Spot Meter of Shadows from a distance

[ki6mf]

i am looking for how you read shadows from a distance. I get the impression the ambient light is throwing my meter readings off when the shadows is several hundred feet/meters away. Any thoughts on what adjustments? I know i can shoot a backup and adjust exposure or change ISO readings to tweak the reading. Anything else I can do?

[mikebarger]

I measure shadows from the shooting position and, so far , haven't had a problem. I make enough other mistakes though.

Mike

[Louie Powell]

I would expect that the error introduced into a spot reading by ambient light and/or glare would be so random that there is no way to do a precise compensation.

So the best you can do is bracket. Do one exposure based on the indicated reading. Then, if you are concerned that the reading was biased by ambient light, expose one or more additional sheets with increased exposure.

The issue of ambient bias is a good argument for a 1 degree spot meter, and is also why Fred Picker offered special versions of both the Pentax and Soligor meter that were modified with improved baffling to reduce ambient bias.

[mikebarger]

I think Wally was using a spotmeter.

Mike

[photographs42]

In most cases you can measure a similar shadow that is close to you. Remember that the shadow value is a combination of science and judgment. The numbers don’t lie, but you have to make a judgment call on what value you want the shadows to be. Light falloff isn’t a factor when dealing with the sun. If something close to you is receiving the same light the shadows should measure the same.
Jerome

[Paul Kierstead]

I get the impression the ambient light is throwing my meter readings off when the shadows is several hundred feet/meters away.

Some good suggestions above, but I am wondering what gives you that impression? Certainly I could see that some spot meters (assuming you are talking about spot meters) could have flare problems if you were facing a very bright light (eg. sun). You could try taking a reading, then shading the lens of the spot meter and taking another and seeing if there is a difference, or even fashioning a quick hood (just as an experiment) to see if your particularly meter is prone to this.

[Jim Michael]

Atmospheric haze can be a factor as particulate matter reflects light and increases in quantity with distance.

[Sevo]

Atmospheric haze and in-meter glare should not alter the light intensity any more than on the camera image - a spot meter effectively is a SLR with a CdS or silicone cell in place of the film.

Even on the Sekonic ViewSpot, which is somewhat less complex than other dedicated spot meters, the meter does not deflect any different if I point a very bright light at its lens - for practical purposes that should be good enough. YMMV when it comes to directional attachments for regular meters, if only because they have very vague spot boundaries.

Sevo

[Jim Michael]

My point was that as your distance changes the reading of the shadow may change due to the contribution from haze, i.e. the contrast changes.

[Mark Sawyer]

Any flare from the "ambient light", atmospheric haze, flare, etc, that appears in the spot metering stage should be fairly closely replicated by the taking lens at the same distance, presuming the lens in the spot meter has semi-similar charactaristics as the taking lens, (both being multi-coated, etc.)

There might be some differences when using a spot meter with an uncoated lens, but taking with a coated lens, or vice-versa, or if you're using lenses with diffusion properties, numerous uncoated air-glass surfaces, etc. That's why I use a special spot meter with interchangeable lensboards so I can meter through my taking lens. It accepts up to 9" square lensboards so I can meter through the really big Petzvals, then switch them to my studio camera for the exposure...

...okay, no, not really.