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Subject: The optics mentioned.
Date: 2012-08-31 17:27:02
From: David Richardson

Hello again.

The lens out of place is the final one a user looks through when looking into the prism viewfinder.

The original "Taking" lenses are all fine. This is the very last element of the 45 degree angle prism.

It is the lens out of which the ground glass of the inner camera is observable.

Subject: Re: The optics mentioned.
Date: 2012-09-01 22:22:36
From: John Thurston

On 8/31/2012 3:26 PM, David Richardson wrote:

> Hello again.
> The lens out of place is the final one a user looks through when looking into the prism viewfinder.
> The original "Taking" lenses are all fine. This is the very last element of the 45 degree angle prism.
> It is the lens out of which the ground glass of the inner camera is observable.

Is this the element in question?
http://www.alaska.net/~thurston/images/IMG_9824a.JPG

If so, my stress level just went way down. The _worst_ case
scenario is that you will have to replace the finder with one
from a Kiev or Hasselbad. The meter in the camera would no
longer work, but everything else would be fine.

There were several versions of the prism. Can you tell us if
your 45-degree prism permits focus ("diopter") adjustments?
________________________________________
John Thurston
Juneau, Alaska
http://stereo.thurstons.us

Subject: Re: The optics mentioned.
Date: 2012-09-03 08:10:38
From: David Richardson

Yes John,

That optic depicted is the one out of place. If someone has a dead camera body for whatever reason, I'd be interested in perhaps purchase of a spare. Somewhere in the house is a Kiev waistlevel finder who's location is unknown.

From: John Thurston
To: MF3D-group@yahoogroups.com
Sent: Saturday, September 1, 2012 9:22 PM
Subject: Re: [MF3D-group] The optics mentioned.

On 8/31/2012 3:26 PM, David Richardson wrote:
> Hello again.
> The lens out of place is the final one a user looks through when looking into the prism viewfinder.
> The original "Taking" lenses are all fine. This is the very last element of the 45 degree angle prism.
> It is the lens out of which the ground glass of the inner camera is observable.

Is this the element in question?
http://www.alaska.net/~thurston/images/IMG_9824a.JPG

If so, my stress level just went way down. The _worst_ case
scenario is that you will have to replace the finder with one
from a Kiev or Hasselbad. The meter in the camera would no
longer work, but everything else would be fine.

There were several versions of the prism. Can you tell us if
your 45-degree prism permits focus ("diopter") adjustments?
________________________________________
John Thurston
Juneau, Alaska
http://stereo.thurstons.us/

Subject: Re: The optics mentioned.
Date: 2012-09-03 08:16:04
From: Bob Aldridge

I've used a Hasselblad waist level finder on my Chinese camera since very soon after I got it.

That camera is heavy enough to start with without mounting a ton of glass on top as well!

Bob Aldridge

On 03/09/2012 15:10, David Richardson wrote:

Yes John,

That optic depicted is the one out of place. If someone has a dead camera body for whatever reason, I'd be interested in perhaps purchase of a spare. Somewhere in the house is a Kiev waistlevel finder who's location is unknown.

From: John Thurston
To: MF3D-group@yahoogroups.com
Sent: Saturday, September 1, 2012 9:22 PM
Subject: Re: [MF3D-group] The optics mentioned.

On 8/31/2012 3:26 PM, David Richardson wrote:
> Hello again.
> The lens out of place is the final one a user looks through when looking into the prism viewfinder.
> The original "Taking" lenses are all fine. This is the very last element of the 45 degree angle prism.
> It is the lens out of which the ground glass of the inner camera is observable.

Is this the element in question?
http://www.alaska.net/~thurston/images/IMG_9824a.JPG

If so, my stress level just went way down. The _worst_ case
scenario is that you will have to replace the finder with one
from a Kiev or Hasselbad. The meter in the camera would no
longer work, but everything else would be fine.

There were several versions of the prism. Can you tell us if
your 45-degree prism permits focus ("diopter") adjustments?
________________________________________
John Thurston
Juneau, Alaska
http://stereo.thurstons.us/

Subject: Re: The optics mentioned.
Date: 2012-09-03 10:07:59
From: John Thurston

> On 8/31/2012 3:26 PM, David Richardson wrote:
>> Hello again.
>> The lens out of place is the final one a user looks through when looking into the prism viewfinder.
>> The original "Taking" lenses are all fine. This is the very last element of the 45 degree angle prism.
>> It is the lens out of which the ground glass of the inner camera is observable.
>
> Is this the element in question?
> http://www.alaska.net/~thurston/images/IMG_9824a.JPG
>
> If so, my stress level just went way down. The _worst_ case
> scenario is that you will have to replace the finder with one
> from a Kiev or Hasselbad. The meter in the camera would no
> longer work, but everything else would be fine.
>
> There were several versions of the prism. Can you tell us if
> your 45-degree prism permits focus ("diopter") adjustments?

On 9/3/2012 7:10 AM, David Richardson wrote:
>> Yes John,
>> That optic depicted is the one out of place. If someone has a dead camera body for whatever reason, I'd be interested in perhaps purchase of a spare. Somewhere in the house is a Kiev waistlevel finder who's location is unknown.

I'd call that the eyepiece of the prism finder.
Now, it's a question of how to return it to is proper location.

I have two different 3D-World prisms. My 90-dgree prism does not have a
focus adjust, but its eyepiece is held in with a simple, threaded
retaining ring. My 45-degree prism does have a focus adjust, and I
suspect that its eyepiece has to be removed from the prism to affect
repairs. (because I can detect no way to remove the outer ring).

Is your 45-degree prism focusing? If not, we can ask someone else
on-list who has a fixed-focus prism to help you out.

As for just getting a replacement 3D World prism, don't be so sure it
will be that easy. The reason to use the 3D World instead of a Kiev or
Hasselbad prism is for the metering. If you don't need the metering,
then grab a (relatively) easily available replacement finder and move on
with your life. If you want the in-camera meter to work, you'll have to
find a replacement 3D World prism of the right type.

The 3D World prism includes the metering element for the camera (the
rest of the meter circuit is in the camera body). I am aware of at least
four different types of metering in these cameras. There were three
different types of electrically connected sensors, and at least one type
of optically connected sensor. (Given 3D World's history, I doubt there
was only one optical type, but that is just doubt and suspicion.) If you
do find a replacement 3D world prism, it must be the right type and you
will probably have to adjust the meter circuit in the camera to
calibrate it for the new sensor.

Can you provide us with any more information, Richard?
Where are you located?
Is the eyepiece focusing or not?
A photo of the eyepiece?

John Thurston
Juneau, Alaska

Subject: Re: The optics mentioned.
Date: 2012-09-03 16:54:48
From: David Richardson

Thanks John,

The lens is the final one and is the one depicted in your photo. What I was hoping for was some advice from Dr.T3D as to where repairs were possible. I live in Washington State near Port Townsend. The degree of focus gained by the threaded outlet off the 45% prism focuses minimally.

I can still focus the camera in the normal manner. The image doesn't appear to change focus point when the knob is turned. Only the ground glass plate changes focus via the from linked optics. I'm just hopeful that I can keep dust out of the optical train.

From: John Thurston
To: MF3D-group@yahoogroups.com
Sent: Monday, September 3, 2012 9:08 AM
Subject: Re: [MF3D-group] The optics mentioned.

> On 8/31/2012 3:26 PM, David Richardson wrote:
>> Hello again.
>> The lens out of place is the final one a user looks through when looking into the prism viewfinder.
>> The original "Taking" lenses are all fine. This is the very last element of the 45 degree angle prism.
>> It is the lens out of which the ground glass of the inner camera is observable.
>
> Is this the element in question?
> http://www.alaska.net/~thurston/images/IMG_9824a.JPG
>
> If so, my stress level just went way down. The _worst_ case
> scenario is that you will have to replace the finder with one
> from a Kiev or Hasselbad. The meter in the camera would no
> longer work, but everything else would be fine.
>
> There were several versions of the prism. Can you tell us if
> your 45-degree prism permits focus ("diopter") adjustments?

On 9/3/2012 7:10 AM, David Richardson wrote:
>> Yes John,
>> That optic depicted is the one out of place. If someone has a dead camera body for whatever reason, I'd be interested in perhaps purchase of a spare. Somewhere in the house is a Kiev waistlevel finder who's location is unknown.

I'd call that the eyepiece of the prism finder.
Now, it's a question of how to return it to is proper location.

I have two different 3D-World prisms. My 90-dgree prism does not have a
focus adjust, but its eyepiece is held in with a simple, threaded
retaining ring. My 45-degree prism does have a focus adjust, and I
suspect that its eyepiece has to be removed from the prism to affect
repairs. (because I can detect no way to remove the outer ring).

Is your 45-degree prism focusing? If not, we can ask someone else
on-list who has a fixed-focus prism to help you out.

As for just getting a replacement 3D World prism, don't be so sure it
will be that easy. The reason to use the 3D World instead of a Kiev or
Hasselbad prism is for the metering. If you don't need the metering,
then grab a (relatively) easily available replacement finder and move on
with your life. If you want the in-camera meter to work, you'll have to
find a replacement 3D World prism of the right type.

The 3D World prism includes the metering element for the camera (the
rest of the meter circuit is in the camera body). I am aware of at least
four different types of metering in these cameras. There were three
different types of electrically connected sensors, and at least one type
of optically connected sensor. (Given 3D World's history, I doubt there
was only one optical type, but that is just doubt and suspicion.) If you
do find a replacement 3D world prism, it must be the right type and you
will probably have to adjust the meter circuit in the camera to
calibrate it for the new sensor.

Can you provide us with any more information, Richard?
Where are you located?
Is the eyepiece focusing or not?
A photo of the eyepiece?

John Thurston
Juneau, Alaska

Subject: Re: The optics mentioned.
Date: 2012-09-03 19:23:37
From: John Thurston

On 9/3/2012 3:54 PM, David Richardson wrote:

> Thanks John,
> The lens is the final one and is the one depicted in your photo. What I was hoping for was some advice from Dr.T3D as to where repairs were possible.

Ahhh. Your original message left me with the impression you were hoping
to fix this yourself. There is no one I can suggest to you as a repair
technician.
If you want to reach George Themelis, check his web page for an email
address: http://www.drt3d.com/
(I won't paste it here because yahoo will just strip it)

> The degree of focus gained by the threaded outlet off the 45% prism focuses minimally.

But it does focus. So it is likely the same version as mine.
I see no easy way to get into the focusing eyepiece. I suspect you will
need to get into the prism housing (likely from the bottom) to reach the
eyepiece.

> I can still focus the camera in the normal manner. The image doesn't appear to change focus point when the knob is turned.

Right. The focus on the eyepiece is only to accommodate differences in
vision. It does not affect the focus of the camera.

John Thurston
Juneau, Alasak