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ACL II light meter - light loss for viewfinder?


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#1 Gregg MacPherson

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Posted 31 January 2013 - 10:04 PM

Does anyone understand how the light meter works in an ACL II? Not from the user's point of view. Thing I'm wondering about is, is there any light loss for the viewfinder? Depending on the light loss I would probably have it removed.

Thanks for any ideas.
Gregg.
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#2 Jason Hinkle (RIP)

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Posted 07 February 2013 - 04:19 AM

Don't quote me but I don't think it causes light loss. It's removed most of the time if you do a Super-16 conversion anyway to make room for the wider viewing area. I am pretty sure that's only because it's physically in the way & doesn't brighten the viewfinder.

Because it's so simplistic I figured there was just a photo-sensitive component kinda pointed at the viewfinder glass or something, rather than the light path going through it. I could be wrong, though. I didn't notice a major difference in the brightness when mine was removed for a Super-16 conversion.

If your viewfinder is dark, Bernie's Laserbrighten service definitely will brighten it up a stop or so.
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#3 Gregg MacPherson

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Posted 07 February 2013 - 06:32 PM

I'm looking at page 25 of the Eclair ACL Camera Operating Manual. There's a picture of the mirror, prism for the meter (1), prism block for the viewfinder (2). The prism (1) is stuck on the back side of prism (2). Intuitively, it seem like the prism (2) back surface is not fully reflective, and even if the prism (1) was not there there would be light loss. But this may be only a fraction of a stop. If I'm missunderstanding this can someone give me a nudge.

I just felt that with light meter, video tap, that light was lost that I would prefer to have for the viewfinder. It's the big kinoptik finder, x10 magnification (almost too big, but great for focusing). The image looks bright, but I haven't done side by side comparisons with Aaton / SR.

Does Bernie's lazer brightening improve on a new GG? If so how does that work. This camera and VF are literally almost new.
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#4 Gregg MacPherson

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Posted 07 February 2013 - 08:56 PM

PS: Camera is already a S16 conversion. Started by Les Bosher, finished by Visual Products. The LED array does crowd the left hand edge of frame but fits OK.
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#5 Boris Belay

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Posted 09 August 2013 - 02:35 PM

 

Hi Gregg,

 

Sorry for the late answer but the answer is yes, and no ;-)

 

Yes, there is, you can see it in your VF if it has a lightmeter built-in : it's the center circle that is slightly yellowish, or at least darker.  That is where some of the GG light is diverted to the lightmeter cell.

 

So, yes, there is some light loss, as you can see, but only in that center spot.

 

Removing the Lightmetering system does not help, since the center spot pellicle is built into the GG and prism optical block.  Not sure why sme technicians remove it for S-16 conversion, it's not necessary and it's a pretty useful feature of the camera.  Some ACLs never had it, by the way, it was a factory option.  I have one of the last ACL II and it didn't have a lightmeter built in (so no center spot either).

 

And yes, you are right, the lightmeter is described in detail, with schema, in the mid-70's user manual (the one that most people have).

 

Cheers,

Boris


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#6 Gregg MacPherson

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Posted 09 August 2013 - 05:39 PM

 

...Sorry for the late answer but the answer is yes, and no ;-)......
Cheers,
Boris


Hey Boris,
Thanks for that. I might need some parts or a liitle advice, and/or have a small job for you. I'll use the last email address I had from you.

Cheers,
Gregg.
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