[AZ-Observing] Re: DLSR Focusing

  • From: "Jimmy Ray" <jimmy_ray@xxxxxxx>
  • To: <az-observing@xxxxxxxxxxxxx>
  • Date: Wed, 4 Jul 2007 13:50:56 -0700

I'd be doing hand springs if I have an image turn out like that! I never 
thought of the zoom feature on the back of the camera, that is a great idea! 
As far as getting it "tweaked" the feathertouch focuser should help get it 
there. On the $$$$ option I do own a copy of ImagesPlus and the cable set. I 
did see a focusing history type setup in the software, I think I see how 
thats going to work out. All I need to get that option going is time and 
getting it configured on my laptop...

Jimmy Ray
----- Original Message ----- 
From: "Chris Schur" <comets133@xxxxxxxxx>
To: <az-observing@xxxxxxxxxxxxx>
Sent: Wednesday, July 04, 2007 12:49
Subject: [AZ-Observing] Re: DLSR Focusing


Jimmy, those 2.5x right angle viewers are not good
enough by a long shot.  They will get you close but
you still will have half your photos out of focus
enogh to ruin an 8x10.  I have the canon expesive one,
and while the optics are not in question, the low
magnification is.  There are two ways around this.
One, is preffered by many accomplised astro imagers,
is to take a 1 second exposure of a nearby star field,
then zoom in on the back of the cameras LCD at full
magnification and examine it. Then take another.  and
another.  After about four or six shots youll have
absolutely perfect focus.  Now thats the best way.
Heres an "almost" best way.  Get a 6x30 finder scope
and refocus in the daytime to be able to see your
ground glass through the back of the camera sharply.
focus on the etched squares.  Now at night you can be
more certain of a critical focus.  Its hard to point
into a camera eyepiece but you MUST have at least 6 -
8x magnification to focus properly.

Third $$$$ option, buy maxim dslr, and get the control
cable from hap griffin cables.  Then you can watch the
action on the big laptop screen.

I hope these suggestions help.  Here is an example of
a dslr image I recently took using an 8x finder to
focus:

http://www.schursastrophotography.com/xtiastro/m7b.html

Good enough for you?

Chris
--- Jimmy Ray <jimmy_ray@xxxxxxx> wrote:

> I'm looking for the group's opinion on DLSR focusing
> when taking
> astrophotos. I find that when I have the camara body
> mounted in prime focus
> (Canon XTi to a 8" or 11" SCT) it is dificult to
> assess focus and to date
> the results haven't been "stellar". I was looking at
> the Canon magifying
> angle finder "C" which has 1.25x and 2.5x and runs
> about $180 delivered.
> Other options or tricks?
>
> Jimmy Ray
>
> --
> See message header for info on list archives or
> unsubscribing, and please
> send personal replies to the author, not the list.
>
>


Take Care,

Chris
Astro: http://www.schursastrophotography.com
Robotics: http://www.schursastrophotography.com/roboticsmain.html



____________________________________________________________________________________
Be a better Globetrotter. Get better travel answers from someone who knows. 
Yahoo! Answers - Check it out.
http://answers.yahoo.com/dir/?link=list&sid=396545469
--
See message header for info on list archives or unsubscribing, and please
send personal replies to the author, not the list.



-- 
No virus found in this incoming message.
Checked by AVG Free Edition.
Version: 7.5.476 / Virus Database: 269.10.0/886 - Release Date: 7/4/2007 
1:40 PM

--
See message header for info on list archives or unsubscribing, and please 
send personal replies to the author, not the list.

Other related posts: