Trivia question

[MediaMagic]

Why is a zoom lens that you twist to zoom called a "two touch" zoom?

[garethhhhh]

A one touch zoom / push pull zoom is so named because it slides in and out like a telescope (and keeps focus at the same time), with a two touch zoom however, you zoom with one ring & focus with the other (you have to touch the lens twice). :wink:

[MediaMagic]

Nice call!

Well, that one certainly didn't last long! less than 10 views! I should have known that question wouldn't last long in this group. :D

Okay, maybe someone else can ask another? could be fun to keep the thread going with some interesting photo trivia.

[iwatkins]

OK, I'll have a go.

Why is an f-stop called an "f-stop" ?

Cheers

Ian

[maderito]

OK, I'll have a go.

Why is an f-stop called an "f-stop" ?

Cheers

Ian
-f stands for focal length (as in ratio of focal length to aperture)

-I vaguely recall that f-stops refer to positions (stops) on a dial.

Do I get 1/2 point if I'm half right?

Do I get a second chance? Like stop = stopping light?

Do you subtract points for wrong answers? What about ties?

Good question :)

[IndyJeff]

garethhhhhh gave a good logical answer there but, in reality the zoom lens is named for Wilson G. Zoom. The man who invented it back in the late 30's.

[PacAce]

garethhhhhh gave a good logical answer there but, in reality the zoom lens is named for Wilson G. Zoom. The man who invented it back in the late 30's.

When I was visiting relatives on my father's side living in the Philippines, my uncle (by marriage) said that the florescent light bulb was invented by and named after a Filipino whose last name was Floro. So as not to embarrass him I just nodded my head and then walked away with a smile and this on my face: :roll:

I wonder if Mr. Floro knew Mr. Zoom? ???

[PeterS45]

Next question: there's a shutter speed without the letter 'B'.

What does it stand for?

[maderito]

garethhhhhh gave a good logical answer there but, in reality the zoom lens is named for Wilson G. Zoom. The man who invented it back in the late 30's.

When I was visiting relatives on my father's side living in the Philippines, my uncle (by marriage) said that the florescent light bulb was invented by and named after a Filipino whose last name was Floro. So as not to embarrass him I just nodded my head and then walked away with a smile and this on my face: :roll:

I wonder if Mr. Floro knew Mr. Zoom? ???

I don't believe so. Mr. Zoom traveled to Japan in the 1960's and met Mr. Kanon and Mr. Loo. On a bright October morning while watching a sunrise, they conceived of the first "Canon Zoom" lens. After some argument, they agreed to call it an "L" lens in recognition of Mr. Loo's contribution - thought to be quite minor at the time.

[Tom W]

OK, I'll have a go.

Why is an f-stop called an "f-stop" ?

Cheers

Ian

Manderito is correct, but there's more.

The f-stop is a ratio of focal length to aperture. In f/1.0, the focal length equals the aperture opening, thus producing a ratio of 1:1. The next setting on the dial, or "stop" is f/1.4. In this case, the aperture equals the focal length of the lens divided by 1.4.

Why this odd number? Because that is the ratio of focal length to aperture that provides 1/2 the light passage through the lens as the previous stop. Each progressive full stop allows half the light as the previous one, so f/2.0 allows half the light of f/1.4 and so on.

The word "stop" simply indicates a setting on the aperture dial that coincides with the doubling or halving of light passage - it is a logical place to stop given that shutter speed is (or was in those days) adjustable in a similar doubling or halving manner. So changing by 1 f-stop provides an equal light increment to changing the shutter speed by 1 increment (for example, from 1/125 to 1/250, a doubling of shutter speed and a halving of the amount of time that light hits the film or sensor).

I don't know why I chose to write a book....

[Tom W]

Next question: there's a shutter speed without the letter 'B'.

What does it stand for?

Its "X". Flash synchronization speed, usually 1/60 second. This synchronization setting allowed the camera's shutter to synch with the bulb-type flash that was the norm "back in the day". :)

[Belmondo]

Next question: there's a shutter speed without the letter 'B'.

What does it stand for?

B stands for Bulb. (If that's your question). I think it referes to squeeze bulbs that activated the shutter. As long as you squeezed the bulb, the shutter stayed open. Today, the shutter stays open as long as the shutter release is pressed when using the B setting.

I think.

Maybe

Perhaps

Possibly

[PeterS45]

B stands for Bulb. (If that's your question). I think it referes to squeeze bulbs that activated the shutter. As long as you squeezed the bulb, the shutter stayed open. Today, the shutter stays open as long as the shutter release is pressed when using the B setting.

I think.

Maybe

Perhaps

Possibly

Almost right. For some reason the Japanese manufacturers changed it into bulb, as in light-bulb, but in fact it is from the word "Ball" because the first (very prehistoric) cameras used a rubber ball you had to squeeze to open the lens for a few seconds. I still own a camera (about 25 years old) where it says "Ball" instead of just "B".

[MediaMagic]

garethhhhhh gave a good logical answer there but, in reality the zoom lens is named for Wilson G. Zoom. The man who invented it back in the late 30's.

When I was visiting relatives on my father's side living in the Philippines, my uncle (by marriage) said that the florescent light bulb was invented by and named after a Filipino whose last name was Floro. So as not to embarrass him I just nodded my head and then walked away with a smile and this on my face: :roll:

I wonder if Mr. Floro knew Mr. Zoom? ???

I don't believe so. Mr. Zoom traveled to Japan in the 1960's and met Mr. Kanon and Mr. Loo. On a bright October morning while watching a sunrise, they conceived of the first "Canon Zoom" lens. After some argument, they agreed to call it an "L" lens in recognition of Mr. Loo's contribution - thought to be quite minor at the time.

Funny story how these guys actually met... Prior to their watching of the sunrise, they had been up all night. They had attended a rather large Japanese party and all of them had eaten tons of nachos made with imported refried Mexican Jumping beans (wrapped in seaweed of course). Well, needless to say Montezuma had his revenge. As they were all waiting in line to use the one imported, um, receptical, a merry woman, Dawn, who was responsible for the "unit" initiated a conversation in which all joined in and began exchanging ideas. Interestingly enough, the lady, whose maiden name was Keye married into a wealthy family of Porcelein Receptical designers. Her full name, Dawn Keye-Crapper.

And now you know... the rest of the story. Isn't photo trivia a hoot? true story there.. :shock:

[stopbath]

Next question: there's a shutter speed without the letter 'B'.

What does it stand for?
If a shutter speed is "without" the letter 'B' then it would be one of the 'others'... Others being 'T', 'X' or a numerical value.

Numerical values would be shutter speeds.
The T would stand for Time.
The X would be the speed at which both shutter curtains are open at once.
A highlighted speed would be the default mechanical speed (no batteries) or the sync speed.
A range of highlighted speeds would denote slow or fast speeds.

Trivia: How does 'T' setting differ from 'B'?

[PeterS45]

Next question: there's a shutter speed without the letter 'B'.

What does it stand for?
If a shutter speed is "without" the letter 'B' then it would be one of the 'others'... Others being 'T', 'X' or a numerical value.

Trivia: How does 'T' setting differ from 'B'?

Okay, you're right. But considering English is not my native language I hope I'm forgiven :oops:

But the text should be ....... speed without numbers but with the letter 'B'.......


Well, the 'X' should be the flash setting because the hot-shoe was also called the X-contact.
But the 'T'? You got me, but give me a few minutes and I should be able te come with the answer (I hope).

[stopbath]

Okay, you're right. But considering English is not my native language I hope I'm forgiven :oops:

But the text should be ....... speed without numbers but with the letter 'B'.......


Well, the 'X' should be the flash setting because the hot-shoe was also called the X-contact.
But the 'T'? You got me, but give me a few minutes and I should be able te come with the answer (I hope).

Forgiven, I misread it at first as "with B"... :)

I recall only one camera with both T and B on it, but I can't recall what camera it was... Some cameras may have T instead of B, and some may have it behave the same as B (since it's not a 'standard'.)

[PeterS45]

I recall only one camera with both T and B on it, but I can't recall what camera it was... Some cameras may have T instead of B, and some may have it behave the same as B (since it's not a 'standard'.)

How about the Canon III from 1951? it has the T as well as the B.

[PeterS45]

OK, found it.

The difference between the B & T (Bacon & Tomatoe??) is that when you use T the first press opens the shutter and the second press closes it again and with the B you have to press the shutter as long as you want to keep it open..... :lol:

[stopbath]

OK, found it.

The difference between the B & T (Bacon & Tomatoe??) is that when you use T the first press opens the shutter and the second press closes it again and with the B you have to press the shutter as long as you want to keep it open..... :lol:
Yes, exactly. Handy for timed shots without a locking cable release. :)

Ok, next question? Anyone?

[PacAce]

OK, so what's the difference between X and FP? ???

[PeterS45]

OK, so what's the difference between X and FP? ???


FP stands for Focal Plane. There's also Super FP:
Most auto flash provides an intense, short duration of 1/1000 - 1/100,000 sec flash burst, that can only expose the film correctly when the shutter is completely open which we normally termed it as workable sync speed; a Super FP flash emits a continuous series of short bursts, like a very fast stroboscope (Repeating flash), from the moment the first curtain starts to travel to the moment the second curtain arrives. This allows the flash to be synchronized at shutter speeds from 1/60 sec to 1/2000 sec. .

[PacAce]

OK, so what's the difference between X and FP? ???


FP stands for Focal Plane. There's also Super FP:
Most auto flash provides an intense, short duration of 1/1000 - 1/100,000 sec flash burst, that can only expose the film correctly when the shutter is completely open which we normally termed it as workable sync speed; a Super FP flash emits a continuous series of short bursts, like a very fast stroboscope (Repeating flash), from the moment the first curtain starts to travel to the moment the second curtain arrives. This allows the flash to be synchronized at shutter speeds from 1/60 sec to 1/2000 sec. .

Very good but I was more interested in the origin of these two terms (or letters).

[Tom W]

Well, the 'X' should be the flash setting because the hot-shoe was also called the X-contact.


I believe my old 1950's Argus has an "X" setting for flash, but nothing even remotely related to a flash shoe, except for two plug connectors on the side where the huge, D-cell powered flash was to be mounted. The camera's X setting used the 1/60 shutter speed and had electric contacts that made inside the camera to complete the circuit between the flash batteries and the disposable flash bulb (you could only use each bulb once).

I think that the "X" setting preceded hot-shoe technology by many years.

I wonder where one can get those flash bulbs these days....

[PeterS45]

I wonder where one can get those flash bulbs these days....

I'm afraid they're history and you'll need a time machine to go and buy some.

[stopbath]

I wonder where one can get those flash bulbs these days....

I'm afraid they're history and you'll need a time machine to go and buy some.
It seems that an Ireland company is making flashbulbs. Meggaflash sells three models http://www.meggaflash.com

Time to get that old folding camera out again. Used flashbulbs make great party treats!

[Tom W]

It seems that an Ireland company is making flashbulbs. Meggaflash sells three models http://www.meggaflash.com

Time to get that old folding camera out again. Used flashbulbs make great party treats!

I never would have expected that they would still be available. Still, I don't think I'll be firing up the old Argus flash any time soon. :)

[Jesper]

You can find a lot of definitions of terms in the dictionary at http://photonotes.org -
Bulb (http://photonotes.org/cgi-bin/entry.pl?id=Bulb)
X-sync (http://photonotes.org/cgi-bin/entry.pl?id=Xsync)
M-sync (http://photonotes.org/cgi-bin/entry.pl?id=Msync)
FP (http://photonotes.org/cgi-bin/entry.pl?id=FP)

Did you know there's not only the f-stop, but also the T-stop (http://photonotes.org/cgi-bin/entry.pl?id=Tstop)?
:wink:

[PacAce]

You can find a lot of definitions of terms in the dictionary at http://photonotes.org -
Bulb (http://photonotes.org/cgi-bin/entry.pl?id=Bulb)
X-sync (http://photonotes.org/cgi-bin/entry.pl?id=Xsync)
M-sync (http://photonotes.org/cgi-bin/entry.pl?id=Msync)
FP (http://photonotes.org/cgi-bin/entry.pl?id=FP)

Did you know there's not only the f-stop, but also the T-stop (http://photonotes.org/cgi-bin/entry.pl?id=Tstop)?
:wink:

<ding, ding, ding, ding>
OK, Jesper gets the prize for figuring out (point you to) what the diff is between the X sync and the FP synch! :)

Where should I mail the prize to? It's a pack of Sylvania Blue Dot flash bulbs! :) :mrgreen:

[stopbath]

You can find a lot of definitions of terms in the dictionary at http://photonotes.org -
Bulb (http://photonotes.org/cgi-bin/entry.pl?id=Bulb)
X-sync (http://photonotes.org/cgi-bin/entry.pl?id=Xsync)
M-sync (http://photonotes.org/cgi-bin/entry.pl?id=Msync)
FP (http://photonotes.org/cgi-bin/entry.pl?id=FP)

Did you know there's not only the f-stop, but also the T-stop (http://photonotes.org/cgi-bin/entry.pl?id=Tstop)?
:wink:
Thanks Jesper for the links.

And no, I didn't know about T-Stops! Excellent.

Quite the site, I even found stop bath (http://photonotes.org/cgi-bin/entry.pl?id=Stopbath)... :) :) :)

[Tom W]

Yes, Jesper, thanks. Good, informative link.

[4walls]

So why does Canon call the shutter priority mode on the camera Tv?

[PacAce]

So why does Canon call the shutter priority mode on the camera Tv?

Tv for Time Value and
Av for Aperture Value!