# calculating ISO etc



## Lexi1016 (Mar 19, 2012)

I am having trouble remembering how to calculate ISO changes with your shutter speed and f-stops. Thanks!


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## umashankar (Mar 19, 2012)

I usually push the ISO based on existing light, if its a 
sunny day 100
bright but bit clowdy (or inside a room) 300 or 400
Dull light 500 - 600
very low light, during or soon after sunset  - 600 - 800
Night -1600 or above

I choose the shutter speed and f numbers accordingly,,
If you are using a tripod and making shots you can reduse ISO and increase the exposure time with requred f numbers...

there is no such fixed formula for composition all you have to do is expriment, Just get to know the basics... You will learn your own unique composition


happy photos


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## Lexi1016 (Mar 19, 2012)

Thank you. I havea question on my test asking my to calculate the shutter speed and f-stop from a certain ISO to another. So, if it was at 1/60 @ 5.6 at an ISO of 400 what would be at 800 for a 1/60 and f stop at ? And shutter speed ? If it was at a 5.6


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## 2WheelPhoto (Mar 19, 2012)

google an ISO/shutter/f-stop chart


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## umashankar (Mar 19, 2012)

Lexi1016 said:


> Thank you. I havea question on my test asking my to calculate the shutter speed and f-stop from a certain ISO to another. So, if it was at 1/60 @ 5.6 at an ISO of 400 what would be at 800 for a 1/60 and f stop at ? And shutter speed ? If it was at a 5.6



I suggest you to go thru this
Sunny 16 rule - Wikipedia, the free encyclopedia


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## Rephargotohp (Mar 19, 2012)

It's easy

Doubling/halving ISO = 1 Stop
Doubling/Halving Shutter speed = 1 Stop
Dividing/Multiplying f/stop by Square root of two....hahaha...OK just use 1.4 = 1 stop. Just make sure you know your f stiops so you don't write f/7.9

If You double your ISO fr0m 400 to 800, Your shutter speed goes from 1/60 to 1/125 ( yes there is no 1/120)


If you double your ISO from 400 to 800, your aperture goes from f/5.6 to f/8

Now that I answered the uestion, "I" get the A on your test


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## Lexi1016 (Mar 19, 2012)

That's exactly what I needed! Thank you!


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## maris (Mar 19, 2012)

I'd be fascinated to know what you are planning. I've never been able to change the ISO of a film in some decades of photography. It's a fixed value characteristic of a film and it is measured by a strict testing protocol. Ok, if you have a particular lighting condition and particular aperture and shutter speed requirements it's good to know what ISO film to buy. But you can't change it.


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## willis_927 (Mar 19, 2012)

maris said:


> I'd be fascinated to know what you are planning. I've never been able to change the ISO of a film in some decades of photography. It's a fixed value characteristic of a film and it is measured by a strict testing protocol. Ok, if you have a particular lighting condition and particular aperture and shutter speed requirements it's good to know what ISO film to buy. But you can't change it.



Unless you have a digital camera, in which case you can change the ISO as you wish...


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## compur (Mar 19, 2012)

maris said:


> I'd be fascinated to know what you are planning. I've never been able to change the ISO of a film in some decades of photography. It's a fixed value characteristic of a film and it is measured by a strict testing protocol. Ok, if you have a particular lighting condition and particular aperture and shutter speed requirements it's good to know what ISO film to buy. But you can't change it.



Most films can be "pushed" or "pulled," that is, shot and processed as if they had higher or lower ISOs than the rated "box speed."


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## maris (Mar 20, 2012)

compur said:


> maris said:
> 
> 
> > I'd be fascinated to know what you are planning. I've never been able to change the ISO of a film in some decades of photography. It's a fixed value characteristic of a film and it is measured by a strict testing protocol. Ok, if you have a particular lighting condition and particular aperture and shutter speed requirements it's good to know what ISO film to buy. But you can't change it.
> ...



Yes! Pushing and pulling film are sophisticated techniques that can change the way pictures look. Advanced photographers do this for special effects or when lighting conditions impose shutter speed and aperture compromises. 

Unfortunately even the most extreme "pushes" don't actually make film much faster or more sensitive to light. A 100 speed film pushed to 400 (say) by extra development will still have empty shadows. What was never recorded by exposure can't be brought out by development. And that pushed 100 speed film won't look like a true 400 speed film. It may look better, it may look worse. Only the photographer knows. It's part of the art.

Pulling film is marginally more useful. But not in terms of actually reducing film speed. Negative-acting film is tolerant of extra exposure, maybe a stop or two or more, but eventually its highlights burn out and no development however mild can save them. Strongly pulled film tends to deliver dense low contrast negatives that are harder to work with and deliver "flat" results. Maybe that's just what the clever photographer needs to record a scene with an extreme brightness range. Again, it's part of the art.

In contrast to modern digital picture-making film does not allow free use of ISO as a third variable in combination with shutter speed and aperture in order to formulate routine exposure strategies.


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## gsgary (Mar 23, 2012)

maris said:


> I'd be fascinated to know what you are planning. I've never been able to change the ISO of a film in some decades of photography. It's a fixed value characteristic of a film and it is measured by a strict testing protocol. Ok, if you have a particular lighting condition and particular aperture and shutter speed requirements it's good to know what ISO film to buy. But you can't change it.



You can pull and push film, one of the best is HP5 (iso400) but can be shot at ISO3200 with good results


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## Helen B (Mar 23, 2012)

gsgary said:


> You can pull and push film, one of the best is HP5 (iso400) but can be shot at ISO3200 with good results



I think that the point is that when you push and pull film there is not very much change in the ISO. There is a change in the EI, not the ISO. You can shoot HP5+ at EI 3200, you can't shoot it at ISO 3200* (I don't think that there is any ISO 3200 B&W film). There is a difference, and that seems to be what maris is saying. The ISO speed of B&W negative film is determined by toe (shadow) exposure at fixed contrast, and that speed doesn't change much. When you push film you make very little difference to the sensitivity of the film at the toe, and all you really do is increase the contrast.

* Unless you ignore the meaning of 'ISO' in terms of film speed - which many people do - but then if you say 'ISO' when you really mean 'EI', what do you say when you really mean 'ISO'?


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## KmH (Mar 23, 2012)

I believe the OP was taking an online test for school.



> .....I havea [sic] question on my test.....[/quote


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## Helen B (Mar 23, 2012)

KmH said:


> I believe the OP was taking an online test for school.
> 
> 
> 
> > .....I havea [sic] question on my test.....



Right. Threads never, ever expand into more general discussions.


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## c.cloudwalker (Mar 23, 2012)

Helen B said:


> KmH said:
> 
> 
> > I believe the OP was taking an online test for school.
> ...



Yes they do and my suggestion to the OP is to take up Film Photography. This way he will set up the ISO at the start of the film and not worry about it for another 35 shots.

OMMMMMMMMMMMMGod!  One less thing to stress out about :lmao:


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## compur (Mar 23, 2012)

maris said:


> A 100 speed film pushed to 400 (say) by extra development will still have empty shadows.



It may or it may not.  Depends completely on the scene and a number of other variables.  



> What was never recorded by exposure can't be brought out by development.


Push processing can and often does bring out details that would otherwise be invisible with normal development.  That is a major reason for doing it.



> And that pushed 100 speed film won't look like a true 400 speed film.



Not necessarily true.  There are too many variables to make a blanket statement like that.  The results of pushing 100 ISO film can look remarkably like like that from a 400 speed film. It would depend on the film and how it was pushed and of course, how it was printed.



> Pulling film is marginally more useful.



I think it's a bit more than "marginal." Pulling film can improve tonal range a great deal and is actually an important part of the Zone System methodology.



> In contrast to modern digital picture-making film does not allow free use of ISO as a third variable in combination with shutter speed and aperture in order to formulate routine exposure strategies.



Not true.  The variable of ISO is just as much a part of film photography as it is in digital photography.  It is just not achieved the same way.  A digital phtographer would press a button or turn a knob, a film shooter would select a different film.


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## gsgary (Mar 24, 2012)

Helen B said:


> gsgary said:
> 
> 
> > You can pull and push film, one of the best is HP5 (iso400) but can be shot at ISO3200 with good results
> ...




You can get Ilford delta 3200 professional


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## Helen B (Mar 24, 2012)

gsgary said:


> Helen B said:
> 
> 
> > I don't think that there is any ISO 3200 B&W film
> ...



You can, but it isn't an ISO 3200 film. Have a look at the Ilford info on it.


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## gsgary (Mar 25, 2012)

Helen B said:


> gsgary said:
> 
> 
> > Helen B said:
> ...




Cheers, i shot some at 6400 wish i'd had my spot meter because i didn't do very well


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## Helen B (Mar 25, 2012)

Thanks for posting that. It's an excellent example of what we're talking about - a film pushed to an EI well above its ISO speed, in this case about three stops over the ISO speed. No shadow detail and high contrast. Delta 3200 is an ISO 800 to 1000 film, and that isn't affected very much by choice of developer and development. As I said, there is no ISO 3200 B&W film.

This is HP5+ exposed at EI 6400:


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## compur (Mar 25, 2012)

This is Ilford XP2 shot with no regard to ISO or metering for that matter. Though this is a wide-latitude chromogenic film, I think it illustrates my feeling that shadow detail is not necessarily that important. I was backstage at a rock concert in Hollywood. (Nikon FM & 28-85 zoom).  Just shot wide open at what I thought the slowest hand-held speed I could get away with since it was so dark (1/30?). Normal C-41 processing. The XP series films are essentially ISO 50-800 with no push/pull required. This is a small copy of the shot (all I have at the moment) but I don't think shadow detail would have added anything to it.


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## Helen B (Mar 25, 2012)

compur said:


> I think it illustrates my feeling that shadow detail is not necessarily that important.
> ...
> The XP series films are essentially ISO 50-800 with no push/pull required.



I think that the point of what I'm trying to say might be getting lost. It isn't about whether or not shadow detail is necessary or important, or about whether HP5+ can be exposed at EI 6400: those are decisions we make ourselves. It is about the ISO speed of a film being pretty much fixed over a small range, because of what 'ISO speed' means. There is a wide misunderstanding of that, as evidenced by what is being said in this thread. Delta 3200 is not an ISO 3200 film, even according to Ilford. XP2 super is not an ISO 50-800 film with or without pull and push. XP2 Super is an ISO 400 film that can be exposed at EI 50 to 800. EI, not ISO. It's not up to us to define ISO speed. The ISO themselves do that. If you wish to use another speed that's perfectly OK, but it isn't the ISO speed. It's really simple.


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## compur (Mar 25, 2012)

^ I agree with you, Helen.  My comments weren't in reference to your posts -- just commenting on the thread's topic and the idea of lost shadow detail raised earlier.


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## Proteus617 (Mar 26, 2012)

Helen-  You forgot about Fuji FP-3000.  But then again, so does everyone else.


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## Helen B (Mar 26, 2012)

Proteus617 said:


> Helen-  You forgot about Fuji FP-3000.  But then again, so does everyone else.



Have you no faith? I didn't forget - Now that FP-100B is scarce I use it all the time in my Polaroid 110B and Mamiya Press. It is an EI 3000 material, not an ISO 3000 material. I checked a box before opening my mouth, though I thought that it would be an EI rating because it is an instant film.


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