The bigger the sensor, the bigger the individual pixels (at a given
megapix). The bigger the pixels, the lower the noise at high ISO.
My Canons has a setting which alters the x-y resolution of the image: L,
M1, M2, M3, and S on the G10, for example. And another setting which
also affects file size: Normal, Fine, and Superfine, which I guess might
relate to the JPEG compression.
Now obviously, a low megapix file has lower ultimate resolution than a
high one, but will save faster, and you can get more on a memory card.
My question is, if you select the lower resolution settings, does the
processing do some combination of the "raw" data and will this reduce
the noise on low light / high ISO images? From some not very scientific
trials, I'm not convinced of any benefit. So is there any point not
using L and Superfine all the time (if you are not trying to shoot fast
sequences, and have plenty of memory, and are happy to post-process for
web use etc).
No doubt this is discussed somewhere on the web, and I have tried
looking but there is a *huge* amount of "noise" out there. Can anyone
suggest any good links or "live" newsgroups? alt.photography doesn't
In my experience there is rarely any reason other than storage space for
using anything but the most pixels and the least compression.
The noise issue relates to the physical sensor pixels so you would not
expect any improvement from most settings other than the ISO. The
difference occurs when you compare two cameras with markedly different
physical sensor sizes.
In these days of multi-gigabyte storage media even storage is not much
of an issue.
Yea, even unto using 'raw mode', if the camera has it. Someone told me,
and I believe it to be triue, that the raw images is a lot better than 8
bits deep and you canm sometimes reciocvver acceptable pictures if you
process the raw file where the JPEG is 'clipped'
I think that is not what he is talking about. high gain on the CCD tens
to introduce random noise into the image. TO an extent reducing te
reoslutin will avrege out te 'final' pixle frtom teh adcabnet ones as well.
well I dunno. I put 250GB on the home server and the wife had filled it
with random TV recordings in 3 months.
(in-ep-toc’-ra-cy) – a system of government where the least capable to lead
On 23/06/2013 22:32, The Natural Philosopher wrote:
Indeed re noise - but at least most of what a camera can do is also
achievable with post-processing on a computer.
Too true 250GB can easily be filled! But my first digital camera had
something silly like 16 MB cards... (or was it even less?) - and at
least 4 GB lasts a bit longer even with huge image file sizes, and is
Which model was that? All the early ones I remember were CF based and
also had a small amount of internal memory so that they could be demo'd
in shop without inserting an expensive CF card. Mine was a Kodak DC-120
which was already about as good as the human eye on a 10s exposure.
I've got a DC-50 which is still in full working order, and still has an
8Megabyte PCMCIA memory card in it. 48 pictures....
My first digital camera was the DC20, which got stolen, along with the
laptop. 8 pictures at VHS resolution as .bmp files or about 50 jpegs,
and transfer them via an RS232 port via a special cable. As they do for
the DC50, Kodak still hold the manual online.
The Digital cameras that I know about that took the 3.5" floppies were
the Sony Mavica range. They were quite popular at the time with schools,
as they needed no special software to read the files, storage was cheap,
and they were robust enough to let the kids loose with them.
On 23/06/2013 22:32, The Natural Philosopher wrote:
The only down side is you run out of media faster.
rec.photo.digital isn't bad.
Raw mode is typically about 12-14bits deep and so an N Mpixel image
occupies about 1.6N MB. A highest quality JPEG is usually around N/2 MB
worst case. Some cameras will save both for you. Saving speed of raw can
be an issue if you are doing multiple frame action shots. It is better
if getting optimum signal to noise is important to you.
Main advantage of raw is when you know you are facing one time subject
material with insane contrast and highlights and shadow detail both
matter. Wedding with bride in white and groom in black velvet being the
most common serious dynamic range challenge. In camera JPEG default will
almost certainly ruin the image with blown highlights.
The only time it is worth using less than the full resolution of the
equipment you are carrying is when you are certain you will never need a
higher resolution image (eg photo for web/eBay selling) or you would
otherwise run out of storage media and have no blanks with you. Given
the relatively low cost of sD cards this is not really an issue today.
It is possible that some cameras do bin the data down when certain magic
ratios are selected (notably saving at 1/4, 1/9, 1/16 sensor size).
Astronomical CCD cameras call this binning and do it to reduce the
readout noise. Some of the newest cameras also take dark frames.
(ie linear factors of 1/2, 1/3, 1/4)
Some cameras also take their own dark frames on time exposures and do a
certain amount of in camera correction for dead/hot pixels etc.
But you can always trade resolution for signal to noise later by low
pass filtering in the post processing chain. You cannot however get back
the pixel data that was thrown away and never stored.
Stored content will always expand to occupy all the space available.
Not for me!
Mushrooms. With stark white parts, some (almost black) parts, and lit by
a mixture of direct sun, filtered sun and, sometimes, flash.
Amazing what can be dragged out of the shadows. But overexposure, whilst
very easy to achieve, is unmanageable.
On 24/06/2013 11:00, The Natural Philosopher wrote:
Yes - and that is the way to go. I have actually been amazed how well
some shots have turned out given the difficult lighting conditions. I
prefer the most "natural" lighting possible so only use flash if essential.
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