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01-19-2012, 05:55 PM   #241
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Only when you enlarge the crop. It's relative scale to the observer changes. This seems to be a difficult thing for people to comprehend, and that's understandable, but what people are forgetting is that perspective is a concept and a perception based on the way the observer is interacting with a projection (in front of the observer) of a 3D scene onto a 2D surface (image plane).

01-19-2012, 06:02 PM   #242
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QuoteOriginally posted by Edvinas Quote
So, cropping is a change of perspective?
QuoteOriginally posted by bossa Quote
Only when you enlarge the crop.
Sorry, but that's just plain wrong. As in, incorrect. DOF will change with enlargement, viewing position, etc. But cropping does NOT change the relationships of the picture elements; their perspective remains constant. (Picture elements are what's in the picture, not what's behind the objective.) This is shown over and over again with series of photos taken of the same subject at the same distance with various focal lengths, enlarged and cropped to the same AOV. Perspective remains EXACTLY the same.
01-19-2012, 06:31 PM   #243
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QuoteQuote:
This is shown over and over again with series of photos taken of the same subject at the same distance with various focal lengths, enlarged and cropped to the same AOV. Perspective remains EXACTLY the same.
Glad to see after 300 posts we are at the basics, again :-)
01-19-2012, 06:47 PM   #244
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QuoteOriginally posted by Edvinas Quote
So, cropping is a change of perspective?
first time hearing that one...

01-19-2012, 06:59 PM   #245
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I know not the best source.
en.wikipedia.org/wiki/Perspective_distortion_(photography)

Note that perspective distortion is caused by distance, not by the lens per se – two shots of the same scene from the same distance will exhibit identical perspective distortion, regardless of lens used. However, since wide-angle lenses have a wider field of view, they are generally used from closer, while telephoto lenses have a narrower field of view and are generally used from further away.
01-19-2012, 07:44 PM   #246
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QuoteOriginally posted by RioRico Quote
Sorry, but that's just plain wrong. As in, incorrect. DOF will change with enlargement, viewing position, etc. But cropping does NOT change the relationships of the picture elements; their perspective remains constant. (Picture elements are what's in the picture, not what's behind the objective.) This is shown over and over again with series of photos taken of the same subject at the same distance with various focal lengths, enlarged and cropped to the same AOV. Perspective remains EXACTLY the same.
I'm not talking about the internal relationships within the photograph. I am talking about the relationship of the observer to the photograph. THAT is perspective and it changes with scale. When you enlarge a crop or use a telephoto lens you separate the radial points out on the horizon that determine perspective relative to the viewer.

I give up at this point.
Cheers
01-19-2012, 08:00 PM   #247
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Hasn't everyone figured out by now you're talking about two totally different topics? One group is talking about "the 2-d representation on a flat surface of the 3-d world". The rest are talking about "where I am standing and the direction I am pointing the camera when I take a photo". Same word, two definitions. BOTH correct. I'm surprised no one has brought up psychological perspective (e.g. "my perspective on religion is blah blah blah") and tried to convince everyone else they are wrong about what they are calling "perspective".
01-19-2012, 08:18 PM   #248
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QuoteOriginally posted by Anvh Quote
first time hearing that one...
but this is what bossa is claiming... According to him using different focal length changes perspective. However I can "change" focal length by cropping picture in post processing....

01-19-2012, 08:23 PM   #249
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I feel 1 stop faster in term of DOF is not really a big difference..
we can still get very shallow DOF with APS-C DSLR...
and nowadays APS-C DSLR is pretty sharp and high ISO is pretty good too..
I do not think people really need go to FF if ur prints are usually in small to medium size..
01-19-2012, 08:50 PM   #250
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QuoteOriginally posted by Edvinas Quote
but this is what bossa is claiming... According to him using different focal length changes perspective. However I can "change" focal length by cropping picture in post processing....
He is saying it in a difficult way.

A 10mm will give you a wider perspective (angle of view) of the world then a 80m lens.
But the word perspective is not normally used in this way in photography because we have other words for it.
It's the same that angle of view means something else in photography then for example in biology.
01-19-2012, 08:55 PM   #251
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QuoteOriginally posted by Anvh Quote
He is saying it in a difficult way.

A 10mm will give you a wider perspective (angle of view) of the world then a 80m lens.
But the word perspective is not normally used in this way in photography because we have other words for it.
It's the same that angle of view means something else in photography then for example in biology.
Well, angle of view is angle of view, not perspective...
01-19-2012, 09:14 PM   #252
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QuoteOriginally posted by Edvinas Quote
Well, angle of view is angle of view, not perspective...
Depends on the context.

Anyway what he is saying the both are very much connected though.
Linear perspective is about that the visual angle decrease with distance so an object further away looks smaller.
With a camera a smaller angle of view will make things look closer so in that aspect they have the same principal right?

It's all about the angles and how we or the camera sees it.
01-19-2012, 09:26 PM   #253
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QuoteOriginally posted by vonBaloney Quote
Hasn't everyone figured out by now you're talking about two totally different topics? One group is talking about "the 2-d representation on a flat surface of the 3-d world". The rest are talking about "where I am standing and the direction I am pointing the camera when I take a photo". Same word, two definitions. BOTH correct. I'm surprised no one has brought up psychological perspective (e.g. "my perspective on religion is blah blah blah") and tried to convince everyone else they are wrong about what they are calling "perspective".
+1

There are two concepts in play here, both fighting for ownership of the word perspective.

The two concepts, hopefully described succinctly enough:

Concept 1) (Let's call this one "Lines, Man!") An overall image can be said to have "lot's of perspective" if there are obvious radial lines, a great deal of convergence or divergence. If you crop that image, or use a different focal length, it will be said to have 'less perspective', because that divergence/convergence is less obvious in the crop than it is when you view the 'whole image'.

"Lot's of perspective", "Less Perspective":




Concept 2) (Let's call this one "Sit Still!") The size relationships of various elements in an image that are different distances from the camera. If you move, the perceived 'distance' between these objects changes. If you crop, or use a different focal length, they do not. This is the concept most photographers are talking about when they talk about perspective, and can be shown with the series of crops I posted earlier.

So... everybody good?

.

Last edited by jsherman999; 01-19-2012 at 09:32 PM.
01-19-2012, 09:28 PM   #254
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QuoteOriginally posted by Edvinas Quote
but this is what bossa is claiming... According to him using different focal length changes perspective. However I can "change" focal length by cropping picture in post processing....
Yes that's right but you can only go one way with that concept [method].
01-19-2012, 09:39 PM   #255
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QuoteOriginally posted by bossa Quote
Yes that's right but you can only go one way with that concept [method].
actually... the sensor has more pixels that are actually shown in the photo, so the images you see are actually slightly cropped.
If you shoot in RAW you can remove that though and it will make your photo look a bit wider.

But we are cheating now though...
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