Death of the slapping mirror

Alfred Molon wrote:
In article , dj_nme
says...
The mirror in the two new Sony Alpha cameras plays no part in the
viewfinder, they have no reflex viewfinder at all and so can't be called
SLR cameras.

In fact Sony is calling it an SLT camera.

I am fully aware of this fact.
That's why I was particularly keen to point out that these cameras
aren't SLR cameras.

On 10-08-27 4:22 , dj_nme wrote:
Alfred Molon wrote:
In article , dj_nme
says...
The mirror in the two new Sony Alpha cameras plays no part in the
viewfinder, they have no reflex viewfinder at all and so can't be
called SLR cameras.

In fact Sony is calling it an SLT camera.

I am fully aware of this fact.
That's why I was particularly keen to point out that these cameras
aren't SLR cameras.

They aren't "less" SLR than the pellicle film "SLRs" that have come
before. IOW, you're raising a non-issue in a quest for pedantic, er,
relief.


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On 10-08-27 11:03 , John A. wrote:
On Fri, 27 Aug 2010 16:43:20 +0200, Alfred Molon
wrote:

In m.au, dj_nme
says...
That's why I was particularly keen to point out that these cameras
aren't SLR cameras.

... which is highly irrelevant.

Ok... do you mean that it's irrelevant that they aren't SLRs, or that
the camera is irrelevant in the slr-systems group?

The former I would say. The cameras are entirely relevant to the group.

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"Alan Browne" wrote in message
news
On 10-08-27 4:22 , dj_nme wrote:
Alfred Molon wrote:
In article , dj_nme
says...
The mirror in the two new Sony Alpha cameras plays no part in the
viewfinder, they have no reflex viewfinder at all and so can't be
called SLR cameras.

In fact Sony is calling it an SLT camera.

I am fully aware of this fact.
That's why I was particularly keen to point out that these cameras
aren't SLR cameras.

They aren't "less" SLR than the pellicle film "SLRs" that have come
before. IOW, you're raising a non-issue in a quest for pedantic, er,
relief.

No, he's right. My opinion was the same as yours until I googled these new
Sony cameras. I had assumed that the mirror was part of the viewfinder
system as in the old Canon Pellix. But it isn't. The mirror's only function
is to divert part of the image-forming rays to the AF system.

So these aren't reflex cameras at all, any more than some old rangefinder
cameras could be called reflex just because they used small beam-splitting
mirrors for other purposes.

"Alfred Molon" wrote in message
...
In article , John A. says...
Ok... do you mean that it's irrelevant that they aren't SLRs, or that
the camera is irrelevant in the slr-systems group?

Since the mirror is going to disappear sooner or later,
rec.photo.digital.SLR-systems will go the way of the dodo.

I guess everything is "going to disappear sooner or later," including
sentient beings who use cameras, but I'll bet the mirror reflex camera is
going to be around for a long, long time.

OVFs will also disappear from most cameras sooner or later, replaced by
EVFs.

Optical VFs have already disappeared from almost all pocket-sized cameras,
having been crowded out by ever-larger LCD screens (and considerations of
cost, no doubt). But a lot of users are unhappy about this, and I wouldn't
be surprised to see them come back. They have not been replaced by EVFs in
such cameras (with very few exceptions such as the Coolpix P60, and that was
quite short-lived).

On 10-08-27 14:58 , Alfred Molon wrote:
In , John A. says...
Ok... do you mean that it's irrelevant that they aren't SLRs, or that
the camera is irrelevant in the slr-systems group?

Since the mirror is going to disappear sooner or later,
rec.photo.digital.SLR-systems will go the way of the dodo.
OVFs will also disappear from most cameras sooner or later, replaced by
EVFs.

I doubt the NG will go, the charter will bend like reeds of grass to
accept it.

I also doubt the mirror will disappear as soon as some believe/hope.

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gmail originated posts are filtered due to spam.

On 10-08-27 15:23 , Neil Harrington wrote:
"Alan wrote in message
news
On 10-08-27 4:22 , dj_nme wrote:
Alfred Molon wrote:
In m.au, dj_nme
says...
The mirror in the two new Sony Alpha cameras plays no part in the
viewfinder, they have no reflex viewfinder at all and so can't be
called SLR cameras.

In fact Sony is calling it an SLT camera.

I am fully aware of this fact.
That's why I was particularly keen to point out that these cameras
aren't SLR cameras.

They aren't "less" SLR than the pellicle film "SLRs" that have come
before. IOW, you're raising a non-issue in a quest for pedantic, er,
relief.

No, he's right. My opinion was the same as yours until I googled these new
Sony cameras. I had assumed that the mirror was part of the viewfinder
system as in the old Canon Pellix. But it isn't. The mirror's only function
is to divert part of the image-forming rays to the AF system.

So these aren't reflex cameras at all, any more than some old rangefinder
cameras could be called reflex just because they used small beam-splitting
mirrors for other purposes.

True enough, but irrelevant to functionality. And nobody said they were
"reflex".

--
gmail originated posts are filtered due to spam.

In article , Bruce
writes

The mirror will, of course, be the most problematic part of the
camera. If it is anything less than spotlessly clean, it will degrade
the image recorded by the sensor.

Much less than the degradation of a less that spotlessly clean sensor
filter stack.

A 10um sized spec of dirt on the filter stack causes dust bunny shadows
on the image, which are small and dense at high f/#s or larger and less
dense with low f/#s. The same sized spec of dust in the middle of the
pellicle mirror would be at least 12mm from the focal plane, so even at
f/16 its effect would be very limited.

At f/16 the light forming each pixel in the centre of the image goes
through a circle of about 0.75mm diameter on the mirror. So that same
10um piece of dirt, which causes objectionable dust bunnies on the
filter at f/16, blocks about 0.02% of the light to the pixel when it is
on the mirror. That's less than 1LSB of the 12-bit signal from each
pixel and less than the peak photon noise itself. In short, except on
highly stacked images, it would be completely invisible.

To have any material effect on the image, dirt on the mirror has to be
enormous compared to the dirt that would be unacceptable on the sensor
filter stack. Dirt particles that size are the easiest to clear either
with blown air or vibrating the pellicle itself.

These so-called "SLT" cameras must be among the most pointless cameras
ever produced. But that's Sony for you. ;-)

No, its just you.
--
Kennedy
Yes, Socrates himself is particularly missed;
A lovely little thinker, but a bugger when he's ****ed.
Python Philosophers (replace 'nospam' with 'kennedym' when replying)

"Alfred Molon" wrote in message
...
In article , Alan Browne
says...
I also doubt the mirror will disappear as soon as some believe/hope.

Huge advantage if that mirror goes:
- no mirror movement vibrations any more (MLU no longer needed)

I've never needed MLU in any case.

- much faster cameras (faster AF, higher frame rate)

You still need a mirror if you want to use phase-detect auto-focus, albeit
that the mirror may not need to move. Higher frame rates will only
interest a minority of today's DSLR users, but sports folk may like it.

- 100% match between viewfinder/LCD image and what is being recorded

Agreed, but of course the electronic viewfinder will need to be a lot
better than the great majority of those seen today, but there are some
signs of improvements there.

- more accurate metering if the main sensor is used for metering

Not convinced - a separate or additional exposure sensor can have a much
greater dynamic range than the main sensor, and so be aware of highlights
which the main sensor clips, and shadow levels where are too dark for the
pixel size of the main sensor. A supplemental exposure sensor would
probably be a worthwhile addition.

Having to use an EVF or LCD for viewing reduces the battery life - a
significant disadvantage.

Cheers,
David

"Alan Browne" wrote in message
news
On 10-08-27 15:23 , Neil Harrington wrote:
"Alan wrote in message
news
On 10-08-27 4:22 , dj_nme wrote:
Alfred Molon wrote:
In m.au, dj_nme
says...
The mirror in the two new Sony Alpha cameras plays no part in the
viewfinder, they have no reflex viewfinder at all and so can't be
called SLR cameras.

In fact Sony is calling it an SLT camera.

I am fully aware of this fact.
That's why I was particularly keen to point out that these cameras
aren't SLR cameras.

They aren't "less" SLR than the pellicle film "SLRs" that have come
before. IOW, you're raising a non-issue in a quest for pedantic, er,
relief.

No, he's right. My opinion was the same as yours until I googled these
new
Sony cameras. I had assumed that the mirror was part of the viewfinder
system as in the old Canon Pellix. But it isn't. The mirror's only
function
is to divert part of the image-forming rays to the AF system.

So these aren't reflex cameras at all, any more than some old rangefinder
cameras could be called reflex just because they used small
beam-splitting
mirrors for other purposes.

True enough, but irrelevant to functionality. And nobody said they were
"reflex".

You just said:
They aren't "less" SLR than the pellicle film "SLRs" [ . . . ]

And I'm sure you know what the R in SLR stands for. The Pellix and the few
others like it were clearly SLRs.