Archived posting to the Leica Users Group, 2010/01/30

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Subject: [Leica] Measuring exposure lag (a long post)
From: steve.barbour at gmail.com (Steve Barbour)
Date: Sat, 30 Jan 2010 18:58:18 -0800
References: <mailman.895.1264899109.73134.lug@leica-users.org> <SNT121-DS21C76264A5F8B89488A6F3D4590@phx.gbl>

On Jan 30, 2010, at 6:48 PM, Aram Langhans wrote:

>> * I cheated when I timed the exposure lag of my Oly E-500 several years 
>> ago.
>> I simply photographed the face of a 1/100 second electric timer. An
>> assistant started the timer. When I saw the hand start to move, I clicked
>> the shutter. The exposure lag (reaction time plus shutter lag) varied
>> between .35 and .45 seconds. Certainly not instantaneous. In this time a
>> baseball thrown by a mediocre pitcher would have traveled about 3/4 of the
>> distance from the pitcher's mound to home plate. Three examples of this
>> measurement of exposure lag are:*
>> 
>> *
> I have used the ruler drop for 35 years as a teacher not so much to 
> measure reaction time but to show how to design an experiment to account 
> for variables and use statistics to analyze the data.  A great method and 
> I am sure it works (I trust gravity).  However, the question is: exactly 
> what is it showing you about the initial question.  Does it really predict 
> the actual reaction when taking a photo.  You mentioned the pitcher 
> throwing a baseball.  I have taken many photos of my nephew when he played 
> baseball. Of course, so  have many other photographers.  How could this be 
> if the ball is already to the plate?  Of course, a photographer 
> anticipates.  They take their past experience and press the shutter to get 
> the shot they want.  No one just reacts, because if they do they will miss 
> the photo no matter how fast the camera is (shutter lag).  Even if it was 
> instantaneous.  HBC had to anticipate the decisive moment.  W/o 
> anticipation, there would be no decisive moment.  So, the whole system 
> must be considered, as you do in your test.  The skill is in anticipating 
> the decisive moment, not reacting to it.


> In your example, to catch the pitch, you must hit the shutter 0.4 seconds 
> before you see the pitch.


perfect Aram...I agree...

likewise for the catcher...

:-)


Steve



> 
> Aram 
> 
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Replies: Reply from sonc.hegr at gmail.com (Sonny Carter) ([Leica] Measuring exposure lag (a long post))
In reply to: Message from leicar at q.com (Aram Langhans) ([Leica] Measuring exposure lag (a long post))