Underexposure with incident metering
- Thread starter lrochfort
- Start date
- Latest activity Latest activity:
- Replies 119
- Views 15K
Roger Hicks
Veteran
For negatives? Of general subjects? A reflected light reading, with the meter tilted slightly down so as to avoid too much sky in the picture. If one part of the subject is darker than another, "favour" that (point the meter towards it more).
This will avoid underexposure unless there are unusually deep shadows that matter, in which case you may need to "fudge" by giving more exposure. Or unless you are photographing (say) a whitewashed Greek village where you may want to cut the exposure in order to get more texture into the white.
An added refinement is to take an incident light reading as well, and use that to decide how big your "fudge factor" is going to be.
Mostly, the truth is that it doesn't matter. If it were as complicated as some people like to make it, no-one would ever get a decent exposure. It's only when you're faced with difficult lighting with a long tonal range, and don't want to sacrifice the shadows or blow the highlights (the latter is much more difficult), that you need to worry at all.
Many people who think they know a great deal about exposure are saved by simple latitude, especially those who habitually expose generously. And, as several people have repeatedly said, implied or demonstrated, just about any metering system can be made to work with a modicum of thought and experience.
Cheers,
R.
This will avoid underexposure unless there are unusually deep shadows that matter, in which case you may need to "fudge" by giving more exposure. Or unless you are photographing (say) a whitewashed Greek village where you may want to cut the exposure in order to get more texture into the white.
An added refinement is to take an incident light reading as well, and use that to decide how big your "fudge factor" is going to be.
Mostly, the truth is that it doesn't matter. If it were as complicated as some people like to make it, no-one would ever get a decent exposure. It's only when you're faced with difficult lighting with a long tonal range, and don't want to sacrifice the shadows or blow the highlights (the latter is much more difficult), that you need to worry at all.
Many people who think they know a great deal about exposure are saved by simple latitude, especially those who habitually expose generously. And, as several people have repeatedly said, implied or demonstrated, just about any metering system can be made to work with a modicum of thought and experience.
Cheers,
R.
icebear
Veteran
There you have it :
All there is to know (apart from Roger knows better 😉) about metering:
You need to meter consistently.
It doesn't really matter too much, if the absolute value is not by the book. As long as you evaluate your results and correct your reading into whatever direction necessary. Aka "fudgin' or experience"😉 You are the one deciding if you are happy with the result in print.
As for the initial post/question:
I guess "don't let direct sun hit the dome" should have been sufficient. Just my $0.02.
It's not a contest out there to meter, development the film acc. to ISO 1234 and match zone 4 perfectly when printed under ISO conditions on a grade 2 paper. I don't get what all the fuss is about. Take it easy 😀
Sparrow
Veteran
... armed with just an incident meter and negative film, if the sun's out then just do sunny f16-1/film speed (iso/asa), but if the subject is in shadow or back-llit open up by two stops ...
... if it's not sunny, then take a reading with the dome pointing away from the subject (in the same lighting conditions) and pointing at the camera's intended position and use that ...
... if you're indoors see post No.85
... later, look carefully at your negatives and adjust your method as necessary; would be my best advice
Rob-F
Likes Leicas
Roger, I actually didn't know that the 18% value was chosen by popular preference. I had imagined it was determined by some highly esoteric method beyond my knowledge. No wonder I couldn't figure out where 18% came from. It's perceptual, not mathematical, eh?
Could you say more about how & why the shape of the Inverdome gives readings that differ from a dome? And how or when I, or we, might profit from using one? I think I still have a Weston around here someplace.
Could you say more about how & why the shape of the Inverdome gives readings that differ from a dome? And how or when I, or we, might profit from using one? I think I still have a Weston around here someplace.
Roger Hicks
Veteran
Dear Rob,
Highlight: Spot on (as it were).
For the latter, see http://www.johndesq.com/pinhole/invercones.htm
Cheers,
R.
David Hughes
David Hughes
Hi,
I often wonder if anyone could notice the difference between an 18% card and a 19% card. My understanding of Weber-Fechner's Law is different from what's quoted here: I forget which post, sorry.
Old Weston's are rather nice to use but you need the instruction manual in front of you. It's rather odd as their 1930's ones were/are simple to understand.
Regards, David
PS An addition to the general advice: carry a notebook and put each exposure in it; don't rely on memory.
Sparrow
Veteran
Yes easily, as a comparison in good light ... the eye is useless at absolute values but really good as a comparator
Rob-F
Likes Leicas
David, the difference between 18% and 19% is one part in 18. Since the eye can discern a brightness change of one part in 100, I think this is within the eye's capability. As I recall, Weber's law just says that the JND is a percentage, or proportion, of the stimulus intensity; and Fechner's Weber's law (as the profs called it in grad school in the '70's) says that the proportionality is logarithmic, not linear. After that it gets trickier, with exceptions based on whether the stimulus is at a low level, or very bright/loud. They didn't go into all that in grad school (I guess clinical types don't need all that detail).
What discrepancies do you suspect? I could try to look it up.
Rob
Edit: such findings are done under laboratory conditions. Whether the difference between 18% and 19% would be noticed "in the field" could possibly be another matter.
Bill Clark
Veteran
For digital I use the in camera light meter to start the process. Then I will look at the histogram to tweak the settings. Then if I need a little garlic light then I will work the settings, getting them set for that, using the histogram as well as the camera viewing screen. Since I run the camera in "M" mode I can make adjustments.
For film, I'm getting back to looking around me w/o a light meter, making the settings from what I see and what I want to record on the film. I did that years ago as I couldn't afford a light meter and, over time to learn, things worked out pretty well back then.
For film, I'm getting back to looking around me w/o a light meter, making the settings from what I see and what I want to record on the film. I did that years ago as I couldn't afford a light meter and, over time to learn, things worked out pretty well back then.
Sparrow
Veteran
.. a good point, well made and culinary advice to boot
Bill Clark
Veteran
Gotta remember f stop controls both ambient and flash. Shutter only affects ambient but I don't want to get to the sync. wall! Although I exceeded in a couple of instances, I'll just crop out the little bit of dark that doesn't get exposed with the flash. That's only a last resort thing to do!
Garlic light is just like a sweet kiss, I use it to enhance the eyes usually or subdue shadows but mostly to show off the eyes. Use lightly, garlic, so the viewer doesn't notice a flash was used. The eyes are the path to the soul.
Garlic light is just like a sweet kiss, I use it to enhance the eyes usually or subdue shadows but mostly to show off the eyes. Use lightly, garlic, so the viewer doesn't notice a flash was used. The eyes are the path to the soul.
Sparrow
Veteran
... so true even today
David Hughes
David Hughes
Rob-F and Sparrow
Rob-F and Sparrow
Hi,
I don't want to go to deeply into this as it was just an aside but it was based on a lot of experience of what I could see as obvious and what others couldn't see.
As for the 18% and 19% cards, side by side I expect people to see it but I also expect a good few won't.
Another aside, I think it gets tricky because the words we use don't mean the same thing to all of us. Look what people say when talking about FoV f'instance.
Regards, David
PS I call it Weber-Fechner Laws to give credit where it's due. It was a very useful Law a long, long time ago when applied to student's lodgings and the relation to vacuum cleaner use, f'instance.
Rob-F and Sparrow
Hi,
I don't want to go to deeply into this as it was just an aside but it was based on a lot of experience of what I could see as obvious and what others couldn't see.
As for the 18% and 19% cards, side by side I expect people to see it but I also expect a good few won't.
Another aside, I think it gets tricky because the words we use don't mean the same thing to all of us. Look what people say when talking about FoV f'instance.
Regards, David
PS I call it Weber-Fechner Laws to give credit where it's due. It was a very useful Law a long, long time ago when applied to student's lodgings and the relation to vacuum cleaner use, f'instance.
Sparrow
Veteran
I recall a paper that suggests it's dependant on illumination although I forget the exact relationship, but that a just noticeable difference is observable in up to 1,000 shades under ideal conditions ...
... of course this could only be a perceptual study so was empirical (fudged) not mathematical (theoretical) 😉
Gumby
Veteran
Psychophysics is based in statistics. There is a greater-than-90% probability that your statement is 100% correct. 😀
I'm sure that y'all can do this yourself but here is a link to some information on that topic: http://en.wikipedia.org/wiki/Psychophysics
p.s. psychophysics is an empirical research method and statistics is mathematical too. That kind of finding is not a simple "opinion poll", which would be statistically based too if done right.
Rob-F
Likes Leicas
The green quote: I agree.
The orange quote: That comment may keep me up tonight. I think you may hear from me about 4AM. Frequency of vacuum usage proportional to the log of time spent in the dorm? Log to the base 10? or ln? I'll think it over.
Rob-F
Likes Leicas
Yes. And also, as a graduate assistant, I got tired of kids saying: "What do you mean, 'significant' ? What is significant to you, might not be significant to me!" (That, after they'd had a semester-long stat course.)
David Hughes
David Hughes
Hi,
I've always found stats extremely useful but the problem is that it throws up things people don't expect and so don't believe; leading to a lot of time spent explaining and sometimes rowing. So nowadays I tread carefully and, since I retired in '91, I suspect I've forgotten most of it or else it's been superseded. Like the old joke about economics; the university used the same question paper each year but changed the answers...
Regards, David
I've always found stats extremely useful but the problem is that it throws up things people don't expect and so don't believe; leading to a lot of time spent explaining and sometimes rowing. So nowadays I tread carefully and, since I retired in '91, I suspect I've forgotten most of it or else it's been superseded. Like the old joke about economics; the university used the same question paper each year but changed the answers...
Regards, David
codester80
A Touch of Light
People concerned with capturing the entire dynamic range of a scene they are photographing are the kind of people who produce boring photographs. Photography is about making decisions and compromises. Photography is about the message. Expose for the message. If it's about the stuff in the shadows, expose for the shadows. If it's about the highlights, expose for the highlights. Forget about getting it all in. You'll never achieve this. EVER. A photographer who says they've achieved a perfect image is a liar. We all continue to take photographs because we're always trying to accomplish the impossible: representing an image we have in our mind's eye perfectly on film and photographic paper.
To the OP I'd suggest there may be something not working properly in your workflow as you said you consistently have the same problem. It might be a faulty meter, shutter, film development. A bit of Sherlock Holmes may be required to solve the issue.
To the OP I'd suggest there may be something not working properly in your workflow as you said you consistently have the same problem. It might be a faulty meter, shutter, film development. A bit of Sherlock Holmes may be required to solve the issue.
Similar threads
