30 SECONDS WITH THE 20D !!!

"Michael A. Covington" wrote in message
...

"Annika1980" wrote in message
...
http://www.pbase.com/bret/image/35233613

That is impressive! Stars to maybe 7th magnitude. You're doing at least
as well as good 400 speed film.

Do you recall the direction in which you were aiming it? I want to try to
identify constellations.

Clearly, you do not have hot pixels. Your exposure was long enough to
lengthen the stars into short trails. There are no "stars" that are not
trailed.

I take it the 20D has the same sensor as the Digital Rebel? or a better
one?

The D rebel has a 6mp sensor the 20D has an 8mp one. They are physically
the same size so the photosites are smaller in the 20d. This has caused
some criticism regarding s/n ratios.

"Michael A. Covington" wrote in message
...

"Annika1980" wrote in message
...
http://www.pbase.com/bret/image/35233613

That is impressive! Stars to maybe 7th magnitude. You're doing at least
as well as good 400 speed film.

Do you recall the direction in which you were aiming it? I want to try to
identify constellations.

Clearly, you do not have hot pixels. Your exposure was long enough to
lengthen the stars into short trails. There are no "stars" that are not
trailed.

I take it the 20D has the same sensor as the Digital Rebel? or a better
one?

The D rebel has a 6mp sensor the 20D has an 8mp one. They are physically
the same size so the photosites are smaller in the 20d. This has caused
some criticism regarding s/n ratios.

Annika1980 wrote:
http://www.pbase.com/bret/image/35233613


I noticed you took the star field photos at ISO 1600. How would they
look if you'd dropped the ISO to say 800, and perhaps increased the
shutter speed by 5-10 seconds?

I'm just curious if ISO 800 would give less noise... Also, is f/3.5 the
widest you can open the aperture at 28mm?

Annika1980 wrote:
http://www.pbase.com/bret/image/35233613


I noticed you took the star field photos at ISO 1600. How would they
look if you'd dropped the ISO to say 800, and perhaps increased the
shutter speed by 5-10 seconds?

I'm just curious if ISO 800 would give less noise... Also, is f/3.5 the
widest you can open the aperture at 28mm?

From: John Honan

I noticed you took the star field photos at ISO 1600. How would they
look if you'd dropped the ISO to say 800, and perhaps increased the
shutter speed by 5-10 seconds?

Less noise with longer streaks.

I'm just curious if ISO 800 would give less noise... Also, is f/3.5 the
widest you can open the aperture at 28mm?

Yes, the 28-135 IS maxs out at f/3.5.
I kinda wished I had taken my 50mm f/1.8
with me.

From: John Honan

I noticed you took the star field photos at ISO 1600. How would they
look if you'd dropped the ISO to say 800, and perhaps increased the
shutter speed by 5-10 seconds?

Less noise with longer streaks.

I'm just curious if ISO 800 would give less noise... Also, is f/3.5 the
widest you can open the aperture at 28mm?

Yes, the 28-135 IS maxs out at f/3.5.
I kinda wished I had taken my 50mm f/1.8
with me.

On Tue, 19 Oct 2004 19:10:55 +0000, Mr Jessop wrote:



The D rebel has a 6mp sensor the 20D has an 8mp one. They are physically
the same size so the photosites are smaller in the 20d. This has caused
some criticism regarding s/n ratios.

How about an untra low noise 1 pixel camera...

;-)

On Tue, 19 Oct 2004 19:10:55 +0000, Mr Jessop wrote:



The D rebel has a 6mp sensor the 20D has an 8mp one. They are physically
the same size so the photosites are smaller in the 20d. This has caused
some criticism regarding s/n ratios.

How about an untra low noise 1 pixel camera...

;-)

"Peter Chant" wrote in message
news
On Tue, 19 Oct 2004 19:10:55 +0000, Mr Jessop wrote:



The D rebel has a 6mp sensor the 20D has an 8mp one. They are physically
the same size so the photosites are smaller in the 20d. This has caused
some criticism regarding s/n ratios.

How about an untra low noise 1 pixel camera...

That is called a photomultiplier tube, and we measure star brightnesses with
them. Really.

--
Clear skies,

Michael A. Covington
Author, Astrophotography for the Amateur
www.covingtoninnovations.com/astromenu.html

"Peter Chant" wrote in message
news
On Tue, 19 Oct 2004 19:10:55 +0000, Mr Jessop wrote:



The D rebel has a 6mp sensor the 20D has an 8mp one. They are physically
the same size so the photosites are smaller in the 20d. This has caused
some criticism regarding s/n ratios.

How about an untra low noise 1 pixel camera...

That is called a photomultiplier tube, and we measure star brightnesses with
them. Really.

--
Clear skies,

Michael A. Covington
Author, Astrophotography for the Amateur
www.covingtoninnovations.com/astromenu.html