Re: Is SMC 55/2 K the best Pentax standard lens? (and 28mm ?)

[frank theriault]

Hi, Peter,

See, now that makes sense.  When the SP500 came out, it was "competing" against the
SP.  Put a 1/1000 shutter speed on it, and the only difference would be the
self-timer.  Not really much incentive to ante up the big bucks for the SP.

By the time the SP1000 came out, the SPII had the hot-shoe, and the SPF had open
aperture metering, so I guess those features were seen as enough of a "draw" to
spend more $$.

thanks,
frank

Peter Alling wrote:

> Remember when the SP1000 came out it was the bargain little brother to the
> Spotmatic F and ESII both of which had wide open metering, as well as other
> advanced, (for the time), features.
>

--
"The optimist thinks this is the best of all possible worlds. The pessimist fears
it is true." -J. Robert
Oppenheimer
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Re: Is SMC 55/2 K the best Pentax standard lens? (and 28mm ?)

[Peter Alling]

That's not entirely true the width of the slit depends on the timing between
the release of the first and the release of the second curtain.  There could
there could easily be problems with calibrating that in a mechanical system.

At 03:10 PM 1/18/2002 -0500, you wrote:
>Focal plane shutters depend on two things for their higher speeds. 1. The
>maximum speed of the curtain. That is also the highest flash sync speed. 2.
>The width of the slit. At speeds above the highest sync speed the second
>curtain is released before the first is fully open, as the delay is reduced
>the effective shutter speed goes up.
>
>So, with a focal plane shutter the highest speed should be every bit as
>accurate as the highest sync speed.
>
>The inaccurateness of higher speeds is from leaf shutter mythology. I say
>mythology because there is a variation of efficiency that has to be taken
>into consideration when measuring the highest speeds. Many people who
>checked their shutters didn't realize that and concluded that the speed was
>not as high as marked. In fact except for lost of tension on very old
>shutters every leaf shutter that I have tested was pretty accurate at the
>highest speed when the compensation for efficiency was factored in.
>
>Ciao,
>graywolf
>[EMAIL PROTECTED]
>
>
>
>- Original Message -
>From: Frantisek Vlcek <[EMAIL PROTECTED]>
>To: David A. Mann <[EMAIL PROTECTED]>
>Sent: Friday, January 18, 2002 4:22 AM
>Subject: Re: Is SMC 55/2 K the best Pentax standard lens? (and 28mm ?)
>
>
> >
> > I heard that most manual shutters can't get precise enough in the
> > super high speeds. That Nikon FM2's shutter isn't much precise in the
> > 1/4000, really like 1/3000 or so. Makes sense. That's why electronic
> > shutters are for.
>-
>This message is from the Pentax-Discuss Mail List.  To unsubscribe,
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Re: Is SMC 55/2 K the best Pentax standard lens? (and 28mm ?)

[Tom Rittenhouse]

Focal plane shutters depend on two things for their higher speeds. 1. The
maximum speed of the curtain. That is also the highest flash sync speed. 2.
The width of the slit. At speeds above the highest sync speed the second
curtain is released before the first is fully open, as the delay is reduced
the effective shutter speed goes up.

So, with a focal plane shutter the highest speed should be every bit as
accurate as the highest sync speed.

The inaccurateness of higher speeds is from leaf shutter mythology. I say
mythology because there is a variation of efficiency that has to be taken
into consideration when measuring the highest speeds. Many people who
checked their shutters didn't realize that and concluded that the speed was
not as high as marked. In fact except for lost of tension on very old
shutters every leaf shutter that I have tested was pretty accurate at the
highest speed when the compensation for efficiency was factored in.

Ciao,
graywolf
[EMAIL PROTECTED]



- Original Message -
From: Frantisek Vlcek <[EMAIL PROTECTED]>
To: David A. Mann <[EMAIL PROTECTED]>
Sent: Friday, January 18, 2002 4:22 AM
Subject: Re: Is SMC 55/2 K the best Pentax standard lens? (and 28mm ?)


>
> I heard that most manual shutters can't get precise enough in the
> super high speeds. That Nikon FM2's shutter isn't much precise in the
> 1/4000, really like 1/3000 or so. Makes sense. That's why electronic
> shutters are for.
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Re: Is SMC 55/2 K the best Pentax standard lens? (and 28mm ?)

[Tom Rittenhouse]

No, no that is not it. The camera under discussion (SP500, IIRC) came out as
a cheaper version of the more expensive camera. The only actual difference
was the shutter speed dial, and of course the model name. 1/1000 second
focal plane shutters have been around since at least the 1930s.

Ciao,
graywolf
[EMAIL PROTECTED]



- Original Message -
From: David A. Mann <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Friday, January 18, 2002 12:51 AM
Subject: Re: Is SMC 55/2 K the best Pentax standard lens? (and 28mm ?)


> Frantisek Vlcek wrote:
>
> > TR> As I understand it the 1/1000 speed
> > TR> worked, it just wasn't marked. Now that is weird marketing!
> >
> > Weird? Even Intel uses such practices :) Otherwise there wouldn't be
> > so much overclocking at one stage in computer evolution.
>
>  I would suggest that the 1/1000 may have worked but might not have been
> consistently accurate enough for Pentax's standards.  When they improved
> their fabrication/manufacturing processes they could achieve the 1/1000 a
bit
> more comfortably so added the label.  I am assuming that all of the
cameras
> manufactured after a certain date had the 1/1000 speed marked.
>
>  Just a thought,
>
>
> - Dave
>
> David A. Mann, B.E. (Elec)
>
> "Why is it that if an adult behaves like a child they lock him up,
>  while children are allowed to run free on the streets?" -- Garfield
> -
> This message is from the Pentax-Discuss Mail List.  To unsubscribe,
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Re: Is SMC 55/2 K the best Pentax standard lens? (and 28mm ?)

[Peter Alling]

The SP 500 was introduced in 1971. The Spotmatic which had a
1/1000 top shutter speed which was introduced in 1964.

At 06:51 PM 1/18/2002 +1300, you wrote:
>Frantisek Vlcek wrote:
>
> > TR> As I understand it the 1/1000 speed
> > TR> worked, it just wasn't marked. Now that is weird marketing!
> >
> > Weird? Even Intel uses such practices :) Otherwise there wouldn't be
> > so much overclocking at one stage in computer evolution.
>
>  I would suggest that the 1/1000 may have worked but might not have been
>consistently accurate enough for Pentax's standards.  When they improved
>their fabrication/manufacturing processes they could achieve the 1/1000 a bit
>more comfortably so added the label.  I am assuming that all of the cameras
>manufactured after a certain date had the 1/1000 speed marked.
>
>  Just a thought,
>
>
>- Dave
>
>David A. Mann, B.E. (Elec)
>
>"Why is it that if an adult behaves like a child they lock him up,
>  while children are allowed to run free on the streets?" -- Garfield
>-
>This message is from the Pentax-Discuss Mail List.  To unsubscribe,
>go to http://www.pdml.net and follow the directions. Don't forget to
>visit the Pentax Users' Gallery at http://pug.komkon.org .
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Re: Is SMC 55/2 K the best Pentax standard lens? (and 28mm ?)

[David A. Mann]

Frantisek Vlcek wrote:

> TR> As I understand it the 1/1000 speed
> TR> worked, it just wasn't marked. Now that is weird marketing!
> 
> Weird? Even Intel uses such practices :) Otherwise there wouldn't be
> so much overclocking at one stage in computer evolution.

 I would suggest that the 1/1000 may have worked but might not have been 
consistently accurate enough for Pentax's standards.  When they improved 
their fabrication/manufacturing processes they could achieve the 1/1000 a bit 
more comfortably so added the label.  I am assuming that all of the cameras 
manufactured after a certain date had the 1/1000 speed marked.

 Just a thought,


- Dave

David A. Mann, B.E. (Elec)

"Why is it that if an adult behaves like a child they lock him up,
 while children are allowed to run free on the streets?" -- Garfield
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Re: Is SMC 55/2 K the best Pentax standard lens? (and 28mm ?)

[Bob Rapp]

The first lens testing I did was back in 70 or so. I pitted my 55 f1.8
up against my 50 f1.4. There was co comparison as the 55 was indeed sharper.
The testing was done with panatomic X and covered all click-stops. The
optimum aperture was between f5.6 and f8.0 for both centre and corner
resolution.
The K series should be nearly the same, although the old Takumars were
better built lenses. Yoshihiko's excellent site seems to confirm this. I use
the 55 on both my screw and k mount cameras as my standard lens even though
I have the 50 f1.4s in both series. I seem to like, in the case of the
Spotmatic, the fact that the viewfinder magnification presents a image that
appears the same as the eye.
The 55 K are not plentiful so if you find one, grab it. Otherwise any of
the f1.4s are very good with the A reported as slightly sharper that the K
and Ms.
I have both the 28 f2.8 and f3.5. There is no comparison, the f3.5 even
wide-open is better that the f2.8 aperture for aperture.

Bob
- Original Message -
From: "A K" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Tuesday, January 15, 2002 9:24 PM
Subject: Is SMC 55/2 K the best Pentax standard lens? (and 28mm ?)


> Hi,
>
> I've read at few places on the net, that an old SMC 55/2 K is  the best
> Pentax standard lens in terms of pure optical quality, regardless of
maximum
> aperture and other factors.
> Is that true?
>
> I currently have SMC 50/1.4 M and SMC 50/1.7 M should I try to find it, or
> should I go for SMC 50/1.4 A?
>
> Maximum aperture is not important for me at all, it is the f5.6 - f11 kind
> of performance that I'm after - but of course, it would be nice if it is
> also good wide open.
>
> I'm not after AF lens since they are very hard to find secondhand in my
> country and frankly, I don't like the manual focus feeling with them.
>
> What about 28mm lens?
> from some posts it seems that SMC 28/3.5 K is the best.
>
> I have the SMC 28/2.8 A and have an 3.5 K on offer for around 75$ should I
> go for it and ditch my old 2.8 A (well, I won't ditch it, I'll use it on
my
> MZ-S on those rare occasions when I need autoeverything program)?
>
> thanks,
>
> Aleksandar
>
>
>
> _
> MSN Photos is the easiest way to share and print your photos:
> http://photos.msn.com/support/worldwide.aspx
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> This message is from the Pentax-Discuss Mail List.  To unsubscribe,
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RE: Is SMC 55/2 K the best Pentax standard lens? (and 28mm ?)

[Paris, Leonard]

That sort of fits the way they used to make transistors.  They tested them
and then put the numbers on them according to which specs they matched the
most closely.  If they matched any spec exactly, they were marked as meeting
MILSPEC requirements.

Len
---

>Seemingly. When Intel makes a line of processors, it markets that line in
>multiple speeds. As the processors come off the line, a certain number
>(determined by marketing) are tested at the highest marketed speed. Those
>that pass are boxed and sold at that speed. Those that don't go back to the
>bin. Most that function pass. Then Intel tests a certain number (again
>determined by marketing) at the next lower speed and so on. They do this to
>maximize their profits from one line. This means that even the lowest speed
>processor off the line was designed for and probably would (not guaranteed)
>operate at the highest speed for which the line was designed. This led to
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Re: Is SMC 55/2 K the best Pentax standard lens? (and 28mm ?)

[Bob Blakely]

Seemingly. When Intel makes a line of processors, it markets that line in
multiple speeds. As the processors come off the line, a certain number
(determined by marketing) are tested at the highest marketed speed. Those
that pass are boxed and sold at that speed. Those that don't go back to the
bin. Most that function pass. Then Intel tests a certain number (again
determined by marketing) at the next lower speed and so on. They do this to
maximize their profits from one line. This means that even the lowest speed
processor off the line was designed for and probably would (not guaranteed)
operate at the highest speed for which the line was designed. This led to
the not too uncommon practice of "overclocking" lower rated CPU's. Intel now
alters it's processors post testing so that they will only operate up to the
packaged speed.

Asahi did not guarantee the accuracy of the unmarked speed, but unlike
Intel, they did not prevent you from selecting it. It's about getting as
much out of the market as you can with minimum change in tooling.

Regards,
Bob...

"Let us contemplate our forefathers, and posterity,
and resolve to maintain the rights bequeathed to us
from the former, for the sake of the latter.
The necessity of the times, more than ever, calls
for our utmost circumspection, deliberation, fortitude,
and perseverance. Let us remember that 'if we
suffer tamely a lawless attack upon our liberty,
we encourage it, and involve others in our doom.'
It is a very serious consideration that millions yet
unborn may be the miserable sharers of the event."
- Samuel Adams, 1771

From: "Tom Rittenhouse" <[EMAIL PROTECTED]>


> Well, they are also the company that left the 1000 shutter speed mark off
> the dial to produce a cheaper camera. As I understand it the 1/1000 speed
> worked, it just wasn't marked. Now that is weird marketing!
>
> From: Fred <[EMAIL PROTECTED]>
>
> > > I've read at few places on the net, that an old SMC 55/2 K is  the
> > > best Pentax standard lens in terms of pure optical quality,
> > > regardless of maximum  aperture and other factors. Is that true?
> >
> > > Maximum aperture is not important for me at all, it is the f5.6 -
> > > f11 kind of performance that I'm after - but of course, it would
> > > be nice if it is also good wide open.
> >
> > Aleksandar:
> >
> > Regarding the K 55/2:  I've never owned that exact lens, but I have
> > owned one of the K 55/1.8 lenses.  However, the two lenses are
> > really the same - both are actually f/1.8 lenses, except that Pentax
> > took some of the 55/1.8's and added a restrictive baffle to them to
> > reduce the aperture to f/2, in order to sell them at a lower price
> > (leaving the "faster" 85/1.8's to sell higher as "premium" 55mm
> > lenses).  Strange marketing concept, but remember that this is
> > Pentax we're discussing here, right?  
> >
> > Anyway, when testing the resolution of that one K 55/1.8 that I had,
> > I found it was fairly soft at larger apertures, but that it became
> > quite sharp starting at f/8 (but not at f/5.6, where it was still
> > somewhat soft).  The most unusual thing about the lens was that it
> > changed so ~dramatically~ going from f/5.6 to f/8.  Unfortunately,
> > its sharpness advantage compared to all the other normal lenses I
> > tested occurred only in the center - its edge sharpness was
> > sometimes less than that of some of the newer Pentax MF normal
> > lenses.
> >
> > Remember, though, that these were only the results of testing one of
> > these lenses against all the others.  See
> > .
> >
> > All in all, I still think that the ~A~ 50/1.4 is the best all-around
> > Pentax normal lens (and I guess that the F and FA versions are
> > optically identical) (but it seems as if the K and M versions are
> > not quite the same).
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Re: Is SMC 55/2 K the best Pentax standard lens? (and 28mm ?)

[Fred]

> I've read at few places on the net, that an old SMC 55/2 K is  the
> best Pentax standard lens in terms of pure optical quality,
> regardless of maximum  aperture and other factors. Is that true?

> Maximum aperture is not important for me at all, it is the f5.6 -
> f11 kind of performance that I'm after - but of course, it would
> be nice if it is also good wide open.

Aleksandar:

Regarding the K 55/2:  I've never owned that exact lens, but I have
owned one of the K 55/1.8 lenses.  However, the two lenses are
really the same - both are actually f/1.8 lenses, except that Pentax
took some of the 55/1.8's and added a restrictive baffle to them to
reduce the aperture to f/2, in order to sell them at a lower price
(leaving the "faster" 85/1.8's to sell higher as "premium" 55mm
lenses).  Strange marketing concept, but remember that this is
Pentax we're discussing here, right?  

Anyway, when testing the resolution of that one K 55/1.8 that I had,
I found it was fairly soft at larger apertures, but that it became
quite sharp starting at f/8 (but not at f/5.6, where it was still
somewhat soft).  The most unusual thing about the lens was that it
changed so ~dramatically~ going from f/5.6 to f/8.  Unfortunately,
its sharpness advantage compared to all the other normal lenses I
tested occurred only in the center - its edge sharpness was
sometimes less than that of some of the newer Pentax MF normal
lenses.

Remember, though, that these were only the results of testing one of
these lenses against all the others.  See
.

All in all, I still think that the ~A~ 50/1.4 is the best all-around
Pentax normal lens (and I guess that the F and FA versions are
optically identical) (but it seems as if the K and M versions are
not quite the same).

Fred
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Re: Is SMC 55/2 K the best Pentax standard lens? (and 28mm ?)

[pdml]

Aleksandar,

I have the 55/2 K and the 55/1.8 K both.  

They are good performers, I happen to like the little extra "Umph" that the 55 
have over a 50.  

Seems more natural to me.

Mark Gosdin
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