Jump to content


Photo

Incident meter, how does it work?

incident meter spot meter

  • Please log in to reply
32 replies to this topic

#1 Hongji Wu

Hongji Wu

    New

  • Basic Members
  • Pip
  • 5 posts
  • Student
  • United States

Posted 13 November 2013 - 05:48 PM

It's a stupid question, but i haven't find any satisfying results on the internet, so the idiot starts to ask! :) 

 

there's something i don't understand about incident meter:

 

We know that when we use the reading from the spot meter, the measured area will be rendered 18% middle gray regardless of the actual reflectance of the area, so we open up or close down the aperture and get a proper exposure.

 

But when we use an incident meter, which takes an average reading of the incoming light onto the object, we don't have any actual reference or benchmark like 18% grey for it to calculate, how could the meter "know" which part is lighter and which part is darker? I see some people answered "using the reading from an incident meter makes a gray card in the same light settings falls into ZONE V" but i got more confused because it kinda explains nothing...

 

Let me be more specific, E.g. How did incident meter calculate the light distribution on an Caucasian face and gives out a reading that replicates the same tone as we see?

 

there may still be misconceptions and errors in my understanding of zone system or both meters, can some one explain it to me in an easy way? That would be very helpful, thanks! :lol:


  • 1

#2 Adrian Sierkowski

Adrian Sierkowski
  • Sustaining Members
  • 7118 posts
  • Cinematographer
  • Los Angeles, Ca

Posted 13 November 2013 - 06:20 PM

Well basically the meter doesn't give a damn. What'll happen is it'll measure the light coming in and say, ok, to make middle grey fall into middle grey, use this exposure. So on your example, let's take a face flatly lit. Spotting it will give us a reading to make that face middle grey, let's say F4, however we know the face isn't middle grey, it should be 1 stop over, so we'd adjust to F2.8

The incident meter, with the dome taking the place of a face, will instead say, hey, the light here should be F2.8 to expose middle grey at middle grey and therefore the range of exposures on the face will reproduce faithfully. In our flat lit face it'll be 1 stop over middle grey, with proper skin tones. If we have a super high contrast face, well then the over and under exposed areas would be over and under exposed with reguard to middle grey (if the overs were +3 stops, they'd be +3 stops, and the shadows -3 if they actually are -3, let's say).

 

Hope that makes sense.


  • 2

#3 Hongji Wu

Hongji Wu

    New

  • Basic Members
  • Pip
  • 5 posts
  • Student
  • United States

Posted 13 November 2013 - 06:53 PM

Well basically the meter doesn't give a damn. What'll happen is it'll measure the light coming in and say, ok, to make middle grey fall into middle grey, use this exposure. So on your example, let's take a face flatly lit. Spotting it will give us a reading to make that face middle grey, let's say F4, however we know the face isn't middle grey, it should be 1 stop over, so we'd adjust to F2.8

The incident meter, with the dome taking the place of a face, will instead say, hey, the light here should be F2.8 to expose middle grey at middle grey and therefore the range of exposures on the face will reproduce faithfully. In our flat lit face it'll be 1 stop over middle grey, with proper skin tones. If we have a super high contrast face, well then the over and under exposed areas would be over and under exposed with reguard to middle grey (if the overs were +3 stops, they'd be +3 stops, and the shadows -3 if they actually are -3, let's say).

 

Hope that makes sense.

Thank you for your reply Adrian !

 

I seem to understand a little bit more, to put it in my own words:

 

incident meter basically collects the incoming light from all direction and get the data of the intensity, they don't need to know what's a darker gray or a lighter gray because it's changing, but the middle point of 18% gray (which is unchangeable as a fact of the reality) is fixed, and that acted as a baseline of calculation. So as long as the reading of the incident meter makes the camera replicate the mid gray tone from the mid gray tone in the actual scene, other lighter or darker areas falls into its place naturally.

 

Am I correct about that ?


  • 1

#4 Adrian Sierkowski

Adrian Sierkowski
  • Sustaining Members
  • 7118 posts
  • Cinematographer
  • Los Angeles, Ca

Posted 13 November 2013 - 07:42 PM

Yep; the key is, the meter makes it so you're exposing middle grey to fall in middle grey, and the rest will fall where they would fall.

For myself; i tend to use incident metering the most-- saving spot to get an idea of where on the scale other things are in relation to my shooting stop (e.g. incident, and get a T2.8 and check a highlight which is at T11 and know, ok, that's 4 stops over my exposure; but it's a highlight so it's all good).


  • 1

#5 Hongji Wu

Hongji Wu

    New

  • Basic Members
  • Pip
  • 5 posts
  • Student
  • United States

Posted 13 November 2013 - 07:52 PM

Yep; the key is, the meter makes it so you're exposing middle grey to fall in middle grey, and the rest will fall where they would fall.

For myself; i tend to use incident metering the most-- saving spot to get an idea of where on the scale other things are in relation to my shooting stop (e.g. incident, and get a T2.8 and check a highlight which is at T11 and know, ok, that's 4 stops over my exposure; but it's a highlight so it's all good).

thanks again Adrien! 


  • 1

#6 MacArthur Bougere

MacArthur Bougere

    New

  • Basic Members
  • Pip
  • 1 posts
  • Cinematographer
  • United States

Posted 07 June 2014 - 05:08 PM

I am sooo glad I ran into this forum topic. It helps so much. Everyone seems to want to give you advice based on dictation rather than the content itself without knowing how to spell things out. 


  • 0

#7 Guy Holt

Guy Holt
  • Basic Members
  • PipPipPipPip
  • 535 posts
  • Gaffer
  • Boston

Posted 08 June 2014 - 08:50 PM

So as long as the reading of the incident meter makes the camera replicate the mid gray tone from the mid gray tone in the actual scene, other lighter or darker areas falls into its place naturally. Am I correct about that ?

 

Yes and no. There does not have to be a mid gray tone (commonly called the “key” tone) in the scene to expose for. This is a complicated subject. The key tone, or mid gray because it appears in the middle of a photographic gray scale,  is the common reference point used by light meters, lab processors, and transfer colorists.  A lab processor knows what density his processed emulsion should be to render mid gray and so he is able to adjust his processing accordingly. A transfer colorist, knows gain will reproduce the luminance of mid gray so he is able to set his gain. Simply put it is the reference point to which we peg all other values on the characteristic curve of the film or digital format we are using. Meters are likewise calibrated for mid gray. For example there are basically two types of meters: incident and spot.  Incident meters read the light falling on your subject. Spot meters read the light reflecting back from your subject.  An incident reading gives you an exposure that after normal processing would  render  an 18% gray card as 18% gray (a specific density of the film) had you held it in front of the camera in the same light.  Incident meters enable you to peg the key tone (18% gray) in this fashion even though there may not be a mid-tone in your scene.

 

A spot meter is then typically used to take reflective readings to see how other objects will expose relative to the key tone that was pegged with the incident meter.  The thing to remember about spot meters is that they want to expose everything as mid gray.  For instance, if you expose a black piece of paper with the reading of a spot meter it will appear as mid gray after normal processing (not pushed or pulled) – likewise for a white piece of paper. But, if you place an incident meter down on the black piece of paper and expose for the incident reading the black paper will be black, and the white paper will be white, after normal processing because you exposed for the key tone by using the incident reading and thereby pegged the other values (white and black) relative to it. If you don’t have an incident meter, but want to peg the key tone under your subject's key light, an old trick is to take a spot meter reading of the palm of your hand under the key light and open up one full stop.  This will give you a close approximation because the average Caucasian flesh tone is one stop more reflective than 18% gray.

 

 

Metering_characteristic_curve.jpg

 

(The “Characteristic Curve” of a high contrast B&W Reversal emulsion. The object of exposure is to place the contrast range of the scene on the straight line portion of the curve so that the different luminances of objects in the scene are reproduced accurately on the film. Mid gray being the common reference point.)

 

You use the reading from the spot meter to be sure that the object you are metering will be within the exposure range (characteristic curve) of the film stock you are using. If the stock has a nine stop range (five stops over before detail burns out, and four stops under before detail blocks up), and your reading of a dark object is six stops under your key tone, it will not be rendered on the film after it is processed normal (to reproduce mid gray as mid gray).

 

Metering_Contrast_Exceeds.jpg

 

(The contrast range of this scene exceeds the film’s exposure range, so when the image is exposed for the light outside the arch (Left Image), detail is lost in the archway. Likewise, if the image is exposed to hold detail in the archway (Right Image), detail is lost outside the arch. Pegging the key tone centers the contrast range of the scene on the straight line portion of the curve such that some detail is lost outside and inside the arch way, but the luminance values of most of the scene are rendered accurately in the middle image.)

 

Since in this situation the contrast range of the scene is beyond the exposure range of the film you have two choices. 1) You can open up and expose for the shadows (over exposing the key tone and blowing out your highlights more in the process) and print down to make mid gray mid gray again. In the end you have the detail in the shadows you want, but in the process you have lost detail in the highlights.  Why?  Because the contrast range of the scene was beyond the exposure range of the film, and you exposed for shadow detail, you burned out the highlights (no detail) so it is not there when you print down to mid gray.  You can't bring it back. Is that bad - not necessarily. It's just another "look."

 

Metering_Scene_Contrast.jpg

 

(The contrast range of this exterior exceeds the exposure range (flat line portion of the “Characteristic Curve”) so shadow details, in his hair and the black velour under the MacBeth Chip Chart, that fall on the bottom of the ”toe” of the curve “block up” (max density) and detail in that area of the frame is lost. Likewise, highlights like the specular sun on the windshield and the white towel, that fall on the upper end of the “shoulder” of the curve “burn out” (min density) ) and detail in that area of the frame is lost. The object of lighting is to compress the contrast range of the scene so that it fits on the straight line portion of the curve so that the different luminances of objects in the scene are reproduced accurately on the film.)

 

Or, 2) you can throw some light into the shadows to bring the reflective value of the dark object within the exposure range of the film (onto the straight portion of its’ characteristic curve) without changing the exposure of the key tone value (mid gray) or blowing out the highlights.  In this fashion you fit the contrast range of your scene into the exposure range of the film emulsion you are using. Of course this is only the starting point. From this “correct” exposure a DP will further manipulate the relationship of the contrast range of a scene to the exposure range of the film stock to create a desired effect. This is old school film exposure theory, but it is a good conceptual frame work for exposing digital video, especially now that you can record "raw" and apply "looks" to the raw data.

 

Metering_Challange.jpg

(Post in this thread the problems in this image and how to fix them)

 

A fun exercise is to shoot a frame with just available light and then think about how you can improve upon it through lighting. For example, identify the problems in the image above and then list how to fix them through lighting and wardrobe.

 

Guy Holt, Gaffer, ScreenLight & Grip, Lighting & Grip Sales and Rentals in Boston


  • 2

#8 Gregory Irwin

Gregory Irwin
  • Sustaining Members
  • 589 posts
  • 1st Assistant Camera
  • Work is based in Los Angeles but I live elsewhere.

Posted 08 June 2014 - 10:33 PM

Guy, you have made an excellent analysis of the principles of exposure. You are right on! I don't think the younger members of our craft truly study "the curve" anymore and relate it to balancing the light. That's ashame. Great post Guy.

G
  • 0

#9 John E Clark

John E Clark
  • Basic Members
  • PipPipPipPip
  • 846 posts
  • Other
  • San Diego

Posted 09 June 2014 - 09:51 AM

Guy, you have made an excellent analysis of the principles of exposure. You are right on! I don't think the younger members of our craft truly study "the curve" anymore and relate it to balancing the light. That's ashame. Great post Guy.

G

 

I don't know that The Curve, and knowledge about it, realtive to Film film processing is all that beneficial.

 

What I'd like is better 'curves' from digital Camera manufacturers, in the DSLR category, about their sensors, relative to say the IRE display. The latter seems to be taking the place of the H-D curves of film.

 

In the olden days, one could get the Kodak data sheet on the film type one was going to use, then one shoot test shots, develop, and measure the resulting densities...

 

These days, with all the hype about 'high Dynamic Range', often it is any one's guess as to the real response curve of the camera, and further, how much 'post' modification that data can take without producing garbage.

 

Last NAB I went around to several major DSLR brand booths and asked the somewhat simple question of 'how does X determine the ISO values for camera Y'... only the Black Magic camera both had someone 'technically' up, at the booth... I got a range of responses to the question at the other big names ranging from... 'that guy is ill today', or 'that guy isn't at the show'... to 'that may be a question for Japan'...

 

In the olden days... a Kodak or Fuji rep would say... 'we use Standard X'... and if I exposed film, developed it per the Kodak data sheet I'd get 'close' to those lab results.

 

I did contact one of the popular rental houses, by email after the show, and the person said they have setups at their facility and I could bring in cameras or test their rental selection with some charts they have setup.

 

Unfortunately I don't make it to LA all that frequently during the work week...


  • 0

#10 Matthew B Clark

Matthew B Clark
  • Basic Members
  • PipPipPip
  • 189 posts
  • Other
  • Chicago, IL

Posted 09 June 2014 - 12:28 PM

 

Yes and no. There does not have to be a mid gray tone (commonly called the “key” tone) in the scene to expose for. This is a complicated subject. The key tone, or mid gray because it appears in the middle of a photographic gray scale,  is the common reference point used by light meters, lab processors, and transfer colorists.  A lab processor knows what density his processed emulsion should be to render mid gray and so he is able to adjust his processing accordingly. A transfer colorist, knows gain will reproduce the luminance of mid gray so he is able to set his gain. Simply put it is the reference point to which we peg all other values on the characteristic curve of the film or digital format we are using. Meters are likewise calibrated for mid gray. For example there are basically two types of meters: incident and spot.  Incident meters read the light falling on your subject. Spot meters read the light reflecting back from your subject.  An incident reading gives you an exposure that after normal processing would  render  an 18% gray card as 18% gray (a specific density of the film) had you held it in front of the camera in the same light.  Incident meters enable you to peg the key tone (18% gray) in this fashion even though there may not be a mid-tone in your scene.

 

A spot meter is then typically used to take reflective readings to see how other objects will expose relative to the key tone that was pegged with the incident meter.  The thing to remember about spot meters is that they want to expose everything as mid gray.  For instance, if you expose a black piece of paper with the reading of a spot meter it will appear as mid gray after normal processing (not pushed or pulled) – likewise for a white piece of paper. But, if you place an incident meter down on the black piece of paper and expose for the incident reading the black paper will be black, and the white paper will be white, after normal processing because you exposed for the key tone by using the incident reading and thereby pegged the other values (white and black) relative to it. If you don’t have an incident meter, but want to peg the key tone under your subject's key light, an old trick is to take a spot meter reading of the palm of your hand under the key light and open up one full stop.  This will give you a close approximation because the average Caucasian flesh tone is one stop more reflective than 18% gray.

 

 

Metering_characteristic_curve.jpg

 

(The “Characteristic Curve” of a high contrast B&W Reversal emulsion. The object of exposure is to place the contrast range of the scene on the straight line portion of the curve so that the different luminances of objects in the scene are reproduced accurately on the film. Mid gray being the common reference point.)

 

You use the reading from the spot meter to be sure that the object you are metering will be within the exposure range (characteristic curve) of the film stock you are using. If the stock has a nine stop range (five stops over before detail burns out, and four stops under before detail blocks up), and your reading of a dark object is six stops under your key tone, it will not be rendered on the film after it is processed normal (to reproduce mid gray as mid gray).

 

Metering_Contrast_Exceeds.jpg

 

(The contrast range of this scene exceeds the film’s exposure range, so when the image is exposed for the light outside the arch (Left Image), detail is lost in the archway. Likewise, if the image is exposed to hold detail in the archway (Right Image), detail is lost outside the arch. Pegging the key tone centers the contrast range of the scene on the straight line portion of the curve such that some detail is lost outside and inside the arch way, but the luminance values of most of the scene are rendered accurately in the middle image.)

 

Since in this situation the contrast range of the scene is beyond the exposure range of the film you have two choices. 1) You can open up and expose for the shadows (over exposing the key tone and blowing out your highlights more in the process) and print down to make mid gray mid gray again. In the end you have the detail in the shadows you want, but in the process you have lost detail in the highlights.  Why?  Because the contrast range of the scene was beyond the exposure range of the film, and you exposed for shadow detail, you burned out the highlights (no detail) so it is not there when you print down to mid gray.  You can't bring it back. Is that bad - not necessarily. It's just another "look."

 

Metering_Scene_Contrast.jpg

 

(The contrast range of this exterior exceeds the exposure range (flat line portion of the “Characteristic Curve”) so shadow details, in his hair and the black velour under the MacBeth Chip Chart, that fall on the bottom of the ”toe” of the curve “block up” (max density) and detail in that area of the frame is lost. Likewise, highlights like the specular sun on the windshield and the white towel, that fall on the upper end of the “shoulder” of the curve “burn out” (min density) ) and detail in that area of the frame is lost. The object of lighting is to compress the contrast range of the scene so that it fits on the straight line portion of the curve so that the different luminances of objects in the scene are reproduced accurately on the film.)

 

Or, 2) you can throw some light into the shadows to bring the reflective value of the dark object within the exposure range of the film (onto the straight portion of its’ characteristic curve) without changing the exposure of the key tone value (mid gray) or blowing out the highlights.  In this fashion you fit the contrast range of your scene into the exposure range of the film emulsion you are using. Of course this is only the starting point. From this “correct” exposure a DP will further manipulate the relationship of the contrast range of a scene to the exposure range of the film stock to create a desired effect. This is old school film exposure theory, but it is a good conceptual frame work for exposing digital video, especially now that you can record "raw" and apply "looks" to the raw data.

 

Metering_Challange.jpg

(Post in this thread the problems in this image and how to fix them)

 

A fun exercise is to shoot a frame with just available light and then think about how you can improve upon it through lighting. For example, identify the problems in the image above and then list how to fix them through lighting and wardrobe.

 

Guy Holt, Gaffer, ScreenLight & Grip, Lighting & Grip Sales and Rentals in Boston

 

I like to imagine that every film stock is as limited as reversal film.  That way it FORCES my brain to think hard about nailing something.  I just don;t like to allow myslef to be acknowledging lattitude. 

 

Negative stocks might have lattitude for miles, yes it might be there, but if you count on it too much, that's when the drunk driving begins.  That vehicle starts to move more erratically.  Sooner or later you'll hit a guard-rail thinking like that. 

 

The funny thing to me is...and I guess this is ironic considering what I just wrote...I follow the incident metering principles mentioned like a hawk, but when it comes to the act of backing it up with a spot meter, and taking it to the next level checking those relative exposures of various sections of a scene etc., I kind of veer off into another direction and do that part based way more on intuition (I have super limited experience, but I already do have a decent grasp on making sure a black is black or a light is light), so it's not that hard to figure out what a scene looks like "by eye" and use your human mind to figure out where to throw a hard or soft light, or bounce or flag something off with an object in the room or whatever.  I mean, you can see (at least I can anyway) when a scene is completely going to have a deep set of blacks and blown out highlights.  I don't think I want to be dallying around spot-metering for that stuff (because I just accept my creativity on that part - in the sense of a "painting" decision, not so much a "chemistry class" decision, if that makes sense). 

 

As for the exercise above...I don't know how you would do it, but I'd throw something over the glass to knock that window down at least two stops and then stick a single 1K above it, aiming downward at 45 degrees to rim their heads and ten bounce it off a white board to fill their faces.  I'd also put a "creative" light on the African American gentleman, coming from the right side, and flag it so it does not hit the Caucasian gentle-woman.  Then, I'd put some lame incidental room light in front of the man, just so it appears like "something" is justifying the extra burst of brightness onto him (but it wouldn't e strong enough to actually "do" much.  Just basically be a prop.


  • 0

#11 Matthew B Clark

Matthew B Clark
  • Basic Members
  • PipPipPip
  • 189 posts
  • Other
  • Chicago, IL

Posted 09 June 2014 - 12:44 PM

Oh!  One more lighting problem!...that background would turn way too black with that window knocked down (it's already in need of repair), so the folks in the background would need another touch of lighting magic.  This I do not know how to do though...because my gut is telling me they HAVE to get it from the direction of that window (simulating the window light) but yeah, there is no room back there, so MAYBE just hide the lights behind the people and tell them to hold still?!  Something like this.


Edited by Matthew B Clark, 09 June 2014 - 12:45 PM.

  • 0

#12 Matthew B Clark

Matthew B Clark
  • Basic Members
  • PipPipPip
  • 189 posts
  • Other
  • Chicago, IL

Posted 09 June 2014 - 12:52 PM

Or actually...maybe just have something aiming across their faces from the side, as a very soft and generic fill that gives a lot of pop to the table surfaces and comes up to hit their faces and sort of distinghuishes whatever activity they are engaged in (in other words, rims the shapes enough, or basically fills key definitions of "them").  I just don't like how you can't see anything back there right now and it needs some creative slash of light to pick up the action.


  • 0

#13 John E Clark

John E Clark
  • Basic Members
  • PipPipPipPip
  • 846 posts
  • Other
  • San Diego

Posted 09 June 2014 - 01:15 PM

Or actually...maybe just have something aiming across their faces from the side, as a very soft and generic fill that gives a lot of pop to the table surfaces and comes up to hit their faces and sort of distinghuishes whatever activity they are engaged in (in other words, rims the shapes enough, or basically fills key definitions of "them").  I just don't like how you can't see anything back there right now and it needs some creative slash of light to pick up the action.

 

The shot of the woman and man, are from one of several 'shoot outs' organized and presented by "Zacuto" a sales and rental house based in Chicago.

 

I don't recall a shot that 'constrasty', but then it has been a while since I've watched the several shootouts...

 

Here's a link to the shoot out I think this still came from:

 

http://www.zacuto.co...ut-revenge-2012


  • 0

#14 Bill DiPietra

Bill DiPietra
  • Sustaining Members
  • 2339 posts
  • Cinematographer
  • New York City

Posted 09 June 2014 - 01:18 PM

Great post, Guy!  That cleared up a lot of things about the curve I always found rather confusing.

 

Thanks!


Edited by Bill DiPietra, 09 June 2014 - 01:19 PM.

  • 0

#15 John E Clark

John E Clark
  • Basic Members
  • PipPipPipPip
  • 846 posts
  • Other
  • San Diego

Posted 09 June 2014 - 01:33 PM

 

I like to imagine that every film stock is as limited as reversal film.  That way it FORCES my brain to think hard about nailing something.  I just don;t like to allow myslef to be acknowledging lattitude. 

 

Negative stocks might have lattitude for miles, yes it might be there, but if you count on it too much, that's when the drunk driving begins.  That vehicle starts to move more erratically.  Sooner or later you'll hit a guard-rail thinking like that. 

 

Negative stocks did not have 'miles' of latitude, especially when one viewed the final print film to be used.

 

There were effects from 'overexposure', even with processing by reducing development times, which may or may not have interfered with the 'aesthetic' look of the film. Grain was in many cases objectionable. So, underexposing, and 'over developing' led to 'more grain'... aka 'noise'.

 

Perhaps not the same type of 'noise' now found objectionable in digital images, but definitely not something 'Hollywood' looked to present... until the 60's and the 'new wave' of realism, wherein grainy images were considered more 'real' as in 'just like newspaper reportage images of 'real' events'.

 

Most 'movie' films of the classic era had ASA values of 16-50. In the 50's that value began to creap up to 100-200 then in the 70's 500... Black and White movie film seems to have fossilized at 250D/200T for Double X which is still made. (I think faster B&W movie filmes may have been developed, but production has been stopped for years...).

 

Tri-X a popular 'highspeed' still B&W had a ASA of 400, and even then when a 35mm negative was blown up... grain was the most signficant detraction... (It was a really great film for 4x5 shooting...).

 

For me, I rated my Tri-X at 200, and could expect about 2 stops of 'latitiude', by compensating with reduced development times. For 'underexposure', perhaps a stop or 1.5 stops, before 'grain' started to become a problem.

 

I'm sure people who used Double X at the time, probably had about the same 'wiggle' room.

 

Color film... what me shoot color film... hell no...


  • 0

#16 Matthew W. Phillips

Matthew W. Phillips
  • Sustaining Members
  • 1792 posts
  • Other

Posted 09 June 2014 - 01:42 PM

 

Negative stocks did not have 'miles' of latitude, especially when one viewed the final print film to be used.

This is crapola and please come back when you obey the forum rules. Thanks.


  • 0

#17 Gregg MacPherson

Gregg MacPherson
  • Basic Members
  • PipPipPipPip
  • 1883 posts
  • Other
  • New Zealand

Posted 09 June 2014 - 03:19 PM

Jedediah Ebonezza Clark of 2006,  on 10 Jun 2014 - 06:33 AM, said

 

"Negative stocks did not have 'miles' of latitude, especially when one viewed the final print film to be used....

 

Most 'movie' films of the classic era had ASA values of 16-50. In the 50's that value began to creap up to 100-200 then in the 70's 500...

 

For me, I rated my Tri-X at 200, and could expect about 2 stops of 'latitiude', by compensating with reduced development times. For 'underexposure', perhaps a stop or 1.5 stops, before 'grain' started to become a problem...."

 

 

In the quest for uniqueness are you giving new definition to the word "latitude" ?

 

I think most color films in the 70s were shot on 100T stock (5254/47).


Edited by Gregg MacPherson, 09 June 2014 - 03:24 PM.

  • 0

#18 John E Clark

John E Clark
  • Basic Members
  • PipPipPipPip
  • 846 posts
  • Other
  • San Diego

Posted 09 June 2014 - 03:29 PM

 

In the quest for uniqueness are you giving new definition to the word "latitude" ?

 

I think most color films in the 70s were shot on 100T stock (5254/47).

 

From the wiki on the film use of the word 'latitidue':

 

http://en.wikipedia....posure_latitude

 

---

Exposure latitude is the extent to which a light-sensitive material can be overexposed or underexposed and still achieve an acceptable result.

---

and

---

It is not to be confused with dynamic range, the range of light intensities a medium can capture simultaneously.

---

 

As for ISO 500... sure... the point being, that only in the last 30 years has Film film stocks gotten any amount of 'speed' to speak of.


  • 0

#19 Matthew W. Phillips

Matthew W. Phillips
  • Sustaining Members
  • 1792 posts
  • Other

Posted 09 June 2014 - 03:45 PM

Never shot tri-X except for stills (which I overexposed at 3 stops and still were fine) but color film can go far more than 2 stops over and still be usable. I am starting to think jecl ark is a troll.


  • 0

#20 Gregg MacPherson

Gregg MacPherson
  • Basic Members
  • PipPipPipPip
  • 1883 posts
  • Other
  • New Zealand

Posted 09 June 2014 - 06:17 PM

Jaqueline  Elizabeth Clark of 2006,  on 10 Jun 2014 - 08:29 AM, said

 

 

"...wiki ...

http://en.wikipedia....posure_latitude

 

Exposure latitude is the extent to which a light-sensitive material can be overexposed or underexposed and still achieve an acceptable result.....

it is not to be confused with dynamic range..."

 

 

I think Matthew B Clark can be forgiven for his exageration in saying that negative film has miles of latitude (I think the common assumption was color negative).  It's relative,  he's excited about it.

 

Not to confuse latitude with dynamic range,  but one can't meaningfully separate (decouple) these two (I can't).  And how is lattitude meaningfully decoupled from the  range of values within a frame.  Unless one assumes a range that is generic,  which may be a common working practice I guess.

 

Too much wiki...


Edited by Gregg MacPherson, 09 June 2014 - 06:21 PM.

  • 0



Also tagged with one or more of these keywords: incident meter, spot meter

Ritter Battery

Abel Cine

The Slider

Gamma Ray Digital Inc

Rig Wheels Passport

Willys Widgets

Media Blackout - Custom Cables and AKS

Opal

FJS International, LLC

Wooden Camera

Tai Audio

Visual Products

Technodolly

Paralinx LLC

CineLab

CineTape

Glidecam

rebotnix Technologies

Metropolis Post

Broadcast Solutions Inc

Aerial Filmworks

Visual Products

Technodolly

Broadcast Solutions Inc

Tai Audio

Glidecam

Paralinx LLC

Rig Wheels Passport

CineLab

Ritter Battery

Metropolis Post

Wooden Camera

Media Blackout - Custom Cables and AKS

Aerial Filmworks

CineTape

Abel Cine

FJS International, LLC

rebotnix Technologies

The Slider

Willys Widgets

Opal

Gamma Ray Digital Inc