Using 35mm still camera as a light meter?

[Mike Buckles]

I know that sounds like a crazy idea...what if you took a newer 35mm still camera with it's advanced exposure reading abilities, set the iso as close to a Kodachrome 40 setting as you could, and matched up the shutter speed too...could you use the 35mm to get readings that you could set your super 8 camera by? Since the 35mm is new and has the latest technology for exposure readings as opposed to the 20+ year old light meters on the Super 8 cameras, and you can take spot readings too, and the 35mm lcd screen gives you the fstops it's recommending, would it be accurate to set your super 8 on that fstop filming the same scene? Or are they 2 different animals? Just a crazy thought I had...maybe i'll try it!

[cameraguy]

<font color="#a62a2a"><font size="1">[ August 31, 2003 08:48 AM: Message edited by: cameraguy ]</font></font>

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Original message reinserted by the moderator to keep the entire topic thread intact.

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Can't see why it wouldn't work just that I would remember to compensate for the light lost to a Super 8 cameras beam-splitter. I am sure after testing and getting used to it all would work well.

<font color="#7BC618" size="1">[ November 24, 2003 03:15 AM: Message edited by: Alex ]</font>

[Alex]

Yes, a 35mm camera could work quite well. The lenses on the Super-8 cameras could have more of a zoom range than the 35mm cameras, so that might be one issue that might not match up.

Converted Polaroids that are sold by fourdesignscompany can give you instant polaroids that reveal your actual contrast values.

The cameras cost around $400 to $500, but they may pay for themselves over time because you may not have to bracket your shots as much.

[Actor]

The problem that I have encountered in doing this is that the lens on my 35mm still camera is a relatively slow f/3.5 while my scoopic's lens is f/1.6. This means that my 35mm camera's light meter will pin out in situations that the scoopic could actually handle. To counter this I set the 35mm at 2 stops more sensitive than the film actually is, e.g., ASA 160 when using K-40. I then take a reading and open up the scoopic two stops from what the meter indicates. If the meter says f/5.6 I set the scoopic at f/2.8.

And of course I have to set the 35mm's shutter speed to match the scoopic (1/60 sec @ 24 fps). Most super8 cams will be 1/30 sec @ 18 fps or 1/45 sec @ 24 fps. If you know your cam's shutter angle you can compute the shutter speed.

Cameraguy's concern about the beam splitter does come into play and I would recommend shooting some tests with a gray card. If you get under/over expossure you can compensate via the ASA setting.

I first used this system with a medium format TLR that came sans light meter. In that case the speeds of the two camera's lenses were close enough that I did not have to go through the mathematical rigmarole. A TLR does not have a beam splitter of course.

[dr.sanchez]

I recently decided to test my equipment instead of relying on the internal Super 8 meter. I bought a fairly decent Sekonic light meter and set up a very elaborate scene in my living room [img]smile.gif[/img] Using two of those 650 watt sun guns and a mask as a model, I took light meter readings of everything in the frame with my handheld as well as with the camera, and documented the distances between lights and model/mask, light meter readings, focal length, frame speed, camera, stock, etc. Basically, I wrote down everything that might be important. Then I took 10-second shots and bracketed everything by at least 2 stops. If my camera wanted f4, I shot it at f1.9, f2.8,f4,f5.6, and f8. I'll get results from Kodak Switzerland in about a week. One problem, though, is I didn't shoot a gray card or color chart in the scene; hopefully when I get it transfered the transferer will not try to adjust anything. Do you guys think this will be much of a problem?

[Alex]

The color card or gray card issue is a good idea.
However, where you put the color card will affect how it reads.

If you put the card farther away from the camera, and then zoom in so it fills the frame, that is adding an additional variable to the result.

If you put the card closer to the camera, the lighting might not identical to the lighting where the action is going on.

In general though, it's good to use a gray card or color chart, but you can get by without one. A color chart's primary purpose for Super-8 is for when you are making a print or transfering to video.

I suspect that from Kodak's point of view in regards to reversal film, it won't affect how they develop your film because they can't see it until the film is developed.

[Actor]

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If you put the card farther away from the camera, and then zoom in so it fills the frame, that is adding an additional variable to the result.
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Actually it does not. I know that's counter intuitive and it took me a long time to get used to it. If you move the camera in then the intensity of the light being metered increases by the inverse square rule, but the area being metered also decreases by the same rule and the two offset each other exactly.

It also works if you zoom in instead of move the camera but I'm not sure I can explain why. Anyway the bottom line is that for practical purposes the "additional variable" does not exist. Have your actor hold the gray card in front of his face; move in or zoom in until the card fills the viewfinder; set your EE-LOCK then move the camera back where you want it; zoom in to focus; zoom back out if you want; compose your shot and shoot.
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If you put the card closer to the camera, the lighting might not identical to the lighting where the action is going on.
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In most cases it won't be, which is why an experienced cinematographer will move/zoom the camera and keep the card where the action is.

[Alex]

What I think is different not is the glass in the camera lens.

The way the camera picks up the image is changed.

Many small factors can add to a significant difference. Lens coatings, number of elements, overall precision of the lens.

I watched the overall levels and contrast values change on my video waveform when I zoom from a wide shot to a close shot with my 3-chip Eng style of video camera.

[Alex]

I just won an auction for a polaroid camera. I will now be able to accurately test what my Kodachrome film will look like before I get the K-40 processed!

Ebay Auction of 4 designs company modified Polaroid Camera (time sensitive)