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| Author |
Message |
| 19 new of 67 responses total. |
eprom
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response 49 of 67:
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Feb 29 06:22 UTC 2004 |
Why is a focal length of 50mm considered a standard? I've been
reading that 50mm is very close to what the human eye see's.
I'm wondering which human is that? when I measure my perphial
viewing angle it's slightly greater than 90 degrees.
which according to this nifty little .swf applet:
http://www.usa.canon.com/eflenses/lens101/focallength
is somewhere between 20mm and 28mm...(i'd estimate 24mm).
Am I gifted?
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rcurl
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response 50 of 67:
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Feb 29 07:53 UTC 2004 |
Its an arbitrary (compromise) value chosen to make cameras moderately
compact but still have good resolution and light-gathering capability
(smaller f). All you get with a longer focal length is a bigger camera
(and image).
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gull
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response 51 of 67:
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Mar 1 18:20 UTC 2004 |
Re resp:49: It's based not on the field of view, but on how you perceive
depth. With lenses shorter than 50mm, depth relationships look
stretched, with distant objects appearing farther away than they really
are. With lenses longer than 50mm, depth relationships are compressed.
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rcurl
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response 52 of 67:
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Mar 1 18:48 UTC 2004 |
I disagree. The effects lie in both field of view and depth of focus.
Otherwise the images are identical (the image is only what can be seen
from that point). I think what you call "depth relationships" are just
depth of focus. You can obtain the same with a shorter focal length by
stopping down (greater f).
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gull
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response 53 of 67:
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Mar 2 04:20 UTC 2004 |
No, I mean perspective, actually. A long lense compresses perspective,
a short lens stretches it. Objects look closer together in a shot taken
with a long lens. There's an excellent demonstration of this at the
bottom of this page: http://www.mendophoto.com/grabshot/focallength.html
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rcurl
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response 54 of 67:
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Mar 2 07:21 UTC 2004 |
But he *moved*. That isn't fair. The effect shown is due to his motion,
where moving further away from the stick (for example) decreases the
apparent size ratio of the stick and objects in the background. If he had
stayed in the same place and changed lenses, and then enlarged the
pictures so that the stick was the same size in all of the prints, there
would be no difference (apart from depth of focus and grain effects).
You can get the same effect he got simply by using the same lens at
different distances, and enlarging the prints to have the stick the
same length in each.
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gull
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response 55 of 67:
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Mar 2 14:55 UTC 2004 |
The point is, if you position yourself to set something up full-frame in
a telephoto lens, objects in the background will look closer to it. If
you position yourself to set something up full-frame in a wide-angle
lens, objects in the background will look more distant. A 50mm lens
splits the difference and results in size relationships that look like
what you would perceive with your eye.
The fact that you can crop and enlarge to get the same effect isn't my
point.
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rcurl
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response 56 of 67:
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Mar 2 16:52 UTC 2004 |
We are saying the same thing up to your conclusion, but the reason for
compromising on 50 mm is that that creates what seems to be the
nearby perspective we see *in the most economical fashion* in terms of
camera size, weight, and film format and processing.
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eprom
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response 57 of 67:
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Apr 27 04:48 UTC 2004 |
what exaclty are these for? They came attacted to my camera straps. I took
them off because i don't have a use for them if I don't know what they're for
http://members.triton.net/eprom/clueless.jpg
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gull
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response 58 of 67:
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Apr 27 14:54 UTC 2004 |
One of them looks like a viewfinder cover. It's used to keep light from
leaking in through the viewfinder during long time exposures, since the
light seal around the mirror is not always perfect.
The other may be a lens cap holder.
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eprom
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response 59 of 67:
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Apr 27 22:23 UTC 2004 |
I think you're right about the viewfinder cover, it fits exactly.
They're both the same, I just positioned them at slightly different angles.
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eprom
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response 60 of 67:
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May 29 00:22 UTC 2004 |
uhh...stupid camera question #4029
I have a Sunpak flash rated at a GN of 59. I need a more
powerful flash...if I get an identical flash and fire them
both at the same time, is it the equivalent of firing a
single flash rated at GN 118?
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eprom
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response 61 of 67:
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Dec 13 21:10 UTC 2004 |
question #34948
approx. what year did Kodachrome 64 first come out?
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rcurl
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response 62 of 67:
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Dec 14 01:01 UTC 2004 |
http://www.screensound.gov.au/glossary.nsf/Pages/Kodachrome?OpenDocument
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eprom
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response 63 of 67:
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Dec 23 18:53 UTC 2004 |
That link you listed didn't really say when Kodachrome 64 came out.
I did a little more checking and according to someone on one of the
Usenet groups, It was introduced as Kodachrome-X in 1963. Prior to
that, kodachrome was only availible in ASA 10 and 25.
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cmcgee
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response 64 of 67:
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Jul 12 14:36 UTC 2006 |
I have an snapshot I'd like to turn digital. Dates from the mid80s, is in
good shape colorwise. I've got an HP1510 scanner. How much better quality
would I get by taking the photo to a professional photo shop for the
transform?
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gull
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response 65 of 67:
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Jul 12 17:35 UTC 2006 |
It depends on what you want to do with the photo, in my opinion.
Better quality doesn't mean anything if the quality from the scanner is
good enough for your purposes. My experience is that the main weakness
of home scanners is color consistency. You may need to learn how to
use your scanner software's color balancing features to get the color
to come out the way you want.
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cmcgee
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response 66 of 67:
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Jul 12 20:14 UTC 2006 |
*grin* I don't think I HAVE color balance on the scanner. I'd have to play
photoshop with it after it's digitized.
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gull
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response 67 of 67:
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Jul 12 21:39 UTC 2006 |
That works, too.
I miss my old Agfa SnapScan scanner. It had a really nice set of color
tools in the TWAIN driver. One of the best features was the ability to
click on a white spot in the photo and have it automatically adjust the
color so that spot actually *was* white.
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