Less noise shooting lower res than the camera is built for?

paddyhazard

macrumors regular
Original poster
Jan 27, 2010
110
0
London
I'm just getting into photography and have a lumix fx38 (fz35 for americans) and am loving it. I know that with a lower res for the same size sensor you usually get better high iso performance which is one of the reasons i went for the now older fz38 instead of the fz100 with 14MP. I still think 12MP is more than i'll ever need so wondering if i switch it down to 10 or 8 MP, will the camera stretch those over the whole sensor, thus giving me better low light performance or is the sensor built for 12MP shooting at a lower res just crops the area on the sensor being used? Low light quality isn't really that important for me as I prefer taking shots outside so I was kind of just wondering.

Thanks
 

luminosity

macrumors 65816
Jan 10, 2006
1,364
0
Arizona
I'm not sure what kind of quality you're looking at, at least when you compare it to a high ISO legend like the D3/700, or the current king, the D3s. All three feature just twelve megapixels, and that does help a good deal.
 

OreoCookie

macrumors 68030
Apr 14, 2001
2,681
70
Sendai, Japan
Just don't: the in-camera resizing algorithm will for sure do a poorer job than whatever image editing app you're using (Photoshop or Pixelmator, for instance). Always capture at full resolution. You can always reproduce the effect of `shooting at lower resolution'* in your computer afterwards. However, if you shoot something at lower resolution, you can never get the additional megapixels you've lost back.

* The camera always captures images at the sensor's native resolution. The camera uses an algorithm to resize the full-res image to whatever lower resolution you've selected. Unless you choose 1/4, 1/9, etc. of your resolution, you will introduce additional artifacts.
 

paddyhazard

macrumors regular
Original poster
Jan 27, 2010
110
0
London
I'm just wondering with a point and shoot, with a relatively small sensor, if you can increase the high iso performance a little bit by shooting lower res. If when you reduce the size size of the photo from your camera maximum resolution, whether the camera will now use the whole of that sensor for 8 or 10 MP, thus decreasing the pixel density, or if the sensor has an set pixel density and reducing the resolution just uses less of the (already small) sensor.

I know any point and shoot high iso performance is very limited by the sensor size and i doubt the above would make much of a difference but i just wondered for those rare times I'd want to use an iso of 400, if reducing the resolution will increase the quality a bit.
 

paddyhazard

macrumors regular
Original poster
Jan 27, 2010
110
0
London
thanks OreoCookie so the camera will always capture at 12Mp and just re-size it to a lower res? That makes sense.
 

Phrasikleia

macrumors 601
Feb 24, 2008
4,077
400
Over there------->
I know any point and shoot high iso performance is very limited by the sensor size and i doubt the above would make much of a difference but i just wondered for those rare times I'd want to use an iso of 400, if reducing the resolution will increase the quality a bit.
No. The sensor's cells are only so sensitive, and asking the camera to process your images to a lower resolution won't make its sensor any more efficient at gathering light.
 

GoCubsGo

macrumors Nehalem
Feb 19, 2005
35,741
146
Don't you lose some quality when you push the ISO down below the camera's base ISO?
 

jackerin

macrumors 6502a
Jun 29, 2008
850
28
Finland

bsamcash

macrumors 6502
Jul 31, 2008
292
194
Cupertino, CA
The sensors always capture at one resolution in its RAW format, then converts it to JPEG at whatever resolution you set. Your best option is to get a camera that can save in RAW then removing the noise in post.
 

a.jfred

macrumors 6502
May 28, 2010
384
17
Austin, TX
Always shoot at the highest resolution you can, at the lowest ISO you can. Even if you don't shoot in RAW, there are programs that remove noise.
 
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