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DSLR that adjusts shutter speed w/ focal length?

 
 
Matt Clara
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      07-22-2007
"Gino" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> Why not buy a lens with IS? Then use Shutter Priority at 1/125 or even
> 1/60.
>


Because IS will do nothing to help with the motion blur of a car, and at
1/60th of a second, it, not to mention its wheel spokes/rims will have
traveled quite a long ways. I believe the second generation IS can help to
minimize up and down motion when panning side to side, so it would be of
benefit, just not in the manner you're suggesting.

--
www.mattclara.com


 
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Gino
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      07-22-2007

"Matt Clara" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> "Gino" <(E-Mail Removed)> wrote in message
> news:(E-Mail Removed)...
>> Why not buy a lens with IS? Then use Shutter Priority at 1/125 or even
>> 1/60.
>>

>
> Because IS will do nothing to help with the motion blur of a car, and at
> 1/60th of a second, it, not to mention its wheel spokes/rims will have
> traveled quite a long ways.


Yes it will, because you are panning with the car.


I believe the second generation IS can help to
> minimize up and down motion when panning side to side, so it would be of
> benefit, just not in the manner you're suggesting.


Yes, I use this.

 
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Richard H.
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      07-22-2007
John Sheehy wrote:
> I'm not sure what you're implying here, but focal length has no effect on
> subject blur, at a given shutter speed. Someone swinging a golf club at
> 1/100 will have the same angular blur at 8mm or 1200mm.


Hi, John.

I agree with the fundamental point, but at tighter focal length
(same distance to subject) the subject fills more of the frame and the
motion blur becomes visually noticable (say, spanning 20 pixels instead
of 2).

Building on your point, I suppose an alternative here may be to adjust
technique to yield the same effect - that is, strive for similar subject
size in the frame, regardless of focal length. Say, as a car/cyclist
approaches or departs, compose with the car at a consistent 50% of the
frame to yield the same visual effect without adjusting the shutter.

Cheers,
Richard
 
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Richard H.
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      07-22-2007
Gino wrote:

> Why not buy a lens with IS? Then use Shutter Priority at 1/125 or even
> 1/60.


Hi, Gino.

Thanks, yes, I usually shoot with a VR lens (70-200; first-generation
VR), and it does help handheld stability when panning with the subject
(i.e., side shots).

For shots that are more head-on, there's less panning and it's more
about shutter speed (the scenario I'm thinking about here).

Cheers,
Richard
 
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Gino
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      07-22-2007
I am not sure exactly what you are trying to achieve. You said "blurred
tires or panned
background" in the original post, however it seems that you actually have a
different objective?

If you want to get rid of the background in head on shots coming towards
you, then use a big aperture and wait until the object comes close. Two
totally different shooting situations.

By all means, post an example of what you are trying to achieve.




"Richard H." <(E-Mail Removed)> wrote in message
news:jWOoi.9621$(E-Mail Removed)...
> Gino wrote:
>
>> Why not buy a lens with IS? Then use Shutter Priority at 1/125 or even
>> 1/60.

>
> Hi, Gino.
>
> Thanks, yes, I usually shoot with a VR lens (70-200; first-generation VR),
> and it does help handheld stability when panning with the subject (i.e.,
> side shots).
>
> For shots that are more head-on, there's less panning and it's more about
> shutter speed (the scenario I'm thinking about here).
>
> Cheers,
> Richard


 
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Pete D
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      07-22-2007

"RichA" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed) ups.com...
> On Jul 22, 11:26 am, John Sheehy <(E-Mail Removed)> wrote:
>> RichA <(E-Mail Removed)> wrote
>> innews:(E-Mail Removed) groups.com:
>>
>> > Seriously, do pro cameras ever have "idiot" modes?
>> > You know, like a little face logo for portraits, a mountain for
>> > landscapes, etc?
>> > When you see that on a Nikon D2Xs, you'll know their days are
>> > numbered.

>>
>> There's nothing "Dummies" or "Idiot" about the OP's request. It is a
>> very logical feature that I desired as soon as I got back into
>> photography a few years ago. In very low light, doing hand-held
>> shooting, Av mode is extremely problematic. I tend to use Av mode when
>> there is ample light for fast shutter speeds, and Tv mode when light is
>> very low, and having a blurred long exposure is worse than having wide-
>> open optics or a little under-exposure. The logical extension to the
>> latter is to have a Tv-pri mode where you set a ratio to focal length,
>> rather than a fixed focal length, very useful for zoom cameras, so you
>> don't get unnecessary under-exposure at the wide end of the zoom range.
>>
>> An intelligent photographer can make good use of automation to their
>> advantage, when they choose one that automates what *they* would do
>> automatically, if they had remembered to do so and had the time.
>>
>> This feature would be more of a true "user-control" than the P mode,
>> which the Pro cameras do have.

>
> Any such mode (like other such modes) would be only the roughest guess
> at what would be needed.
> There is no way you could ever make it even marginally precise. How
> does the camera know how fast the action is?
> Maybe in the future, a system of sensor feedback (could the sensor
> detect subject motion?) accelerometers in-camera could be used to
> facilitate something more accurate.


Well not unless you have one of the crappy liveview cameras, please
anythiing but that. Played with a 410 on the weekend for a anout an hour,
would have to be the mostly poorly implimented D-SLR I have ever use, just
bloody aweful, even worse ergonomics than the 350D.


 
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John Sheehy
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      07-22-2007
RichA <(E-Mail Removed)> wrote in news:1185129101.588430.145000
@w3g2000hsg.googlegroups.com:

> Any such mode (like other such modes) would be only the roughest guess
> at what would be needed.
> There is no way you could ever make it even marginally precise. How
> does the camera know how fast the action is?
> Maybe in the future, a system of sensor feedback (could the sensor
> detect subject motion?) accelerometers in-camera could be used to
> facilitate something more accurate.


I was talking about the TV-pri mode that used a shutter speed proportional
to the focal length. As I would implement it, it would be set to a user-
determined ratio (to account for individual shake, tolerance levels, and
IS).

--

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

 
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John Sheehy
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      07-22-2007
"Richard H." <(E-Mail Removed)> wrote in
news:aXMoi.12959$(E-Mail Removed):

> Alas, it sounds like this might be a pipedream. Unfortunate, knowing
> that it'd be pretty easily implemented. Maybe one day camera firmware
> will go open source, and we can tweak away.


That's what we need; these companies have no imagination.

--

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

 
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Richard H.
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      07-22-2007
John Sheehy wrote:
> RichA <(E-Mail Removed)> wrote:
>
>>Any such mode (like other such modes) would be only the roughest guess
>>at what would be needed.
>>There is no way you could ever make it even marginally precise. How
>>does the camera know how fast the action is?
>>Maybe in the future, a system of sensor feedback (could the sensor
>>detect subject motion?) accelerometers in-camera could be used to
>>facilitate something more accurate.

>
> I was talking about the TV-pri mode that used a shutter speed proportional
> to the focal length. As I would implement it, it would be set to a user-
> determined ratio (to account for individual shake, tolerance levels, and
> IS).


Right.

So, if you set it to 1/500 at f/5.6 then zoomed in to 1/2 the field of
view, have the camera adjust to 1/1000 and f/4 - the same EV, but
settings auto-shifted to keep the shutter speed proportionate to the
focal length.

Nikon's selectable Program mode seems to be along these lines, but
requires auto-metering. I.e., you can select from a range of
shutter/aperture combinations within the same EV - just spin the
thumbwheel while in Program mode.

According to the docs, it should adjust shutter speed along a slope
based on the focal length, if auto-metering works for you. (From the
scenario you describe, it sounds like it won't quite.)

Cheers,
Richard
 
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John Sheehy
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      07-22-2007
"Matt Clara" <(E-Mail Removed)> wrote in
news(E-Mail Removed):

> That was my first thought, too, but here's another way of thinking
> about it: Imagine two 8x10s, one a wide angle of a golfer taking a
> swing, the other a close-up of the club head as it's in motion. Same
> shutter speed reveals the same amount of movement, let's say, a half
> an inch. In the wide angle image, that half an inch will occupy a
> tiny fraction of the print's surface, so little that it's a saleable
> image. In the close-up, it would occupy considerably more. So to get
> a saleable image with the close-up, he has to up his shutter speed.


So then, it's still not focal length, but magnification of the subject,
that is relevant.

--

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><<> <>>< <>>< ><<> <>>< ><<> ><<> <>><

 
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