Something to ponder!

Never heard so much nonsense.


That's becuase the field of view is much narrower. The prerspective remains the same



.

And that, if you read back to the beginning, was exactly the point I was bringing up. I for one am finding my self more and more happy to use a shorter focal length lens prime knowing that I can crop it to a longer one due to the improved sensors and fact that I don't print above 8x10. I was confused about perspective, but now realise that perspective is only effected by the relative position of yourself and the objects in the frame, so even better!

Indeed the great thing about shooting wide and cropping is that you have much more leeway to tune the composition at home.

In fact I've often made two or three different compositions out of one wide shot

Oh! Dear ....... Does this mean that the great Ansel Adams was
wrong as well as me! From "The Print" and remember he was using
10x8 high quality contact prints direct from 10x8 negatives and
had a very good eye .....

"To obtain a literal view of the perspective, then view the image from a distance that is the same as the focal length of the lens that was used to take the picture."
Also stated is that "If the print is enlarged 2 times then also double the viewing distance to keep the same perspective."

So if your trying to compare different FL's...... some enlarged
you can't look at them all from the same distance So that
invalidates the usual every lens has the same perspective illusion

App to calculate viewing distances.....
http://visualimpact.anl.gov/pvdcalc/index.cfm

Viewing distance = focal length x degree of enlargement seems
quite popular.

This guy has actually done some test shots comparing prints to
actual....
http://www.grahamreedlightingcameraman.com/articles.htm

http://www.grahamreedlightingcameraman.com/articles/perspective.pdf

-

I know I might not be thinking straight having just watched Spurs in action, but why on earth have you started going on about where you view the picture from?

I too am losing the will to live.

My old teacher always used to say that empty ships make the most noise...................yawn I wonder how long you (Algi)will keep this up?? ten pages? your credibility plummeting all the time?

Tony you can't magnify one photo and compare it to another
unmagnified. All the tests I've seen are invalidated and
nothing more than an illusion.

Now for some nice bedtime reading, which actually used proper
controls/procedures.

http://www.journalofvision.org/content/12/5/8.full

I'm sure you'll want to read it all and keep a PDF
but for a quick example look at fig. 8 The Red Bed.

The top row taken from the same position with different focal
lengths shows quite clearly that the perspective does change
with focal length. Amongst other things the near corner
of the bed sinks lower in each shot.

The bottom row taken with a fixed lens and moved on a dolly
for each shot shows that perspective just moves as you would
expect. Quite obvious that it's the same lens.

"Even Leonardo da Vinci described perceptual distortions when paintings were not viewed from the correct distance and advised painters of realistic scenes to make sure the viewer could view near the COP."
---

No Algi - I won't. How many people on this thread have tried to correct you? 15? And please stop being so bloody condescending. At least I've learned something from this.

Goodnight.

TonyM Wrote:

Smeggy wrote:

What both of you say, makes a lot of sense. but

I'll come back to a different topic in this forum.
Suddenly the idea of higher pixel count is very desirable.
Not long ago, when I barracked for FF with 34Mp sensors, There was a big outcry: "Why would you want more pixels?, The only and best pixel count is 16Mp on Pentax Aps-C, larger pixel count is to noisy, to large , have to buy new tele lenses" Forgetting The ability to crop and arrive at the same resolution, forgetting you have to buy new WA lenses, because you can not add to it. "Why would I ever need anything to what I have now".

And so on, in a negative fashion. The comment: You can always buy a wider angle lens, is not quite as simple. Because all other things being equal, the same WA lens always shows more on a bigger sensor.

The best example is the new K3 with 24Mp. Everybody raves about the resolution.

So, slowly most of you seem to get the idea, that with new techniques, higher pixel count is desirable.

Regards, Horst

DanielH wrote.

This is not the way to discuss things. Algi tries to prove his point and others try to disprove it. This should be a technical discussion.
Not getting to personal.
Algie's credibility does not plummet. Because in a proper discussion
credibility does not plummet, just because the other party tries honestly to prove a point.

Regards, Horst

[quote:3496ace15f="Algernon
I'm sure you'll want to read it all and keep a PDF
but for a quick example look at fig. 8 The Red Bed.

The top row taken from the same position with different focal
lengths shows quite clearly that the perspective does change
with focal length. Amongst other things the near corner
of the bed sinks lower in each shot.

The bottom row taken with a fixed lens and moved on a dolly
for each shot shows that perspective just moves as you would
expect. Quite obvious that it's the same lens.

---[/quote]Algi, you are clearly either winding everybody up, or are genuinely convinced that you are correct. I wonder if you simply have a different definition of perspective to the majority of posters on this thread.

This red bed image sequence is a nice one to illustrate the point:

1) Try drawing a line along any straight edge in one of the picture in the top row (e.g. the bottom edge of the metal bar on the head rest).

2) Now copy this line and move it on top of the same straight edge feature in the other images in the top row. You must keep the copied lines parallel (i.e. don't rotate them) - I did this in MS Word, but many packages will let you do this. You'll find that it stays perfectly lined up with the same feature in all four images on the top row (NB if you do this for a few different lines in different directions then you'll be able to locate the vanishing points for the perspective). This is because the perspective is the same in all four images in the top row. That is, the perspective does not change with focal length.

3) Now do the same for the four images in the bottom row. You'll find that the copied lines no longer match up with the feature in the other images. Again, the bottom edge of the metal bar on the head rest illustrates this nicely). This is because the perspective changes in all four images in the bottom row.

Convinced yet?

Tony, if there's one redeeming thing about this thread, it's you.

True. But that isn't what's happening.

Algy's basic misunderstanding is the confusion of different magnification (which lenses of different focal length definitely do have), with different perspective, which is where object A and object B appear at different relative sizes (which only happens if the camera position changes).

This is why, for instance, he cites the magnification of a smaller crop from Tony's wider angle shot, as somehow 'not fair', where in fact, it shows precisely the relevant point, namely that the different lenses magnify differently, but show the same perspective at the same distance.

Until Algy understands this difference, he will continue to spout nonsense and post irrelevant links.

To a point. We're getting to where the resolution of the lens is going to limit the usefulness of Squillion mega pixel sensors.

note: I'd still prefer a better high ISO performance instead of increasing amounts of pixels.