Another Dumb Question

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If I open up 4 stops, then is it ƒ2.8 or ƒ4? :blackeye:
Or 1/250 or 1/500?

Trying to shoot ISO 1.6 film
The guide says that if you can't set at ISO 1.6, then set to ASA 25 and "open up 4 stops" - Would this be shutter speed stops or aperture stops?
 
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It's saying to increase the amount of light that you are bringing in to your film.

So, actually both shutter speed stops or aperture or both. Every time you double the time the shutter is open that's opening up 1 stop. For example, if you were shooting at 1/250 of a second, you could change that to twice as long, that is 1/125 of a second, and you would be opening up 1 stop. Change 1/125 of a second to 1/60 of a second, you would be opening up another stop.

If you increase the size of the aperture 1 step, say from f4 to f2.8, (the smaller the f-number the larger the aperture), you would be increasing 1 stop.
 
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It's saying to increase the amount of light that you are bringing in to your film.

So, actually both shutter speed stops or aperture or both. Every time you double the time the shutter is open that's opening up 1 stop. For example, if you were shooting at 1/250 of a second, you could change that to twice as long, that is 1/125 of a second, and you would be opening up 1 stop. Change 1/125 of a second to 1/60 of a second, you would be opening up another stop.

If you increase the size of the aperture 1 step, say from f4 to f2.8, (the smaller the f-number the larger the aperture), you would be increasing 1 stop.
Okay....so if I shoot at say 1/500, bright and sunny, what would aperture be?
 
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It's saying to increase the amount of light that you are bringing in to your film.

So, actually both shutter speed stops or aperture or both. Every time you double the time the shutter is open that's opening up 1 stop. For example, if you were shooting at 1/250 of a second, you could change that to twice as long, that is 1/125 of a second, and you would be opening up 1 stop. Change 1/125 of a second to 1/60 of a second, you would be opening up another stop.

If you increase the size of the aperture 1 step, say from f4 to f2.8, (the smaller the f-number the larger the aperture), you would be increasing 1 stop.
So ah...If I shot bright and sunny at ƒ4, what would shutter speed be?
 
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So ah...If I shot bright and sunny at ƒ4, what would shutter speed be?
Using the 'sunny 16' rule: the shutter speed is 1 divided by the !SO at f/16 if the lighting is bright and sunny. (in math: shutter speed = 1/ISO @ f/16)

So f/4 is 4 stops more light than f/16, so shutter speed = 1/!SO times 4, which is 0.16 sec (1/1.6 x 4), or about 1/6 of a second.

That is some seriously slow film! What is it normally used for?
 
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Using the 'sunny 16' rule: the shutter speed is 1 divided by the !SO at f/16 if the lighting is bright and sunny. (in math: shutter speed = 1/ISO @ f/16)

So f/4 is 4 stops more light than 1/16, so shutter speed = 1/!SO times 4, which is 0.16 sec (1/1.6 x 4), or about 1/6 of a second.

That is some seriously slow film! What is it normally used for?
Thanks Chris!
So let me see if I understand this.

1) The film is ASA 1.6 but I'm pushing it to ASA 25
2) So "adding 4 stops" would mean shoot at ƒ4 then?

Here's what I have: https://filmphotographystore.com/products/35mm-color-kodak-super-low-speed-1-roll

And here's what it says about shooting it: "How do I meter for iso 1.6? You must dial the iso manually into your camera or meter. If you camera can't be set to iso 1.6, you can dial in iso 25 then open up 4 more stops"
 
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Enjoy playing. I am an old fart and shot a lot of kodachrome- asa 10, we shot at asa13 to underexpose a little.
First, I would recommend REALLY getting a handle on exposure. How shutterspeed, aperture and iso work together. This all needs to make sense, so you can make appropriate decisions out in the field. We go out with a plan- but that never works. The light is never exactly as you imagined. We need to be able to think on our feet, so these numbers and adjustments need to be second nature.
I have a lot of experience in pushing film. In college as a chemist I worked with our art department for a year to push films 5 stops. TriX 400 went to 12,800. Grain looked like bowling balls. Unless grain is part of your art, I would limit my expectations of chemically pushing film 4stops. What you likely need to do is set your camera for asa/iso 25 and overexpose the film 4 stops. You could do that by altering shutterspeed or aperture, likely both. That is why having a true handle on these variables is vital. The sunny 16 rule will get you close, but what if the sun goes behind a cloud. You need to know how to adjust without really thinking about it. Personally I would recommend the book Understanding Exposure by Peterson.
Have fun playing.
Gary
 
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Enjoy playing. I am an old fart and shot a lot of kodachrome- asa 10, we shot at asa13 to underexpose a little.
First, I would recommend REALLY getting a handle on exposure. How shutterspeed, aperture and iso work together. This all needs to make sense, so you can make appropriate decisions out in the field. We go out with a plan- but that never works. The light is never exactly as you imagined. We need to be able to think on our feet, so these numbers and adjustments need to be second nature.
I have a lot of experience in pushing film. In college as a chemist I worked with our art department for a year to push films 5 stops. TriX 400 went to 12,800. Grain looked like bowling balls. Unless grain is part of your art, I would limit my expectations of chemically pushing film 4stops. What you likely need to do is set your camera for asa/iso 25 and overexpose the film 4 stops. You could do that by altering shutterspeed or aperture, likely both. That is why having a true handle on these variables is vital. The sunny 16 rule will get you close, but what if the sun goes behind a cloud. You need to know how to adjust without really thinking about it. Personally I would recommend the book Understanding Exposure by Peterson.
Have fun playing.
Gary
Thanks!
I'm fine with understanding exposure/shutter speed/aperture/ISO-ASA, no problems there.

I've just never done any push/pull work until now...
 
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I think they meant the "Push 4 stops" for developing purposes....
No, that's not what the quote you provided in Post #13 means. It means that by setting the camera at ISO 25 when the film is actually ISO 1.6, you are letting four stops less light onto the film than the film was designed for. So, you have to also compensate for that by setting your aperture and/or shutter to allow four stops more light onto the film.
 
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Think of it as you need four times as much light.
I'm sure you're aware that four more stops is not four times as much light and that you just slipped up before you had enough coffee or whatever. :) For those following along who don't understand the details, each stop doubles the amount of light. When you double the amount of light four times, it becomes 16 times more light.
 
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A stop is always a power of 2. So four stops is 2 to the power of 4, which is 16 times.

For shutter speeds you would simply multiply the time by 16 for 4 more stops of light.

For apertures it is 4 stops, traditional stop settings are 2, 2.8, 4, 5.6, 8, 11, 16.
So if it was 11 it would now be 2.8, to give 4 more stops of light.
 
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I'm fine with exposure/shutter speed/aperture/ISO-ASA, no problems there.
It's understandable that you seem fine with it because you can use your camera to automatically make everything happen. However, it's also clear from your questions that you don't understand what a stop means and you don't understand how to manually adjust your camera in terms of stops. That's also understandable. I agree with Gary that it would be immensely helpful for you, especially in this situation when your camera doesn't have the capability of setting the ISO of your film, to gain full command of understanding the terminology and implications about a stop of light.
 
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No, that's not what the quote you provided in Post #13 means. It means that by setting the camera at ISO 25 when the film is actually ISO 1.6, you are letting four stops less light onto the film than the film was designed for. So, you have to also compensate for that by setting your aperture and/or shutter to allow four stops more light onto the film.
But I would still have to have it developed by pushing 4 stops - correct?
 

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