Ujjwal Mukherjee |
F-stop for ISO 100 film Jon, in one of your earlier responses to another question you had given the following tip of f-stop variation for a ISO-400 film. You said "if you are using ISO 400 film, you can trade f-stops for faster shutter speeds: f/16 @ 1/500th f/11 @ 1/1000th f/8 @ 1/2000th " Now my question to you will be... what if I use a ISO-100 film. Does the same trade apply for ISO-100 also? I have a Canon EOS Elan IIE SLR and I am going on a vacation to Europe which will cover all the popular places around Europe. What film speed you would recommend considering most of the snaps will be taken in the day time during the tour. Also whether Fuji or Kodak will give more color to the photographs if you recommend ISO-100 film.
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John A. Lind |
Ujjwal, The ISO rating of a film can be directly related to exposure settings. Doubling an ISO is the equivalent of a stop faster exposure. Cut the ISO in half and it's the equivalent of a stop slower exposure. ISO 100 film is two stops slower than ISO 400. This makes the trade-off of stops for shutter speeds shift by two stops compared to what I gave for ISO 400: f/16 @ 1/125th These are all within 1/3 f-stop under direct sunlight for a clear, sunny day (the f/16 sunny day rule) starting about an a half-hour after sunrise to about a half-hour before sunset. The test is sharp, distinct shadows. This rule is f/16 @ 1/(film ISO) for the shutter speed will get you within about 1/3 stop under these conditions . . . and you can trade shutter speed for f-stops as shown above. If the subject is under an overcast sky or in shade, this must be modified for more exposure. Here are some guidelines for how much esposure to add to the "sunny f/16 rule": Thus, if you were use f/11 @ 1/250th under direct sun on a clear day, you would use f/11 @ 1/60th, or f/8 @ 1/125th, etc. in "Cloudy Bright" conditions. I would use ISO 100 or ISO 200 film if you intend to shoot everything, or nearly everything outdoors. Choice would depend on how wide the lens can open up. ISO 400 could get you into trouble with few shutter/aperture choices under "Bright Sun" with a clear sky. If your lens is fast enough, at least f/2.8, you can continue doing landscapes and architecturals (versus things like car racing) hand held even under heavy overcast. If you have a slower zoom (about f/4.5 or f/5.6 zoomed out), ISO 200 might be a better choice. In ISO 100 color negative, my selection would be Kodak Royal Gold, or Fuji Reala. Both are extremely fine grained, general purpose consumer films with a some saturation. They both handle skin tones well. I don't use much color negative any more except for portraiture and some shots for special applications; I've been using Kodachrome 64 slide film for scenic and architectural for some time. Film choice is very much a personal one based on subject material and what you want for your images. There is no truly right or wrong choice. Hope this helps. -- John
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Jeff S. Kennedy |
I haven't bought consumer print film for a while but they used to print those guidlines inside the box. You might check the next time you open a box of film. They may not any more since all cameras now come with built in meters. The guidlines were intended to help photographers without meters. You are better off learning how to use your meter.
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Ujjwal Mukherjee |
Thanks John, for your valuable inputs to f-stop trade-off with ISO-100 film. Now please note that I have a Canon USM V 1:3.5-5.6 Zoom Lens with my Canon EOS Camera. I would like to quote a part of your response here as I had not given this info. About the lens to you earlier, You said that "If your lens is fast enough, at least f/2.8, you can continue doing landscapes and architecturals (versus things like car racing) hand-held even under heavy overcast. If you have a slower zoom (about f/4.5 or f/5.6 zoomed out), ISO 200 might be a better choice." Now since I have a 3.5-5.6 USM V Lens I am little confused as where do I place this lens. Is it fast lens (as it is USM V) or not very fast(because it is f/3.5-f/5.6)?
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John A. Lind |
Yes, a recommended exposure settings table is printed on the inside of Kodak's 35mm film boxes. Peel back the flaps carefully where they're glued and unfold the box to read it. I don't believe Fuji or Agfa include data sheets any more, but I haven't looked recently. I agree with Jeff's advice to avoid running with no meter. This is how I use the "sunny 16 rule:" a. Planning for a shoot: b. Sanity check during a shoot: c. Severe cold weather (10 F and below): -- John
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John A. Lind |
Ujjwal, I would class the 3.5-5.6 USM V Lens as "relatively slow" by 35mm format standards. It's not how fast it can focus, but the widest possible aperture. In 35mm format I'm accustomed to manual focus systems with f/1.4 50mm lenses and many other prime focal lengths being f/2 or f/2.8. f/3.5 is only 1/3 stop faster than f/4, so I tend to think of an f/3.5 lens as I would an f/4 in this respect. Many auto-focus lenses are slower than manual focus lenses with the same focal length from older, manual focus systems. Both auto and manual focus zooms tend to be slower than prime lenses. What is "fast" and "slow" are relative. In medium format (120 and 220 film) an f/2.8 lens is "fast" and an f/4 lens is not considered "slow," although it's not really a "fast" one either. The lenses for manual focus medium format systems are often two stops, sometimes one stop slower than their equivalents for 35mm format. -- John
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