISO setting, use flash as best as
I can, etc.

I've been taking all of my pictures at a reslution of 2048 by 1536.

My friend claims that I could reduce noise levels even further if I
lowered the resolution of my images; say down to 1600 by 1200.

Since I don't have access to my camera right now, I wonder if any of
you can elaborate on the topic. Does lowering the resolution lower the
noise level?

I wish I could just try it out and see for myself right now.
Thanks for all/any responses you may have.

- VR

VR wrote:
> Hello everyone,
>
> I own a Canon Powershot A70 (3.2 Megapixel) digital camera and I'm
> trying to come up with images that have as low of a noise level as
> possible.
>
> I strive to take my shots with a low ISO setting, use flash as best as
> I can, etc.
>
> I've been taking all of my pictures at a reslution of 2048 by 1536.
>
> My friend claims that I could reduce noise levels even further if I
> lowered the resolution of my images; say down to 1600 by 1200.
>
> Since I don't have access to my camera right now, I wonder if any of
> you can elaborate on the topic. Does lowering the resolution lower the
> noise level?
>
> I wish I could just try it out and see for myself right now.
> Thanks for all/any responses you may have.
>


Hi...

With all due respect, your friend is terribly misguided.

Do the best you can, with your current size images. If
absolutely necessary clean up afterwards with Noise Ninja
or Neat Image.

Take care.

Ken

Thanks for the quick reply, Ken.

My friend explained that interpolation may be what's causing the noise
in my photos, and thus suggested that I "lower the resolution."

While I'm not too well informed about interpolation, I'll try Neat
Image again -- I've used it before -- and maybe even try the resolution
idea. I guess it doesn't hurt to try!
Again, thanks for your swift response.

VR

"VR" <> wrote in news:1104734269.689399.106940
@c13g2000cwb.googlegroups.com:

> Thanks for the quick reply, Ken.
>
> My friend explained that interpolation may be what's causing the noise
> in my photos, and thus suggested that I "lower the resolution."

Perhaps you misunderstood him. While downsampling does smooth the image -
by blurring it, basically - you also lose information you need for printing
at decent sizes.

Now, maybe what he meant is that your camera uses interpolation at that
resolution, and *shooting* at a lower, non-interpolated rez would be a good
idea.

And that would be right.

However, 2048 x 1536 is a native mode of the A70. That's not the problem.

What "Quality" seeting are you using?

> While I'm not too well informed about interpolation,

In general, it sucks.

> I'll try Neat
> Image again -- I've used it before -- and maybe even try the resolution
> idea. I guess it doesn't hurt to try!

Sounds like the best idea.

"Eric Gill" <> schrieb
> "VR" <> wrote
>> My friend explained that interpolation may be what's causing the noise
>> in my photos, and thus suggested that I "lower the resolution."
>
> Perhaps you misunderstood him. While downsampling does smooth the image -
> by blurring it, basically - you also lose information you need for
> printing
> at decent sizes.
Think so too, interpolation never causes noise. Real noise is a random
pattern.
But downsampling depends on the filter. A gaussian filter for example
creates a more blurred image while a sinc based filter is pretty sharp.

--
Regards
Jürgen
http://cpicture.de/en

VR wrote:
> Hello everyone,
>
> I own a Canon Powershot A70 (3.2 Megapixel) digital camera and I'm
> trying to come up with images that have as low of a noise level as
> possible.
>
> I strive to take my shots with a low ISO setting, use flash as best as
> I can, etc.
>
> I've been taking all of my pictures at a reslution of 2048 by 1536.
>
> My friend claims that I could reduce noise levels even further if I
> lowered the resolution of my images; say down to 1600 by 1200.
>
> Since I don't have access to my camera right now, I wonder if any of
> you can elaborate on the topic. Does lowering the resolution lower the
> noise level?
>
> I wish I could just try it out and see for myself right now.
> Thanks for all/any responses you may have.
>
> - VR
>

First, shooting at lower resolution will NOT decrease your noise level.
Your camera CAPTURES images at 2048x1536 pixels regardless of how you
save them. If you SAVE at 1600 x 1200 pixels, the camera will do the
downsampling before it saves the image to memory. But once the
downsampling is done, the discarded information cannot be recovered. If
you SAVE the image at 2048 x 1536 pixels you can always downsample in
your photo editor. But you will have the best image your camera can
produce. You will need all those pixels if you ever want to print an
8x10 at high quality.
If your camera permits, (I'm sure it does) you CAN reduce your noise
level by choosing the lowest ISO rating for your shots. This number is
typically 50 or 100.
But when using low ISO numbers you must have a decent amount of light to
get a good picture.

Think of the ISO setting exactly the way you would when selecting film.
ISO 50 = finest grain (lowest noise) for bright sunny days.
ISO 100 = slight grain for average cloudy bright days
ISO 200 = coarser grain for cloudy days.
ISO 400 = coarser grain for overcast days .
ISO 800 etc...
Bob Williams

No, no... I didn't mean "shoot at 2048 x 1536 and then downsample the
image with software." I was saying "shoot at a lower resolution right
away." But I suppose that's not gonna improve my images.

Eric, I'm using the "Superfine" quality setting.

http://img.photobucket.com/albums/v4...4/IMG_0025.jpg
This is a shot of my dog I did a few days back. Notice the noise around
the puppy's ear? (That's where it's very visible.) This is also not the
original resolution. (It was taken in 2048 x 1536 -- the posted image
is 1024 by 76.

I'm a pretty lame rookie photographer and am just getting into the
whole digital stuff. I always try to get the best pictures using the
"manual settings" that the camera lets you set on your own, yet people
tell me the "Auto" usually works best.
I don't know, I guess I'll learn as I go!

VR

Bob, what would I use for an image that I want to shoot indoors at
night with somewhat direct, yet soft lighting?

VR wrote:

> Bob, what would I use for an image that I want to shoot indoors at
> night with somewhat direct, yet soft lighting?
>

A classical SLR with a very fast lens and 1600 ASA film possibly push
processed to 3200 ASA.

PS you can usually hide some of your noise by selectively blurring the
blue channel. It is worrying that your half sized dog image still shows
quite a bit of noise - could be your software has a poor choice of
downsampling algorithm or the original was underexposed and taken in
very poor light. Try using the camera in automatic mode for a while.

Averaging over 4 pixels (or alternatively median filtering) will
disguise the noise but you will lose resolution too.

Regards,
Martin Brown

VR wrote:
> No, no... I didn't mean "shoot at 2048 x 1536 and then downsample the
> image with software." I was saying "shoot at a lower resolution right
> away." But I suppose that's not gonna improve my images.
>

You can't change how the camera records the image. What you are doing
is changing the way the camera saves the image. It will downsample it as it
saves it.


> Eric, I'm using the "Superfine" quality setting.
>
> http://img.photobucket.com/albums/v4...4/IMG_0025.jpg
> This is a shot of my dog I did a few days back. Notice the noise
> around the puppy's ear? (That's where it's very visible.) This is
> also not the original resolution. (It was taken in 2048 x 1536 -- the
> posted image is 1024 by 76.
>
> I'm a pretty lame rookie photographer and am just getting into the
> whole digital stuff. I always try to get the best pictures using the
> "manual settings" that the camera lets you set on your own, yet people
> tell me the "Auto" usually works best.
> I don't know, I guess I'll learn as I go!
>
> VR

--
Joseph Meehan

26 + 6 = 1 It's Irish Math