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Author Topic: Shooting the Moon  (Read 23631 times)
gwarrellow
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« Reply #20 on: February 17, 2004, 11:20:40 AM »
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Assuming one is using a camera telephoto lens and not a telescope.
I'm sorry Ray I don't understand.  Your initial comment indicated that the other cameras would "outperform" the 1Ds but I have the impression that your talking about image scale rather than quality.  Is that right?  Remember the 1Ds has significantly more pixels to play with so much more opportunity for cropping.
Regards,
Graham
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Howard Smith
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« Reply #21 on: February 19, 2004, 01:19:21 PM »
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If you use Adams' "Exposure Formula,"  then the "sunny 16" would be 1/16 @ 1/250.  His key f/stop is the square root of the film speed.   16 squared is 256 (or 250 to photographers).  So f/16 @ 1/250 using ISO 250 would put his moon in Zone V.  Give it 2 stops more exposure to put the moon in Zone VII, you get f/16 @ 1/60.  Add about 1 1/3 stops to go to ISO 100, f/11 @ 1/80.  That's well within a third stop of BJL's f/11 @ 1/100 for ISO 100 setting.  The sunny-16 would give a stop less exposure (f/16 @ /100) which is likely adequate and would give a much more pleasing result than the washed out white disc.

Ray, I don't think you have missed anything except Zone VIII pushing over exposed.  I don't know the dynamic range of your digital camera, but on chrome film, the moon would be getting prety close to blown out.  For slide film with a small dynamic range, maybe f/11 @ 1/ISO would be pretty good.

In his discussion of "Moon and Half Dome," Adams says that for moon exposures at night (not late evening which is the time the above dicussion is about), his exposures range between Zone IV thru Zone VIII and the details will be "subdues or exaggerated as desired."  But again, Adams is talking about black and white film with maybe 10 or 11 stops of latitde as apposed slide film with 5ish stops.  So Zone VIII is getting pretty far up for color film.  "as desired" says there is some latitude in personal taste.
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Howard Smith
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« Reply #22 on: February 18, 2004, 01:29:12 PM »
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The photo is "Moonrise" over Hernandez.  It is detailed in "Examples, The Making of 40 Photographs."

Adams said he knew the moon had a liminance of 250 c/ft2.  He used this and the Exposure Formula to determine his exposure.

The Exposure Formula is discussed in "The Negative" by Adams.  It says that the key f/stop is the square root of the film speed.  The shutter speed is the reciprical of the luminance in c/ft2.  This will place the subject in Zone V.  He exposed the moon for Zone VII, which he claims is ideal.  (The modern problem is not many meters read in c/ft2.)

In the discussion of "Moon and Half Dome," Adams provides some information on selecting the exposure for the moon in the evening and in the dark.
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Howard Smith
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« Reply #23 on: February 20, 2004, 09:12:54 AM »
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What I was trying to say was:

Adams exposed for the moon and let the landscape fall where ever.  He then tried to salage the landscape as much as possible while developing the negative.  He still had a difficult to print negative.  He even itensified the lower part of the negative later to help.

More commonly, photographer expose for the landscape and let the moon fall where ever, usually over exposed.  Not much can be done to help an over exposed moon during processing or printing.  No detail is no detail.
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Howard Smith
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« Reply #24 on: March 12, 2004, 09:56:27 AM »
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Scott, Ansel Adams' exposure formula would give f/14 @ 1/250.  That is about 1 2/3 stops less than your image.  I would have given about a stop less exposure.

With film, it is my experience that the ISO isn't as fast as the manufactorer claims in order to suit my tastes.  Most filmsI find are about 2/3s of a stop slower.  Do you know if digital camera subject to the same "over rating?"
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scott kirkpatrick
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« Reply #25 on: March 13, 2004, 04:16:16 PM »
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I think I got it rightside up, so that the darker areas look like a rabbit (the Chinese interpretation).  I've seen it come up the other way when you use a good telescope and view with the camera's lens through the telescope objective, as in this very impressive shot:

http://www.dpreview.com/forums/read.asp?fo...message=3094625

Or perhaps you are right and things look different from Oz.

scott
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Richard Dawson
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« Reply #26 on: February 08, 2004, 12:24:43 AM »
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You might find this article useful.

 http://www.u-net.com/ph/mas/observe/lunar-p/lunar-p.htm

Richard
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b.e.wilson
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« Reply #27 on: February 08, 2004, 09:40:06 AM »
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Since moon exposures are about the same as you'd use for a bright day, typical exposures of the moon at night will include no detail of the sky or the foreground at all.

Many images of the moon in its surroundings are faked by taking a shot of a night scene (exposed properly for a night scene) and dropping in a properly-exposed image of the moon. If the moon is added close to its original size, position, and orientation, it doesn't look too bad. It's tricky to do if you want the interaction of moonlight and clouds near the moon, however, and maybe a three-stop ND grad could help. Shame nobody produces a spot ND that would bring the moon brightness down to match the surrounding brightness. That'd be fun to play with.
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gwarrellow
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« Reply #28 on: February 08, 2004, 12:04:44 PM »
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Exegeter,

Let me suggest you stop your lens down to f4 or f5.6 and try shooting the moon in twilight. You may have more chance of correctly exposing both the moon and any clouds but you will need to experiment.

If you are looking for a good lunar photo opportunity then there are two nice ones coming up this month. On Feb 23 the crescent moon and Venus will be close together and on Feb 25th the crescent moon and Mars are very close at dusk.

I have downloaded the Michael Oates exposure calculator from the website Richard mentioned earlier and printed it onto photo quality paper. It's nice and simple to put together. Using the calculator it seems that an exposure of around f5.6, 1/30, ASA100 should do the trick for the Venus and Mars conjunctions I mentioned above.

Graham
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DMcLarty
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« Reply #29 on: February 08, 2004, 09:07:02 PM »
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I have been out in to the cold the last two full moons and taken a number of shots

here a couple of examples of my results. This one was taken later at night after the moon had risen past the lower clouds and atmospheric gasses


Setting for this one were
Date/Time: 2003:12:09 20:58:36 Minus 32 C Huh
Shutter speed: 1/125 sec
Aperture: 14.0
Exposure mode: Manual
Self-timer: 10 secs & Mirror locked up to allow the canera and lens to stop vibrating.
ISO: 200
Lens: 500.0 mm plus 1.4 x
AF mode: Manual Focus
Tripod etc.

The second a combination of two images taken just before the moon set at 09:30 am is more likely what needs to be done to get clouds and moon all in one image. I used PS to blend the two images together. Micheals Tutorial is great for this.



The first shot settings was at
Shutter speed: 1/30 sec the second shot for the land exsposure was 1/20 sec
Aperture: 11.0
Exposure mode: Manual
Self-timer: 2 secs Mirror locked up
ISO: 200
Lens: 500.0 mm

To get both the clouds and moon as you want in the samples you pretty well need blend two images together. Expose one for the moon and then one for the clouds. You will notice the moon does move quickly at higher magnifications so if you have a land mark in the image you may find blending will be harder.
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Howard Smith
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« Reply #30 on: February 09, 2004, 03:40:17 PM »
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Re you getting"bellows extension factor" mixed up with magnification by focal length?
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Howard Smith
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« Reply #31 on: February 10, 2004, 09:59:00 AM »
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OK.   The moon is on the order of 15 BILLION inches away.  So, M is about 6x10(-11).  Even if you assume the moon is 3000 miles away, M would be about 5x10(-9).  I have never thought of that as a "correction factor" considering the accuracy and repeatability of the shutter speed,  f/stop, meter reading (or rule of thumb), effects of the atmosphere and film speed, and the practicality that exposure within a quarter stop is plenty close enough.  No exposure correction is needed - even as a matter of degree or because you used the sunny-16 rule instead of any light meter.  Besides, you just cannot physically do it.

The error in correctly exposing the moon using a TTL, even a fairly small spot, is large because the meter will be reading a lot of black.  The calculated exposure will try to make that gray, so the moon will be over exposed.

The exposure guideline given above by Graham is sunny-16 plus 4 2/3 stops.  The conclusion would be that sunny-16 doesn't work all that well all the time.  There are a lot of variables to deal with (magnification not being one of them).

The two samples given by DMcLarty I would judge to be over exposed, maybe a stop and a half for the first, maybe more for the morning moon.
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Ray
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« Reply #32 on: February 15, 2004, 06:42:08 PM »
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Oh! I forgot to add, if it's just the moon you're after, this is one of those occasions when both the 10D and SD10 will outperform the 1Ds. Just thought I'd slip that one in, to clear the waters.  Cheesy
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Ray
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« Reply #33 on: February 17, 2004, 06:26:44 PM »
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Okay! Here's my reasoning. I hope I'm not falling into one of those counter-intuitive traps, so you'll have to check my maths.  Cheesy

The data I used for the basis of these calculations I got from the Dpreview site, ie. the D60 sensor has 135 pixels per mm, the 1Ds sensor 113.5 pixels per mm and the SD9/10 sensor 109.5 pixels per mm. (I'm referring here to full pixels containing red, green and blue elements whether interpolated or not.)

Measuring the diameter of the moon on my shot with D60/400mm combination, I find it's 3.78mm on the sensor, which translates to 510 pixels in diameter on the D60, 429 pixels on the 1Ds and 414 pixels on the SD10 sensor (using the correct terminology describing the SD10 as a 3.43MP camera).

Since it's been established that the SD9 outresolves the D60 by a noticeable margin, we can make the satement that one SD9/10 pixel has the value of two D60 pixels for any given area of sensor.

Since it's been established, on this forum at great length, that the Canon 10D does indeed exhibit higher resolution than the 1Ds when using identical lenses on both cameras, I think it's a fair assumption to make that one SD10 pixel is also worth two 1Ds pixels.

To normalise the figures for all three cameras, we get 510 pixels across the moon diameter with the D60, 429 pixels with the 1Ds and 414 x (square root of 2) = 580 pixels with the SD10.

Now I'm sure everyone would be prepared to accept that a moon that's 580 pixels wide will have significantly higher resolution that the same moon that's only 429 pixels wide.

Okay! 400mm is not particularly long. I believe the longest lens that would fit all three cameras would be the Sigma 800mm. The moon now becomes 7.56mm in diameter on all three sensors. Let's add a 2x extender. It becomes 15.12mm in diameter. Oops! The SD10 is now cropping the image and the D60 is borderline. (However, if it isn't a full moon, you'd probably still fit it in the frame  Cheesy ).

Even if we compare the 1Ds/800mm/2x combination with the SD10/800mm/1.4x combination, we're comparing 1427 SD10 pixels with 1716 1Ds pixels. The images might be on a par, but it's doubtful. A 1.4x extender at best offers a marginal improvement. A 2x extender is even more marginal. Those extra pixels in the 1Ds image would not be doing much.

I rest my case. Thanks for giving me the opportunity to exercise my mind with some basic maths, and I'm sure you'll point out any errors in my reasoning  Cheesy .
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BJL
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« Reply #34 on: February 18, 2004, 12:15:15 PM »
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Ansel Adams produced one of the most famous moon photographs; I forget the title, but I mean the one in New Mexico with gravestones in the foreground lit by the last of the setting sun and some details in clouds too. Adams has written a detailed discussion of his exposure decisions (with no light meter available!) that kept detail in all the main elements, and it has been reproduced in various books, both his own, and volume 1 of the "Ansel Adams" books by Schaeffer. I will try to dig up a detailed reference.
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BJL
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« Reply #35 on: February 19, 2004, 08:54:17 AM »
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A full moon on a clear night, about half way between the horizon and the mid point in the sky, required a 90th sec at F8 and ISO 100. With this exposure, the histogram was not quite fully to the right.
I think we are dealing with two different but legitimate approaches; roughly, mine is for "JPEG, ready to print" while yours is for "raw with optimal information, but needing post-processing".
 
   Putting the histogram all the way to the right in this situation will have a spike for the moon at the right edge, between three and four stops above middle gray, or in the old currency, between Zones 8 and 9. On a straight print, I would expect that to give the washed out white disc that Ansel Adams comments disparagingly about in his discussion of "Moonrise", and which relates to his lower placement at about Zone 7. Indeed, your "expose to the right" exposure levels are one or two stops higher than the f/11 I suggested, so the numbers all match up.

  That sort of "overexposure" is not necessarily wrong in the digital world, since you can then compensate down by a stop or two in post-processing, and maybe that is a better approach for retaining shadow detail in a high contrast subject like this one; the option I described was based instead on the old fashioned idea of getting the exposure of the moon right "straight out of the camera", as I would think is still needed when using JPEG recording instead of raw.
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scott kirkpatrick
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« Reply #36 on: March 12, 2004, 04:09:19 PM »
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The moonshot that I posted looks sharper than the ones taken at 1/500 and f/8 or f/11, I believe, because the craters on the upper right edge of the moon were more clearly resolved with a little overexposure of the main surface of the moon.  So that does not conflict with the Ansel Adams rule, it's just because the important part of the image is facing nearly at right angles to the camera.

scott
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Ray
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« Reply #37 on: March 13, 2004, 10:07:45 AM »
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The image can be darkened to taste with 'levles'. The main concern is to avoid blowing out any highlights. The D60 at 100 ISO is actually 125 (according to dpreview). My exposure at 1/90th at f8 and 100 ISO is really 125 ISO or about 1/125th at 100 ISO or 1/250th at ISO 200, which is the identical exposure that Scott has used.

My moon looks very similar to Scott's (hope you haven't infringed my copyright Scott  Cheesy ), except the white crater, lower right, that looks like a pole, is upper left on my shot.

Could this be because I'm in Australia, or has one of us inadvertently processed the image upside down  Huh  Cheesy
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scott kirkpatrick
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« Reply #38 on: March 10, 2004, 11:53:07 AM »
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Well, another full moon has gone by, so here's my contribution to this thread:

http://www.pbase.com/image/26739799.jpg

Olympus E-1 with 50-200 (at 200) plus 1.4X extender, tripod, 3 sec delay after the mirror goes up, plus viewfinder blackout.  I shot it raw at 1/250 at f/8 ISO 200, and used Olympus Viewer to make a JPG.  I took two more bracketed images each one stop further down, but this one was best.  The histogram was totally uninformative, since there are so few moon pixels in the frame, but I think this was exposed to the right, and the slight push to ISO 200 spreads it out a bit.
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Exegeter
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« Reply #39 on: February 08, 2004, 01:23:48 AM »
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Thank you very much.  so f16 @ 50 seconds for iso 100?
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