Mamiya C33 - Exposure Index Scale

[schonphotography]

<p>I was looking over the manual recently to my Mamiya C33, in which they vaguely talked about an "exposure index scale", which is explained in depth below. I see no such scale on the side of the ground glass where it appears it should be in the manual. Is this something I need to worry about when I'm shooting landscapes? The only thought I had was that the scale might be inside the focusing hood, which I do not currently own.</p>

<p>Thank you for your thoughts and help with this.</p>

<p>(Link to manual is here, page 9 of manual is expsure index scale: <em>http://www.cameramanuals.org/mamiya_pdf/mamiya_c33_pro.pdf</em> )<br>

The manual quotes " As the distance between the lens and film becomes greater, the light value will be lower provided the aperture is constant. In this case, the exposure must be increased. First, take a light meter reading to obtain the exposure and make the correction based on the exposure index given by the camera. Figures given on the left side of the ground glass show exposure index. If the reading of the scale is 2 with object in focus, this indicates the necessity of doubling the exposure. For example, if the exposure meter calls for F8 at 1/60 sec., it is necessary to adjust to 1/60 at F5.6 or 1/30 sec. at F8."</p>

<div></div>

[dave_s]

<p>It's etched faintly on the left edge of the ground glass itself. If you don't have it, then perhaps your ground glass was replaced with a plain screen, at some time over the last 40 years.</p>

<p>The compensation is the same thing that view camera guys call 'bellows factor', and it becomes an issue for close-up photography. No compensation is needed for landscapes or other distant objects. When you get to about portrait distance, you might want to open up an extra half stop.</p>

[mike_rosenlof2]

<p>As the previoius reply said, it's engraved on the ground glass itself. All of the Mamiya-made screens have it. I have a 3rd party screen Beattie or Maxwell, I think, that doesn't have this scale. I guess 'all' really would mean all since mamiya first added this feature to the cameras!<br>

It's only accurate if you dial in the correct lens focal length on the side of the camera (mine is 330f, so I'm not positive the 33 works the same way). After that, the same pointer that indicates parallax cutoff points at the approximate exposure factor.<br>

You could write appropriate marks on your screen with a Sharpie, or grease pencil or something, they're always in the same place. Your manual page can give you approximate placing. Easy enough to measure. 1.5x is 11.5mm from the top edge of the screen (the actual GG part), 2x is about 21mm, 2.5 is 29.5mm 3x is 37mm.</p>

 

[schonphotography]

<p>Thank you so much for your help, I guess the screen is 3rd party (a friend gave it to me a few months back for free). I'll see if I can work out the markings, and I'm glad to know the shots from a trip I just took won't be thrown off in exposure.</p>

[chris_waller]

<p>There is also an exposure compensation scale on the side of the focussing-rack rails. I am not at home at the moment but I'll have a look at my C33 when I get back.</p>

[marc_batters]

<p>There is also an available circular calculator, in PDF download, from Graham Patterson's, Mamiya TLR site.<br /> Copy and cut-out the three pieces, then thumb tack to a piece of cardboard. <br /> At this moment, I'm unable to find the site that has an exact size download of a stencil,<br /> a stencil that could be used to mark your existing ground glass screen. <br /> The stencils are out there, I just can't find them again.</p>

<p>Alex, that page link you have in the OP isn't to far from being the same size as the Mamiya screen.<br>

Burn a copy of that for a stencil pattern.</p>