Using an external light meter with Canon Auto Zoom
Posted 24 August 2005 - 11:54 PM
Here's my problem. I don't know what the fu** I'm doing. I need to set a shutter on the light meter, but I don't know how that works, exactly. I have access to two meters--this super cheapo analogue meter that does spot and ambient, and a nicer digital one that does ambient only. Neither, to my knowledge has shutter angle settings, only time settings. This is what's throwing me off--I don't know how to set that. I found specs on the 814 that says it's got a shutter angle of 155 (it's not variable). I don't know how or if that translates to a "time" setting.
Do you set the shutter "time" on your meter according to the frame rate? If so, the 814 only shoots 12, 18, and 24fps (well, you can do single shot too).
I tried to find a battery for the electric eye, but no luck so far (it wants a 2 zinc air cell, PX625 equivalents, 1.35v), and I figured I'd be able to see what the electric eye wanted, and match the shutter speed on the light meter so that the stop read the same at the equivalent ASA.
I'm shooting on K40, if that matters--indoors, so it'll be the 40 ISO.
Please help. Lost in film land.
Posted 25 August 2005 - 03:24 AM
Posted 25 August 2005 - 11:38 AM
Posted 25 August 2005 - 01:52 PM
For 18fps with a 180-degree shutter:
1/18 x 180/360 = 1/36 second.
Do you have an instruction manual for your meter? Have you looked for a copy on the Internet?
Posted 25 August 2005 - 03:22 PM
I now realize I've forgotten how to manually multiply fractions. Goddamnit.
Edited by Josh Bass, 25 August 2005 - 03:27 PM.
Posted 25 August 2005 - 03:39 PM
Ok, I think I got it. Being that my camera does 3 frame rates, 12, 18, and 24fps (oh yeah, and single shot), and has a constant 155 degree shutter, we get this:
for 12 fps: 1/12 * 155/360 = 1/27.9 (numbers rounded)
for 18 fps: 1/18 * 155/360 = 1/41.8 (numbers rounded)
for 24 fps: 1/24 * 155/360 = 1/55.7 (numbers rounded)
Did I do that right? It seems like I did, since I did the math myself for the 18 fps/180 degree shutter example you posted, and got the same answer by the same method.
I basically multiplied the framerate by 360 and divided by the shutter angle of 155 for each one of those. Stupid junior high math.
Posted 25 August 2005 - 07:32 PM
Ok, I don't know where the site that I got the 155 shutter from is, but I found on the "super 8 list" page, that the camera's listed as having a 220 degree shutter. Copied and pasted from there:
Weight: 1720 g
Lens: Canon zoom 1,4 / 7,5 - 60 mm
Auto / Manual Zoom
Frame rates: 12, 18, 24 + single frame
Shutter degree: 220
Manual / Auto Exposure
4 X AA batteries
Made in Japan"
Can anyone verify?
Posted 25 August 2005 - 10:08 PM
A DP friend of mine told me to round to the next shutter speed on whatever meter, since I'd be sure to get some weird numbers.
For example, 12fps with the 200 shutter comes to 1/19.6 , so I called it 1/15.
Posted 28 August 2005 - 02:02 AM