Olympus-OM
[Top] [All Lists]

Re: [OM] Flash question on RFF

Subject: Re: [OM] Flash question on RFF
From: Chuck Norcutt <chucknorcutt@xxxxxxxxxxxxxxxx>
Date: Thu, 20 Nov 2008 13:54:05 -0500
His response indicates he is using LR-44 batteries in the camera.  Those 
will no doubt get him through tonight's shoot and probably through the 
several days he indicates may follow.  But in a month or so (with the 
camera sitting on the shelf) they will be dead... or at least as far as 
the OM-2sp is concerned since battery voltage for the pair will have 
dropped below the (IIRC) 2.2 volts needed to operate the shutter.  If 
using alkaline a spare pair of cells would be a wise investment.  Silver 
oxides, on the other hand, will likely last some 6-9 months as shelf 
sitters in the camera.

Chuck Norcutt

Tom Fenwick wrote:
> Done...
> Tom
> 
> 2008/11/20 Chuck Norcutt <chucknorcutt@xxxxxxxxxxxxxxxx>
> 
>> In re-reading my response I note that I said: "The reason you may not
>> have seen the ready light come on is that you may have been doing test
>> shots without film in the camera."  This is not true for the ready light
>> in its "ready" role.  It's only true for the ready light in it's
>> flashing role as a good exposure indicator.  If the ready light is not
>> visible in the viewfinder with a steady glow when the flash itself is
>> powered on and indicating ready then something is wrong.
>>
>> Dr. Flash
>>
>>
>> Chuck Norcutt wrote:
>>> I suspect that he may not be fully sorted yet.  I don't belong to the
>>> Rangefinder forum so perhaps you or Piers might post some of this.
>>>
>>> First, a warning based on the poster's intent to use the T32 at 20
>>> meters.  Using the T32's calculator panel (on the auto/manual side of
>>> the panel) you can see that, even at ISO 400, an f/2.8 lens will be
>>> required to reach 20 meters.  Actually, the calculator panel indicates
>>> something between f/4 and f/2.8 which my manual calculations show to be
>>> f/3.1.  However, since most flash manufacturers generally fib by at
>>> least 1/3 stop on their guide numbers (and the T32 is no exception) the
>>> actual requirement at 20 meters and ISO 400 will likely be f/2.8.  If
>>> you don't have an f/2.8 lens that will reach the distance required then
>>> a film faster than ISO 400 will be required or else accept a stop or
>>> more of underexposure.
>>>
>>> Of course, this all assumes that the T32 is the only light source.  If
>>> shooting a stage production, for example, which provides moderately
>>> bright ambient light a slower film and lens may be OK.  It also assumes
>>> that you don't have the T32 "zoom adapter" which narrows the angle of
>>> view and raises the ISO 100 guide number to as high as 42 at the 135mm
>>> setting.  In any case, be aware that the T32 may be approaching its
>>> limits here.
>>>
>>> Now to some questions that were posed but not answered.  Yes, the OM-2sp
>>> has a "flash ready" signal in the viewfinder.  It's at the extreme upper
>>> left of the viewfinder and is a green (or red) square with the symbol of
>>> a lighting bolt in the center.  The flash ready signal glows when the
>>> flash is charged and blinks very rapidly for a couple of seconds after a
>>> *correct* exposure had been made.  If it simply goes out then there has
>>> been an under or overexposure which is indicated by "under" and "over"
>>> (text) indicators between the top of the shutter speed scale and the
>>> flash ready signal.  These may be extremely difficult to see under dark
>>> conditions since they are not illuminated like the ready signal is.  The
>>> "over" indicator sits directly above the shutter speed scale and the
>>> "under" indicator is above that.  It may be possible to see them better
>>> if you use the viewfinder illuminator button (right side of camera below
>>> the prism) but it only stays on for 10 seconds and it's difficult to
>>> coordinate that with your shot.
>>>
>>> If your OM-2sp has a green ready light in the viewfinder then it's the
>>> original design which draws its power from the camera batteries.  If the
>>> ready light is red then it's a later design which draws its power from
>>> the flash batteries.  Olympus modified many or the original green type
>>> to the red type because of complaints about excess battery drain to
>>> power the ready light.  Just be aware that, when the flash is powered on
>>>   the camera may be using more power than usual if you have the green
>>> ready light.  In any case, be sure to use fresh batteries and make sure
>>> you are using silver oxide rather than alkaline batteries.  Alkaline
>>> batteries will not last very long in OM cameras such as the 2sp which do
>>> not have on/off switches.
>>>
>>> The reason you may not have seen the ready light come on is that you may
>>> have been doing test shots without film in the camera.  The OM-2sp's
>>> exposure system is TTL OTF (Off The Film) which means the metering
>>> system reads the light reflected from the film during actual exposure.
>>> If there is no film in the camera the only thing the meter sees is
>>> reflection from the black pressure plate.  Not much to reflect from and
>>> certainly not enough to indicate a correct exposure.  If you have a test
>>> roll put that in the camera before doing exposure tests.
>>>
>>> With the camera in Program or auto mode and the T32 in use in TTL mode
>>> (calculator panel turned to the blank side) or in "normal auto" mode
>>> (calculator panel outward) the "auto check" light on the back of the
>>> flash should blink like the ready light does to indicate a good
>>> exposure.  No blink, something was wrong.  If the camera is in manual
>>> mode and the flash is in "normal auto" mode the flash will respond to
>>> its own internal sensor and flash the "auto check" light by itself
>>> without camera assistance.  In that case no film is required in the
>>> camera to do an exposure test since the TTL flash circuitry is not
>>> involved.  A test flash can also be made with the test button on the
>>> back of the flash.  If in "normal auto" mode the "auto check" light will
>>> blink if a good exposure was indicated.  When the flash is in manual
>>> mode the "auto check" can't be used since the flash has no indication of
>>> the aperture in use.
>>>
>>> Dr. Flash
>>>
>>>
>>>
>>>
>>>
>>>
>>> Tom Fenwick wrote:
>>>> Nice one Piers.  I like that gentleman's pictures and thought someone
>> ought
>>>> to sort him out!
>>>> Tom
>>>>
>>>> 2008/11/20 Piers Hemy <piers@xxxxxxxx>
>>>>
>>>>> Done
>>>>>
>>>>> -----Original Message-----
>>>>> From: Tom Fenwick [mailto:super.wide@xxxxxxxxx]
>>>>> Sent: 20 November 2008 10:53
>>>>> To: Olympus Camera Discussion
>>>>> Subject: [OM] Flash question on RFF
>>>>>
>>>>> One for you lot here:
>>>>> http://www.rangefinderforum.com/forums/showthread.php?threadid=66456
>>>>>
>>>>> Tom
>>>>>
>>>>>
>> ------------------------------------------------------------------------
>>>>>
>>>>> No virus found in this incoming message.
>>>>> Checked by AVG - http://www.avg.com
>>>>> Version: 8.0.175 / Virus Database: 270.9.8/1801 - Release Date:
>> 11/20/2008 9:11 AM
>> --
>> _________________________________________________________________
>> Options: http://lists.thomasclausen.net/mailman/listinfo/olympus
>> Archives: http://lists.thomasclausen.net/mailman/private/olympus/
>> Themed Olympus Photo Exhibition: http://www.tope.nl/
>>
>>
>>
>> ------------------------------------------------------------------------
>>
>>
>> No virus found in this incoming message.
>> Checked by AVG - http://www.avg.com 
>> Version: 8.0.175 / Virus Database: 270.9.8/1801 - Release Date: 11/20/2008 
>> 9:11 AM
>>
-- 
_________________________________________________________________
Options: http://lists.thomasclausen.net/mailman/listinfo/olympus
Archives: http://lists.thomasclausen.net/mailman/private/olympus/
Themed Olympus Photo Exhibition: http://www.tope.nl/

<Prev in Thread] Current Thread [Next in Thread>
Sponsored by Tako
Impressum | Datenschutz