Manual focusing for moon picture

After getting some good responses for taking pictures of the moon, I gave it
a try last night with a half moon showing. I need to spend more time at
this, but I did get one shot that was not bad. I was using a 300mm
(actually 480mm due to 1.6x) telephoto (75-300mm lens) with my Rebel using
f/5.6 and an exposure time of 1/30.

The one good picture showed a surprising amount of detail. The problem was
that it was slightly out of focus. Any suggestions on how to do a better
job focusing in this situation? I was using manual focus. After taking the
picture, I could use the LCD zoom feature and it looked reasonable. When I
got the image on my computer, I could tell it was not as good as it could
have been. I have found that with this camera, it does a much better job at
auto-focusing than I can do manually. Should I auto-focus to some object in
the distance and then switch it to manual leaving the focus alone for a moon
picture? Maybe an f/8 with a slightly longer exposure time? I don't think
my exposure time was too slow thereby allowing the moon to move because I
didn't see any blurring around the edge.

Jeff

"Jeff Durham" wrote in message
...
auto-focusing than I can do manually. Should I auto-focus to some object
in
the distance and then switch it to manual leaving the focus alone for a
moon
picture? Maybe an f/8 with a slightly longer exposure time? I don't
think
my exposure time was too slow thereby allowing the moon to move because I
didn't see any blurring around the edge.


Why not auto-focus on the moon itself? It's clear and bright enough.

I am pretty certain I tried that and the camera failed to auto focus on it.
It was a half moon and I was doing this from my backyard with some light
coming from neighboring houses and my own. I will try this again from a
darker location and try out the auto focus again.

Jeff


"Mick Sterbs" wrote in message
...

"Jeff Durham" wrote in message
...
auto-focusing than I can do manually. Should I auto-focus to some
object
in
the distance and then switch it to manual leaving the focus alone for a
moon
picture? Maybe an f/8 with a slightly longer exposure time? I don't
think
my exposure time was too slow thereby allowing the moon to move because
I
didn't see any blurring around the edge.


Why not auto-focus on the moon itself? It's clear and bright enough.

On Thu, 24 Jun 2004 14:08:03 GMT, "Jeff Durham"
wrote:

After getting some good responses for taking pictures of the moon, I gave it
a try last night with a half moon showing. I need to spend more time at
this, but I did get one shot that was not bad. I was using a 300mm
(actually 480mm due to 1.6x) telephoto (75-300mm lens) with my Rebel using
f/5.6 and an exposure time of 1/30.

The one good picture showed a surprising amount of detail. The problem was
that it was slightly out of focus. Any suggestions on how to do a better
job focusing in this situation? I was using manual focus. After taking the
picture, I could use the LCD zoom feature and it looked reasonable. When I
got the image on my computer, I could tell it was not as good as it could
have been. I have found that with this camera, it does a much better job at
auto-focusing than I can do manually. Should I auto-focus to some object in
the distance and then switch it to manual leaving the focus alone for a moon
picture? Maybe an f/8 with a slightly longer exposure time? I don't think
my exposure time was too slow thereby allowing the moon to move because I
didn't see any blurring around the edge.

Jeff


I have found that most tel-adapters are not afocal with the main
lens (afocal meaning no-refocusing needed). Manually focusing the
main lens to infinity while using a telephoto adapter is usually a
sure way to get an out of focus picture. Rely on auto-focusing to
confirm this, reading off what focal distance the camera found best.
Then learn to use that setting for future shots. You might also want
to bracket your focus a little as an experiment to see if you can do
slightly better than auto-focus (I found this to be especially true
on shots of the moon, even during an lunar eclipse. On my camera
with a telephoto adapter, I found best infinity focus to be about
23-27 ft. varying with the f/stop and brightness/contrast of
subject.) You will also get a sharper image if you don't use either
an extremely small or large settings of the f/stop of your lens. The
smaller f/stops in digital cameras are at the limits of the physics
of light and softness will be introduced by diffraction of the
wavelengths of light. The larger apertures incorporate more glass
and are prone to error from more reflective scatter and (normally
insignificant) errors in lens quality.

It will be a process of trial & error to find the best settings in
focus and f/stop for a telephoto image of the moon.


(The above problems are also true when doing infra-red photography
with the main camera lens alone. I found that on my camera I need to
focus at about 28 inches for day-lit scenery normally needing an
infinity setting. A surprising amount of compensation.)

"Jeff Durham" wrote in message
...
After getting some good responses for taking pictures of the moon, I gave
it
a try last night with a half moon showing. I need to spend more time at
this, but I did get one shot that was not bad. I was using a 300mm
(actually 480mm due to 1.6x) telephoto (75-300mm lens) with my Rebel using
f/5.6 and an exposure time of 1/30.

The one good picture showed a surprising amount of detail. The problem
was
that it was slightly out of focus. Any suggestions on how to do a better
job focusing in this situation? I was using manual focus. After taking
the
picture, I could use the LCD zoom feature and it looked reasonable. When
I
got the image on my computer, I could tell it was not as good as it could
have been. I have found that with this camera, it does a much better job
at
auto-focusing than I can do manually. Should I auto-focus to some object
in
the distance and then switch it to manual leaving the focus alone for a
moon
picture? Maybe an f/8 with a slightly longer exposure time? I don't
think
my exposure time was too slow thereby allowing the moon to move because I
didn't see any blurring around the edge.

Jeff

You can't do better than setting the focus at infinity.

"Jeff Durham" writes:

The one good picture showed a surprising amount of detail. The problem was
that it was slightly out of focus. Any suggestions on how to do a better
job focusing in this situation? I was using manual focus. After taking the

This is a surprise. Did the moon look in focus when you were composing the
photo? I'd look for other reasons for blur.

I shoot 35mm slides, so I'm not sure how to make this formula work in
digital:
e = 600/fl
where e is the exposure time in seconds and fl is the focal length of the
lens.

So for 35mm and a 480mm lens, e = 600/480 = 1.25 secs is the maximum time
before the moon (and stars) begin to blur from movement. Your exposure
_seems_ to be within that limit (again, whether this formula applies at all
in LCDs with the magnification factor is a mystery to me, but it's a
starting point). I'd look at the tripod. Did you kick it? Is it rock
stable? When you triggered the exposure, did you jiggle the camera?

The other thing is to take some photos of very distant objects after manual
focussing. It may be that the camera or lens is slightly out of whack (my
camera wouldn't focus on infinity, and the lens mount had a screw loose,
making the mount itelf the wrong distance from the film plane). Maybe you
thought you'd focussed on infinity and just missed it.

Try, try again.

--
Philip Stripling | email to the replyto address is presumed
Legal Assistance on the Web | spam and read later. email to philip@
http://www.PhilipStripling.com/ | my domain is read daily.

"Jeff Durham" wrote in
:

After getting some good responses for taking pictures of the moon, I
gave it a try last night with a half moon showing. I need to spend
more time at this, but I did get one shot that was not bad. I was
using a 300mm (actually 480mm due to 1.6x) telephoto (75-300mm lens)
with my Rebel using f/5.6 and an exposure time of 1/30.

The one good picture showed a surprising amount of detail. The
problem was that it was slightly out of focus. Any suggestions on how
to do a better job focusing in this situation? I was using manual
focus. After taking the picture, I could use the LCD zoom feature and
it looked reasonable. When I got the image on my computer, I could
tell it was not as good as it could have been. I have found that with
this camera, it does a much better job at auto-focusing than I can do
manually. Should I auto-focus to some object in the distance and then
switch it to manual leaving the focus alone for a moon picture? Maybe
an f/8 with a slightly longer exposure time? I don't think my
exposure time was too slow thereby allowing the moon to move because I
didn't see any blurring around the edge.

Focus on a distant treeline in daylight and use two pieces of masking
tape, one on the fixed lens barrel, one on the focus ring, to make a
matching mark between the two for 'infinity' focus. Use this as your
starting point.

Do not trust the stopping point of the focus ring. Most zooms
nowadays extend beyond the optimal infinity mark and begin to defocus
again. So you're going to semi-trust your eyes in good conditions.

When the moon's out again, use this mark as your focus point. But
also shoot a couple of frames slightly to either side of this mark,
'bracketing' it. This way you have a little bit of leeway in your original
determination of infinity focus.

Also, Canon's 75-300 is slightly soft wide open at 300mm, but it
improves greatly as you stop the aperture down. Shoot a few frames at f8
and f11, adjusting shutter speed and/or ISO accordingly, and see if you
don't coax some improvement from it.

Use a flashlight to examine the lens frequently for condensation,
too. If it's humid, do NOT switch the lens outdoors - you could introduce
condensation onto an interior lens element and this takes forever to clear.
Also, if it's a warm night and your equipment has been stored in cooler
areas (like air conditioning), allow a half hour or better outdoorsm fully
capped, for the lenses to reach ambient temperature before trying to use
them. And don't assume this will prevent condensation - astronomers know
glass will collect humidity in the right conditions no matter how long it's
been acclimated to them.

Good luck!


- Al.

--
To reply, insert dash in address to separate G and I in the domain

I am very new to this camera and lens. Here is a dumb question. How do you
set this lens to infinity? It is a Canon 300D with a Canon EF 75-300mm
lens. I can crank the focus ring all of the way down, but things at a
distance are not in focus. I have to back it off some to go back to focus.

Through the viewfinder, I got the moon in reasonable focus. It is only when
I went to look at the image on my computer that I could see that it was
slightly out of focus. Soon, I will have a website up to start posting
pictures because the picture says it all. It is hard to see the detail
through the lens with the camera mounted on the tripod looking up 45 degrees
into the sky to know that it is in focus. :-)

At this point, I would say it is my focusing ability rather than the lens
and camera other than the lens being touchy to focus. The other evening, I
took a few pictures of a distant object at night. With manual focus, I
noticed the end result being slightly out of focus when reviewing the
picture on my computer where the camera's autofocus was dead on.

Jeff


"Phil Stripling" wrote in message
...
"Jeff Durham" writes:

The one good picture showed a surprising amount of detail. The problem
was
that it was slightly out of focus. Any suggestions on how to do a
better
job focusing in this situation? I was using manual focus. After taking
the

This is a surprise. Did the moon look in focus when you were composing the
photo? I'd look for other reasons for blur.

I shoot 35mm slides, so I'm not sure how to make this formula work in
digital:
e = 600/fl
where e is the exposure time in seconds and fl is the focal length of the
lens.

So for 35mm and a 480mm lens, e = 600/480 = 1.25 secs is the maximum time
before the moon (and stars) begin to blur from movement. Your exposure
_seems_ to be within that limit (again, whether this formula applies at
all
in LCDs with the magnification factor is a mystery to me, but it's a
starting point). I'd look at the tripod. Did you kick it? Is it rock
stable? When you triggered the exposure, did you jiggle the camera?

The other thing is to take some photos of very distant objects after
manual
focussing. It may be that the camera or lens is slightly out of whack (my
camera wouldn't focus on infinity, and the lens mount had a screw loose,
making the mount itelf the wrong distance from the film plane). Maybe you
thought you'd focussed on infinity and just missed it.

Try, try again.

--
Philip Stripling | email to the replyto address is presumed
Legal Assistance on the Web | spam and read later. email to philip@
http://www.PhilipStripling.com/ | my domain is read daily.

I will give your suggestions a try. I am in full manual mode and using a
tripod. I will also try the autofocus again. This could be just an
overexposure situation.

Thanks,
Jeff

"Jim Townsend" wrote in message
...
Jeff Durham wrote:

After getting some good responses for taking pictures of the moon, I
gave it
a try last night with a half moon showing. I need to spend more time at
this, but I did get one shot that was not bad. I was using a 300mm
(actually 480mm due to 1.6x) telephoto (75-300mm lens) with my Rebel
using
f/5.6 and an exposure time of 1/30.

You should be using about 1/60 @ f/16 for a half moon at
ISO 100..

I suspect your image is slightly overexposed rather than out of
focus. (Canon has an excellent autofocus system).. Overexposure will
blow out the white areas causing a lack of detail.

Are you shooting in full manual ? You have to in order to photograph
the moon. This is because of the way it meters light. Your camera
doesn't have spot metering and a lot of black sky is being averaged
into the automatic exposure system. The black sky makes the
camera think there is less light despite the moon being very
bright.

Take a few shots starting at what I suggested and then some with
increased and decreased exposure times. Keep the best ones :-)

Finally, Are you using a tripod ? You *won't* get clear shots at 1/30 -
1/60 second without one..

"Jeff Durham" wrote in message . ..
After getting some good responses for taking pictures of the moon, I gave it
a try last night with a half moon showing. I need to spend more time at
this, but I did get one shot that was not bad. I was using a 300mm
(actually 480mm due to 1.6x) telephoto (75-300mm lens) with my Rebel using
f/5.6 and an exposure time of 1/30.

The one good picture showed a surprising amount of detail.

Can we see it?

The problem was
that it was slightly out of focus. Any suggestions on how to do a better
job focusing in this situation? I was using manual focus. After taking the
picture, I could use the LCD zoom feature and it looked reasonable. When I
got the image on my computer, I could tell it was not as good as it could
have been.

That's a major problem with the Canon, it uses a 25% size JPEG
thumbnail for the LCD display, making proper assement of focus
impossible. The other major problem is auto focus play. Not a great
combo.

I have found that with this camera, it does a much better job at
auto-focusing than I can do manually. Should I auto-focus to some object in
the distance and then switch it to manual leaving the focus alone for a moon
picture? Maybe an f/8 with a slightly longer exposure time? I don't think
my exposure time was too slow thereby allowing the moon to move because I
didn't see any blurring around the edge.

Anytime you are on a tripod at night shoot desired daytime parameters
if at all possible--i.e. always ISO 100 and generally f6.7-9.5, but
that is lens dependent.