Hi all.
As I am reading threads with two days lag (the web version is
_that_ slow), it all might have been answered already. I address
the issue of "bellows factor" and its difference in tele or
wideangle slr lenses, as well as T stop.
1) f/stop can't be just focal length/front di
Kinda slams the door in the face of anyone not using ~your~ preferred
method, eh?
Regards,
Anthony Farr
- Original Message -
From: "Rob Brigham" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Monday, 24 September 2001 11:04 PM
Subject: RE: lens brightness
observation
is of little consiquence to the subject.
--graywolf
- Original Message -
From: PAUL STENQUIST <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Tuesday, September 25, 2001 5:46 AM
Subject: Re: lens brightness
> Motion pictures are shot on negative film. A positiv
"William Robb" <[EMAIL PROTECTED]> quotes:
> "The f number of the lens equals the focal length divided by the
> diameter of the entrance pupil of the aperture".
...and it's important to note, that the "entrance pupil" is _not_ the
physical front element of the lens (although with long focal leng
On Mon 2001-09-24 (09:19), Shel Belinkoff wrote:
> Martin Trautmann wrote:
> > Real numbers are not required: If it's not enough light, the exposure
> > meter will double your time, whether the selected aperture is called 2.8
> > or 3.5, whether it is a faked or real number, as long as you do need
- Original Message -
From: <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Monday, September 24, 2001 1:35 PM
Subject: Re: lens brightness
> OK folks, I hear what you are saying.
>
> Now, tell me how interchangeable lenses are used along with those fancy hand
hel
focal length
(25mm in this case). In this case Chris is right retro-focus lens are far
bulkier than non-retrofocus lens.
--graywolf
- Original Message -
From: Chris Brogden <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Monday, September 24, 2001 1:34 PM
Subject: Re: len
.
--graywolf
- Original Message -
From: Rofini <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Monday, September 24, 2001 1:03 PM
Subject: Re: lens brightness
> Shel wrote:
>
> >Well, Martin, there's a fly in your intellectual ointment: What
> >happens to ex
Wright <[EMAIL PROTECTED]>
To: PDML <[EMAIL PROTECTED]>
Sent: Monday, September 24, 2001 1:00 AM
Subject: lens brightness
> I have heard remarks that a 200/2.8 prime will transmit more light than an
> 80-200/2.8 zoom. Is this true? I thought a 200/2.8 was a 200/2.8 whether it
> be
- Original Message -
From: "Pål Jensen" <
Subject: Re: lens brightness
> Bob wrote:
>
> > Now, tell me how interchangeable lenses are used along with
those fancy hand held light meters. When you take out your
Pentax Spot Meter, do you adjust it every time yo
- Original Message -
From: <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Monday, September 24, 2001 11:35 AM
Subject: Re: lens brightness
> OK folks, I hear what you are saying.
>
> Now, tell me how interchangeable lenses are used along with
those fancy hand hel
- Original Message -
From: "Shel Belinkoff"
Subject: Re: lens brightness
> Ivan Prenosil wrote, re effective lens aperture:
>
> > It can't be (as people sometimes say on this list) as simple
as
> > lens diameter divided by focal length; otherwise my
FA
I'm just having a hard day an' I'm constipated.
Regards,
Bob...
---
"In the carboniferous epoch
we were promised perpetual peace.
They swore if we gave up our weapons
that the wars of the tribes would cease.
But when we disarmed they sold us,
and delivered us, bound, t
Bob Blakely wrote:
> Thank you for failing to properly attribute
> quotes. - and this from a group that is
> probably zealous about copyrights and proper
> tribulation of their photo work!
>
> Sheesh!
Sorry Bob, from work thru AOL Anywhere Mail, quoting is a miserable task - PITA. I
appreciate
The difference among f/stops on modern lenses with excellent coatings is (supposedly)
exceptionally small. Some zoom lenses may show differences when used with slides and
compared side to side with primes by someone with an exceptionally critical eye, I
suppose. I'll bet that even this us usually
Shel wrote:
> Since I use rangefinder cameras, hand-held meters, and even cameras
> with non-ttl metering, and the exposures are correct regardless of how
> I meter, and regardless of which lenses I use, how might that be
> explained?
It can only be explained with that you're not very critical
Bob wrote:
> Now, tell me how interchangeable lenses are used along with those fancy hand held
>light meters. When you take out your Pentax Spot Meter, do you adjust it every time
>you put a different lens on the camera? Oh, the T-value for that lens is 1/2 stop
>better than this one?
> (I'm
On Mon, 24 Sep 2001, Chris Brogden wrote:
>That might have something to do with lens-to-film distance. Maybe the
>smaller mount doesn't need as large an opening because it's closer to the
>film plane than the K-mount? (Total guess) That being said, it happens
[...]
No guess at all. Did every
Shel Belinkoff wrote:
[snip]
> ...I've noticed that newer lenses transmit more light than some
> older lenses, due in part, I'm sure, to the coatings used. F2.8 seems
> to be the same for all my newer lenses, but F2.8 is a little
> underexposed with some earlier lenses.
One of the American ma
Right.
And closely related to the info from Wheatfield Willie given earlier, f-stops are
computations of DOF. On many medium format cameras, esp. those with bellows focusing,
you'll see a scale on the side which instructs the user regarding exposure and focus
distance. Look at a photo of the
Hi,
I noticed the same thing today. Few days ago I bought M42 > Kmount
adapter to enable the recently acquired screw mount SMC Takumar
3,5/28. Just today I met with a friend who owns Carl Zeiss Jena
135/3.5 lens (which was made for Practica cameras and has M42 mount)
with intention to compare
t.fi/private/raimo.korhonen
-Alkuperäinen viesti-
Lähettäjä: [EMAIL PROTECTED] <[EMAIL PROTECTED]>
Vastaanottaja: [EMAIL PROTECTED] <[EMAIL PROTECTED]>
Päivä: 24. syyskuuta 2001 19:58
Aihe: Re: lens brightness
>OK folks, I hear what you are saying.
>
>Now, tell me h
-
Lähettäjä: Rofini <[EMAIL PROTECTED]>
Vastaanottaja: [EMAIL PROTECTED] <[EMAIL PROTECTED]>
Päivä: 24. syyskuuta 2001 19:48
Aihe: Re: lens brightness
>Shel wrote:
>
>Well, Martin, there's a fly in your intellectual ointment: What
>happens to exposure calculations w
Ivan Prenosil wrote, re effective lens aperture:
> It can't be (as people sometimes say on this list) as simple as
> lens diameter divided by focal length; otherwise my FA28-70/4
> could not be constant aperture zoom :-)
Hi ...
Like you, I don't believe it's as simple as diameter/focal length,
Rob Brigham wrote:
>
> Unless you set the aperture from the body - then you will know the
> aperture!
...except I can't do that with my LX, ME Super or 67. And yes, there
are zooms for the 67 (two of 'em!). :)
-Aaron
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Yes.
Note: The lenses of almost all motion picture cameras use T-stops (measure
of light transmission). At one time in the industry, before the excellent
coatings of today and when the lenses of these cameras were mounted on
turrets, there could be a significant difference between an f/stop and a
- Original Message -
From:
Subject: Re: lens brightness
> > I have heard remarks that a 200/2.8 prime will transmit more
> > light than an 80-200/2.8 zoom. Is this true? I thought a
> > 200/2.8 was a 200/2.8 whether it be a prime or part of a
zoom.
> > Thanks fo
On Mon 2001-09-24 (15:33), HUDERER Bernd wrote:
> Nowadays with automatic cameras constant aperture zooms got rare.
True: only some Pentax AF lenses have constant aperture values:
FA 20-35/4
F 24-50/4
FA 28-70/4
FA* 28-70/2,8
FA* 80-200/2,8
F* 250-600/5,6
FA* 250-600/5,6
That's only 7 out of
Martin Trautmann wrote:
> Constant aperture is done by adjustment 'tricks' of the
> efficient aperture
> - the diaphragm blades can be closed for shorter focal lengths.
>
> In fact I don't know why this should be done. 28-70/3.5-4.0 should be
> superior to 28-70/4.0!?
I suppose one point is, t
Unless you set the aperture from the body - then you will know the
aperture!
> -Original Message-
> From: Aaron Reynolds [mailto:[EMAIL PROTECTED]]
> Sent: 24 September 2001 13:43
> To: [EMAIL PROTECTED]
> Subject: Re: lens brightness
>
>
> Martin Trautmann
Martin Trautmann wrote:
> In fact I don't know why this should be done. 28-70/3.5-4.0 should be
> superior to 28-70/4.0!?
...unless you use a hand-held meter, in which case you won't be able to
set your exposure exactly because you don't know what aperture your lens
is at.
-Aaron
-
This message
Hi,
On 2001.09.24, at 20:39, [EMAIL PROTECTED] wrote:
>> I have heard remarks that a 200/2.8 prime will transmit more
>> light than an 80-200/2.8 zoom. Is this true? I thought a
>> 200/2.8 was a 200/2.8 whether it be a prime or part of a zoom.
>
> I'm with you 2.8 is 2.8. Two different lenses,
On Mon 2001-09-24 (13:32), Ivan Prenosil wrote:
> It can't be (as people sometimes say on this list) as simple as
> lens diameter divided by focal length; otherwise my FA28-70/4
> could not be constant aperture zoom :-)
Constant aperture is done by adjustment 'tricks' of the efficient aperture
-
On Mon 2001-09-24 (07:39), [EMAIL PROTECTED] wrote:
> > I have heard remarks that a 200/2.8 prime will transmit more
> > light than an 80-200/2.8 zoom. Is this true? I thought a
> > 200/2.8 was a 200/2.8 whether it be a prime or part of a zoom.
> > Thanks for any help.
>
> I'm with you 2.8 is 2.
> I have heard remarks that a 200/2.8 prime will transmit more
> light than an 80-200/2.8 zoom. Is this true? I thought a
> 200/2.8 was a 200/2.8 whether it be a prime or part of a zoom.
> Thanks for any help.
I'm with you 2.8 is 2.8. Two different lenses, if calibrated properly,
should delive
> I have heard remarks that a 200/2.8 prime will transmit more light than an
> 80-200/2.8 zoom. Is this true? I thought a 200/2.8 was a 200/2.8 whether it
> be a prime or part of a zoom.
I believe 2.8 should be "effective" aperture, i.e. it should reflect lens construction,
light loss in glass, e
. In any
case TTL metering would compensate automatically.
Regards
Nenad
- Original Message -
From: Nicholas Wright <[EMAIL PROTECTED]>
To: PDML <[EMAIL PROTECTED]>
Sent: Monday, September 24, 2001 1:00 PM
Subject: lens brightness
> I have heard remarks that a 200/2.8 prim
From: "Nicholas Wright"
Subject: lens brightness
> I have heard remarks that a 200/2.8 prime will transmit more
light than an
> 80-200/2.8 zoom. Is this true? I thought a 200/2.8 was a
200/2.8 whether it
> be a prime or part of a zoom. Thanks for any help.
The maximum ape
I have heard remarks that a 200/2.8 prime will transmit more light than an
80-200/2.8 zoom. Is this true? I thought a 200/2.8 was a 200/2.8 whether it
be a prime or part of a zoom. Thanks for any help.
Nick
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