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Image Stabilisation - How many extra f stops?

 
 
Mark M
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      10-06-2004

"Roland Karlsson" <(E-Mail Removed)> wrote in message
news:Xns957AC32D22E03klotjohan@130.133.1.4...
> "Mark M" <(E-Mail Removed)> wrote in
> news:IIL8d.28579$Hz.8050@fed1read04:
>
> > IS does NOT have a direct effect on focus.
> > Blur from motion is another thing altogether.
> > If you're using IS on a stationary tripod, then it will NOT look as
> > crisp as a non-IS shot (exception being IS modes on some lenses that
> > take tripod use into account). But this has NOTHING to do with focus.
> > You were indicating that IS changes focus. It does not.
> > If there is blurring resulting from IS, it has to do with slight
> > **introduced** movement from IS that can produce a drift...but NOT a
> > drift, forward or backward that effects focus...but simply slight
> > motion blur from the lateral image drift.

>
> Ahhh ... those theoretical vs practical discussions
>
> I think that JPS understands that the real danger with
> using IS with tripod is the sideways drift of the image
> when the IS does bogus adjustments.
>
> But ... to say that there are NO focus drift is probably
> not true. The drift may be very small, even without any
> real significance. But to avoid it totally is not possible.
> And for anyone of us to know if it is significant or not
> we need to make lots of tests. And even then - the sideways
> drift might make it impossible to detect.


He described having to actually wait for focus on his camera because it
"drifted" out of...and into focus. He was talking about a **broken** lens!!
OK. No problem. BUT... -He then applied his observations about a BROKEN
lens...to the formation of his opinion about ALL IS lenses.

I'm all for practicality, which is why I've detailed the differences above.
Practicality calls for using IS in it's real and practical applications.
He's describing not only tripod comparisons using IS, but also a BROKEN IS
lens!!
-This is why he's receiving scrutiny here, and why I believe it deserved a
comment.


 
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Mark M
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      10-06-2004

"Roland Karlsson" <(E-Mail Removed)> wrote in message
news:Xns957AC0DA928A8klotjohan@130.133.1.4...
> "Mark M" <(E-Mail Removed)> wrote in
> news:9ad8d.13721$Hz.13122@fed1read04:
>
> >> But it would change the area of the image seen by the auto-focus

sensor.
> >> Couldn't that confuse the AF system?

> >
> > I've not seen that happen...
> >

>
> This kind of issues cannot be resolved by what anyone has seen or
> not. I assume that those that makes the lenses have the answer to
> this. I also assume that, if the IS confuses the AF, then they
> have made sure that it still works. Therefore - you cannot see it.
>
> I am 100% sure that both AF and IS makes the mechanism more
> fragile and that the best solution - when you have time and
> a stable enough tripod - is to do without them.
>
> But - in real life - in most situations - both increases
> the number of sharp pictures.


I think we basically agree here.

Perhaps I should have expanded my statement to say, "I have not seen that in
my own significant IS lens experience, nor have I ever heard of or read
anything citing similar problems on this or any other forum."



 
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Roland Karlsson
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      10-07-2004
"Mark M" <(E-Mail Removed)> wrote in
news:v%_8d.91$a85.42@fed1read04:

> He described having to actually wait for focus on his camera because
> it "drifted" out of...and into focus. He was talking about a
> **broken** lens!! OK. No problem. BUT... -He then applied his
> observations about a BROKEN lens...to the formation of his opinion
> about ALL IS lenses.
>
> I'm all for practicality, which is why I've detailed the differences
> above. Practicality calls for using IS in it's real and practical
> applications. He's describing not only tripod comparisons using IS,
> but also a BROKEN IS lens!!
> -This is why he's receiving scrutiny here, and why I believe it
> deserved a comment.
>


You ar right of course. Maybe I have a little more experience
with JPS He is a very sensible person with a good logic,
maybe a little too theoretical. And he likes to argue; sometimes,
just like me, somewhat too much We are not all that different.


/Roland
 
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Hans-Georg Michna
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Posts: n/a
 
      10-07-2004
On 6 Oct 2004 16:57:29 GMT, Roland Karlsson
<(E-Mail Removed)> wrote:

>I am 100% sure that both AF and IS makes the mechanism more
>fragile and that the best solution - when you have time and
>a stable enough tripod - is to do without them.


Roland,

hehe, by that argument you'd be best off not to use any camera
at all. In fact, you'd be best off in a tree eating bananas.
(

>But - in real life - in most situations - both increases
>the number of sharp pictures.


Right.

Hans-Georg

--
No mail, please.
 
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JPS@no.komm
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      10-07-2004
In message <v%_8d.91$a85.42@fed1read04>,
"Mark M" <(E-Mail Removed)> wrote:

>"Roland Karlsson" <(E-Mail Removed)> wrote in message
>news:Xns957AC32D22E03klotjohan@130.133.1.4...
>> "Mark M" <(E-Mail Removed)> wrote in
>> news:IIL8d.28579$Hz.8050@fed1read04:
>>
>> > IS does NOT have a direct effect on focus.
>> > Blur from motion is another thing altogether.
>> > If you're using IS on a stationary tripod, then it will NOT look as
>> > crisp as a non-IS shot (exception being IS modes on some lenses that
>> > take tripod use into account). But this has NOTHING to do with focus.
>> > You were indicating that IS changes focus. It does not.
>> > If there is blurring resulting from IS, it has to do with slight
>> > **introduced** movement from IS that can produce a drift...but NOT a
>> > drift, forward or backward that effects focus...but simply slight
>> > motion blur from the lateral image drift.

>>
>> Ahhh ... those theoretical vs practical discussions
>>
>> I think that JPS understands that the real danger with
>> using IS with tripod is the sideways drift of the image
>> when the IS does bogus adjustments.
>>
>> But ... to say that there are NO focus drift is probably
>> not true. The drift may be very small, even without any
>> real significance. But to avoid it totally is not possible.
>> And for anyone of us to know if it is significant or not
>> we need to make lots of tests. And even then - the sideways
>> drift might make it impossible to detect.

>
>He described having to actually wait for focus on his camera because it
>"drifted" out of...and into focus. He was talking about a **broken** lens!!


I never hid that fact. It was a starting point for speculation.

>OK. No problem. BUT... -He then applied his observations about a BROKEN
>lens...to the formation of his opinion about ALL IS lenses.


No, you liar, I said that *maybe* they all breathe to some degree. I
stated no opinion. I made a hypothesis. I speculated. YOU, the
ignorant illiterate, read that as a firm statement. You do this all the
time. You casually read people's posts, and declare them nonsense,
without given them much thought or the benefit of the doubt. You are a
borderline troll.

>I'm all for practicality, which is why I've detailed the differences above.
>Practicality calls for using IS in it's real and practical applications.
>He's describing not only tripod comparisons using IS,


I already explained to you that the tripod was for maintaining
subject-to-camera distance only, and should be done on a cheap, wobbly
tripod and disturbed before the exposure.

>but also a BROKEN IS
>lens!!


The broken lens only served as food for thought. I never tried to prove
anything with it. You really need to learn to shut up and pay attention
before typing.

>-This is why he's receiving scrutiny here, and why I believe it deserved a
>comment.



--

<>>< ><<> ><<> <>>< ><<> <>>< <>>< ><<>
John P Sheehy <(E-Mail Removed)>
><<> <>>< <>>< ><<> <>>< ><<> ><<> <>><

 
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Mark M
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Posts: n/a
 
      10-08-2004

<(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> In message <v%_8d.91$a85.42@fed1read04>,
> "Mark M" <(E-Mail Removed)> wrote:
>
> >"Roland Karlsson" <(E-Mail Removed)> wrote in message
> >news:Xns957AC32D22E03klotjohan@130.133.1.4...
> >> "Mark M" <(E-Mail Removed)> wrote in
> >> news:IIL8d.28579$Hz.8050@fed1read04:
> >>
> >> > IS does NOT have a direct effect on focus.
> >> > Blur from motion is another thing altogether.
> >> > If you're using IS on a stationary tripod, then it will NOT look as
> >> > crisp as a non-IS shot (exception being IS modes on some lenses that
> >> > take tripod use into account). But this has NOTHING to do with

focus.
> >> > You were indicating that IS changes focus. It does not.
> >> > If there is blurring resulting from IS, it has to do with slight
> >> > **introduced** movement from IS that can produce a drift...but NOT a
> >> > drift, forward or backward that effects focus...but simply slight
> >> > motion blur from the lateral image drift.
> >>
> >> Ahhh ... those theoretical vs practical discussions
> >>
> >> I think that JPS understands that the real danger with
> >> using IS with tripod is the sideways drift of the image
> >> when the IS does bogus adjustments.
> >>
> >> But ... to say that there are NO focus drift is probably
> >> not true. The drift may be very small, even without any
> >> real significance. But to avoid it totally is not possible.
> >> And for anyone of us to know if it is significant or not
> >> we need to make lots of tests. And even then - the sideways
> >> drift might make it impossible to detect.

> >
> >He described having to actually wait for focus on his camera because it
> >"drifted" out of...and into focus. He was talking about a **broken**

lens!!
>
> I never hid that fact. It was a starting point for speculation.


Great!
-And I didn't agree with your speculations.
So what?

> >OK. No problem. BUT... -He then applied his observations about a

BROKEN
> >lens...to the formation of his opinion about ALL IS lenses.

>
> No, you liar, I said that *maybe* they all breathe to some degree.


Great! And I think that was a poorly contructed hypothesis.
But so what! Someone disagrees with you and you fall all to pieces.

>I
> stated no opinion. I made a hypothesis. I speculated. YOU, the
> ignorant illiterate, read that as a firm statement. You do this all the
> time. You casually read people's posts, and declare them nonsense,
> without given them much thought or the benefit of the doubt. You are a
> borderline troll.


Feel free to kill-file me as you please.
That way I can comment on your posts without fearing I've upset your
tea-cup.
You made a connection with your broken lens and working IS lenses, and then
took offense when I disagreed with your line of reasoning.
You can pick at my wording all you like, but all I really did was question
your logic in moving from the broken lens to working lenses, and in talking
about focus in ways shich may have led others to adopt incorrect assumptions
regarding what IS does and does not do in practice.

I note that while you wonder if I'm a "troll" you are busy calling names
like liar, illiterate, and etc. I think it's fair to say you are acting the
troll here.
I have disagreed with your line of thinking and you have immediately taken
offense.

Get over it.

> >I'm all for practicality, which is why I've detailed the differences

above.
> >Practicality calls for using IS in it's real and practical applications.
> >He's describing not only tripod comparisons using IS,

>
> I already explained to you that the tripod was for maintaining
> subject-to-camera distance only, and should be done on a cheap, wobbly
> tripod and disturbed before the exposure.
>
> >but also a BROKEN IS
> >lens!!

>
> The broken lens only served as food for thought. I never tried to prove
> anything with it. You really need to learn to shut up and pay attention
> before typing.


You don't have to present your thoughts as "proof" before someone can
legitimately disagree with the direction they were clearly leading you. I
feel you led into a direction that is not supported by the facts of IS
operation.
If you feel it is somehow out of bounds to voice disagreement with your
premise, then I would simply say that you need to expand definition of what
you consider legitimate discussion.

> >-This is why he's receiving scrutiny here, and why I believe it deserved

a
> >comment.


Please note that others agree with me here. That doesn't make me correct,
but I hardly think you have cause to be so angry.


 
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Roland Karlsson
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      10-08-2004
Hans-Georg Michna <(E-Mail Removed)> wrote in
news:(E-Mail Removed):

>>I am 100% sure that both AF and IS makes the mechanism more
>>fragile and that the best solution - when you have time and
>>a stable enough tripod - is to do without them.

>
> Roland,
>
> hehe, by that argument you'd be best off not to use any camera
> at all. In fact, you'd be best off in a tree eating bananas.


Hmmmm ... maybe you are just trying to be funny.

I hope you are aware of that lots of pictures _are_
taken with cameras on stable tripods.


/Roland
 
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Linda_N
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      10-08-2004
"Roland Karlsson" <(E-Mail Removed)> wrote in message
news:Xns957CB185147FEklotjohan@130.133.1.4...
> Hans-Georg Michna <(E-Mail Removed)> wrote in
> news:(E-Mail Removed):
>
>>>I am 100% sure that both AF and IS makes the mechanism more
>>>fragile and that the best solution - when you have time and
>>>a stable enough tripod - is to do without them.

>>
>> Roland,
>>
>> hehe, by that argument you'd be best off not to use any camera
>> at all. In fact, you'd be best off in a tree eating bananas.

>
> Hmmmm ... maybe you are just trying to be funny.
>
>

No 'trying' about it! It was funny. When I read it the drink I just sipped
almost got sprayed on my monitor screen.

PSSST, Roland, I know you were being sarcastic reply, not to worry

Linda


 
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