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Author Topic: canyon  (Read 5459 times)

Slobodan Blagojevic

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Re: canyon
« Reply #20 on: October 29, 2012, 02:35:15 pm »

... Perspective on such a scale that the human mind doesn't connect it to viewing depth. Usually they converge towards the sun since that is an element in the image. In this case the sun is not in the image and convergence happens in the opposite direction.

Huh?

EDIT: Apparently, there is such a thing as anti-crepuscular rays (seen opposite the sun in the sky). Good to learn something new.

However, another site claims "you must have your back to the sun or sunset point to see them."
« Last Edit: October 29, 2012, 02:55:41 pm by Slobodan Blagojevic »
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IanBrowne

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Re: canyon
« Reply #21 on: October 29, 2012, 05:37:10 pm »

 not enough images have been taken to make the panorama IMO. With a subject like this I would take up to 15-20 frames so i have heavy overlapping. And shock horrors, i use AV and usually hand held.....yep too lazy to get the tripod out  :-[ . And I make sure I leave plenty of space at the top and bottom.
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RSL

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Re: canyon
« Reply #22 on: October 29, 2012, 06:16:18 pm »

I scratch my head when people get going on technicalities. They do it all the time on fora like Nikonians. Over there they're a lot more interested in equipment and technique than they are in photographs. In this case I don't understand what all the fuss is about. Either the picture's good or it's not. As it happens, the picture is good, whether or not the "rays" are crepuscular (actually meaning "dim, like twilight") and whether or not they appear to line up with the exact angle of the sun.

Seems to me crepuscular rays are an illusion anyway. Under certain atmospheric conditions they appear to branch out from the sun, but the sun is far enough away that in a practical sense sunlight is collimated, meaning rays of sunlight can't really branch out unless something interferes with them. So the idea that crepuscular rays have to follow the path of direct sunlight doesn't hold up.
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Jeremy Roussak

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Re: canyon
« Reply #23 on: October 29, 2012, 06:20:12 pm »

not enough images have been taken to make the panorama IMO. With a subject like this I would take up to 15-20 frames so i have heavy overlapping. And shock horrors, i use AV and usually hand held.....yep too lazy to get the tripod out  :-[ . And I make sure I leave plenty of space at the top and bottom.

So explain, please, how more overlap would have led to a "better" panorama. 20% overlap is, as far as I can tell, plenty; and I suspect that there's more than that here.

At the same time I was at Cape Royal, a fellow-Englishman was there with about 5 cameras on Gigapan mounts. Maybe he'd meet your criteria.

Jeremy
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Jeremy Roussak

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Re: canyon
« Reply #24 on: October 29, 2012, 06:24:31 pm »

It looks to me that the shot #4 is a bit lighter and more contrasty in the overlap areas than #3. Also, I do not notice the rays in #3's overlap area (though it is possible they appeared just as you moved the camera between shots). Increasing contrast in further post-processing probably amplified the effect of the "crepuscular" rays. I am using quotation marks as I am not certain anymore they are really so.

Was there a polarizer used, or any other type of filter, even UV? Lens hood? It is possible that the lighter sky area in #4 is a filter-induced flare.

Yes, it does look a little lighter. The fifth frame, which I didn't use, is lighter still.

No polariser, no; but I keep a Hoya 1A mounted all the time. I had the Canon hood fitted. I rather doubt there was any flare: as my shivering well demonstrated, I (and hence the lens) was in shade the entire time.

Jeremy
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churly

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Re: canyon
« Reply #25 on: October 29, 2012, 07:37:10 pm »

Maybe this helps a bit.

As I see it, Jeremy was facing almost west when he took this shot so the sun was behind him and over his left shoulder.  The rays that Slobodan are tracing are projected onto a nearly north-south plane so the perspective is distorted.  Here is an image which I was never able to process well but perhaps illustrates the point.  In this case we are also facing west but the sun is obviously in front of us.  The crepuscular rays that clearly project back to the sun take on a variety of apparent angles when projected onto the image plane.


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Chuck Hurich

IanBrowne

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Re: canyon
« Reply #26 on: October 29, 2012, 09:15:37 pm »

So explain, please, how more overlap would have led to a "better" panorama. 20% overlap is, as far as I can tell, plenty; and I suspect that there's more than that here.


by overlapping heavily means a smaller part of each image is used  and if there is a little variation in exposure it is not as noticeable. As I said i usually hand hold the camera and heavily overlapping means nothing is left out. Works for me most of the time. I feel many make panoramas sound to hard the do. LOL the Lumis 200 does panoramas in camera but annoying only at 27 mm. I wouldn't bother using it. 
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