The eye and the lens

Hi all!
Not a big deal, but I always thought that what we see through our eyes is
equivalent in size to what we see through a 50mm lens.
The other day, I was out taking pictures with my 5D Mark II with a Canon
Zoom EF 70-300 mm 1:4-5.6 IS USM.
Unless I'm grossly mistaken, at 70mm, the object I was aiming at looked a
wee bit smaller with the lens at 70mm than with my eyes without the glass.
Any explanation, please?
Tyanks,
Marcel

"celcius" wrote in message
...
Hi all!
Not a big deal, but I always thought that what we see through our eyes is
equivalent in size to what we see through a 50mm lens.
The other day, I was out taking pictures with my 5D Mark II with a Canon
Zoom EF 70-300 mm 1:4-5.6 IS USM.
Unless I'm grossly mistaken, at 70mm, the object I was aiming at looked a
wee bit smaller with the lens at 70mm than with my eyes without the glass.
Any explanation, please?

That's the magnification the viewfinder's set up to be.

When you walk into a room, what you see is somewhat wider than a 24mm lens.

There's nothing "normal" about 50mm. It's way to long to show spaces as we
see them, and way to short to isolate the subject as we do when we
concentrate on something that enters our field of vision. It's just a length
that's convenient for the camera companies to make.

--
David J. Littleboy
Tokyo, Japan

"celcius" wrote in
:
Not a big deal, but I always thought that what we see through our eyes
is equivalent in size to what we see through a 50mm lens.
The other day, I was out taking pictures with my 5D Mark II with a
Canon Zoom EF 70-300 mm 1:4-5.6 IS USM.
Unless I'm grossly mistaken, at 70mm, the object I was aiming at
looked a wee bit smaller with the lens at 70mm than with my eyes
without the glass. Any explanation, please?

The viewfinder has a magnification factor of less than 1. Because of this,
objects look smaller. For 5D the factor is 0.71, cheaper cameras have a
smaller magnification and professional models a greater one.

celcius wrote:
Hi all!
Not a big deal, but I always thought that what we see through our eyes
is equivalent in size to what we see through a 50mm lens.

Only in the grossest sense. Anywhere from about 40 - 60mm could be said
to roughly approximate it. The way a lens/camera captures an "image" is
very different than human vision (optics, information, eye movement,
psychological...)

The other day, I was out taking pictures with my 5D Mark II with a Canon
Zoom EF 70-300 mm 1:4-5.6 IS USM.
Unless I'm grossly mistaken, at 70mm, the object I was aiming at looked
a wee bit smaller with the lens at 70mm than with my eyes without the
glass.

That's the magnification factor of the viewfinder which seems to always
be smaller than 1.0 on 35mm cameras.

"celcius" wrote in message
...

Not a big deal, but I always thought that what we see through our eyes is equivalent in size to what we see through a 50mm lens.
The other day, I was out taking pictures with my 5D Mark II with a Canon Zoom EF 70-300 mm 1:4-5.6 IS USM.
Unless I'm grossly mistaken, at 70mm, the object I was aiming at looked a wee bit smaller with the lens at 70mm than with my eyes
without the glass.
Any explanation, please?
Tyanks,
Marcel

The others have pointed out that the difference in magnification you
see relative to "reality" is an arbitrary choice made by the designer
of the camera's viewing optics, but there is much more involved
when it comes to what we see. We can see from more than 180
degrees in width, or pay close attention to far less than 1 degree.
Much more on how our vision is different from photography is on
my web site, at --
http://www.donferrario.com/ruether/s...erspective.htm
www.donferrario.com/ruether/eyes-view.htm
http://www.donferrario.com/ruether/b...d-contrast.htm
http://www.donferrario.com/ruether/l...erspective.htm
http://www.donferrario.com/ruether/l...tion_types.htm
Basically, it is not possible to accurately duplicate in a photograph
(or to capture in a photograph) much at all about "reality" except
in VERY rare (and uninteresting) cases. And, as a "lead-in"
tidbit for the above articles, few people realize that we actually
see in fisheye (curved) perspective, but it is easy to both prove
and to show that we do...;-)
--DR

"David Ruether" wrote in message ...
"celcius" wrote in message
...

Not a big deal, but I always thought that what we see through our eyes is equivalent in size to what we see through a 50mm lens.
The other day, I was out taking pictures with my 5D Mark II with a Canon Zoom EF 70-300 mm 1:4-5.6 IS USM.
Unless I'm grossly mistaken, at 70mm, the object I was aiming at l
ooked a wee bit smaller with the lens at 70mm than with my eyes without the glass.
Any explanation, please?
Tyanks,
Marcel

The others have pointed out that the difference in magnification you
see relative to "reality" is an arbitrary choice made by the designer
of the camera's viewing optics, but there is much more involved
when it comes to what we see. We can see from more than 180
degrees in width, or pay close attention to far less than 1 degree.
Much more on how our vision is different from photography is on
my web site, at --
http://www.donferrario.com/ruether/s...erspective.htm
www.donferrario.com/ruether/eyes-view.htm
http://www.donferrario.com/ruether/b...d-contrast.htm
http://www.donferrario.com/ruether/l...erspective.htm
http://www.donferrario.com/ruether/l...tion_types.htm
Basically, it is not possible to accurately duplicate in a photograph
(or to capture in a photograph) much at all about "reality" except
in VERY rare (and uninteresting) cases. And, as a "lead-in"
tidbit for the above articles, few people realize that we actually
see in fisheye (curved) perspective, but it is easy to both prove
and to show that we do...;-)
--DR

There is another link to add, at --
http://www.donferrario.com/ruether/l...tive_types.htm
--DR

"celcius" wrote in message
...
Hi all!
Not a big deal, but I always thought that what we see through our eyes is
equivalent in size to what we see through a 50mm lens.
The other day, I was out taking pictures with my 5D Mark II with a Canon
Zoom EF 70-300 mm 1:4-5.6 IS USM.
Unless I'm grossly mistaken, at 70mm, the object I was aiming at looked a
wee bit smaller with the lens at 70mm than with my eyes without the glass.
Any explanation, please?
Tyanks,
Marcel


Thanks to all of you.
I'll have to digest this at a slowwwwwwww pace. ;-)
However, I see the simplistic approach to what I was told corresponds to
what the eye / 50mm lens see.
Cheers,
Marcel

Matti Vuori wrote:
"celcius" wrote in
:
Not a big deal, but I always thought that what we see through our eyes
is equivalent in size to what we see through a 50mm lens.
The other day, I was out taking pictures with my 5D Mark II with a
Canon Zoom EF 70-300 mm 1:4-5.6 IS USM.
Unless I'm grossly mistaken, at 70mm, the object I was aiming at
looked a wee bit smaller with the lens at 70mm than with my eyes
without the glass. Any explanation, please?

The viewfinder has a magnification factor of less than 1. Because of this,
objects look smaller. For 5D the factor is 0.71, cheaper cameras have a
smaller magnification and professional models a greater one.

Not necessarily, too much magnification means you have to take your
eyeglasses off and/or move your eye around to see the corners of the
focus screen & exposure data.

On my D700 (compact FX with compromises), 75mm matches the perspective I
see with bare eyes. That is a sort of irrelevant coincidence although in
an ideal world it might match something closer to 50mm, that might not
be practical. Explanation of why 50mm is normal in my next reply to the OP.



--
Paul Furman
www.edgehill.net
www.baynatives.com

all google groups messages filtered due to spam

celcius wrote:

Any explanation, please?

If you hold an 8x10 print at arm's length, that's about 50mm for full
frame. Now hold an empty 8x10 frame at arm's length like a movie
director framing a shot and you'll see the relevance of a normal field
of view.

Also, the normal lens for a given format can be loosely defined as the
diagonal of the sensor/film, so for 35mm the diagonal is about 45mm, for
large format, it's proportionally larger, etc. This is directly related
to the ease of making lenses for that format and for the same optical
reasons, this is just a comfortable magnification without too severe of
a difference from what you see looking at an 8x10 print and without
crazy wide angle 'distortions'.

One way of checking this arm's-length concept is to print a super-wide
scene then put on your reading glasses & look at it from just a few
inches away and the distortions don't look crazy any more, it looks
fine. But you can't easily concentrate on the whole scene either.

An interesting test is to ask people to frame what they think is a
normal field of view with their hands like a movie director. Most people
will choose something too wide but if you ask them to choose from a set
of prints, people can spot the 'normal' lens with a street scene or
something with plenty of familiar cues. It is still surprising to me how
narrow a normal lens' FOV is when assessed this way but not surprising
to look at prints.

--
Paul Furman
www.edgehill.net
www.baynatives.com

all google groups messages filtered due to spam

"Paul Furman" wrote in message
...
celcius wrote:

Any explanation, please?

If you hold an 8x10 print at arm's length, that's about 50mm for full
frame. Now hold an empty 8x10 frame at arm's length like a movie director
framing a shot and you'll see the relevance of a normal field of view.

Also, the normal lens for a given format can be loosely defined as the
diagonal of the sensor/film, so for 35mm the diagonal is about 45mm, for
large format, it's proportionally larger, etc. This is directly related to
the ease of making lenses for that format and for the same optical
reasons, this is just a comfortable magnification without too severe of a
difference from what you see looking at an 8x10 print and without crazy
wide angle 'distortions'.

One way of checking this arm's-length concept is to print a super-wide
scene then put on your reading glasses & look at it from just a few inches
away and the distortions don't look crazy any more, it looks fine. But you
can't easily concentrate on the whole scene either.

An interesting test is to ask people to frame what they think is a normal
field of view with their hands like a movie director. Most people will
choose something too wide but if you ask them to choose from a set of
prints, people can spot the 'normal' lens with a street scene or something
with plenty of familiar cues. It is still surprising to me how narrow a
normal lens' FOV is when assessed this way but not surprising to look at
prints.

--
Thanks Paul for taking the time to answer.
I don't know whether I was clear enough but I wasn't referring to field of
view, which I understand is much wider with the naked eye that even with a
24mm lens.
When I reflected upon this, I was aiming at a stop sign and such other
items. Looking through the 70mm lens, the stop sign was a bit smaller than
looking at it with the naked eye. I didn't have my glasses on and wasn't
interested in how clear I could see it, simply the overall size of it.
In your last post, You said that "75mm matches the perspective I see with
bare eyes". This verifies to almost a iota what my experience was (a tad
smaller with a 70mm, of course about the same size with a 75mm. Can we say
then, that the size of an object as seen through the naked eye is the same
as with a 75mm lens (with a full size sensor)?
Regards,
Marcel