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02-05-2014, 08:54 AM   #1
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Exposure metering quirks of a Spotmatic

I'm wrapping up my first roll of film (in ages!) in my SP500. The metering system sure seems to give me some odd values! I want to know if I have a malfunctioning meter or if the SP500 is just quirky. I rarely use spot metering on my K-30 and I'm unschooled in how to properly play the system. Of course, I know to use it when I'm shooting into the sun, or with excessive shadows, etc

I have Kodak 100 TMAX film loaded right now. Looking out at a bright sunny day with snow on the ground I find myself reading proper exposure at f/16 at 1/1000s. Does that sound right?

02-05-2014, 09:09 AM   #2
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The meter will tend to bring anything it sees to 18% grey, that's what it does. Of course if you point it at snow, which should be white, it would try to make it grey, thus underexpose it. Looking at the tables over here, your SP500 gives a 2 stop underexposure, which is to be expected.

Also, with negative film, it's always better to overexpose rather than underexpose.

Spotmatics do not use spot metering, just regular center-weighted. Read this.

Last edited by kcobain1992; 02-05-2014 at 09:15 AM.
02-05-2014, 10:26 AM   #3
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Thanks for the replies! The wiki article on EVs was an interesting read. I did not know that Spotmatics typically underexpose by 2 stops. Do most people adjust their ASA film speed dial to compensate so the meter needle can be used as advertised?
02-05-2014, 10:37 AM   #4
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No, you got it wrong. Spotmatics do not underexpose by 2 stops, they just assume you are shooting grey stuff, that's what any meter does. Obviously, snow is white and not grey, so you have to override the reading from the meter, because you KNOW you're shooting snow, and the camera doesn't, and overexpose by 2 steps

02-05-2014, 10:44 AM   #5
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Remember the sunny f16 rule. Shutter speed of 1/iso (sec.) at f/16. Then make adjustments from there. Sunny snow scene 1/2 to 1 stop less, dull sun w/ strong shadows 1 stop more, weak shadows 2 stops more, and so forth. Look up and read about it. Later w/ b&W you will improve if you pay attention to shadows and how they are lit. But basically the sunny f/16 rule is more accurate than reflected light meters under challenging conditions such as high bight sun.
02-05-2014, 10:49 AM   #6
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QuoteOriginally posted by 6BQ5 Quote
I rarely use spot metering on my K-30 and I'm unschooled in how to properly play the system.
As noted above, your SP 500 does not have a spot meter. Despite the camera name, it meters the entire frame.

QuoteQuote:
I did not know that Spotmatics typically underexpose by 2 stops.
They don't. As with all other meters, the meter in your camera evaluates the entire world as if it were an 18% gray card. For most subjects this works quite well. On the other hand, sunlit snow is at least four stops brighter than an 18% gray card in the same light. So, if you accept the camera's meter reading for a frame of sunlit snow, the negative will be four stops underexposed.

Since most snowy subjects are not all snow and include thing like trees, buildings, and sky, a good rule of thumb is to add two stops exposure compensation in that case. If you are shooting people in a snowy scene you can also move in close and meter off their face and then move back to take the picture. This is equivalent to using AE lock on a more sophisticated camera. The same strategy works well at the beach or any other place where a large part of the scene is very bright.

I carry an 18% gray card in my bag and use it for metering in difficult lighting. An incident light reading from a hand-held meter accomplishes much the same thing.

There are some good books out there on exposure for photography. It is worth spending some time learning.


Steve

Last edited by stevebrot; 02-05-2014 at 12:36 PM.
02-05-2014, 02:00 PM   #7
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I am familiar with the concept of the sunny 16 rule but have never used it since I have been digital shooter primarily. When I was out in the snow yesterday I had enough sense in my mind to Google it on my phone and try taking another shot. Half of my film will probably be pitch black and the other half will probably be blank white!
02-05-2014, 02:26 PM   #8
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You can use the back of your hand as incident light meter;
Metering from the back of your hand (for Caucasians) gives a reading approximately one stop lighter than an 18% grey card. So you just meter off your hand (back of hand placed in same light as subject) and increase exposure by one stop and all should be right.
The palm does not tan so it should be 2 stop lighter than 18%

02-05-2014, 03:20 PM   #9
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The Spotmatic series built-in exposure meter averages the reading from the entire focus screen.
Typically large dark or bright portions (e.g. deep shadows or sky) will tend to "fool" your camera's exposure meter.
With experience it will become second nature to bias exposure to account for this.
Until then a closeup reading of your subject is the easiest way to ensure proper exposure.

Chris

Last edited by ChrisPlatt; 02-05-2014 at 04:41 PM.
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