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Author Topic: shooting the moon  (Read 20493 times)
howard smith
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« Reply #20 on: September 21, 2005, 05:17:44 AM »
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Jan, if you didn't use a polarizer, your exposure is "Moony/8."  It appears that Sunny/16 + 8 stops would be a white disc.  If the image size is small, maybe a lack of detail might not be noticed.
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jani
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« Reply #21 on: September 21, 2005, 05:27:33 AM »
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Jan, if you didn't use a polarizer, your exposure is "Moony/8."  It appears that Sunny/16 + 8 stops would be a white disc.  If the image size is small, maybe a lack of detail might not be noticed.
Unfortunately, I have no recollection of what I used for that exact shot. I know that some of the images I took of the Moon in January/February were with a polarizer, but I stupidly forgot to take a note of that.
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Jan
rags
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« Reply #22 on: September 21, 2005, 10:59:37 AM »
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Even though the moon is essentially at infinity keeping the lens at infinity doesn't seem to give a sharp image. I say this from my exprience last weekend and to see a sharp image in the viewfinder I have to rotate the focus ring very slightly away from infinity!
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howard smith
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« Reply #23 on: September 21, 2005, 11:26:00 AM »
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Perhaps the focus issue of the moon is due to the air-vacuum interface not present in teresterial photos or an infinity error in the lens.  If nothing else, we can all agree that the moon is at photographic infinity.
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dandill
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« Reply #24 on: September 21, 2005, 11:55:18 AM »
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I have found Focusing for Astrophotography helpful.

Dan
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Dan Dill
Jonathan Wienke
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« Reply #25 on: September 21, 2005, 12:18:38 PM »
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I say this from my exprience last weekend and to see a sharp image in the viewfinder I have to rotate the focus ring very slightly away from infinity!
That's due to the fact that many lenses (all Canon-brand glass that I've seen or tried) allows the focus ring to mechanically travel a little past the infinity focus position. This allows compensation to be made for factors that affect infinity focus position like temperature (and the resulting expansion & contraction), barometric pressure (which makes corresponding changes in air density) an other physical factors that can affect the precise position of exact infinity focus.
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howard smith
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« Reply #26 on: September 21, 2005, 12:36:21 PM »
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That ought to do it.  "Infinity" isn't infinity but a little past infinity.  I couldn't resist.
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Anon E. Mouse
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« Reply #27 on: September 21, 2005, 07:46:39 PM »
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The atmoshere does not cause a shift in focus. The moon will alway be at infinity. The atmoshere can distort the image of the moon at the horizon (flattening), but apparent size of the moon is the same no matter its position above the horizon. Turbulence in the atmoshere will also shift the image of the moon causing soft, blurred details. It is posible to stack multiple short exposures to reduce the affects of turbulance with progams like Registax. This is a common technique in astrophotography.

The moon is a bright object and can be visible at almost any time of day. However, exposures can vary with the phase of the moon and its relative position above the horizon.
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Buddy Thomason
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« Reply #28 on: September 23, 2005, 06:09:18 PM »
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I too love to 'shoot the moon.'  I have learned that I must use a shutter speed of 1/15 or faster.  I have also learned that on different nights, though the eye cannot tell a difference, there is a large variation in clarity of atmosphere - astrophotographers and astronomers know this.  As a result I try to be prepared to capture different sorts of images as illustrated below:  
1) Very clear (to the camera) night (blue fringing is my error in post-processing).
http://www.fototime.com/219C138DFEB9C38/orig.jpg  
2) Looked clear but the camera said not, so I opted to over-expose the moon itself and get the clouds around it as it began to rise above horizon.  
http://www.fototime.com/B67FD93BDD3141C/orig.jpg  
http://www.fototime.com/B8F981617DB3FF9/orig.jpg  
3)  Sometimes I'm just happy to stand in the back yard and experiment.  
http://www.fototime.com/DEC922845EDD524/orig.jpg  
4)  Sometimes I can even find a use for poor shots of the moon if they have a virtue I can use in, for example, CD jewell-case cover art for sharing with friends (ie not for publication)  
http://www.fototime.com/EB99DCFFA1A0F5E/orig.jpg  

And finally I have learned that, at least for my dyslexic self, instead of trying to remember pat formulas for lunar exposure I just start firing away, checking my LCD screen for histogram and focus, adjusting shutter speed, aperture and/or ISO as needed until I start closing in on something that looks good.  

As mentioned above, I have given up trying to use autofocus.  It's manual exposure, manual focus (to just a little shy of infinity), tripod, mirror lock-up, 2 sec delay and cable release all the way for me.

The Canon 500 f4.0 L with 1.4 extender and my 1D MKII, appropriately mounted  on top of my tripod with carbon fiber legs is the cat's meow set-up as far as I can tell.  The backyard shot above that's obviously way compensated was captured with the same camera and tripod but with the Canon 70-200 f2.8 L zoom.  

Shooting the moon, because of its unique challenges, has taught me some good stuff and given me more confidence in other wierd situations.  

Happy exposures!
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Lin Evans
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« Reply #29 on: September 28, 2005, 06:36:33 PM »
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ISO 100 - F14 - 1/50 sec

Lin

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Lin
Anon E. Mouse
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« Reply #30 on: September 28, 2005, 06:49:37 PM »
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Lin, what did you use to take that?
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Lin Evans
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« Reply #31 on: September 28, 2005, 07:25:44 PM »
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Lin, what did you use to take that?
Hi Anon,

A Canon D30 using a Meade ETX-90 celestial mirror (scope) which has a fixed F14 aperture and 1250mm focal length. With the 1.6x reduced FOV of the D30 it's a 2000mm FOV equivalency.

Best regards,

Lin
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Lin
Anon E. Mouse
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« Reply #32 on: September 28, 2005, 07:31:20 PM »
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Excellent. It is amazing what you can do with these small Maksutov Cassegrain telescopes. That must have been a great night. The seeing where I live is awful most of the time.
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Lin Evans
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« Reply #33 on: September 28, 2005, 07:47:07 PM »
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Excellent. It is amazing what you can do with these small Maksutov Cassegrain telescopes. That must have been a great night. The seeing where I live is awful most of the time.
Yes, here in Colorado in the winter we have some good atmospheric conditions on clear nights. The Meade works well for "digiscoping" either for moon/planets or for terrestrial purposes though I frequently use my Swarovski ST-80HD as a lens as well. The moon is always a fun target and a challenge at times. I've always admired photographers who can capture a good "moonscape" and get both the terrestrial details and the moon both in proper exposure. The only way I've ever managed to do it justice is by shooting two frames RAW without moving the camera, exposing one for the moon and one for the earth then combining the two in PhotoShop. Ansel did it well with "Moonrise, Hernandez New Mexico" but the shot was actually taken during daylight hours and then he dodged, burned and used chemical intensifiers to get everything looking like a late evening shot. The problem is that if you expose long enough at night to get the terrestrial details right then the moon is way overexposed. If you expose for the moon you have to deal with trying to pull details from deep shadows - not an easy task...

Lin
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Lin
dandill
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« Reply #34 on: September 28, 2005, 08:02:18 PM »
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Hi Lin.

Can you give details of how you used the D30 with the telescope? Attachment? Focus?

Thanks
Dan
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Dan Dill
Lin Evans
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« Reply #35 on: September 28, 2005, 08:55:02 PM »
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Hi Lin.

Can you give details of how you used the D30 with the telescope? Attachment? Focus?

Thanks
Dan
Hi Dan,

Meade has a dedicated camera port which accepts a Meade "T" adapter which in turn accepts a standard Canon "T" connector so that the camera body is directly connected to the scope. No electronic communication then is possible between the "lens" and camera body so that all settings must be made manually. The Meade has a "flip" switch which transfers the view from the eyepiece to the camera port so that looking through the viewfinder on the camera allows the photographer to see the subject. Focus is accomplished with the same focus knob as used to focus the telescope. Once focus has been set the Canon remote release is used to first lock up the mirror, then after approximately a four second period for damping vibrations the second press of the remote release trips the shutter. Because the Meade has motorized tracking the moon is still within the proper frame and the capture is made.

Best regards,

Lin
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Lin
dandill
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« Reply #36 on: September 29, 2005, 10:04:15 AM »
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Focus is accomplished with the same focus knob as used to focus the telescope.
Is any focusing of the camera necessary? Or do you set it to infinity and then fine tune with the Meade focus?
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Dan Dill
howard smith
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« Reply #37 on: September 29, 2005, 11:33:56 AM »
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I have been looking around at Moon photos.  Many are over exposed.  The moon appears brighter than it really is because it is the brightest thing around at night.  The moon is gray than many images show.  I still like sunny/16 with perhaps a little extra exposure for atmospheric effects.
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Lin Evans
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« Reply #38 on: September 29, 2005, 04:26:23 PM »
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Focus is accomplished with the same focus knob as used to focus the telescope.
Is any focusing of the camera necessary? Or do you set it to infinity and then fine tune with the Meade focus?
You can't set it to "infinity" because there is no lens other than the telescope. The "T" connector attaches to the camera body on one side and to the Meade "T" adapter which is attached to the scope on the other side. The camera's lens with an SLR or dSLR has been removed and replaced by the telescope.

If you are using a fixed lens digicam and shooting through a telescope eyepiece, then you would first adjust the focus on the scope, then on the camera then again on the scope and again on the camera until you had the best focus possible. This is called an "afocal" connection.

Best regards,

Lin
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Lin
dandill
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« Reply #39 on: September 29, 2005, 04:45:50 PM »
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The camera's lens with an SLR or dSLR has been removed and replaced by the telescope.
Got it! Thanks again.

Dan
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Dan Dill
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