New Nikon J1/V1 sensors = half the surface area of micro 4/3rds!

Neil Harrington wrote:
Wolfgang Weisselberg wrote:
Neil Harrington wrote:
Wolfgang Weisselberg wrote:
Neil Harrington wrote:
Wolfgang Weisselberg wrote:
Neil Harrington wrote:
Wolfgang Weisselberg wrote:

Canon does have cross sensors that are capable of f/8, but work
with increased quality at f/2.8 or faster ... and since they
work the same way, this means it's not physically impossible to
build split-image focus helpers that can do both --- i.e.
without sacrificing focussing accuracy at larger apertures.

Not a *single* split-image rangefinder prism, though.

There are varifocal spectacles, so why should that be impossible?

Progressives. How could they have anything to do with this?

They demonstrate that such things are possible.

Why would there be any question about that? And what does that have
to do with split-image rangefinder prisms?

If progressives are possible, variable opening aperture
spit-image rangefinders are probably possible, too.

It's an interesting idea, but I'd sure like to see it diagrammed.

Would you understand it?


I've never heard of such an arrangement, though. The
Canon system you mention of course will only give f/8 accuracy at
anything less than f/2.8.

Still enough to stay within DOF on the target.

Maybe, maybe not. If you really needed that feature at f/2.8 you'd
need it at f/3 as well,

You've got an f/3 lens for your camera? Or does your AF not
focus at wide open?

I have one f/2.8-4 zoom lens, yes. At some focal length it is f/3,
obviously.

Not necessarily. The lens could be built to jump the
aperture at certain focal lengts by actuating the aperture a
bit when turning the focus ring.

guffaw!
"jump the aperture"?! Come on.

So what happens in a variable max opening lens when your
camera says that it's now no longer f/2.8, but f/3.2 or
f/3.5?


And would you belive them if they told you they did?

Probably, if they explained how they did it. The Katzeye site you've
given above makes no such explanation,

99% of the buyers wouldn't be able to follow such an explanation,
(many probably don't even grasp how a split prism really works ---
and they don't care!) no matter how simple it was, and I guess
it's not simple.

It sure doesn't look simple.

nor does it make the claim that you're
implying.

What part of
The Katz EyeT "Plus" series of focusing screens has a unique
split prism design which overcomes the "blackout" problem,
without sacrificing large aperture sensitivity.
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
didn't you find?

I don't know, it was about a couple of weeks ago. I've read a million things
since then.

4 weeks is 28 days is 672 hours is 40,320 minutes is
2,419,200 seconds. You read a new thing every 2.5 seconds
and never sleep?


A split-image rangefinder prism works by using the distance between opposite
sides of the available aperture as the rangefinder base. In order to do what
is claimed above for KatzEye's product, it would have to be able to this at
different maximum apertures, such that even the much shorter RF base of,
say, f/9 would be usable (albeit at reduced RF accuracy of course) without
blacking out either half. That seems to imply that the RF prisms could not
be the usual shallow angled surfaces, but at least one of the long surfaces
would have to be curved in some way rather than flat.

How could this be done and still keep the image parts within the RF section
sharp all over, as they normally are with such a device? I'm trying to
imagine what such a progressive "prism" might look like in the viewfinder.

You could buy a KatzEye and find out. :-)

-Wolfgang

Wolfgang Weisselberg wrote:
Neil Harrington wrote:
Wolfgang Weisselberg wrote:
Neil Harrington wrote:
Wolfgang Weisselberg wrote:
Neil Harrington wrote:
Wolfgang Weisselberg wrote:
Neil Harrington wrote:
Wolfgang Weisselberg wrote:

Canon does have cross sensors that are capable of f/8, but
work with increased quality at f/2.8 or faster ... and since
they work the same way, this means it's not physically
impossible to build split-image focus helpers that can do
both --- i.e. without sacrificing focussing accuracy at
larger apertures.

Not a *single* split-image rangefinder prism, though.

There are varifocal spectacles, so why should that be
impossible?

Progressives. How could they have anything to do with this?

They demonstrate that such things are possible.

Why would there be any question about that? And what does that have
to do with split-image rangefinder prisms?

If progressives are possible, variable opening aperture
spit-image rangefinders are probably possible, too.

It's an interesting idea, but I'd sure like to see it diagrammed.

Would you understand it?

Probably, if it were properly diagrammed.



I've never heard of such an arrangement, though. The
Canon system you mention of course will only give f/8 accuracy
at anything less than f/2.8.

Still enough to stay within DOF on the target.

Maybe, maybe not. If you really needed that feature at f/2.8
you'd need it at f/3 as well,

You've got an f/3 lens for your camera? Or does your AF not
focus at wide open?

I have one f/2.8-4 zoom lens, yes. At some focal length it is f/3,
obviously.

Not necessarily. The lens could be built to jump the
aperture at certain focal lengts by actuating the aperture a
bit when turning the focus ring.

guffaw!
"jump the aperture"?! Come on.

So what happens in a variable max opening lens when your
camera says that it's now no longer f/2.8, but f/3.2 or
f/3.5?

Then that's what it is. What does that have to do with "jump[ing] the
aperture"? There is no such "jump" as the max aperture changes with a change
in focal length, which is what I assume you mean.



And would you belive them if they told you they did?

Probably, if they explained how they did it. The Katzeye site
you've given above makes no such explanation,

99% of the buyers wouldn't be able to follow such an explanation,
(many probably don't even grasp how a split prism really works ---
and they don't care!) no matter how simple it was, and I guess
it's not simple.

It sure doesn't look simple.

nor does it make the claim that you're
implying. What part of
The Katz EyeT "Plus" series of focusing screens has a unique
split prism design which overcomes the "blackout" problem,
without sacrificing large aperture sensitivity.
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
didn't you find?

I don't know, it was about a couple of weeks ago. I've read a
million things since then.

4 weeks is 28 days is 672 hours is 40,320 minutes is
2,419,200 seconds. You read a new thing every 2.5 seconds
and never sleep?

Depends on what's on Fox News.



A split-image rangefinder prism works by using the distance between
opposite sides of the available aperture as the rangefinder base. In
order to do what is claimed above for KatzEye's product, it would
have to be able to this at different maximum apertures, such that
even the much shorter RF base of, say, f/9 would be usable (albeit
at reduced RF accuracy of course) without blacking out either half.
That seems to imply that the RF prisms could not be the usual
shallow angled surfaces, but at least one of the long surfaces would
have to be curved in some way rather than flat.

How could this be done and still keep the image parts within the RF
section sharp all over, as they normally are with such a device? I'm
trying to imagine what such a progressive "prism" might look like in
the viewfinder.

You could buy a KatzEye and find out. :-)

Would it come with a proper diagram?

Neil Harrington wrote:
Wolfgang Weisselberg wrote:
Neil Harrington wrote:
Wolfgang Weisselberg wrote:
Neil Harrington wrote:
Wolfgang Weisselberg wrote:
Neil Harrington wrote:
Wolfgang Weisselberg wrote:
Neil Harrington wrote:
Wolfgang Weisselberg wrote:



Not necessarily. The lens could be built to jump the
aperture at certain focal lengts by actuating the aperture a
bit when turning the focus ring.

guffaw!
"jump the aperture"?! Come on.

So what happens in a variable max opening lens when your
camera says that it's now no longer f/2.8, but f/3.2 or
f/3.5?

Then that's what it is.

So there is f/2.8 jumping to f/3.2?

What does that have to do with "jump[ing] the
aperture"? There is no such "jump" as the max aperture changes with a change
in focal length, which is what I assume you mean.

Are you saying there never can be a jump?
In that case you'll have to prove it's physically impossible
to build any contraption that could behave like that.

While pondering that, keep in mind there are lenses with
multiple focal ranges that jump between them.


And would you belive them if they told you they did?

Probably, if they explained how they did it. The Katzeye site
you've given above makes no such explanation,

99% of the buyers wouldn't be able to follow such an explanation,
(many probably don't even grasp how a split prism really works ---
and they don't care!) no matter how simple it was, and I guess
it's not simple.

It sure doesn't look simple.

nor does it make the claim that you're
implying. What part of
The Katz EyeT "Plus" series of focusing screens has a unique
split prism design which overcomes the "blackout" problem,
without sacrificing large aperture sensitivity.
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
didn't you find?

I don't know, it was about a couple of weeks ago. I've read a
million things since then.

4 weeks is 28 days is 672 hours is 40,320 minutes is
2,419,200 seconds. You read a new thing every 2.5 seconds
and never sleep?

Depends on what's on Fox News.

Then Fox news is worthless.


A split-image rangefinder prism works by using the distance between
opposite sides of the available aperture as the rangefinder base. In
order to do what is claimed above for KatzEye's product, it would
have to be able to this at different maximum apertures, such that
even the much shorter RF base of, say, f/9 would be usable (albeit
at reduced RF accuracy of course) without blacking out either half.
That seems to imply that the RF prisms could not be the usual
shallow angled surfaces, but at least one of the long surfaces would
have to be curved in some way rather than flat.

How could this be done and still keep the image parts within the RF
section sharp all over, as they normally are with such a device? I'm
trying to imagine what such a progressive "prism" might look like in
the viewfinder.

You could buy a KatzEye and find out. :-)

Would it come with a proper diagram?

I guess the instruction manual has diagrams ...

-Wolfgang

Wolfgang Weisselberg wrote:
Neil Harrington wrote:
Wolfgang Weisselberg wrote:
Neil Harrington wrote:
Wolfgang Weisselberg wrote:
Neil Harrington wrote:
Wolfgang Weisselberg wrote:
Neil Harrington wrote:
Wolfgang Weisselberg wrote:
Neil Harrington wrote:
Wolfgang Weisselberg wrote:



Not necessarily. The lens could be built to jump the
aperture at certain focal lengts by actuating the aperture a
bit when turning the focus ring.

guffaw!
"jump the aperture"?! Come on.

So what happens in a variable max opening lens when your
camera says that it's now no longer f/2.8, but f/3.2 or
f/3.5?

Then that's what it is.

So there is f/2.8 jumping to f/3.2?

No. There is f/2.8 and there is f/3.2. No jumping is implied.

At one time I was 28 years old. Later I was 32 years old. That does not mean
I jumped from 28 to 32.


What does that have to do with "jump[ing] the
aperture"? There is no such "jump" as the max aperture changes with
a change in focal length, which is what I assume you mean.

Are you saying there never can be a jump?

No, I'm not saying that at all. A lens with Waterhouse stops does of course
jump from one f-stop to another. But we are not talking about anything like
that, are we?

In that case you'll have to prove it's physically impossible
to build any contraption that could behave like that.

While pondering that, keep in mind there are lenses with
multiple focal ranges that jump between them.

Well, there have been dual-focal-length lenses but I haven't seen any
marketed for many years.



And would you belive them if they told you they did?

Probably, if they explained how they did it. The Katzeye site
you've given above makes no such explanation,

99% of the buyers wouldn't be able to follow such an explanation,
(many probably don't even grasp how a split prism really works ---
and they don't care!) no matter how simple it was, and I guess
it's not simple.

It sure doesn't look simple.

nor does it make the claim that you're
implying. What part of
The Katz EyeT "Plus" series of focusing screens has a unique
split prism design which overcomes the "blackout" problem,
without sacrificing large aperture sensitivity.
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
didn't you find?

I don't know, it was about a couple of weeks ago. I've read a
million things since then.

4 weeks is 28 days is 672 hours is 40,320 minutes is
2,419,200 seconds. You read a new thing every 2.5 seconds
and never sleep?

Depends on what's on Fox News.

Then Fox news is worthless.

That's a worthless reply.



A split-image rangefinder prism works by using the distance between
opposite sides of the available aperture as the rangefinder base.
In order to do what is claimed above for KatzEye's product, it
would have to be able to this at different maximum apertures, such
that even the much shorter RF base of, say, f/9 would be usable
(albeit at reduced RF accuracy of course) without blacking out
either half. That seems to imply that the RF prisms could not be
the usual shallow angled surfaces, but at least one of the long
surfaces would have to be curved in some way rather than flat.

How could this be done and still keep the image parts within the RF
section sharp all over, as they normally are with such a device?
I'm trying to imagine what such a progressive "prism" might look
like in the viewfinder.

You could buy a KatzEye and find out. :-)

Would it come with a proper diagram?

I guess the instruction manual has diagrams ...

A guess is not a satisfactory answer.

Neil Harrington wrote:
Wolfgang Weisselberg wrote:
Neil Harrington wrote:
Wolfgang Weisselberg wrote:
Neil Harrington wrote:
Wolfgang Weisselberg wrote:
Neil Harrington wrote:
Wolfgang Weisselberg wrote:
Neil Harrington wrote:
Wolfgang Weisselberg wrote:
Neil Harrington wrote:
Wolfgang Weisselberg wrote:

Not necessarily. The lens could be built to jump the
aperture at certain focal lengts by actuating the aperture a
bit when turning the focus ring.

guffaw!
"jump the aperture"?! Come on.

So what happens in a variable max opening lens when your
camera says that it's now no longer f/2.8, but f/3.2 or
f/3.5?

Then that's what it is.

So there is f/2.8 jumping to f/3.2?

No. There is f/2.8 and there is f/3.2. No jumping is implied.

At one time I was 28 years old. Later I was 32 years old. That does not mean
I jumped from 28 to 32.

True, but does that mean that the lens creeps through f/2.8
to f/3.0 while still reporting f/2.8, and then creeps from
f/3.0 to f/3.2 while already reporting f/3.2 --- and that
that's the *only* possible way to implement it, because you
*cannot* influence the aperture blades depending on the focal
length, even given power, a cpu and actuators for the blades?

What does that have to do with "jump[ing] the
aperture"? There is no such "jump" as the max aperture changes with
a change in focal length, which is what I assume you mean.

Are you saying there never can be a jump?

No, I'm not saying that at all. A lens with Waterhouse stops does of course
jump from one f-stop to another. But we are not talking about anything like
that, are we?

We are not. However, lenses can be build to have a similar
effect when changing the focal length.

In that case you'll have to prove it's physically impossible
to build any contraption that could behave like that.

While pondering that, keep in mind there are lenses with
multiple focal ranges that jump between them.

Well, there have been dual-focal-length lenses but I haven't seen any
marketed for many years.

There has been a triple-focal-length lens within the last 10
years.

And would you belive them if they told you they did?

Probably, if they explained how they did it. The Katzeye site
you've given above makes no such explanation,

99% of the buyers wouldn't be able to follow such an explanation,
(many probably don't even grasp how a split prism really works ---
and they don't care!) no matter how simple it was, and I guess
it's not simple.

It sure doesn't look simple.

nor does it make the claim that you're
implying. What part of
The Katz EyeT "Plus" series of focusing screens has a unique
split prism design which overcomes the "blackout" problem,
without sacrificing large aperture sensitivity.
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
didn't you find?

I don't know, it was about a couple of weeks ago. I've read a
million things since then.

4 weeks is 28 days is 672 hours is 40,320 minutes is
2,419,200 seconds. You read a new thing every 2.5 seconds
and never sleep?

Depends on what's on Fox News.

Then Fox news is worthless.

That's a worthless reply.

Even ignoring sleep, no more than 2.5 seconds per news? A tabloid
has vastly more in depth articles of 200 odd words.


A split-image rangefinder prism works by using the distance between
opposite sides of the available aperture as the rangefinder base.
In order to do what is claimed above for KatzEye's product, it
would have to be able to this at different maximum apertures, such
that even the much shorter RF base of, say, f/9 would be usable
(albeit at reduced RF accuracy of course) without blacking out
either half. That seems to imply that the RF prisms could not be
the usual shallow angled surfaces, but at least one of the long
surfaces would have to be curved in some way rather than flat.

How could this be done and still keep the image parts within the RF
section sharp all over, as they normally are with such a device?
I'm trying to imagine what such a progressive "prism" might look
like in the viewfinder.

You could buy a KatzEye and find out. :-)

Would it come with a proper diagram?

I guess the instruction manual has diagrams ...

A guess is not a satisfactory answer.

Maybe you are intelligent enough to ask the KatzEye people
yourself. I do assume you manage to tie your own shoe laces?


-Wolfgang