There was a post a short time ago regarding changing the stereo base
to use wide angle lenses on a TL-120 stereo camera. I see no reason
whatsoever for doing this. In the shots I've taken with 55mm lenses on
the standard 62mm base, I have yet to find somebody who notices the
difference between shots using 80mm lenses and 55mm lenses while
looking through a standard viewer. In the current folio I included a
shot of street buskers. I asked outright if anyone knew these were
wide angle shots. Here are the comments so far:

"No it didn't really click in these were wide angles. I remember Boris
Starosta once said that wide angle generate a sense of intimacy with
the subjects as the mind read suble cues that you are closer than
usual and maybe inside personal space. I did not feel that with this
scene."

"No sense that this is a wide shot, no distortion so the lenses are
very good. The extra depth of field from a wide lens is always welcome
with MF."

"i can't tell the difference with the wide angle lenses. good shot
though!"

In contrast, images I have taken with 180mm lenses are very distorted
and the effect is quite noticeable. Everything is a cardboard cutout,
very unnatural. I would recommend anyone trying wide angle lenses on
their Chinese MF3D camera, but I would not waste time and money on
telephoto lenses.

Sam

I would recommend anyone trying wide angle lenses on

> their Chinese MF3D camera, but I would not waste time and money on
> telephoto lenses.
>
> Sam
>

Hi Sam!

I looked in the internet for wideangle lenses and there are a few
photo shops offering some adapters with the factor 0.5x. That means
putting these lenses in front of my TL120 lenses would give me a 40mm
lens instead of the normal 80mm. Do you think, or anybody else here,
that this would be worth a try? Has anyone else tried to fix some
adapter lenses on the TL120 lenses? What experiences did you make?

I would be very interested in your answers before I buy some of these
wideangle lenses! Best regards, Chris

chrisjachner wrote:

> I looked in the internet for wideangle lenses and there
> are a few photo shops offering some adapters with the
> factor 0.5x.

There was discussion of this in the group around July.
I bought a pair but didn't like the image quality. I boxed
them up to return but never actually got them in the mail.
They are still sitting on the shelf by my front door :(

My note of July 3 can be found at:
http://tech.groups.yahoo.com/group/MF3D-group/message/1215

There followed a discussion of different wide angle adapters
which lasted a couple of weeks.
--
John Thurston
Juneau Alaska
http://stereo.thurstons.us

Chris,

My experience with this type of adapter lead to very poor results. I
used some in a trip to Thailand several years ago on my Stereopro, and
most were somewhat soft (especially at the edges) and had considerable
flare.

That said, if you get some at a good price it's worth the experiment.
Just make sure to take some shots without the adapter for backup!

Sam

--- In MF3D-group@yahoogroups.com, "chrisjachner"
wrote:

>
> I would recommend anyone trying wide angle lenses on
> > their Chinese MF3D camera, but I would not waste time and money on
> > telephoto lenses.
> >
> > Sam
> >
>
> Hi Sam!
>
> I looked in the internet for wideangle lenses and there are a few
> photo shops offering some adapters with the factor 0.5x. That means
> putting these lenses in front of my TL120 lenses would give me a 40mm
> lens instead of the normal 80mm. Do you think, or anybody else here,
> that this would be worth a try? Has anyone else tried to fix some
> adapter lenses on the TL120 lenses? What experiences did you make?
>
> I would be very interested in your answers before I buy some of these
> wideangle lenses! Best regards, Chris
>

Uhh, perhaps if this was missed... I REPLACED the 80mm lenses on my
TL-120 with true wideangle lenses, Mamiya 55mm Sekors. I did not use
an adapter.

Sam

> chrisjachner wrote:
>
>> I looked in the internet for wideangle lenses and there
>> are a few photo shops offering some adapters with the
>> factor 0.5x.
>
> There was discussion of this in the group around July.
> I bought a pair but didn't like the image quality. I boxed
> them up to return but never actually got them in the mail.
> They are still sitting on the shelf by my front door :(
>
> My note of July 3 can be found at:
> http://tech.groups.yahoo.com/group/MF3D-group/message/1215
>
> There followed a discussion of different wide angle adapters
> which lasted a couple of weeks.

At that time I did not bother posting pictures of my TL-120 with lens attachements on but if someone want to take a look at what one must not do :

http://www.patrickdube.ca/photos/20070709_TL120_37mm_WA/


BTW, I have finished my "MF20 Exhibition Cube" (this is how I call this thing ;-). Go to my web site ( http://www.patrickdube.ca ) and click on the TL120 thumbnail picture to see it.


Patrick



_________________________________________________________________
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It's' a beautiful display, Patrick.
But expensive ! Let's see, 20 viewers at $40 each is $800 for just the viewers.
And they are not even available anymore. That thing is going to be worth a fortune some day :-)

Bob

>*********** REPLY SEPARATOR ***********
>
>On 12/6/2007 at 8:24 PM Patrick Dube wrote:
>
>
>BTW, I have finished my "MF20 Exhibition Cube" (this is how I call this
>thing ;-). Go to my web site ( http://www.patrickdube.ca ) and click on
>the TL120 thumbnail picture to see it.
>
>Patrick
>

--- In MF3D-group@yahoogroups.com, "Bob Schlesinger" wrote:

>
> It's' a beautiful display, Patrick.
> But expensive ! Let's see, 20 viewers at $40 each is $800 for just

the viewers.

> And they are not even available anymore. That thing is going to be

worth a fortune some day :-)

That would be nice. I just finished an 8-viewer gig in the vein of
Franklin Londin. Of course I built LED light boxes for each gooseneck-
mounted viewer, only to learn that 3DWorld will soon supply some
version of such (probably no more expensive and much less work for
me!). Such is the story of (my) life......

But, compare the cost of 20 viewers (more like $30 each from DrT :-).
You get twice as many views as the ugly rotary vending-machine viewer,
and multiple stations for those huge crowds of MF'ers. Nice Patrick.

John

> To: MF3D-group@yahoogroups.com
> From: bob@bobschlesinger.com
> Date: Thu, 6 Dec 2007 17:41:54 -0800
> Subject: [MF3D-group] Re: Exhibition Cube (was Wide Angled Lenses on TL-120)
>
>
> It's' a beautiful display, Patrick.

Thanks for your comment Bob!

> But expensive ! Let's see, 20 viewers at $40 each is $800 for just the viewers.

Fortunately I paid a bit less than 30$ (shipping included) for each viewer but the total cost for the whole project was more than I expected. The machined cut acrylic plaques I designed to mask each viewer cost 22$ each if I remember correctly.


Now I'm faced at a bigger challenge: Taking pictures that I'm really proud of to put in those 20 viewers :-)


Patrick
_________________________________________________________________
Exercise your brain! Try Flexicon!
http://puzzles.sympatico.msn.ca/chicktionary/index.html?icid=htmlsig

>That would be nice. I just finished an 8-viewer gig in the vein of
>Franklin Londin. Of course I built LED light boxes for each gooseneck-
>mounted viewer, only to learn that 3DWorld will soon supply some
>version of such (probably no more expensive and much less work for
>me!). Such is the story of (my) life......
>

I also wish I didn't have to build the LED light boxes and use the next version of the 3D World viewers but knowing that this updated viewer will also have focusing abilities I'm glad I used the discontinued ones. I wanted full idiot proof viewers so the last thing I wanted is people touching (and probably breaking) the focusing adjustment and later having other people not getting a sharp image and not knowing why...

Patrick
_________________________________________________________________
Use fowl language with Chicktionary. Click here to start playing!
http://puzzles.sympatico.msn.ca/chicktionary/index.html?icid=htmlsig

--- In MF3D-group@yahoogroups.com, Patrick Dube
wrote:

> I also wish I didn't have to build the LED light boxes and use the

next version of the 3D World viewers but knowing that this updated
viewer will also have focusing abilities I'm glad I used the
discontinued ones. I wanted full idiot proof viewers so the last thing
I wanted is people touching (and probably breaking) the focusing
adjustment and later having other people not getting a sharp image and
not knowing why...

I hadn't thought of that aspect. Good point.

I can't see too well in the normal viewer without using reading
glasses. I suppose anyone with similar issues always takes such when
going to an art gallery, etc., but maybe not. Looking forward to
seeing what the new version looks like.

John

I've found that contrary to the manufacturer's publicity, wide angle
and telephoto adapters change the exposure characteristics as well.
If you're using print film, this isn't a problem, but with slide film -
you might end up running a few rolls through before you get the
exposure dead on. Again, the manufacturers will claim that these
devices are exposure neutral, but in my experience they will change
the relative value of your apertures - which can only be corrected
through trial and error.
Steve

coronet3d wrote:

> I've found that contrary to the manufacturer's publicity,
> wide angle and telephoto adapters change the exposure
> characteristics as well. If you're using print film, this
> isn't a problem, but with slide film - you might end up
> running a few rolls through before you get the exposure
> dead on. Again, the manufacturers will claim that these
> devices are exposure neutral, but in my experience they
> will change the relative value of your apertures - which
> can only be corrected through trial and error.

I don't understand, Steve. Please help.

If the adapters are changing the values of my apertures, why
will they not change them in proportion to their
focal-length multiplier?

If I have an 80mm lens, an aperture of f/10 would be an
opening of 8mm. Wouldn't it?

If I take that same opening but slap a .5 multiplier on it,
I'll have a 40mm lens with an 8mm aperture which is f/5.
Isn't it?
--
John Thurston
Juneau Alaska
http://stereo.thurstons.us

--- In MF3D-group@yahoogroups.com, John Thurston wrote:

> If I have an 80mm lens, an aperture of f/10 would be an
> opening of 8mm. Wouldn't it?
>
> If I take that same opening but slap a .5 multiplier on it,
> I'll have a 40mm lens with an 8mm aperture which is f/5.
> Isn't it?
> --
> John Thurston
> Juneau Alaska
> http://stereo.thurstons.us
>

As I would understand it. If you have an 80mm lens and the aperture
is 10mm and you add a .5 multiplier, it is still an 80mm lens and
10mm aperture, only with a wider angle of coverage. Any change in
exposure is a result of light passing through those extra elements,
which will be minimal.
To change the f-number, you need an actual change in focal length
such as a 35-70, f:3.5-4 zoom. Now to make it more confusing look at
the Nikon 16mm fisheye lens. How can this lens have a 180* angle of
view if a 15mm lens has an angle of 110*? Other 180* lenses are 8mm
and 10mm. Evidently angle of view is not dependent on focal length.

I have noticed that using these suppimental lenses, that the focus
distance changes; so don't rely on the distance scale. You may know
the Steinhill Redufocus. They call it that because you need to redo
the focus. 25ft is focused at 15ft or so.

Rod S

--- In MF3D-group@yahoogroups.com, "roderickdsage" wrote:

>
> --- In MF3D-group@yahoogroups.com, John Thurston wrote:
>
> > If I have an 80mm lens, an aperture of f/10 would be an
> > opening of 8mm. Wouldn't it?
> >
> > If I take that same opening but slap a .5 multiplier on it,
> > I'll have a 40mm lens with an 8mm aperture which is f/5.
> > Isn't it?
> > --
> > John Thurston
> > Juneau Alaska
> > http://stereo.thurstons.us
> >
>
> As I would understand it. If you have an 80mm lens and the aperture
> is 10mm and you add a .5 multiplier, it is still an 80mm lens and
> 10mm aperture, only with a wider angle of coverage. Any change in
> exposure is a result of light passing through those extra elements,
> which will be minimal.
> To change the f-number, you need an actual change in focal length
> such as a 35-70, f:3.5-4 zoom. Now to make it more confusing look

at

> the Nikon 16mm fisheye lens. How can this lens have a 180* angle of
> view if a 15mm lens has an angle of 110*? Other 180* lenses are 8mm
> and 10mm. Evidently angle of view is not dependent on focal length.
>
> I have noticed that using these suppimental lenses, that the focus
> distance changes; so don't rely on the distance scale. You may know
> the Steinhill Redufocus. They call it that because you need to redo
> the focus. 25ft is focused at 15ft or so.
>
> Rod S
>

Hi All,
It really all comes down to the quality of the engineering
and what equipment it is meant to work with. It can be like trying to
put a GM gearbox on a Ford. In 2001 I bought an Olympus E-10 digital
SLR which has a fixed 4x zoom lens, 35-140mm(equiv.)F2.0-F2.4 , for
which I bought the add-on wide and tele converters to take it out to
28mm & 200mm respectively. These high quality screw-ons were totally
designed to work with the main lens perfectly without decreasing the
light gathering power,ie with the wide, it's still F2, and with the
tele, it's still F2.4 , with no focus shift at all, and without loss
of sharpness. To achieve this the objective diameters are
considerably larger than the main lens, and IMO, this is the heart of
the matter. If the add-on lens is large enough compared to the main
lens, there won't be any light loss ,and if it is SPECIFICALLY
designed for the lens in question, no focal shift, for which of
course these generic add-ons don't qualify. Personally, I wouldn't
touch them.
Cheers, Peter

> Hi All,
> It really all comes down to the quality of the engineering
> and what equipment it is meant to work with. It can be like trying to
> put a GM gearbox on a Ford. In 2001 I bought an Olympus E-10 digital
> SLR which has a fixed 4x zoom lens, 35-140mm(equiv.)F2.0-F2.4 , for
> which I bought the add-on wide and tele converters to take it out to
> 28mm & 200mm respectively. These high quality screw-ons were totally
> designed to work with the main lens perfectly without decreasing the
> light gathering power,ie with the wide, it's still F2, and with the
> tele, it's still F2.4 , with no focus shift at all, and without loss
> of sharpness. To achieve this the objective diameters are
> considerably larger than the main lens, and IMO, this is the heart of
> the matter. If the add-on lens is large enough compared to the main
> lens, there won't be any light loss ,and if it is SPECIFICALLY
> designed for the lens in question, no focal shift, for which of
> course these generic add-ons don't qualify. Personally, I wouldn't
> touch them.
> Cheers, Peter
>

Hi Peter!
If I understand you right, it would be possible to create a wide angle
lens for the TL120, that would deliver good pictures?! So, it`s just a
question of quality and the right "coordination" with the main lens on
the camera?! If so, we should ask the 3D World crew to design such a
lens for the TL120 and sell it to us for e reasonable price!!!
Kind regards, Chris

--- In MF3D-group@yahoogroups.com, "chrisjachner"
wrote:

> Hi Peter!
> If I understand you right, it would be possible to create a wide angle
> lens for the TL120, that would deliver good pictures?! So, it`s just a
> question of quality and the right "coordination" with the main lens on
> the camera?! If so, we should ask the 3D World crew to design such a
> lens for the TL120 and sell it to us for e reasonable price!!!
> Kind regards, Chris
>

Hi Chris,
My point exactly, but I wouldn't hold my breath waiting for 3D World to
help us out on that one! The market just isn't big enough. We can wish
though.
Cheers, Peter

--- In MF3D-group@yahoogroups.com, John Thurston
wrote:

> I don't understand, Steve. Please help.
>
> If the adapters are changing the values of my apertures, why
> will they not change them in proportion to their
> focal-length multiplier?
>
> If I have an 80mm lens, an aperture of f/10 would be an
> opening of 8mm. Wouldn't it?
>
> If I take that same opening but slap a .5 multiplier on it,
> I'll have a 40mm lens with an 8mm aperture which is f/5.
> Isn't it?

I'm not a lens engineer so I'm just guessing why I've encountered
exposure errors using these devices. A more knowledgable friend
told me that it's due to "bellows effect". All I'm saying is if you
use one of these devices don't be surprised to find your exposure
fouled up. The only "fix" I've found is to run a few rolls through
and adjust accordingly. It would be nice to see some "true" WA
lenses mounted on the TL120. Maybe then I'd buy one.
Steve