Megapixel setting for available light.

On Apr 23, 7:31 am, "j...@wexfordpress.com" <j....DeleteThis@wexfordpress.com>
wrote:
> In available light situations I have been taking pictures with my
> FujiFilm E900 set at 5 megapixels. I can go up to a maximum of 9.1
> megapixels or down to lower values. I know that higher settings
> generate a larger image on the card. But is there any effect, positive
> or negative, on the available light situation? Is vulnerablitity to
> camera shake increased, decreased or stay the same with higher pixel
> density?
>
> I have years with film cameras but this is my first digital. I can set
> shutter speed and/or aperture manually but I have been using the
> automatic settings.
>
> John Culleton

Higher noise can result, because in some cases when the camera
downsamples, this tends to average the noise a bit.

Same thing for camera shake. The motion blur can be more noticable at
the higher resolution- BUT, if you downsample in an editor, you will
get the same thing as in the camera downsampled image.

So there is no advantage to shooting in the downsampled mode. You can
always do the same thing yourself afterwords, and compare. If the
high res shot is okay, fine. Otherwise you can downsample and use
that.
 >> Stay informed about: Megapixel setting for available light. 

Well different cameras do different things I guess. My primary
experience is with Panasonics and Leicas small sensor cameras and they
work as I described.

On Apr 23, 8:23 am, Ed Ruf <"Ed Ruf (REPLY to E-MAIL IN SIG!)"
<egruf_usen....DeleteThis@cox.net>> wrote:
> On 23 Apr 2007 05:50:07 -0700, in rec.photo.digital KenS
>
> <ksarg....DeleteThis@uwf.edu> wrote:
> >Probably not - I say "probably" because I don't know this particular
> >camera. But in general when you use a lower resolution setting, the
> >sensor image is cropped - that is, you only use part of the sensor.
> >And that part of the sensor is recording the same number of megapixels
> >it would if you were at full resolution. The pixels are the same size
> >in other words.
>
> I would tend to say the opposite. That lower resolutions are not
> cropped but down sampled over the whole sensor. Works this way with my
> three P&S cameras, as well as my two dslrs.
> -
> Ed Ruf (Usen...@EdwardG.Ruf.com)http://edwardgruf.com/Digital_Photography/General/index.html
 >> Stay informed about: Megapixel setting for available light. 

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 >> Stay informed about: Megapixel setting for available light. 

ksargent.DeleteThis@uwf.edu (KenS) wrote in
news:1177332607.020306.69230@b75g2000hsg.googlegroups.com:

> Probably not - I say "probably" because I don't know this
> particular camera. But in general when you use a lower resolution
> setting, the sensor image is cropped - that is, you only use part
> of the sensor. And that part of the sensor is recording the same
> number of megapixels it would if you were at full resolution. The
> pixels are the same size in other words.

Wait; if they worked that way, wouldn't the image scale change as you
changed resolution?

Since the lens is still projecting the image over the full sensor,
the technique you're talking about would result in taking only part
of the image.

--
Bert Hyman | St. Paul, MN | bert.DeleteThis@iphouse.com
 >> Stay informed about: Megapixel setting for available light. 

Looks like I may have been wrong - I was actually thinking about the
extended optical zoom the FZ cameras offer (which does work as I
described) and the aspect ratio change on the D-Lux 3 - which also
involves a resolution change, and, once again, is a crop of the
sensor.

Sorry about the confusion.

Ken


On Apr 23, 9:50 am, Bert Hyman <b... DeleteThis @iphouse.com> wrote:
> ksarg... DeleteThis @uwf.edu (KenS) wrote innews:1177332607.020306.69230@b75g2000hsg.googlegroups.com:
>
> > Probably not - I say "probably" because I don't know this
> > particular camera. But in general when you use a lower resolution
> > setting, the sensor image is cropped - that is, you only use part
> > of the sensor. And that part of the sensor is recording the same
> > number of megapixels it would if you were at full resolution. The
> > pixels are the same size in other words.
>
> Wait; if they worked that way, wouldn't the image scale change as you
> changed resolution?
>
> Since the lens is still projecting the image over the full sensor,
> the technique you're talking about would result in taking only part
> of the image.
>
> --
> Bert Hyman | St. Paul, MN | b... DeleteThis @iphouse.com
 >> Stay informed about: Megapixel setting for available light. 

Well as you see in my previous posting, I said that I was in error.
Regarding the Leica D-Lux - the camera does crop to produce the 3:2
and 4:3 aspect ratios - which also result in a smaller MP count as
well. Given that particular camera has no OVF, there are no framing
marks. One sees the result on the LCD monitor.

The extended optical zoom of the Panasonics is a crop and does result
in a lower MP value (hence my original statement) - and is not the
same as a digital zoom. Once again - an EVF rather than an OVF - so
no crop marks there either.

Sorry for the confusion.

Ken

On Apr 23, 3:48 pm, "Ed Ruf (REPLY to E-MAIL IN SIG!)"
<egruf_usen....TakeThisOut@cox.net> wrote:
> On 23 Apr 2007 07:46:14 -0700, in rec.photo.digital KenS <ksarg....TakeThisOut@uwf.edu>
> wrote:
>
> >Well different cameras do different things I guess. My primary
> >experience is with Panasonics and Leicas small sensor cameras and they
> >work as I described.
>
> Care to give a model #? I've heard of cameras that crop using digital zoom,
> but not different sized images. If this is truly the case are there crop
> marks in the viewfinder for each resolution?
> --
> Ed Ruf (Usen...@EdwardGRuf.com)http://edwardgruf.com/Digital_Photography/General/index.html
 >> Stay informed about: Megapixel setting for available light. 

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 >> Stay informed about: Megapixel setting for available light. 

David,

Asi understand it, the difference is this: digital zoom resizes the
image to the camera's native resolution resulting in a loss of image
quality. Extended Optical Zoom (at least the Panny variety) does not
resize the image; in other words (given an 8 MP camera), DZ crops and
then upsizes to the full 8 MP; EOZ simply crops without any upsizing
resulting in a smaller MP image.

Ken


On Apr 24, 5:17 am, "David J Taylor" <david-tay....DeleteThis@blueyonder.not-this-
bit.nor-this-part.co.uk> wrote:
> KenS wrote:
>
> []
>
> > The extended optical zoom of the Panasonics is a crop and does result
> > in a lower MP value (hence my original statement) - and is not the
> > same as a digital zoom. Once again - an EVF rather than an OVF - so
> > no crop marks there either.
>
> > Sorry for the confusion.
>
> > Ken
>
> Ken,
>
> I don't have one of those cameras, but to me it seems just the same as
> digital zoom (except perhaps not carried to such silly extremes). If the
> zoomed image is 5MP instead of standard 8MP, is the extension in focal
> length then sqrt (8/5), i.e. about 1.26 times?
>
> Thanks,
> David
 >> Stay informed about: Megapixel setting for available light. 

On April 23, 2007, KenS wrote:

>The extended optical zoom of the
> Panasonics is a crop and does result in
> a lower MP value (hence my original
> statement) - and is not the same as a
> digital zoom.

I have a Panasonic FZ5, and its 12X optical zoom does NOT use cropping.
By definition, optical zoom is accomplished using the lens only, not by
cropping, as that is what digital zoom is, an upscaled image from a
cropped sensor.

John

Visit my macro and close-up photography album at:
http://picasaweb.google.com/jpdenk60477/MacroAndCloseupPhotos
 >> Stay informed about: Megapixel setting for available light. 

KenS wrote:
[]
> The extended optical zoom of the Panasonics is a crop and does result
> in a lower MP value (hence my original statement) - and is not the
> same as a digital zoom. Once again - an EVF rather than an OVF - so
> no crop marks there either.
>
> Sorry for the confusion.
>
> Ken

Ken,

I don't have one of those cameras, but to me it seems just the same as
digital zoom (except perhaps not carried to such silly extremes). If the
zoomed image is 5MP instead of standard 8MP, is the extension in focal
length then sqrt (8/5), i.e. about 1.26 times?

Thanks,
David
 >> Stay informed about: Megapixel setting for available light. 

I'm not talking about the optical zoom - I'm talking about what
Panasonic calls the "EXTENDED Optical zoom." Entirely different
thing. My FZ30 has it - I'm not sure whether your FX5 does or not.
But it is not the same as the 12X optical zoom and yes, it uses
cropping.

Ken

On Apr 24, 7:27 am, jpd....TakeThisOut@webtv.net (John D.) wrote:
> On April 23, 2007, KenS wrote:
>
> >The extended optical zoom of the
> > Panasonics is a crop and does result in
> > a lower MP value (hence my original
> > statement) - and is not the same as a
> > digital zoom.
>
> I have a Panasonic FZ5, and its 12X optical zoom does NOT use cropping.
> By definition, optical zoom is accomplished using the lens only, not by
> cropping, as that is what digital zoom is, an upscaled image from a
> cropped sensor.
>
> John
>
> Visit my macro and close-up photography album at:http://picasaweb.google.com/jpdenk60477/MacroAndCloseupPhotos
 >> Stay informed about: Megapixel setting for available light. 

KenS wrote:
> David,
>
> Asi understand it, the difference is this: digital zoom resizes the
> image to the camera's native resolution resulting in a loss of image
> quality. Extended Optical Zoom (at least the Panny variety) does not
> resize the image; in other words (given an 8 MP camera), DZ crops and
> then upsizes to the full 8 MP; EOZ simply crops without any upsizing
> resulting in a smaller MP image.
>
> Ken

Yes, I agree, and I've just posted the maths by which I reached that
conclusion.

Cheers,
David
 >> Stay informed about: Megapixel setting for available light. 

John D. wrote:
[]
> I have a Panasonic FZ5, and its 12X optical zoom does NOT use
> cropping. By definition, optical zoom is accomplished using the lens
> only, not by cropping, as that is what digital zoom is, an upscaled
> image from a cropped sensor.
>
> John

Same camera here, but I think later models use a small amount of digital
crop, after the full optical zoom has been reached, which reduces the
pixel count and the field of view.

Considering the Panasonic FZ8, for example, the optical zoom is 12X with
the full 7.2MP resolution, but it also offers 14.4X zoom with 5MP and 18X
zoom with 3MP. If this is crop, then 7.2MP cropped to 5MP reduces the
angle of view by 1.2 times [sqrt (7.2 /.5)], which would make the apparent
zoom 1.2 x 12X, i.e. 14.4X. Similarly, for the second level crop, sqrt
(7.2 / 3) is ~1.55, so the zoom would be 1.5 x 12X, i.e. 18X.

Reference:
http://www.dpreview.com/reviews/panasonicfz8/

So having looked at the numbers, I conclude that what these cameras offer
is an in-camera crop, decreasing both the number of pixels and the
field-of-view proportionately. Saves cropping afterwards, and magnifies
the image in the EVF compared to the non-cropped case. There is no
interpolation involved as with digital zoom.

Cheers,
David
 >> Stay informed about: Megapixel setting for available light.