may be go to this group

and see this post

Do you get what you pay for?



they discus about the automatic or autoranging in software dinamic limit to
256 gray

jack 47'N 71'W



> Hello Randy,
>
> Randy Porter wrote:
> > Back to the other issue, yes, it is defaulting to the highest
> > resolution, and I can capture AVI just fine. I assume when
> > people are taking AVI's of the moon/planets, they do this
> > at a lower resolution to keep the size of the
> > file smaller?
>
> No, what you typically do is to capture at the native resolution of the
> image sensor. For most cameras in the past this has been 640x480. This is
> the best way to retrieve as much information as possible. If you reduce
the
> frame size, you lose information. If you increase the frame size, you
don't
> get any more information, just bigger files.
>
> So the principle is usually to use the native image sensor resolution.
>
> > If I try to select a lower resolution I get the Microsoft Send Report
> > error. When viewing the Event Viewer logs, below is the error
> > I"m seeing.
>
> This is because you are doing it in the dialog that is built into the
> driver, and is really "out of reach" from the rest of the wxAstroCapture
> software, as Martin explained. See more below.
>
> > I may not understand what your saying below, I'm not changing any
> > Format change in the cameras software, this is an option in your
program.
> > Under Camera/Driver Dialogs/Format, the Stream tab gives you options to
> > change the framerate, RBG24, Resolution, etc.
>
> This feature exists only on Windows, and is just telling the windows
camera
> driver to show the built in driver dialog. This dialog is not designed by
> us, it belongs to the camera driver. You can find the same dialog in other
> camera capture programs. This makes it easier to write some simple capture
> software, but the downside is that we don't get any information from the
> drive about what you have done.
>
> Alternatively, if you use the "Properties" button, you are using the
dialogs
> that we have designed. Then we know what things have been changed, and can
> act accordingly. Also, it works on Linux, unlike the Windows driver dialog
> which has no counterpart on Linux.
>
> > I can't find a tutorial anywhere, so I figured most people reduce
> > this to keep the filesize down?
>
> Reduced file size destroys information as mentioned and it has also the
> problem you have experienced. I think the best option is to either capture
> at the full native resolution or capture a subframe at full native
> resolution. That way you can get native resolution and smaller file.
>
> Observe that resolution refers to the image sensor only. Changing the
> scaling of the image is not the same as changing resolution.
>
> Hope this at least explains more
>
> Regards
> Carsten A. Arnholm
> http://arnholm.org/
> N59.776 E10.457
>
>
>
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