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11-30-2014, 05:45 AM   #31
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The first pentaprism camera was Contax S in 1947-1948.

Pentax had offered first camera with pentaprism in 1957, not 1952.
First Japanese 35mm SLR was made by Asahi Optical Co. in 1952.
Pentax - Camera-wiki.org - The free camera encyclopedia

11-30-2014, 07:24 AM   #32
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QuoteOriginally posted by Mistral75 Quote
Huh...

What about the Zeiss Ikon prototypes from 1936-37? What about the Contax S and Rectaflex Standard (Telemaco Corsi, Italy), both from 1947?



The Asahiflex I (prototype: 1951; mass production: 1952) was 'only' the first Japanese 35mm SLR. And there was no pentaprism in the Asahiflex; the first Asahi Optical SLR with a pentaprism was the Asahi Pentax from 1957.

By the way, the name 'Pentax' was originally a registered trademark of Zeiss Ikon. It was taken by Asahi Optical in 1957

If you want a mirror-linked world's first from Asahi Optical, just pick the successful instant-return mirror of Asahiflex IIB in 1954 -this world's first was the first of many from Asahi Optical in the field of SLR.
Interesting.
Here is "my" source :
Brief History of Pentax Cameras - Photoxels
Maybe did i interpret it aproximately or wrongly.
If the date is wrong, i don't think the name is.
Please don't get rid of both baby and bath-water...
11-30-2014, 07:41 AM   #33
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QuoteOriginally posted by Zygonyx Quote
Interesting.
Here is "my" source :
Brief History of Pentax Cameras - Photoxels
Maybe did i interpret it approximately or wrongly.
If the date is wrong, i don't think the name is.
Please don't get rid of both baby and bath-water...
Thank you for the link. Your source states what I wrote on the former page:

"1952. Asahiflex I is the first Japanese 35mm SLR (Single Lens Reflex) camera.

1954. (...) The Asahiflex II has the world's first instant return mirror system.

1957. Another coup by Pentax with the use of a pentaprism in the viewfinder of the Asahi Pentax SLR.
"

Except that, when they write "It is also the first time that the name Pentax (PENTAprism refleX) is used on a camera" I uphold that the name Pentax comes from PENTAprism ConTAX (even though the war and its consequences prevented Zeiss Ikon to use the brand they had registered). But this is not material.
11-30-2014, 12:14 PM   #34
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Pentax sounds nevertheless rather material as a commercial name, related to reflex and pentaprism.
That was my only point, in relation to this thread.
And forgive me if i didn't study in a jesuit institue.

11-30-2014, 01:16 PM   #35
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12-02-2014, 11:59 PM   #36
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QuoteOriginally posted by Mistral75 Quote
" I uphold that the name Pentax comes from PENTAprism ConTAX (even though the war and its consequences prevented Zeiss Ikon to use the brand they had registered). But this is not material.
PENtaprism ConTAX applies to the original Zeiss trademark which they chose not to use and subsequently sold to Asahi. PENTAX as we know it is derived from PENTAprism refleX (or PENTAprism asahifleX if you prefer). Note that PENTAprism CONtax also gave us Pentacon in East Germany.
12-03-2014, 04:04 AM   #37
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QuoteOriginally posted by JimmyDranox Quote
I think that the main problem is not technical or financial, but psychological. How can someone sell a camera as an autofocus one, if every user must do calibration tests with every lens, before use it. Some lenses have small difference in focus for different distances, especially cheap zooms. A calibration test for such a lens will require time, patience and skills, and most people would not want to do this.

I'm sure that every manufacturer makes this kind of tests, to make lenses as parfocal as possible, and camera as reliable as can be in their focusing system, but still, their is a small margin of error.
It might be possible to have a menu item that will calibrate a lens, but I thought the problems with lenses were the firmware installed on the ROM chip in the lens. Ultimately lenses should go the way of Sigma with the USB dock for fine adjustments of the in lens chips. Perhaps with every generation of camera comes new firmware which makes certain accessories unusable like flashes and lenses.

---------- Post added 12-03-14 at 09:28 PM ----------

QuoteOriginally posted by Mistral75 Quote
Ricoh were just (11 November 2014) granted a patent on a translucent mirror with adjustable transmission rate: light transmission rate is adjustable from 50 to 100%, i.e. reflection rate varies from 50 to 0%.

Ricoh ???????????????????????????????So-net???

With such a device, you can either, and successively, improve the efficiency of the autofocus sensor in low light by increasing the reflection rate and improve that of the image sensor by increasing the transmission rate (SLT scheme with an electronic viewfinder) or, if you keep the optical viewfinder (Pellix scheme), successively improve the brightness of the viewfinder by increasing the reflection rate then the efficiency of the imaging sensor in increasing the transmission rate.

The better of both worlds.
Your link shows the patent was filed in 2013. It sounds very interesting,it will be interesting to see a Pentax product with this technology in it. It looks like it can solve the mirror slap problem, and retain the K-mount. It must be one of those special pieces of "Smart Glass" or something.
12-03-2014, 06:57 AM   #38
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This could be great for mirrorless, if the removed the mirror slap and the machanical shutter it would be very quiet. Also if they could somehow move the electronics behind the sensor to another location and just have the lcd (not sure if this is possible) behind the sensor, then they could reduce the thickness. Finally without the pentrism it would be very light. If they did all of this and gave it a retro look like the old mx with a very good build quality it would be a hit.

Just saying

---------- Post added 12-03-14 at 07:05 AM ----------

QuoteOriginally posted by Belnan Quote
This could be great for mirrorless, if the removed the mirror slap and the machanical shutter it would be very quiet. Also if they could somehow move the electronics behind the sensor to another location and just have the lcd (not sure if this is possible) behind the sensor, then they could reduce the thickness. Finally without the pentrism it would be very light. If they did all of this and gave it a retro look like the old mx with a very good build quality it would be a hit.

Just saying
Acually just remove the rear lcd altogether and use the electronic veiwfinder and could litterally be a modern clone of the old mx.

Hey wasnt there a rumor about a camera without a rear lcd?

12-03-2014, 07:12 AM   #39
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Sorry, but...
- this is a mirror, the result can't be a mirrorless camera
- its purpose is to reflect part of the light to an optical viewfinder, the pentaprism will stay.
12-03-2014, 07:48 AM   #40
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QuoteOriginally posted by Mistral75 Quote
Semi-transparent stationary reflex mirror in an SLR is nothing new. Canon Pellix in 1965 used such mirror to let about two-thirds of the light from the lens pass directly through to the film, while the rest was reflected to the viewfinder and CdS meter cell for the TTL exposure measurement.

Sony's Single-Lens Translucent technology uses a semi-transparent fixed mirror which diverts about 30% of the incoming light to a phase-detection autofocus sensor, while the remaining 70% strikes the image sensor, which in turn feeds the electronic viewfinder. This design allows for full-time phase-detection autofocus during electronic viewfinder, live view, and video recording operation.

The drawback of these technologies is the loss of light:

- Canon Pellix: about - 0.5 EV in the exposure through the semitransparent mirror and about - 1.7 EV dimmer finder compared to using a fully reflecting mirror
- Sony SLT: about - 0.5 EV in exposure because of the portion of incoming light diverted to the autofocus sensor.

Ricoh were just (11 November 2014) granted a patent on a translucent mirror with adjustable transmission rate: light transmission rate is adjustable from 50 to 100%, i.e. reflection rate varies from 50 to 0%.

Ricoh ???????????????????????????????So-net???

With such a device, you can either, and successively, improve the efficiency of the autofocus sensor in low light by increasing the reflection rate and improve that of the image sensor by increasing the transmission rate (SLT scheme with an electronic viewfinder) or, if you keep the optical viewfinder (Pellix scheme), successively improve the brightness of the viewfinder by increasing the reflection rate then the efficiency of the imaging sensor in increasing the transmission rate.

The better of both worlds.
How fast can a mirror like this switch between 50% and 100%? It sounds like cool technology and I would love to see it if it works really well.
12-03-2014, 07:49 AM   #41
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QuoteOriginally posted by Belnan Quote
This could be great for mirrorless, if the removed the mirror slap and the machanical shutter it would be very quiet. Also if they could somehow move the electronics behind the sensor to another location and just have the lcd (not sure if this is possible) behind the sensor, then they could reduce the thickness. Finally without the pentrism it would be very light. If they did all of this and gave it a retro look like the old mx with a very good build quality it would be a hit.

Just saying

---------- Post added 12-03-14 at 07:05 AM ----------



Acually just remove the rear lcd altogether and use the electronic veiwfinder and could litterally be a modern clone of the old mx.

Hey wasnt there a rumor about a camera without a rear lcd?
Sorry, but for me is hard to understand. What is so great at the old cameras design? I've used it, cause I'm not young anymore, and I still have 2 of my old film cameras, but from my point of view, the contemporary design of DSLR is much, much better.

A camera without rear LCD? Today? Are you kidding? Will be the shortest way to disaster.
12-03-2014, 08:14 AM   #42
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QuoteOriginally posted by JimmyDranox Quote
Sorry, but for me is hard to understand. What is so great at the old cameras design? I've used it, cause I'm not young anymore, and I still have 2 of my old film cameras, but from my point of view, the contemporary design of DSLR is much, much better.

A camera without rear LCD? Today? Are you kidding? Will be the shortest way to disaster.
I was somewhat joking about the no lcd thing on the back, I would want it. I agree it would be a failure, but it was mentioned in another rumor.
12-03-2014, 08:57 AM   #43
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QuoteOriginally posted by JimmyDranox Quote
A camera without rear LCD? Today? Are you kidding? Will be the shortest way to disaster.
Yeah. I once bought a KM but it didn't have a Memo Holder for the yellow end flap of the Kodachrome box.

I traded it in for a KX.





12-03-2014, 10:26 AM   #44
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QuoteOriginally posted by monochrome Quote
Yeah. I once bought a KM but it didn't have a Memo Holder for the yellow end flap of the Kodachrome box.

I traded it in for a KX.





Once ...when? I'm sure it was a film camera. Ohhh, I'd forget to say, a digital camera without a display will be a disaster. Or, maybe when we will be able to control the camera by telepathy, will be OK.
12-03-2014, 10:41 AM   #45
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QuoteOriginally posted by JimmyDranox Quote
(...)

A camera without rear LCD? Today? Are you kidding? Will be the shortest way to disaster.
Says who?



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