| |
Main
Date: 02 Oct 2006 19:52:41
From: bad madison
Subject: Digital Rebel XT
|
Is the Canon Digital Rebel XT a good buy for astrophotography?
|
|
| |
Date: 02 Oct 2006 20:45:51
From: Davoud
Subject: Re: Digital Rebel XT
|
bad madison wrote:
> Is the Canon Digital Rebel XT a good buy for astrophotography?
A very good buy. Not the best way to take astrophotographs, perhaps,
but a very good way for a relatively small investment. There is an
example here
<http://www.sfaaa.com/board/viewtopic.php?t=198&sid=02b984f1057f65da573d
74d00b1dcd17 > and general information here <http://tinyurl.com/g8jjh>.
Davoud
--
usenet *at* davidillig *dawt* com
|
| | |
Date: 02 Oct 2006 23:22:44
From: Joe S.
Subject: Re: Digital Rebel XT
|
"Davoud" <see@below.net > wrote in message
news:021020062045512832%see@below.net...
> bad madison wrote:
>
>> Is the Canon Digital Rebel XT a good buy for astrophotography?
>
> A very good buy. Not the best way to take astrophotographs, perhaps,
> but a very good way for a relatively small investment. There is an
> example here
> <http://www.sfaaa.com/board/viewtopic.php?t=198&sid=02b984f1057f65da573d
> 74d00b1dcd17> and general information here <http://tinyurl.com/g8jjh>.
>
> Davoud
>
> --
> usenet *at* davidillig *dawt* com
I have a film Rebel G and an EOS 630. While both are excellent cameras,
they -- as do all other SLR's -- drive me nuts with the noise they make --
mirror slap, film advance, etc. Is the digital SLR just as noisy???
I guess the days of the old silent Leicas are gone forever.
|
| | | |
Date: 03 Oct 2006 04:32:02
From: Chris L Peterson
Subject: Re: Digital Rebel XT
|
On Mon, 2 2006 23:22:44 -0400, "Joe S." <anon@mous.net > wrote:
>I have a film Rebel G and an EOS 630. While both are excellent cameras,
>they -- as do all other SLR's -- drive me nuts with the noise they make --
>mirror slap, film advance, etc. Is the digital SLR just as noisy???
All DSLRs make some noise when the mirror flips up and when the shutter
opens and closes. I find the Canon cameras to be fairly quiet, and of
course there is no film advance, which is usually what makes the most
noise with film bodies. When using a DSLR for astroimaging it is
generally a good idea to lock up the mirror, or to use a mode that moves
the mirror well in advance of opening the shutter. All Canons can do
this, but I don't know about other cameras.
_________________________________________________
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com
|
| | | |
Date: 03 Oct 2006 01:09:05
From: Davoud
Subject: Re: Digital Rebel XT
|
In article <efsl6e0hjh@news3.newsguy.com >, Joe S. <anon@mous.net> wrote:
bad madison:
> >> Is the Canon Digital Rebel XT a good buy for astrophotography?
Davoud:
> > A very good buy. Not the best way to take astrophotographs, perhaps,
> > but a very good way for a relatively small investment. There is an
> > example here
> > <http://www.sfaaa.com/board/viewtopic.php?t=198&sid=02b984f1057f65da573d
74d00b1dcd17 > and general information here <http://tinyurl.com/g8jjh>.
Joe S.:
> I have a film Rebel G and an EOS 630. While both are excellent cameras,
> they -- as do all other SLR's -- drive me nuts with the noise they make --
> mirror slap, film advance, etc. Is the digital SLR just as noisy???
My 20D is quieter than any film SLR I have used.
> I guess the days of the old silent Leicas are gone forever.
Absolutely not! The new Leica M8 rangefinder is said to be the quietest
rangefinder Leica has ever made. It has a /ten/ megapixel low-noise
/CCD/ detector and it will sell for only $5295 when it hits the stores
in November.
Davoud
--
usenet *at* davidillig *dawt* com
|
| |
Date: 02 Oct 2006 16:42:52
From: RMOLLISE
Subject: Re: Digital Rebel XT
|
bad madison wrote:
> Is the Canon Digital Rebel XT a good buy for astrophotography?
Hi:
Only you know what's a "good deal" for you. However, I'd say that, yes,
it's a pretty good deal; especially if you plan on using it for
terrestrial imaging, too. People have and are doing tremendous work
with these cameras, but I don't think even they would deny that a
chilled astronomical CCD cam is probably "better" for the sky if that's
your only interest.
Peace,
Rod Mollise
|
| | |
Date: 03 Oct 2006 04:36:50
From: Sam Wormley
Subject: Re: Digital Rebel XT
|
bad madison wrote:
> Is the Canon Digital Rebel XT a good buy for astrophotography?
>
Surface Brightness of Deep-Sky Objects Measured with a Digital Camera
http://www.clarkvision.com/astro/surface-brightness-profiles/introduction.html
|
| | | |
Date: 03 Oct 2006 14:56:38
From: micheel
Subject: Re: Digital Rebel XT
|
"Sam Wormley" <swormley1@mchsi.com > wrote in message
news:CNlUg.87990$aJ.60773@attbi_s21...
> bad madison wrote:
>> Is the Canon Digital Rebel XT a good buy for astrophotography?
>>
>
> Surface Brightness of Deep-Sky Objects Measured with a Digital Camera
>
> http://www.clarkvision.com/astro/surface-brightness-profiles/introduction.html
This has little value to the OP.
|
| | | | |
Date: 03 Oct 2006 15:13:56
From: Chris L Peterson
Subject: Re: Digital Rebel XT
|
On Tue, 03 2006 14:56:38 GMT, "micheel" <\\much//@telusplanet.net >
wrote:
>This has little value to the OP.
It may or may not. But for sure it has more value than your reply!
_________________________________________________
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com
|
| | |
Date: 02 Oct 2006 20:21:20
From: Ray Porter
Subject: Re: Digital Rebel XT
|
In a similar vein, how about the new 400 XTi? Will the higher resolution be
a problem for astrophotography? I'm going to buy one of these cameras in
the near future and I'm having a hard time deciding between the XT and the
new XTi.
Thanks,
Ray Porter
"RMOLLISE" <rmollise@hotmail.com > wrote in message
news:1159832572.710928.91300@b28g2000cwb.googlegroups.com...
>
> bad madison wrote:
>> Is the Canon Digital Rebel XT a good buy for astrophotography?
>
> Hi:
>
> Only you know what's a "good deal" for you. However, I'd say that, yes,
> it's a pretty good deal; especially if you plan on using it for
> terrestrial imaging, too. People have and are doing tremendous work
> with these cameras, but I don't think even they would deny that a
> chilled astronomical CCD cam is probably "better" for the sky if that's
> your only interest.
>
> Peace,
> Rod Mollise
>
|
| | | |
Date: 02 Oct 2006 22:49:59
From: Joe S.
Subject: Re: Digital Rebel XT
|
"Ray Porter" <lrporternc@bellsouth.net > wrote in message
news:42iUg.27959$eW5.17662@bignews5.bellsouth.net...
> In a similar vein, how about the new 400 XTi? Will the higher resolution
> be a problem for astrophotography? I'm going to buy one of these cameras
> in the near future and I'm having a hard time deciding between the XT and
> the new XTi.
>
> Thanks,
> Ray Porter
Are you the same Ray Porter who was in RAFAOBC 1-68, Fort Sill, OK, summer
of 1967?
|
| | | | |
Date: 03 Oct 2006 07:11:45
From: Ray Porter
Subject: Re: Digital Rebel XT
|
"Joe S." <anon@mous.net > wrote in message
news:efsj960ec4@news3.newsguy.com...
>
> Are you the same Ray Porter who was in RAFAOBC 1-68, Fort Sill, OK, summer
> of 1967?
Nope, sorry. I served my time but I was at Ft. Gordon, GA in the winter of
1979.
Ray Porter
|
| |
Date: 03 Oct 2006 08:54:41
From: Stephen Paul
Subject: Re: Digital Rebel XT
|
bad madison wrote:
> Is the Canon Digital Rebel XT a good buy for astrophotography?
>
As others have indicated, basically yes, it is. Especially for the
beginner, or the casual imager.
There is work involved in imaging with a DSLR, as with imaging using any
medium in general.
For the casual, or beginning imager, the disadvantage of the DSLR over
the Astro-CCD camera is primarily in the post processing.
An Astro-CCD camera can take much longer exposure "light" frames due to
cooling and the deeper capacity of charge per pixel offered by a CCD.
This means that you can take less images of longer duration which
precludes the need for complicated and time consuming post processing.
As it is expected by manufacture to be used primarily for exposure times
of 30 seconds or less, a non-cooled CMOS DSLR requires multiple shorter
exposure frames to be stacked during processing.
The advantage of the DSLR for astro-imaging in my opinion as a casual
imager, is that there are accessories available that preclude the need
for computer operations at the telescope. For example, Stellar
Technologies makes a focusing tool that works very well, and Canon has
the TC-80N3 camera controller which allows programming the number of
exposures, then length of the exposure, and the time between exposures.
If you can also get your hands on a used SBIG ST4 autoguider, you will
have everything you need to do automated long sequences of short exposures.
With these three accessories (and a good mount), you can achieve focus,
program the camera, start the sequence, and go off to do other things.
Here's a picture of a setup that I've used in the past:
http://tinyurl.com/nzw8o
The image of M42 on my site was taken with this setup, although you need
to be aware that my Rebel is modified by Hutech, with the internal IR
blocking filter replaced with a wider band pass filter to make it more
sensitive to H-alpha and the red end of the spectrum.
Also, before going hog-wild and buying the Losmandy G-11 and the ST4, I
had some pleasing results using a well polar aligned AS CG-5 mount, a
StarHoc 8-4 (8" F4 reflector) and unguided 30 second exposures at ISO
800 and ISO 1600.
I think it works out pretty much that the less expensive the solution,
the more work in post processing. For example, with the CG-5 I would
have to go through the frames and toss a bunch that had hit a glitch in
the tracking, rendering the frame unusable due to elongated stars. With
the G-11 unguided, I discard far less, and with the ST4, I rarely have
to toss a single frame.
Of course the other advantage is that having gone through the process of
upgrading mounts and learning to use an autoguider, once able to afford
an astro-CCD, the next step should be quite a lot easier.
HTH,
Steve Paul
|
| |
Date: 06 Oct 2006 10:52:51
From: Steve Sherman
Subject: Re: Digital Rebel XT
|
The imager device does not seem to matter nearly as much
as the image processing software.
All you need is something that will collect photons.
The rest is all image processing software.
Kind of like paint by numbers.
Steve
bad madison wrote:
> Is the Canon Digital Rebel XT a good buy for astrophotography?
>
>
|
| | |
Date: 06 Oct 2006 15:03:23
From: Chris L Peterson
Subject: Re: Digital Rebel XT
|
On Fri, 06 2006 10:52:51 -0400, Steve Sherman
<smsherm@bellsouth.net > wrote:
>The imager device does not seem to matter nearly as much
>as the image processing software.
>All you need is something that will collect photons.
>The rest is all image processing software.
>Kind of like paint by numbers.
That could not be farther from the truth. No amount of processing can
make up for bad data, and data quality is strongly dependent on the
quality of the equipment. While the Rebel XT is a good instrument for
beginning astroimagers, it does not "collect photons" nearly as well as
more specialized instruments, and this is apparent in the quality of
astroimages published.
_________________________________________________
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com
|
| |
Date: 06 Oct 2006 13:20:29
From: laura halliday
Subject: Re: Digital Rebel XT
|
Chris L Peterson wrote:
> I certainly wasn't indicting DSLRs- they are capable of producing fine
> astroimages. But they don't do as well as specialized astrocameras
> (which is hardly surprising), and Steve is wrong if he thinks that
> processing can make up for the difference.
Total agreement. GIGO.
Another point is that, unless you spend a *lot* of money,
astronomical CCD camera have tiny sensors. An APS-size
sensor makes it a lot easier to find things and take
pictures of them.
Laura Halliday VE7LDH "Que les nuages soient notre
Grid: CN89mg pied a terre..."
ICBM: 49 16.05 N 122 56.92 W - Hospital/Shafte
|
| | |
Date: 06 Oct 2006 23:27:32
From: Ashbury
Subject: Re: Digital Rebel XT
|
What about the new XTi? Does it have mirror lockup?
|
| | | |
Date: 07 Oct 2006 00:41:51
From: Sam Wormley
Subject: Re: Digital Rebel XT
|
Ashbury wrote:
> What about the new XTi? Does it have mirror lockup?
>
>
http://www.robgalbraith.com/public_files/Canon_Rebel_XTi_White_Paper.pdf
|
| | | | |
Date: 07 Oct 2006 02:55:11
From: Ashbury
Subject: Re: Digital Rebel XT
|
"Sam Wormley" <swormley1@mchsi.com > wrote in message
news:jJCVg.185221$FQ1.157673@attbi_s71...
> Ashbury wrote:
>> What about the new XTi? Does it have mirror lockup?
>
>
> http://www.robgalbraith.com/public_files/Canon_Rebel_XTi_White_Paper.pdf
AH....page seven suggests that it does. C.Fn 7-1 but it doesn't tell you
if it is timed or
continuous.
Still..this camera seems perfect for CMOS
|
| | | | | |
Date: 07 Oct 2006 03:01:13
From: Sam Wormley
Subject: Re: Digital Rebel XT
|
Ashbury wrote:
> "Sam Wormley" <swormley1@mchsi.com> wrote in message
> news:jJCVg.185221$FQ1.157673@attbi_s71...
>> Ashbury wrote:
>>> What about the new XTi? Does it have mirror lockup?
>>
>> http://www.robgalbraith.com/public_files/Canon_Rebel_XTi_White_Paper.pdf
>
> AH....page seven suggests that it does. C.Fn 7-1 but it doesn't tell you
> if it is timed or
> continuous.
>
> Still..this camera seems perfect for CMOS
>
>
If it's like my Canon dSLR, the first squeeze of the remote
locks up the mirror and the second opens the shutter.
|
| | | | | |
Date: 07 Oct 2006 15:08:01
From: Phil Wheeler
Subject: Re: Digital Rebel XT
|
Ashbury wrote:
> "Sam Wormley" <swormley1@mchsi.com> wrote in message
> news:jJCVg.185221$FQ1.157673@attbi_s71...
>> Ashbury wrote:
>>> What about the new XTi? Does it have mirror lockup?
>>
>> http://www.robgalbraith.com/public_files/Canon_Rebel_XTi_White_Paper.pdf
>
> AH....page seven suggests that it does. C.Fn 7-1 but it doesn't tell you
> if it is timed or
> continuous.
>
> Still..this camera seems perfect for CMOS
>
>
I'm about to read the details, but the
self-cleaning sensor is attractive: I have to
clean the one in my 20D pretty frequently.
Phil
|
| | | | |
Date: 07 Oct 2006 02:48:37
From: Ashbury
Subject: Re: Digital Rebel XT
|
"Sam Wormley" <swormley1@mchsi.com > wrote in message
news:jJCVg.185221$FQ1.157673@attbi_s71...
> Ashbury wrote:
>> What about the new XTi? Does it have mirror lockup?
>
>
> http://www.robgalbraith.com/public_files/Canon_Rebel_XTi_White_Paper.pdf
a simple yes or no would do nicely thank you.
|
| | | | | |
Date: 07 Oct 2006 02:54:58
From: Sam Wormley
Subject: Re: Digital Rebel XT
|
Ashbury wrote:
> "Sam Wormley" <swormley1@mchsi.com> wrote in message
> news:jJCVg.185221$FQ1.157673@attbi_s71...
>> Ashbury wrote:
>>> What about the new XTi? Does it have mirror lockup?
>>
>> http://www.robgalbraith.com/public_files/Canon_Rebel_XTi_White_Paper.pdf
>
> a simple yes or no would do nicely thank you.
>
>
Yes
|
| | |
Date: 06 Oct 2006 19:25:48
From: Steve Sherman
Subject: Re: Digital Rebel XT
|
laura halliday wrote:
> Chris L Peterson wrote:
>
>
>>I certainly wasn't indicting DSLRs- they are capable of producing fine
>>astroimages. But they don't do as well as specialized astrocameras
>>(which is hardly surprising), and Steve is wrong if he thinks that
>>processing can make up for the difference.
>
>
> Total agreement. GIGO.
>
> Another point is that, unless you spend a *lot* of money,
> astronomical CCD camera have tiny sensors. An APS-size
> sensor makes it a lot easier to find things and take
> pictures of them.
>
> Laura Halliday VE7LDH "Que les nuages soient notre
> Grid: CN89mg pied a terre..."
> ICBM: 49 16.05 N 122 56.92 W - Hospital/Shafte
>
You are all correct.
My comment was very poorly worded. My point was that
with image processing software and the knowledge of it's
use, you can get something from almost nothing.
If the intent is astronomical images, forget the Rebel.
If the intent is move from film to a CCD camera, then a Rebel
is OK.
By the way, did you all note that all the responses were
about the same -
"if you don't have the data, you can't process the data"
Steve
|
| | | |
Date: 06 Oct 2006 19:50:02
From: Ray Porter
Subject: Re: Digital Rebel XT
|
"Steve Sherman" <smsherm@bellsouth.net > wrote in message
news:WxBVg.27054$8s6.20981@bignews4.bellsouth.net...
> If the intent is astronomical images, forget the Rebel.
> If the intent is move from film to a CCD camera, then a Rebel
> is OK.
Sorry but I have to disagree with this statement. We have several club
members with dedicated cameras (up to and including SBIG ST-10. We have a
couple of other imagers who have moved exclusively to digital SLRs (a Rebel
initially followed by moves up to a modified 20D and a 5D). In side by side
comparisons my (admittedly aging) eyes simply can't see any significant
advantage in either camp. Yes, the ST-10 can make very long exposures and
capture stunning images in a single shot and it can reach deeper. The DSLRs
can take stunning images by taking several much shorter exposures and
staking. For many of us, the ease of use and significantly lower price of
admission for very comparable results on most objects most amateurs are
interested in, makes the DSLR a very excellent choice.
As for post-processing time, it sounds like there's not really that much
difference if you listen to the serious imagers in our club. The guy with
the ST 10 (mounted on an AP mount with a customer 16" RC) averages about 2
images a night when you combine actual exposure time and post-processing.
The guy with the 5D produces a lot more images per night and often with very
little post-processing beyond stacking.
I admit the dedicated, cooled CCD is better. But for the price difference
and the beauty of the images achievable, the DSLRs are giving the dedicated
cameras a serious run for the money.
Ray Porter
|
| | | | |
Date: 07 Oct 2006 02:48:36
From: Ashbury
Subject: Re: Digital Rebel XT
|
"Ray Porter" <ray_porter@alumni.unc.edu > wrote in message
news:ygDVg.34864$tT6.12903@bignews7.bellsouth.net...
>
> "Steve Sherman" <smsherm@bellsouth.net> wrote in message
> news:WxBVg.27054$8s6.20981@bignews4.bellsouth.net...
>> If the intent is astronomical images, forget the Rebel.
>> If the intent is move from film to a CCD camera, then a Rebel
>> is OK.
>
> Sorry but I have to disagree with this statement. We have several club
> members with dedicated cameras (up to and including SBIG ST-10. We have a
> couple of other imagers who have moved exclusively to digital SLRs (a
> Rebel initially followed by moves up to a modified 20D and a 5D). In side
> by side comparisons my (admittedly aging) eyes simply can't see any
> significant advantage in either camp. Yes, the ST-10 can make very long
> exposures and capture stunning images in a single shot and it can reach
> deeper. The DSLRs can take stunning images by taking several much shorter
> exposures and staking. For many of us, the ease of use and significantly
> lower price of admission for very comparable results on most objects most
> amateurs are interested in, makes the DSLR a very excellent choice.
>
> As for post-processing time, it sounds like there's not really that much
> difference if you listen to the serious imagers in our club. The guy with
> the ST 10 (mounted on an AP mount with a customer 16" RC) averages about 2
> images a night when you combine actual exposure time and post-processing.
> The guy with the 5D produces a lot more images per night and often with
> very little post-processing beyond stacking.
>
> I admit the dedicated, cooled CCD is better. But for the price difference
> and the beauty of the images achievable, the DSLRs are giving the
> dedicated cameras a serious run for the money.
>
>
>
> Ray Porter
Allelulia mother of God!!
|
| |
Date: 06 Oct 2006 11:18:08
From: laura halliday
Subject: Re: Digital Rebel XT
|
Chris L Peterson wrote:
> That could not be farther from the truth. No amount of processing can
> make up for bad data, and data quality is strongly dependent on the
> quality of the equipment. While the Rebel XT is a good instrument for
> beginning astroimagers, it does not "collect photons" nearly as well as
> more specialized instruments, and this is apparent in the quality of
> astroimages published.
Can't say I completely agree with you on this one. IMHO,
the fact that people are publishing crummy pictures is the
result of excessive enthusiasm, and not an indictment of
the cameras themselves.
But I also agree wholeheartedly on the quality of the input
data: if the raw pictures are poor, no amount of processing
can fix them. No matter what the marketing people say,
just because it's digital doesn't mean you can cease being
fanatic about focus, polar alignment, and all the usual
goodies.
Sure, the Canon DSLRs have their limitations. But for pretty
pictures of relatively bright objects at modest initial cost,
they are hard to beat.
Laura Halliday VE7LDH "Que les nuages soient notre
Grid: CN89mg pied a terre..."
ICBM: 49 16.05 N 122 56.92 W - Hospital/Shafte
|
| | |
Date: 06 Oct 2006 18:26:49
From: Chris L Peterson
Subject: Re: Digital Rebel XT
|
On 6 2006 11:18:08 -0700, "laura halliday" <marsgal42@hotmail.com >
wrote:
>Can't say I completely agree with you on this one. IMHO,
>the fact that people are publishing crummy pictures is the
>result of excessive enthusiasm, and not an indictment of
>the cameras themselves.
I certainly wasn't indicting DSLRs- they are capable of producing fine
astroimages. But they don't do as well as specialized astrocameras
(which is hardly surprising), and Steve is wrong if he thinks that
processing can make up for the difference.
_________________________________________________
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com
|
|
