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Does performance increase using a 4mp (or 5mp or 6 mp) camera at the 3mp setting?

 
 
mrsgator88
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      02-07-2006
Hello,

I am curious if anyone has ever studied using their high MP camera at the
3mp setting. What I want to know is,

1) Do response times increase? (because of less data to deal with)
2) Does 400 ISO noise decrease? (from effectively larger sensor size per
pixel)
3) Any other effect good or bad? (other than the obvious decrease is
resolution.)

Thanks, Steve


 
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Ed Ruf
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      02-07-2006
On Tue, 07 Feb 2006 13:39:13 GMT, in rec.photo.digital "mrsgator88"
<(E-Mail Removed)> wrote:

>Hello,
>
>I am curious if anyone has ever studied using their high MP camera at the
>3mp setting. What I want to know is,
>
>1) Do response times increase? (because of less data to deal with)


No. Most every camera still uses all the pixels and then down samples.

>2) Does 400 ISO noise decrease? (from effectively larger sensor size per
>pixel)


By down sampling it is reduced.

>3) Any other effect good or bad? (other than the obvious decrease is
>resolution.)


You have lost control over the down sampling. A better approach ,imo,
is to take the image at high resolution. Filter noise as req'd with
Neat Image, Noise Ninja, whatever, then down sample.
__________________________________________________ ______
Ed Ruf Lifetime AMA# 344007 ((E-Mail Removed))
See images taken with my CP-990/5700 & D70 at
http://EdwardGRuf.com
 
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Daniel Silevitch
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      02-07-2006
On Tue, 07 Feb 2006 08:49:37 -0500, Ed Ruf <(E-Mail Removed)> wrote:
> On Tue, 07 Feb 2006 13:39:13 GMT, in rec.photo.digital "mrsgator88"
><(E-Mail Removed)> wrote:
>
>>Hello,
>>
>>I am curious if anyone has ever studied using their high MP camera at the
>>3mp setting. What I want to know is,
>>
>>1) Do response times increase? (because of less data to deal with)

>
> No. Most every camera still uses all the pixels and then down samples.


The FZ30 has an "Extended Optical Zoom" mode where it uses only the
central region of the sensor to increase the effective focal length of
the lens. Obviously, this only works when you are in a lower-resolution
mode. At lower zooms, though, it uses the entire sensor and downsamples.

-dms
 
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Ed Ruf
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      02-07-2006
On Tue, 07 Feb 2006 14:19:09 GMT, in rec.photo.digital Daniel
Silevitch <(E-Mail Removed)> wrote:

>On Tue, 07 Feb 2006 08:49:37 -0500, Ed Ruf <(E-Mail Removed)> wrote:
>> On Tue, 07 Feb 2006 13:39:13 GMT, in rec.photo.digital "mrsgator88"
>><(E-Mail Removed)> wrote:
>>
>>>Hello,
>>>
>>>I am curious if anyone has ever studied using their high MP camera at the
>>>3mp setting. What I want to know is,
>>>
>>>1) Do response times increase? (because of less data to deal with)

>>
>> No. Most every camera still uses all the pixels and then down samples.

>
>The FZ30 has an "Extended Optical Zoom" mode where it uses only the
>central region of the sensor to increase the effective focal length of
>the lens. Obviously, this only works when you are in a lower-resolution
>mode. At lower zooms, though, it uses the entire sensor and downsamples.


More like marketing hype imo, given the name. There are a few cameras
that similarly just crop giving a smaller FOV in less pixels. Again,
imo you're better off taking the full image and cropping it yourself,
as you then have control of the processing afterwards.
__________________________________________________ ______
Ed Ruf Lifetime AMA# 344007 ((E-Mail Removed))
See images taken with my CP-990/5700 & D70 at
http://EdwardGRuf.com
 
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Daniel Silevitch
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      02-07-2006
On Tue, 07 Feb 2006 09:26:08 -0500, Ed Ruf <(E-Mail Removed)> wrote:
> On Tue, 07 Feb 2006 14:19:09 GMT, in rec.photo.digital Daniel
> Silevitch <(E-Mail Removed)> wrote:
>
>>On Tue, 07 Feb 2006 08:49:37 -0500, Ed Ruf <(E-Mail Removed)> wrote:
>>> No. Most every camera still uses all the pixels and then down samples.

>>
>>The FZ30 has an "Extended Optical Zoom" mode where it uses only the
>>central region of the sensor to increase the effective focal length of
>>the lens. Obviously, this only works when you are in a lower-resolution
>>mode. At lower zooms, though, it uses the entire sensor and downsamples.

>
> More like marketing hype imo, given the name. There are a few cameras
> that similarly just crop giving a smaller FOV in less pixels. Again,
> imo you're better off taking the full image and cropping it yourself,
> as you then have control of the processing afterwards.


It's not _quite_ as useless as it sounds. I can think of one big reason
why you'd want it: to save space on the memory card. If you know that
you just want the central region of an image, why not save a 3MP version
rather than taking up 8 MP worth of card storage?

Similarly, if you're shooting in 3 MP mode anyway to stretch card space,
this gives you more zoom range to play with. Consider two scenarios:

1) Shoot with 8 MP across the entire sensor, downsample in-camera to 3
MP, and save. In post-processing, crop out everything but the middle
third (by area) of the picture. Optionally, upsample your 1 MP cropped
file back up to 3 MP.

2) Shoot with the 3 MP at the center of the sensor. Save.

I'd argue that scenario 2 would give the better picture. Sure, you lose
the flexibility of choosing exactly where to crop that you'd have if you
saved the 8 MP original, but on the flip side, you can get nearly 3
times as many shots onto a card.

-dms
 
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Ed Ruf
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      02-07-2006
On Tue, 07 Feb 2006 14:46:57 GMT, in rec.photo.digital Daniel
Silevitch <(E-Mail Removed)> wrote:

>It's not _quite_ as useless as it sounds. I can think of one big reason
>why you'd want it: to save space on the memory card. If you know that
>you just want the central region of an image, why not save a 3MP version
>rather than taking up 8 MP worth of card storage?
>
>Similarly, if you're shooting in 3 MP mode anyway to stretch card space,
>this gives you more zoom range to play with. Consider two scenarios:
>
>1) Shoot with 8 MP across the entire sensor, downsample in-camera to 3
>MP, and save. In post-processing, crop out everything but the middle
>third (by area) of the picture. Optionally, upsample your 1 MP cropped
>file back up to 3 MP.
>
>2) Shoot with the 3 MP at the center of the sensor. Save.
>
>I'd argue that scenario 2 would give the better picture. Sure, you lose
>the flexibility of choosing exactly where to crop that you'd have if you
>saved the 8 MP original, but on the flip side, you can get nearly 3
>times as many shots onto a card.


Agreed under those circumstances. Though given how cheap storage is
these days not a scenario I would elect to follow.
__________________________________________________ ______
Ed Ruf Lifetime AMA# 344007 ((E-Mail Removed))
See images taken with my CP-990/5700 & D70 at
http://EdwardGRuf.com
 
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Ben Brugman
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      02-07-2006
Theory
A camera with X mp pixels.
Using it on X/2 mp pixels.
The camera has to recalculate every pixel according to a complex algoritm.
Because both the length and the width get decreased by the squareroot of 2
in length.
Most camera's will need some time for this.
But if storage is very slow, this can be faster.

Going form X pixels to X/4 mp pixels. Now a fast algoritm can be used.
because the pixels off the sensor align with the pixels in the resulting
picture.
This can result in a faster mode for calculating and for storing.
(But then you go from 4 to 1 MP or from 6 to 1.5 MP).

Depending on the algoritm noise can decrease if pixels are bundled.

Bad effects if you go from X to X/2 pixels that each pixel has to be
recalculated,
doing this some information gets distributed over several pixels, to
counteract this
some sharpening is applied. This in general is not good.

Going from X to X/4 these effects are probably none existing or less.

In real life.
A D70 is a lot slower if you process to X/2 pixels.
A D70 is a lot faster if you process to X/4 pixels, it processes fast and
can store
more pictures in the buffer.

Ben Brugman


"mrsgator88" <(E-Mail Removed)> schreef in bericht
news:5q1Gf.27922$(E-Mail Removed). net...
> Hello,
>
> I am curious if anyone has ever studied using their high MP camera at the
> 3mp setting. What I want to know is,
>
> 1) Do response times increase? (because of less data to deal with)
> 2) Does 400 ISO noise decrease? (from effectively larger sensor size per
> pixel)
> 3) Any other effect good or bad? (other than the obvious decrease is
> resolution.)
>
> Thanks, Steve
>



 
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