Changing rating of film mid roll?

[yoz]

Do you have a scanner and edit software ? You might be better doing the postproduction yourself some labs don’t deal well with dense negatives

No im just starting out. I do have Lightroom

 

[BrianShaw]

No im just starting out. I do have Lightroom

Why don’t you do a small experiment… take a picture at box speed and “normal exposure”, then bracket around that baseline exposure to see what the effect will be from “changing the film speed” on the same roll. Use half stop steps up to 2 stops on both sides of the normal exposure. Have film processed normally by a reputable lab. Evaluate the negative rather than prints as the exposure may adjusted during printing to make the print look like a normal exposure. If possible, have an incorrect Ed proof sheet printed so you can see the difference between frames. Keep good notes of the exposure used for each frame

 

[macfred]

Maybe this is interesting for someone.

... All film was developed normally, with no push or pull processing ...

http://canadianfilmlab.com/2014/04/24/film-stock-and-exposure-comparisons-kodak-portra-and-fuji/

 

[BrianShaw]

Maybe this is interesting for someone.

... All film was developed normally, with no push or pull processing ...

http://canadianfilmlab.com/2014/04/24/film-stock-and-exposure-comparisons-kodak-portra-and-fuji/

Homework assignment completed!

 

[foc]

Maybe this is interesting for someone.

... All film was developed normally, with no push or pull processing ...

http://canadianfilmlab.com/2014/04/24/film-stock-and-exposure-comparisons-kodak-portra-and-fuji/

Excellent example, have it bookmarked. Thanks for posting the link.

 

[Mr Bill]

From what i have read anymore than 2 stops, sees colours go wonky

I note that you are talking specifically about Portra 400, right? My past experience has been mainly with the 160 version(s). But I've been told that the 400 has nearly identical characteristics, aside from the speed.

My personal experience with Portra 160 (and its predecessors, prior Kodak Professional portrait/wedding films) is that the color response remains stable over a fairly wide exposure range. I should be clear on the exact situation - this was under studio lighting conditions, and color was evaluated via optical printing onto color paper. We made test exposures, using a variety of models (different complexions/hair colors) over a wide exposure range. All of the prints were hand balanced to match "density" and color, then evaluated in properly-lit color booths. The results were: from roughly 1 f-stop underexposed to 3 or 4 stops overexposed, the color matching was virtually identical (professional color correctors could not tell them apart). In other words, no wonky color. Other films - I dunno for sure; I have not specifically tested them, other than a couple of now defunct Fuji portrait/wedding films (they behaved same as the Kodak).

A couple years ago I made a more detailed post; if you don't mind burning up a little time, it's here: https://www.photrio.com/forum/threa...-of-color-neg-film.168506/page-3#post-2192714

To clarify how this exposure series relates to rating film speed let me try to explain a couple of things. First, the ISO speed: this includes two numbers, the first of which is like the 400 in Portra 400 film. Each time you double or halve that value is equivalent to an exposure change of one "f-stop." So when the film is rated normally, and assuming that the exposure metering is "correct," there will be some specific combination of lens aperture (aka f-stop setting) and shutter speed. If you were to change either of these in order to cut the exposure by half (either close down the aperture by one stop, or cut the shutter duration in half) this is equivalent to doubling the ISO speed number from 400 to 800. Likewise, increasing the exposure is equivalent to metering at a reduced ISO speed. So in the test I described, varying exposure from 1 f-stop underexposed to 4 stops overexposed, this should be equivalent to metering with ISO film speeds ranging from film speed = 800 (1 stop underexposed) to film speed = 25 (4 stops overexposed).

One last comment, related to the lighting: virtually all current color neg films are rated for photographic "daylight," meaning a "color temperature" of about 5500K (as I recall; see manufacturer data sheet for the film). And this is the only time when your exposure is strictly correct. How so? Well, the color film has essentially three color-sensitive layers. They are sensitive to, roughly, reddish, greenish, and bluish light. The three color-sensitive layers are speed-balanced to each other only under the "correct" condition of lighting for the film - typically 5500K daylight. In any other color of light the match is not exactly right - for example, one of the color-sensitive layers may be over or underexposed relative to another layer. Now, in the tests I was involved with, we used studio flash, which is daylight balanced. So it was ideal for the test film. If you are shooting under non-ideal lighting - a different color temperature - it is probably a good idea to increase exposure a bit to make sure that none of the color layers gets into the range of underexposure.

 

[Les Sarile]

From what i have read anymore than 2 stops, sees colours go wonky

Processed normally at box speed, Kodak Portra 400 can tolerate a considerable amount of overexposure and some underexposure as shown below.

Kodak Portra 400 exposure range by Les DMess, on Flickr

With some exposure compensation during the scan and in post, I have found that I can easily work with overexposures of +8 and underexposures of -3 stops - depending on subject matter.

 

[JNP]

No im just starting out. I do have Lightroom

That might work.

 

[Alan Edward Klein]

Processed normally at box speed, Kodak Portra 400 can tolerate a considerable amount of overexposure and some underexposure as shown below.

Kodak Portra 400 exposure range by Les DMess, on Flickr

With some exposure compensation during the scan and in post, I have found that I can easily work with overexposures of +8 and underexposures of -3 stops - depending on subject matter.

Les, Box speed 0 doesn't;t look right. A little too light. No? Which one do you think is the "right" exposure?

 

[MattKing]

Les, Box speed 0 doesn't;t look right. A little too light. No? Which one do you think is the "right" exposure?

I expect that we are dealing here with all the vagaries of internet sharing and monitor calibration, because on my laptop that particular exposure looks to display as optimum or close to optimum.

 

[Alan Edward Klein]

I expect that we are dealing here with all the vagaries of internet sharing and monitor calibration, because on my laptop that particular exposure looks to display as optimum or close to optimum.

My monitor is calibrated. In any case, I think photos like crayons make bad samplings. How do you know what the original colors are? The box colors don't look right at "0". Better off with people in an outdoor shot with trees, grass, sky, and clouds. A more natural picture to determine color fidelity.

 

[DREW WILEY]

Tolerate considerable range of, uh, er, outright exposure error? Reminds me of eating for a full week as a student on a low budget. Sunday. beef chuck roast with taters, onions; and carrots. Monday, beef stew; Tuesday, beef stew supplemented with rice; Wednesday, Beef-rice porridge; Thursday; porridge soup; Friday, even more watered-down soup; Saturday, dishwater from the sink? Thats exactly what these "film latitude" samples look like. Yeah, there's something there the whole time; but what does it taste like? - at a certain point, just like sudsy dishwater itself. These color film were engineered for BOX SPEED usage. If someone want to recklessly shoot from the hip with them, that's their prerogative. But don't invite me to the shootout.

 

[Les Sarile]

Les, Box speed 0 doesn't;t look right. A little too light. No? Which one do you think is the "right" exposure?

I setup indoor lights and used my Sekonic meter to determine optimum exposure and set my camera accordingly and varied shutter speed to get the over and under exposure range.

I expect that we are dealing here with all the vagaries of internet sharing and monitor calibration, because on my laptop that particular exposure looks to display as optimum or close to optimum.

Couldn't have been better articulated!

Tolerate considerable range of, uh, er, outright exposure error? Reminds me of eating for a full week as a student on a low budget. Sunday. beef chuck roast with taters, onions; and carrots. Monday, beef stew; Tuesday, beef stew supplemented with rice; Wednesday, Beef-rice porridge; Thursday; porridge soup; Friday, even more watered-down soup; Saturday, dishwater from the sink? Thats exactly what these "film latitude" samples look like. Yeah, there's something there the whole time; but what does it taste like? - at a certain point, just like sudsy dishwater itself. These color film were engineered for BOX SPEED usage. If someone want to recklessly shoot from the hip with them, that's their prerogative. But don't invite me to the shootout.

Of course you're right, they were designed to provide optimum results at box speed under ideal lighting conditions. However, conditions are hardly ever optimum or perhaps one wants to vary from the norm - artistic choices, so I choose to shoot this tests with all the films I have used so that I will know what I can work with from shot to final product taking into account my personal workflow and taste.

For instance, I come upon this scene and my camera meter recommends to me that optimal exposure at the aperture I have chosen was 1/60. However, this was near fall and the water was hardly flowing and I figure I needed at least a 2 secomd exposure to get this effect I wanted. That would mean a 7 stop deviation. Since I know the range of this Fuji 100 color negative film, I didn't think it would be a problem for the film and my workflow.

Fuji 100-26-26B by Les DMess, on Flickr

Certainly you - and others, may have chosen to shoot it any number of ways or pass on it completely. All artistic choices.

 

[DREW WILEY]

Box speed itself makes no distinction between "ideal" and "less than ideal" conditions. I have six decades of outdoor photography with all kinds of color film and multiple camera formats which tells me that. It's just a matter of correct metering. Slowing down an exposure like that to a second or two has nothing to do with "deviating 7 stops", just the appropriate aperture for that amount of time; or else, bring along an ND filter. But with 100-speed film in a shaded area, I'm questioning what actually happened, since you shouldn't have needed to fuss with any stops of "deviation" to accomplish that. But whatever .... you bagged it anyway. So congrats.

Anyway, the whole world is my "Lightroom". Get it right the first time, with real light.

 

[Alan Edward Klein]

I setup indoor lights and used my Sekonic meter to determine optimum exposure and set my camera accordingly and varied shutter speed to get the over and under exposure range.



Couldn't have been better articulated!



Of course you're right, they were designed to provide optimum results at box speed under ideal lighting conditions. However, conditions are hardly ever optimum or perhaps one wants to vary from the norm - artistic choices, so I choose to shoot this tests with all the films I have used so that I will know what I can work with from shot to final product taking into account my personal workflow and taste.

For instance, I come upon this scene and my camera meter recommends to me that optimal exposure at the aperture I have chosen was 1/60. However, this was near fall and the water was hardly flowing and I figure I needed at least a 2 secomd exposure to get this effect I wanted. That would mean a 7 stop deviation. Since I know the range of this Fuji 100 color negative film, I didn't think it would be a problem for the film and my workflow.

Fuji 100-26-26B by Les DMess, on Flickr

Certainly you - and others, may have chosen to shoot it any number of ways or pass on it completely. All artistic choices.

Nice shot Les. Just so I understand what you wrote. Did you add 7 stops to the shot? You just changed the shutter to 2 seconds leaving the aperture the same as the meter told you at 1/60th? (You didn;t mention anything about what the aperture was with the meter reading or what you shot it at.).

 

[Les Sarile]

Box speed itself makes no distinction between "ideal" and "less than ideal" conditions. I have six decades of outdoor photography with all kinds of color film and multiple camera formats which tells me that. It's just a matter of correct metering. Slowing down an exposure like that to a second or two has nothing to do with "deviating 7 stops", just the appropriate aperture for that amount of time; or else, bring along an ND filter. But with 100-speed film in a shaded area, I'm questioning what actually happened, since you shouldn't have needed to fuss with any stops of "deviation" to accomplish that. But whatever .... you bagged it anyway. So congrats.

Anyway, the whole world is my "Lightroom". Get it right the first time, with real light.

Now that you reminded me, I suppose I too have had 6 decades of photography. My how time flies when you're having fun!
Regarding metering of the scene, you may not know it was taken during daylight. Although the averaging meter recommended 1/60 at the aperture I needed, the scene does include bright elements as well deep shadows behind the waterfall. Waterdrip really and why I needed the 2 seconds. Regardless, I am happy with the way it turned out.

Nice shot Les. Just so I understand what you wrote. Did you add 7 stops to the shot? You just changed the shutter to 2 seconds leaving the aperture the same as the meter told you at 1/60th? (You didn;t mention anything about what the aperture was with the meter reading or what you shot it at.).

Exactly right, I left the aperture where I needed it and simply decreased the shutter speed 7 stops from the recommended 1/60 to 2 seconds. I know the water effect is probably overdone but I like it!

 

[Sirius Glass]

You would have to ask them if they can do that for you. If you want to use 2 rolls, you can carefully rewind the film into the cassette, leaving some leader exposed and note on the cassette the number of exposures taken and the ISO you used. Load a new roll and shoot at your other rating, doing the same. You now have the choice of reloading the camera with either roll and finish it at the marked rating, taking care to advance the film, shooting at your camera's fastest shutter speed and smallest aperture with the lens cap on for the number of frames you had previously shot, plus a couple for safety. Or just process your half-shot rolls. But that method does not really allow you to really change the speed mid-roll, just shoot 2 rolls at different speeds. At which point you might as well be shooting different films.

If you want to change film mid roll, Pieter12 tells you how to do it, if you have a camera that lets you manually rewind. Just stop rewinding when you hear the film come off the spool. However, if your camera powers the rewind, depending on your camera, you may or may not be able to keep the film from completely rewinding the film into the cassette. It depends on the camera model.

 

[Sirius Glass]

Why don’t you do a small experiment… take a picture at box speed and “normal exposure”, then bracket around that baseline exposure to see what the effect will be from “changing the film speed” on the same roll. Use half stop steps up to 2 stops on both sides of the normal exposure. Have film processed normally by a reputable lab. Evaluate the negative rather than prints as the exposure may adjusted during printing to make the print look like a normal exposure. If possible, have an incorrect Ed proof sheet printed so you can see the difference between frames. Keep good notes of the exposure used for each frame

Excellent recommendation!

 

[Alan Edward Klein]

If you want to change film mid roll, Pieter12 tells you how to do it, if you have a camera that lets you manually rewind. Just stop rewinding when you hear the film come off the spool. However, if your camera powers the rewind, depending on your camera, you may or may not be able to keep the film from completely rewinding the film into the cassette. It depends on the camera model.

Be ready to pull the battery to stop the rewind.

 

[Sirius Glass]

If you want to change film mid roll, Pieter12 tells you how to do it, if you have a camera that lets you manually rewind. Just stop rewinding when you hear the film come off the spool. However, if your camera powers the rewind, depending on your camera, you may or may not be able to keep the film from completely rewinding the film into the cassette. It depends on the camera model.

Be ready to pull the battery to stop the rewind.

Some models have you hold extra buttons to stop the film leader from being pulled back in.

 

[JNP]

Anyway, the whole world is my "Lightroom". Get it right the first time, with real light.

Post after post of anti digital comments does the well ever run dry? If you took time to read the thread, you will see @yoz is going in the light and making camera exposures. As someone unfamiliar with analog cameras the OP is wondering if one can adjust the ISO seamlessly mid roll like with a digital camera. Light room and photoshop have been around for decades and are tools most photographers and labs use to make prints, and it is a toll the OP can use to help familiarize themselves with analog picture taking.

 

[koraks]

Well, some people's light is more equal than others, you know

 

[DREW WILEY]

JNP - don't get worked up. Removing all the secondary hurdles in advance is often the most efficient way to teach someone how to run down the track most smoothly. Start from the real start. It's a different race. Digital analogies just get in the way.
Instead, imagine a film camera which doesn't take a roll at all. No different, exposure-wise. And in this case, some wild film latitude myth is just getting perpetuated by a wrong conclusion why it somehow turned out anyway, which inevitably goes back to the basic question of metering itself. Something just doesn't add up.

 

[JNP]

Well, some people's light is more equal than others, you know

I know! That's brilliant LOL.

JNP - don't get worked up. Removing all the secondary hurdles in advance is often the most efficient way to teach someone how to run down the track most smoothly. Start from the real start. It's a different race. Digital analogies just get in the way.
Instead, imagine a film camera which doesn't take a roll at all. No different, exposure-wise. And in this case, some wild film latitude myth is just getting perpetuated by a wrong conclusion why it somehow turned out anyway.
Otherwise, go complain on the hybrid section of the forum, not here. That way, I won't have to bother listening to it.

DREW
It was just suggested that if the lab prints weren't satisfactory editing oneself might be a good skill to have. @yoz wasn't familiar with analog cameras. No fantasizing necessary.

 

[DREW WILEY]

Well, one way or another, as long as someone gets from Point A to B one way or another, that's all that ultimately counts, and I wish them luck. But standing in line at the lab to drop of or pick up my own C41 processed work (that's all I personally use any commercial lab for), or at the camera store buying film etc, I often have opportunity to chat with people of various ages transitioning from digital imaging to real film. And half the battle is just clearing their minds of all that unnecessary complication, as if a bulldozer were needed. Just start over, learn the basics from the beginning, instead of endless "lost in translation" complications.