Recommendations on taking a picture of the moon

(Fred McKenzie) wrote:

By the way, I don't think a telescope makes a very good lens - just a
relatively cheap way to get a long focal length. Use of a good photographic
lens may produce a sharper image when enlarged, than a longer telescope that
requires less magnification.

It depends on the telescope (price is a good indication), but in
geneal, you are correct.

Also, it is hard to manually focus some
telescopes (like mine!), and autofocus does not work for small f/stops. I
think you need f/8 or larger for AF to work.

Focus is a bitch. Professional and high-end amateur astronomers use
motorized systems (with readouts) that do micro-steps as they monitor
image output. After even one night of trying to focus a camera on the
night sky is enough to know why ...

It would be interesting to know if the Canon EOS mount can be used in
a manner like this. Does the body know where the lens "is"? (I'd
guess not though.)

Anyways, the next best thing is to cover your aperture with a piece of
paper with two or three holes cut in it. Out of focus stars (which
are the only reliable target focus) show up as multiple images.
Tweak focus until they merge into one. Remove the mask and start
imaging. See www.google.com: hartmann mask

A viewfinder magnifier is a help here. I splurged on the Canon Angle
Finder C, which does the magnification trick (2.5x), but also serves
as a neck-saving right-angle viewfinder. Sadly, the optical quality
of this implement leaves alot to be desired ...

The moon is a big gray rock in direct sunlight. Because of the contrast
between the moon and the background night sky, you may not be able to use the
camera's auto exposure system.

This is hardly an issue with a digital camera: start with the
camera's AE recommendation and just keep tweaking the exposure until
you like the pictures.

It would be interesting to know if the Canon EOS mount can be used in
a manner like this. Does the body know where the lens "is"? (I'd
guess not though.)

eawckyegcy-

I'm not sure I understand your question. I had a T-Mount adapter for my old
telescope (Celestron C-90) from use with the old Olympus OM-2. The Canon
Digital Rebel only needed the matching EOS-to-T-Mount adapter, which the camera
store had in stock.

For pictures of the moon and/or the stars, auto exposure is not likely to work.
I used full manual control for the moon shots. For daytime terestrial shots,
I use the setting where you select the f/stop and the camera's autoexposure
system selects the shutter speed.

The camera certainly does not know where the lens f/stop is set. It only knows
how much light is hitting the sensor.

Fred

"Jeff Durham" wrote in message ...
Thanks for the site recommendation. That is exactly what I was looking for.
I was hoping that it would not take a big telephoto lens, but it does. From
the images produced, 800mm does a reasonable job, but 1600mm or bigger is
much better.

Focal length is important but overall optical resolution and subtle
color accuracy of the system is the really important thing. See...

http://www.pbase.com/imageprocessing/foveon_color_moon

"Jeff Durham" wrote in message ...
Thanks for the site recommendation. That is exactly what I was looking for.
I was hoping that it would not take a big telephoto lens, but it does. From
the images produced, 800mm does a reasonable job, but 1600mm or bigger is
much better.

Focal length is important but overall optical resolution and subtle
color accuracy of the system is the really important thing. See...

http://www.pbase.com/imageprocessing/foveon_color_moon

Georgette Preddy wrote:

"Jeff Durham" wrote in message ...

Thanks for the site recommendation. That is exactly what I was looking for.
I was hoping that it would not take a big telephoto lens, but it does. From
the images produced, 800mm does a reasonable job, but 1600mm or bigger is
much better.


Focal length is important but overall optical resolution and subtle
color accuracy of the system is the really important thing. See...
this warning:

The person posting under the name of George or Georgette Preddy (and
other pseudonyms) has an ungrounded but zealous faith that current
implementation of the Foveon chip is superior to all other chip
technologies. He will cite portions of reviews to ostensibly support his
claims, and will repeat, ad naseum, complete lines of out-of-context
material.

His claims may well be ignored, or at the very least verified since most
of them are extreme distortions and some are out and out fabrications."


Moreover, "Mr." "Preddy" has claimed to be a photographer (pro!), but
cannot bring himself to post a single picture with EXIF info that he
shot himself, in spite of repeated requests and challenges to do so.

Apparently he loathes anything related to Canon and loves everything
about Sigma cameras and lenses. His "claims" may be ignored, and he is
doing Sigma, and anyone related to the Foveon chip, no good at all by
arousing ire, increasing the N/S ratio, and generally spamming this
newsgroup.

--
John McWilliams