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A dSLR's fastest shutter-speed is really no faster than its flash-sync speed.

 
 
Allen
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      07-07-2007
SelfImporantName wrote:
<snip self-important ramblings>
What a perfect choice for a posting name! But did you have to use so
many lines justifying it? Couldn't you just have posted the obvious fact
that you are a self-importnat jerk?
Allen
 
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dave
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      07-07-2007
On Sat, 07 Jul 2007 00:35:07 -0500, SelfImporantName
<(E-Mail Removed)> wrote:

>Considering that a dSLR is using a mechanical shutter, just like the old ones in
>film SLRs, the true fastest shutter-speed is really no faster than its highest
>flash-sync speed -- when the imaging chip is completely exposed without either
>shutter-curtain covering any portion of it.


>There's just no getting around this mechanical and image-distorting limitation
>in a dSLR. Just like there was no getting around this limitation in last
>century's SLRs. It's built into the very design of it.
>
>Pity.
>
>They should always mention this in any reviews on dSLRs, so all those
>"intelligent" pros will also realize they are paying to get last-century's
>faults and limitations.
>
>It's so nice having an advanced P&S camera that will sync the flash up to
>1/2500th of a second. Proving that that's its true shutter-speed. Zero image
>distortions caused by a mechanically slow shutter-curtain.
>

..............total nonsense deleted............................
>
>(If I had just bought a dslr today and thought about this, I'd be *really*
>****ed about my purchase right now. I wonder why all those other dSLR owners
>never mention this to newbies when it's so painfully obvious.)


Focal plane shutter travel has not been a factor for more than fifty
years and you would know that if you only even used, let alone owned,
one. If you can stop the action there will be no visible distortion.
Shooting a monitor or TV screen at speeds faster than their refresh
rate will cause distortion regardless of shutter type.

 
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Gordon Freeman
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      07-07-2007
John Bean <(E-Mail Removed)> wrote:

> On Sat, 7 Jul 2007 21:37:31 +0900, "David J. Littleboy"
> <(E-Mail Removed)> wrote:


>>Actually, many of the better P&S cameras have shutters. The Sony sensors
>>require a mechanical shutter to avoid really nasty smear problems.

>
> But to split hairs even finer David, they usually (always?)
> just use the aperture mecanism for the purpose so they still
> don't have a dedicated shutter in the same sense a SLR has.


But that's no different to many 35mm point and shoots, at the end of the
day it's still a shutter - it opens and closes - even if it also acts as
the iris.
 
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David J. Littleboy
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      07-07-2007

"John Bean" <(E-Mail Removed)> wrote:
> "David J. Littleboy" <(E-Mail Removed)> wrote:
>>"John Bean" <(E-Mail Removed)> wrote:
>>> On Sat, 7 Jul 2007 18:34:05 +1000, "Pete D"
>>> <(E-Mail Removed)> wrote:
>>>
>>>>Sorry to burst your bubble but your P&S does not have a shutter.
>>>
>>> It *might* have Pete, I'll give him the benefit of the doubt
>>> on that one. It's unlikely though

>>
>>Actually, many of the better P&S cameras have shutters. The Sony sensors
>>require a mechanical shutter to avoid really nasty smear problems.

>
> But to split hairs even finer David, they usually (always?)
> just use the aperture mecanism for the purpose


I think you are splitting hairs beyond what even I would. Leaf shutters live
in the lens at the same point as the aperture, but in film cameras, were
always a mechanically separate structure. I doubt that that design would
change. (I have taken apart leaf shutter film cameras, but I've never
disassembled a P&S dcam.)

> so they still
> don't have a dedicated shutter in the same sense a SLR has.


Again, a leaf shutter has always been seen as very much the same sort of
thing as a FP shutter.

(Four (Agfa folder, Rollei TLR, Fuji GS645S, Mamiya 7) out of five (vs.
Mamiya 645) of the film cameras here have leaf shutters, so I'm rather
familiar with the beasts...)

David J. Littleboy
Tokyo, Japan


 
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John Bean
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      07-07-2007
On 07 Jul 2007 14:30:19 GMT, Gordon Freeman
<(E-Mail Removed)> wrote:

>John Bean <(E-Mail Removed)> wrote:
>
>> On Sat, 7 Jul 2007 21:37:31 +0900, "David J. Littleboy"
>> <(E-Mail Removed)> wrote:

>
>>>Actually, many of the better P&S cameras have shutters. The Sony sensors
>>>require a mechanical shutter to avoid really nasty smear problems.

>>
>> But to split hairs even finer David, they usually (always?)
>> just use the aperture mecanism for the purpose so they still
>> don't have a dedicated shutter in the same sense a SLR has.

>
>But that's no different to many 35mm point and shoots, at the end of the
>day it's still a shutter - it opens and closes - even if it also acts as
>the iris.


Yes and no, Cheap film cameras did this purely to save cost,
better cameras usually have a "proper" shutter. But even
high-end digital P&S cameras use this method if they are
forced to do so, normally they use no shutter of any sort. I
can't think of any that have a "proper" shutter.

SLRs - film or digital - invariably use a mechanical
shutter.

Anyway it's all a bit moot to the OPs attempted criticism of
focal plane shutters in SLRs

--
John Bean
 
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John Bean
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      07-07-2007
On Sat, 7 Jul 2007 23:44:24 +0900, "David J. Littleboy"
<(E-Mail Removed)> wrote:

>
>"John Bean" <(E-Mail Removed)> wrote:
>> "David J. Littleboy" <(E-Mail Removed)> wrote:
>>>"John Bean" <(E-Mail Removed)> wrote:
>>>> On Sat, 7 Jul 2007 18:34:05 +1000, "Pete D"
>>>> <(E-Mail Removed)> wrote:
>>>>
>>>>>Sorry to burst your bubble but your P&S does not have a shutter.
>>>>
>>>> It *might* have Pete, I'll give him the benefit of the doubt
>>>> on that one. It's unlikely though
>>>
>>>Actually, many of the better P&S cameras have shutters. The Sony sensors
>>>require a mechanical shutter to avoid really nasty smear problems.

>>
>> But to split hairs even finer David, they usually (always?)
>> just use the aperture mecanism for the purpose

>
>I think you are splitting hairs beyond what even I would. Leaf shutters live
>in the lens at the same point as the aperture, but in film cameras, were
>always a mechanically separate structure.


Exactly - a seperate mechanism, seperate controls. Shutter
and iris are not the same thing. That was all I was saying
about the lack of *dedicated* shutter, they use the aperture
blades instead.

>> so they still
>> don't have a dedicated shutter in the same sense a SLR has.

>
>Again, a leaf shutter has always been seen as very much the same sort of
>thing as a FP shutter.


A leaf shutter isn't part of a set of aperture blades, it's
a seperate, self-contained mechanism. The digital P&S
doesn't have a leaf shutter; when I said it had no
*dedicated* shutter I meant it uses the aperture blades to
perform a similar (but not quite identical) function. No
leaf shutters that I'm familiar with could match the speed
range of most digicam shutters, and there's a good reason
for that.

>(Four (Agfa folder, Rollei TLR, Fuji GS645S, Mamiya 7) out of five (vs.
>Mamiya 645) of the film cameras here have leaf shutters, so I'm rather
>familiar with the beasts...)


So am I. But we weren't arguing about leaf shutters so no
need to claim bragging rights

--
John Bean
 
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Tony Hwang
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      07-07-2007
SelfImporantName wrote:
> Considering that a dSLR is using a mechanical shutter, just like the old ones in
> film SLRs, the true fastest shutter-speed is really no faster than its highest
> flash-sync speed -- when the imaging chip is completely exposed without either
> shutter-curtain covering any portion of it.
>
> Sure, you can crank up the shutter-speed by moving those two shutter-curtains
> closer together, making a very very narrow slit pass in front of the imaging
> chip. But that just means that *anything* that's moving in that image will be
> distorted. Just like in the SLR days. The beating of a bird's wing will be
> unnaturally curved. A circular tire passing by will be elongated and oval. A
> baseball pitcher's arm will be slightly bent in the wrong places. A diver
> falling into a pool of water will be unnaturally shorter or longer than they
> should be. (Or unnaturally distorted diagonally if the shutter curtains in your
> dSLR move horizontally.) The very same problems that we faced in SLR days. This
> problem is no different than if you tried to take your own photo by holding your
> face over a flat-bed scanner and slowly rotating your face while it was being
> scanned. A slower example of how *any* dSLR will not give you a true image of
> anything moving faster than its shutter's flash-sync speed.
>
> There's just no getting around this mechanical and image-distorting limitation
> in a dSLR. Just like there was no getting around this limitation in last
> century's SLRs. It's built into the very design of it.
>
> Pity.
>
> They should always mention this in any reviews on dSLRs, so all those
> "intelligent" pros will also realize they are paying to get last-century's
> faults and limitations.
>
> It's so nice having an advanced P&S camera that will sync the flash up to
> 1/2500th of a second. Proving that that's its true shutter-speed. Zero image
> distortions caused by a mechanically slow shutter-curtain.
>
> You can easily and simply prove it to yourself by holding your dSLR at 45
> degrees tilt to your monitor and trying to take a picture of the monitor
> display's scan-lines at shutter-speeds faster than its flash-sync speed. You'll
> find a badly bent lighted area in your resulting dSLR image, the higher the
> shutter-speed the more distorted it will become. Instead of a few well defined,
> perfectly even, parallel lines, that you will find when taking that same image
> with a P&S camera that doesn't depend on a mechanical curtain-style shutter. A
> P&S camera can stop/capture the activity of those scan lines or any fast moving
> object accurately, a dSLR shutter cannot, will not.
>
> (If I had just bought a dslr today and thought about this, I'd be *really*
> ****ed about my purchase right now. I wonder why all those other dSLR owners
> never mention this to newbies when it's so painfully obvious.)

Hmmm,
Humbuck!
 
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Alan Browne
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Posts: n/a
 
      07-07-2007
SelfImporantName wrote:
> Considering that a dSLR is using a mechanical shutter, just like the old ones in
> film SLRs, the true fastest shutter-speed is really no faster than its highest
> flash-sync speed -- when the imaging chip is completely exposed without either
> shutter-curtain covering any portion of it.
>
> Sure, you can crank up the shutter-speed by moving those two shutter-curtains
> closer together, making a very very narrow slit pass in front of the imaging
> chip. But that just means that *anything* that's moving in that image will be
> distorted. Just like in the SLR days. The beating of a bird's wing will be
> unnaturally curved. A circular tire passing by will be elongated and oval. A
> baseball pitcher's arm will be slightly bent in the wrong places. A diver
> falling into a pool of water will be unnaturally shorter or longer than they
> should be. (Or unnaturally distorted diagonally if the shutter curtains in your
> dSLR move horizontally.) The very same problems that we faced in SLR days. This
> problem is no different than if you tried to take your own photo by holding your
> face over a flat-bed scanner and slowly rotating your face while it was being
> scanned. A slower example of how *any* dSLR will not give you a true image of
> anything moving faster than its shutter's flash-sync speed.


The current world of DSLR's is, simply put, replacing the film with a
sensor. Surely this occured to you? The "SLR days" are not over.

For that matter, shutter flash-sync is only as precise as the flash
duration. If you shoot a large flash (say a Canon 580EX) at 1/64 power,
then you are in the realm of 10's of microseconds. But the same flash
shot full power (1/1) will last for over 1 millisecond (slower than 1/1000).




--
-- r.p.e.35mm user resource: http://www.aliasimages.com/rpe35mmur.htm
-- r.p.d.slr-systems: http://www.aliasimages.com/rpdslrsysur.htm
-- [SI] gallery & rulz: http://www.pbase.com/shootin
-- e-meil: Remove FreeLunch.
 
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X-Man
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      07-07-2007
On Sat, 07 Jul 2007 00:35:07 -0500, SelfImporantName <(E-Mail Removed)>
wrote:

>Considering that a dSLR is using a mechanical shutter, just like the old ones in
>film SLRs, the true fastest shutter-speed is really no faster than its highest
>flash-sync speed -- when the imaging chip is completely exposed without either
>shutter-curtain covering any portion of it.
>
>Sure, you can crank up the shutter-speed by moving those two shutter-curtains
>closer together, making a very very narrow slit pass in front of the imaging
>chip. But that just means that *anything* that's moving in that image will be
>distorted. Just like in the SLR days. The beating of a bird's wing will be
>unnaturally curved. A circular tire passing by will be elongated and oval. A
>baseball pitcher's arm will be slightly bent in the wrong places. A diver
>falling into a pool of water will be unnaturally shorter or longer than they
>should be. (Or unnaturally distorted diagonally if the shutter curtains in your
>dSLR move horizontally.) The very same problems that we faced in SLR days. This
>problem is no different than if you tried to take your own photo by holding your
>face over a flat-bed scanner and slowly rotating your face while it was being
>scanned. A slower example of how *any* dSLR will not give you a true image of
>anything moving faster than its shutter's flash-sync speed.
>
>There's just no getting around this mechanical and image-distorting limitation
>in a dSLR. Just like there was no getting around this limitation in last
>century's SLRs. It's built into the very design of it.
>
>Pity.
>
>They should always mention this in any reviews on dSLRs, so all those
>"intelligent" pros will also realize they are paying to get last-century's
>faults and limitations.
>
>It's so nice having an advanced P&S camera that will sync the flash up to
>1/2500th of a second. Proving that that's its true shutter-speed. Zero image
>distortions caused by a mechanically slow shutter-curtain.
>
>You can easily and simply prove it to yourself by holding your dSLR at 45
>degrees tilt to your monitor and trying to take a picture of the monitor
>display's scan-lines at shutter-speeds faster than its flash-sync speed. You'll
>find a badly bent lighted area in your resulting dSLR image, the higher the
>shutter-speed the more distorted it will become. Instead of a few well defined,
>perfectly even, parallel lines, that you will find when taking that same image
>with a P&S camera that doesn't depend on a mechanical curtain-style shutter. A
>P&S camera can stop/capture the activity of those scan lines or any fast moving
>object accurately, a dSLR shutter cannot, will not.
>
>(If I had just bought a dslr today and thought about this, I'd be *really*
>****ed about my purchase right now. I wonder why all those other dSLR owners
>never mention this to newbies when it's so painfully obvious.)



LOL!!!!!!!!!!!!!!!!!!!!!!!!

Let me mark this down as reason #157 of why to NEVER purchase a DSLR! I may move
the to reason #1 position. Who on earth would want a camera that takes photos
where ANY moving subject is intentionally distorted??? Maybe this is why DSLR
owners think the way they do, THEY LOVE DISTORTIONS!!!
LOL!!!!!!!!!!!!!!!!!!!!!!!! No wonder they can't see what's wrong!!! LOL!!!!

Thanks!

I read the replies of the fool DSLR whiners trying to evade the issue and brush
it under the carpet. This is PRICELESS!!! LOL!!!!!!!!!!!!!!!!!!!!!!!!! Some of
them don't even want to think it happens, or that ALL cameras do this!
LOL!!!!!!!!!

This made reading this newsgroup worth it today!!

 
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SelfImporantName
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      07-07-2007
On Sat, 7 Jul 2007 18:34:05 +1000, "Pete D" <(E-Mail Removed)> wrote:

>Sorry to burst your bubble but your P&S does not have a shutter.
>


Sorry to burst your bubble, but nowhere do I mention nor claim that the P&S
camera is relying on a mechanical shutter. It is merely noted as "shutter-speed"
when mentioned in relation to P&S cameras. Some do have mechanical shutters,
concentric with the light-path away from the focal-plane, and are not plagued by
this horrendous subject-distorting problem of curtain-style focal-plane
shutters. Some only have electronic shutters. But in most every case there is
some kind of mechanism to protect the sensor from exposure to bright lights when
not in use.

Why everyone went-off on what kind of shutter a P&S camera uses or does not use
is a mystery to me. I guess if they distract themselves from and don't think
about this subject-distorting problem inherent in every dSLR it'll make it go
away.

Just imagine, all those millions perhaps billions of photos taken and displayed
so proudly for the last so-many years with dSLRs .... each and every one of them
most likely contains distorted subjects to one degree or another. Even if the
subject is moving slow the moving portions exposed while the shutter is opening
and closing will still contain some distortion. The viewer not realizing this
just accepts that distorted view of reality as normal. In fact, one reply here
even claimed how proud they were of accepting a distorted view of reality as
normal.

How sad that is.

dSLR = recording a distorted view of reality

There's no way to refute that, try as you might. The only way you will ever
accurately capture a moving subject with a dSLR is by using a high-powered flash
and f/stops so small as to extinguish all ambient light from your intended
image. I don't see many people doing that. That relegates the dSLR only good for
indoor party photos taken in dimly lit rooms or art studies arranged in
still-life poses. I'll pass on that photography-crippling limitation thank-you.
 
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