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Tim Huggins
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, August 08, 2005 - 09:16 am: | 
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My Pen FT meters differently depending on the orientation of the camera. When the camera is held in "portrait" orientation the meter overexposes by one half stop versus holding the camera in "landscape" orientation. i.e. If I meter a scene in "portrait" and the meter shows "2", when I rotate the camera 90 degrees to "landscape" the meter will show "2-1/2".
This behavior is the same regardless of whether the focal axis of the camera is horizontal or vertical - so it is not a gravity effect. It is also 100% repeatable, even on a grey card - so it is not caused by subtle differences in composition. According to my OM 4, the "true" exposure is about half way between the two readings. --> Is this normal for a Pen FT? Does anyone have a fix for this?
On a related question, is there a drop in replacement for the old mercury battery? |
Jonathan
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, August 08, 2005 - 04:34 pm: |
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You can buy adaptors which let you use a normal silver oxide battery. There are a couple of pages on this website with advice about batteries.
However, most Pen Fs are way out no matter what battery is used, due to aging of the cell.
I'd be very happy with a Pen F meter as accurate as yours! Most are much worse, no matter which way up you hold them. Which battery are you using for the results you described?
The only reason I can think of for the different readings is polarization of light, though that seems unlikely. Sorry I can't suggest much.
Jonathan |
rick oleson
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, August 08, 2005 - 06:05 pm: |
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You are saying that, if you hold the camera with the lens pointed straight up at the sky, the meter changes by 1/2 stop as you rotate it 90 degrees about the lens axis?
I've never heard of anything like that happening with any camera. I have no idea what could cause it.
The nearest thing to a drop in replacement for a mercury cell is a zinc-air cell. The closest one (other than a Wein cell, which is an exact drop-in) to the PX625 cell of the Pen FT is a #675 hearing aid battery. This has the correct voltage, but it is smaller in diameter than the original cell and you'll need to make up the space with something.... some people use a rubber O-ring for this. |
John Shriver
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, October 01, 2005 - 06:13 pm: |
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I think the light take-off for the meter in a Pen FT is through a partly silvered mirror surface in the porroprism system, which is why the viewfinder is noticably dimmer than the Pen F and Pen FV. So perhaps the party silvered mirror is indeed senstive to the polarization of the light, as in auto-focus cameras.
http://john.shriver.home.comcast.net |
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