Half Dome picture from some where around Turlock


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Nov 30, 2012 - 03:34pm PT
I decided to analyze the photo referred to in the original post to see if it had been photoshopped.

The EXIF data from the original image records that the camera was an Olympus E-3 and that the focal length was 400mm (the photographer also states it was a 400mm lens). The EXIF also says that the image was processed using Silkypix software which is RAW image processing software. Being captured in RAW rather than JPEG format and processed in the RAW state may explain why it doesn’t look like the typical JPEG. All digital cameras have built in software that converts the image from RAW to JPEG format. The software built into cameras usually isn’t all that great. The image also has an embedded color profile.

Olympus E-3 has:
18.00 × 13.50 mm (0.7087 x 0.5315 inch) sensor
3648 × 2736 pixels (10.1 megapixels)
Aspect 4:3

The width of the field of view is 2arctan(9mm/400mm) or 2.57 degrees. The height of the field of view is 1.93 degrees. If the image hasn’t been cropped and ignoring small angle errors, in the original 1600x1200 pixel image, 1 degree is about 620 pixels. I believe the error in estimating angles this way is about 0.1% and much smaller than my other errors. I drew lines on the image at 1/10th degree intervals from which I find the left eave of the grain elevator is about 0.94 degrees left of image center and the peak of the shed roof is about 0.62 degrees right of image center.

Image with 1/10th degree grid. Grid scale may be off by 12 or 13%
Image with 1/10th degree grid. Grid scale may be off by 12 or 13%
Credit: Banquo

TOPO! Tells me that the top of Half Dome is 65.95 miles from the elevator on a bearing of 77.59 degrees (clockwise from north). In the reverse direction, the bearing from Half Dome to the elevator is 77.59+180=257.59 degrees.

Bearing and distance from Montpelier to Half Dome
Bearing and distance from Montpelier to Half Dome
Credit: Banquo

I copied some images from Google satellite and made a composite so I could lay things out. I drew a line from the left eave of the elevator roof on a bearing of 77.59-0.94 degrees and one from the peak of the shed roof at a bearing of 77.59+0.62 degrees. I extended these lines until they intersected. From the intersection I added a third line at a bearing of 77.59 degrees to represent image center and the summit of Half Dome.

Red lines are the bearings to the elevator, the shed roof and Half Dom...
Red lines are the bearings to the elevator, the shed roof and Half Dome. The lines converge in the canal.
Credit: Banquo

The lines intersect on the canal which is short of Hall Road where the photographer says he took the photo. If I extend the line it intersects Hall Road 0.65 miles south of E. Keyes Road. The photographer says he took the photo on Hall Road 0.65 miles south of E. Keyes Road. The fact that my projection came up a little short of Hall Road tells me that he cropped the image a bit, probably to put Half Dome in the image center or otherwise make it look better. Most likely it was cropped to level the image if the camera wasn't level.

Credit: Banquo

The intersection of my lines is 1.36 miles from the elevator while Hall Road is 1.57 miles which suggests he cropped the photo about 13.3%. The camera sensor is 3648 pixels wide so if he reduced by half he should get 1824 pixel width. The image is 1600 wide which is a reduction of 12.3% from 1824 pixels.

So, it seems clear to me that the image was taken from the exact spot he says it was taken from with the camera and lens he reports. I believe it has been cropped 12 or 13%. The image has also been processed for sharpness which has left some odd defects when inspected at full resolution. It doesn’t look like what the eye or a telescope sees because cameras don’t see the same way the human eye does and it has been enhanced a bit.

Also, the 2000 foot high NW face of Half Dome should be about arctan(2000/65.95*5280)=0.33 degrees high in the image which it appears to be although you can’t see the bottom of the face. Also, the grid scale is probably off due to the cropping.

Edit addition:
The dirt berm in the foreground is probably the canal. The dirt ramp to the right can be seen in the satellite image.

Trad climber
under the sea
Nov 30, 2012 - 03:59pm PT
^^^nice work!

but they still wont believe you...


Gym climber
Berkeley, CA
Nov 30, 2012 - 04:02pm PT
I think one of the most interesting things about this side view is getting a more accurate perspective of the relative heights of features within Yosemite (e.g. El Cap, Halfdome, and the mountains behind). When you're up in it, you just can't see that as clearly.
Ed Hartouni

Trad climber
Livermore, CA
Nov 30, 2012 - 07:23pm PT
good work!
another interesting thing is that all of those locally vertical faces we seen in the Valley are leaning back about 1º (or more) from the vantage point of the Central Valley, which can distort the scene.

I don't doubt that shot at all, and am planning on getting it myself at some point in the not to distant future!

Ed Hartouni

Trad climber
Livermore, CA
Dec 19, 2012 - 11:48pm PT
right now the weather seems iffy for the Wed, Dec 26 Moonrise

Weather Underground forecast is for 100% overcast those three days,

NWS is not so dire... but 20% chance of precip. on Wed...

and the UWa 3 day model forecast looks complicated... but it's more than 3 days away...

Jerry Dodrill

Dec 20, 2012 - 01:00am PT
Lets keep an eye on it.
Mike Bolte

Trad climber
Planet Earth
Dec 20, 2012 - 02:57am PT
Funny that this got bumped. Was at Lick Observatory today. It was very clear. First time I have ever seen Half Dome from there. Took a shot:

Half Dome from Lick Observatory on Mt Hamilton. 300mm lens, image crop...
Half Dome from Lick Observatory on Mt Hamilton. 300mm lens, image cropped to around 600mm equivalent. Click for a larger version.
Credit: Mike Bolte
Ed Hartouni

Trad climber
Livermore, CA
Dec 20, 2012 - 03:47am PT
nice Mike!
mouse from merced

Trad climber
The finger of fate, my friends, is fickle.
Dec 20, 2012 - 04:05am PT
The Lick shot's so good, it's about the type of clarity needed to produce valley shot, but even moreso for the definitive shot, I bet.

Night before last I mentioned in a thread that yesterday was looking like it was gonna be such a day. It was cloudy up top above the Sierra day before yesterday, the wind was strong and cold out of the west, and the clouds were headed east quickly. Yesterday morning was a disappointment, really, though the view of the mtns was great, it wasn't crystal from cown here.

Dec 20, 2012 - 12:22pm PT
Nice shot, Mike!

You can get a litle more detail out of that with a little photoshop. It compares nicely to the photo you posted upthread;


I think I dropped you a line earlier, I'd love to take a look at high-res versions of each.

Trad climber
Fresno CA
Dec 20, 2012 - 02:48pm PT
Very nice, Mike.

The view of the mountains has been excellent here the last couple of days. I can see crack systems on Patterson Bluff on the way home, with Mt. Goddard's new coat of snow in the background. Now if I only had remembered my camera (or even my phone).


Trad climber
Dec 20, 2012 - 04:38pm PT
I love this thread and subject. Thanks guys.

Mother Earth is pretty amazing!
Ed Hartouni

Trad climber
Livermore, CA
Dec 21, 2012 - 02:16am PT
So this thing is 100 percent?
I think so... it'll be fun to getting the shots, look at Mike's image... from Mt. Hamilton, it's amazing.
Ed Hartouni

Trad climber
Livermore, CA
Dec 22, 2012 - 01:48am PT
Wed Dec 26 is still looking cloudy and possibly wet...
though the weather is certainly unsettled

Thur Dec 27 might have a weather window: clearing skies through the day and clear by 6pm (sunset at 4:50pm, which is when the moon rises... that would be spectacular timing with a snowy alpinglow on the Sierra crest..

Humidity seems a bit high...

Jebus H Bomz

Reno, Nuh VAAAA duh
Dec 22, 2012 - 01:52am PT
I think it's sick to see Yose (the landscape of my dreams) juxtaposed against the central valley (the landscape of my childhood).

Trad climber
Can't get here from there
Dec 22, 2012 - 08:17am PT
Well I thought it had been chopped, but I'll admit my first take was wrong.

It's damn amazing though.
Ed Hartouni

Trad climber
Livermore, CA
Dec 22, 2012 - 02:28pm PT
here is the Moon rise ephemeris

the apparent altitude is calculated taking into account atmospheric refraction using Saemundson's expression:

R = 1.02/tan((pi/180)*(h+10.3/(h+5.11))/60 (in degrees)

and h is the true altitude (in degrees) the apparent altitude is:

h0 = h + R

[see Meeus p106 eq(16.4)]

that location is "good enough" for altitude... and time.

The Sierra Crest is at an altitude of about 1.2º to 1.5º (estimated from my previous attempt)

The bearings are shown on the map:

the red lines point to Half Dome, the central one at 65º and the upper and lower ones being 0.25º on either side, the angular diameter of the moon is 0.5º

the jagged white line is the Half Dome sight boundary, it is visible to the west of that line...

Given the existence of orchards of some sort along the Central Yosemite Hwy. (Hwy 140) it looks like good viewing would be in the field south of the Hwy, and west of Lincoln Rd, though no public roads access the west side of that apparently open field... another option is to go north on Sultana Dr. just a bit south of the aquaduct where there seem to be open fields...

The weather is still wavering for these days... Th is still "partially cloudy" and is worse than the previous Weather Underground report... The NWS calls it "partially sunny" with a chance of rain.

Sunset is around 16:50 for these days.
Stay tuned
Dingus Milktoast

Gym climber
And every fool knows, a dog needs a home, and...
Dec 22, 2012 - 02:35pm PT
From a sunnier day in Fed, 09... those vineyards and orchards are pretty. They won't be in bloom yet of course

Good food can be found nearby too.

Good luck! Seems like if the rain don't getchya the fog will. Gotta hope for a wind.
mouse from merced

Trad climber
The finger of fate, my friends, is fickle.
Dec 22, 2012 - 02:52pm PT
Kinda makes it tough to navigate this thread when we get extra-large photos posted. Just saying...
Ed Hartouni

Trad climber
Livermore, CA
Dec 22, 2012 - 02:58pm PT
suck it up mouse... tough to read microscopic print at 800x600 pixels...

DMT has his Half Dome shot...
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