The Moon with a telephoto lens and teleconverters

In message ,
"Bart van der Wolf" wrote:

Looks good, with all the glass in between moon and sensor.

Teleconverters seems to be very easy, engineering-wise, compared to
regular lenses. Contrary to popular opinion, most halfway-decent
teleconverters do not compromise the prime lens in any significant way;
they merely stretch the center of the focal plane over a larger area,
exposing the limitations of the prime.
--


John P Sheehy

wrote:

17 stacked JPEG's on a night of better than average "seeing".

I've been prowling around various astronomy photos sites and seen
mention of this several times. I understand the idea, but not the
technique. What software do you use for stacking the images?


--
Eric Schreiber
www.ericschreiber.com

Eric Schreiber wrote:
wrote:


17 stacked JPEG's on a night of better than average "seeing".


I've been prowling around various astronomy photos sites and seen
mention of this several times. I understand the idea, but not the
technique. What software do you use for stacking the images?



registax (free) http://registax.astronomy.net/

ImagesPlus (not free) http://www.mlunsold.com/

Roger

Roger N. Clark (change username to rnclark) wrote:

registax (free) http://registax.astronomy.net/
ImagesPlus (not free) http://www.mlunsold.com/

Thanks Roger. I've bookmarked the sites.


--
Eric Schreiber
www.ericschreiber.com

"Roger N. Clark (change username to rnclark)" wrote
in :

Bart van der Wolf wrote:

"Roger N. Clark (change username to rnclark)"
wrote in message ...

Here is a recent attempt at photographing the moon with
a telephoto lens, on a stationary tripod:
http://clarkvision.com/galleries/gal...Z3F3658-60-c-5
x-700.html



Looks good, with all the glass in between moon and sensor.
Just curious, how do you get optimal focus (any special tricks, or
multiple tries on manual)?

Bart

Bart,
The 1D Mark II autofocuses at f/8 and stacked teleconverters
only report one magnification, so with a 2x teleconverter
on the lens, f/8 is reported to the camera, then adding
the 1.4x between the 2x and camera, the camera still
sees f/8 and still autofocuses well. So I used
autofocus on the moon at f/11.2.

Roger


....
you used AUTOFOCUS?!
are you a complete retard or something?
do you have no idea whatsoever how your lense works?!

--
http://www.neopets.com/refer.phtml?username=moosespet

wrote in
oups.com:

Roger N. Clark (change username to rnclark) wrote:


http://clarkvision.com/galleries/gal...F3658-60-c-5x-
700.html

Wait for a calmer atmosphere (winter is, from my experience, the worst
- spring and fall are better) and/or stack more frames. Here is one
of mine:

http://www.photo.net/photodb/photo?photo_id=2745849

17 stacked JPEG's on a night of better than average "seeing". The
image was subject to a Laplacian sharpen post-stack, and maybe a bit
of USM after it was resized to 1280x1024 (it makes a wonderful
desktop).

For precision focus, do not depend on AF: get the Canon Angle Finder
C or equivalent and manually focus. It works _much_ better, despite
the poor quality of the "C"'s image. However, this comment is based
on Canon 10D experience; maybe the 1DMkII's AF is more trustworthy.
(And your image appears to have suffered more from turbulence than
focus.)

there's no need for autofocus at all when you're shooting something like
the moon.
geeze. this is why it's a -bad- thing to go and learn photoSHOP instead of
photoGRAPHY.
there's a little loopy symbol on your lense, you know what it is?

--
http://www.neopets.com/refer.phtml?username=moosespet

"Jon Pike" wrote in message
59...
SNIP
there's a little loopy symbol on your lense, you know what it is?

The focus-ring can rotated beyond the infinity marker, thus enabling
to compensate for thermal effects.

Bart

Jon Pike wrote:

"Roger N. Clark (change username to rnclark)" wrote
in :


Bart van der Wolf wrote:

"Roger N. Clark (change username to rnclark)"
wrote in message ...


Here is a recent attempt at photographing the moon with
a telephoto lens, on a stationary tripod:
http://clarkvision.com/galleries/gal...Z3F3658-60-c-5
x-700.html



Looks good, with all the glass in between moon and sensor.
Just curious, how do you get optimal focus (any special tricks, or
multiple tries on manual)?

Bart

Bart,
The 1D Mark II autofocuses at f/8 and stacked teleconverters
only report one magnification, so with a 2x teleconverter
on the lens, f/8 is reported to the camera, then adding
the 1.4x between the 2x and camera, the camera still
sees f/8 and still autofocuses well. So I used
autofocus on the moon at f/11.2.

Roger



...
you used AUTOFOCUS?!
are you a complete retard or something?
do you have no idea whatsoever how your lense works?!


There is no need for a response like this. You are showing
who is the retard. You are also a well known troll
who attacks with little knowledge of your subject.
Others reading can google "Jon Pike" and see this for themselves.

Jon, you obviously have no clue as to the
superb capabilities of the 1D Mark II
camera, and its auto focus accuracy. The image speaks
for itself. The pixel scale on the image is at about
the 10% MTF level of a diffraction limited system. The
Richardson-Lucey restoration I did improved the MTF
to about 50%. It would be tough to do much better
with a 5-inch aperture lens. The focus had to be
essentially perfect to achieve that image.
For me, doing images this way is also a test of the
system, as one needs to use auto focus when imaging
animals in action, which I do a lot of. With animals
in action, there is no time for manual focus.
See my bear gallery:
http://www.clarkvision.com/galleries/gallery.bear

Roger

Jon Pike wrote:

there's no need for autofocus at all when you're shooting something like
the moon.
geeze. this is why it's a -bad- thing to go and learn photoSHOP instead of
photoGRAPHY.
there's a little loopy symbol on your lense, you know what it is?

There is no need for a response like this. You are showing
who is the retard. You are also a well known troll
who attacks with little knowledge of your subject.
Others reading can google "Jon Pike" and see this for themselves.

Jon, you obviously have no clue as to the
superb capabilities of the 1D Mark II
camera, and its auto focus accuracy. The image speaks
for itself. The pixel scale on the image is at about
the 10% MTF level of a diffraction limited system. The
Richardson-Lucey restoration I did improved the MTF
to about 50%. It would be tough to do much better
with a 5-inch aperture lens. The focus had to be
essentially perfect to achieve that image.
For me, doing images this way is also a test of the
system, as one needs to use auto focus when imaging
animals in action, which I do a lot of. With animals
in action, there is no time for manual focus.
See my bear gallery:
http://www.clarkvision.com/galleries/gallery.bear

Roger

wrote in message
...
In message ,
"Bart van der Wolf" wrote:

Looks good, with all the glass in between moon and sensor.

Teleconverters seems to be very easy, engineering-wise, compared to
regular lenses. Contrary to popular opinion, most halfway-decent
teleconverters do not compromise the prime lens in any significant
way;
they merely stretch the center of the focal plane over a larger
area,
exposing the limitations of the prime.

That's correct, and the moon will be in the center of the image.
However, the converter/extender still requires a good lens in front of
it, otherwise it just magnifies rubbish.

Bart