Photographic – Film Types and Film Speed


The final result of your photographic ventures is a roll of film, a handful of prints, or a box of slides. Other than your choice of lens, the film choice will have the biggest impact on the quality of the final results.

DIGITAL CAMERAS

While most of this is irrelevant for digital cameras, “film” speed still applies. In this case, the speed affects the noise level rather than grain size but the final result is somewhat similar. Choose the smallest ISO for the required shutter speed, ie to allow hand-held shooting or freezing sports action.

CHOOSING A FILM

1. the First choice is slide (positive) or print (negative) film.

Print

greater exposure latitude (some 9 stops vs 5 stops for slide)

cheaper

easy for prints

ideal for cheap compact cameras

Slide (also known as reversal or transparency film)

greater color saturation and contrast (especially in professional film)

no “middle-man” adjusting color balance or exposure

much easier to digitize

requires a good camera to obtain correct exposure

As slide film has 5 stops of latitude, correct exposure is much more critical than print film. This means the use of a camera with a precision auto-exposure meter such as an SLR filme xxx (or very good compact) or using a light meter.

Black and white film is all negative nowadays. There was a wonderful black and white slide film offering from Agfa called Dia Direct. Now long discontinued. There are some techniques for creating B+W slides from negative film.

Slides are also a better choice if you want to take film pictures and then digitize them. Negatives are notoriously difficult to color correct after scanning. You can look at the slide and compare it with the digitized version to get an accurate color balance. Prints do not give you a valid reference point!

Summary: if you want prints to go for print film. Slides if quality or scanning.

2. Next choice is film speed.

As with everything else in life, choosing the film speed is an exercise in compromise. Slower film speeds (smaller ISO) have a finer grain but the greater light required means slower shutter speeds and could interfere with picture taking. Faster film speeds allow for faster shutter speeds but the increased grain size can be distracting.

ISO 100 or slower for the finest grain. Use in good lighting conditions such as bright sunny days.

ISO 200 is a good general-purpose film for slower lenses such as those found on compact cameras or zoom lenses. In print film, this speed has all but replaced ISO 100 as the quality of modern films has grain comparable to or better than last year’s ISO 100.

ISO 400. Where you require faster shutter speeds for action shots or in medium to low lighting conditions. Grain is getting noticeable at this speed.

ISO 1000 or faster. Use in low lighting conditions such as indoors and at dusk. The grain is quite noticeable. One can exploit this resulting in grainy, gritty photographs.

STORING FILM

As film ages its color changes. This color cast is subtle but noticeable. For example, a brand new film fresh from the factory might have a slight red color cast whereas the same film (and same batch) that has sat on a shop’s shelf for a year might have a slight green cast. At some point in its age, the film will have an optimum color balance where the color cast is at a minimum.

For a print film, this effect can usually be ignored as the photo labs’ printing machines will automatically compensate for this cast and produce acceptable prints (though probably inaccurate). Slide film is more sensitive because you view the film itself not prints.

The manufacturer knows this and will endeavor to have the film shipped and on the shelves when it is almost at optimum so that is optimum (or near-optimum) for the time it is expected to be on the shelves. Think of fruit in the grocers. The new bananas arrive slightly green and ripen on the shelves.

Manufacturers also make “professional” films. This is the same as the non-pro film (though often it is better quality) but has been allowed to age at the manufacturers to optimum color balance. The extra cost for pro film assures this. Some camera shops and photo labs have a fridge containing professional slide film – keeping the film cool slows this aging process. Storing film in your fridge helps to keep it fresh if stored for a period or in hot climates. Keep them in their containers.

You should get films processed as soon as possible after exposure as the latent image will begin fading.

Films beyond expiry dates can still be used but you should exercise caution. Do not use them for anything important. As well as the aforementioned color cast, which might be significant, the film can dry out and crack. The result is printed that looks like crazy paving! (I’ve had this experience with an old black and white film). Buy film as you need it. Extreme temperatures and moisture can make the film suffer, so store them in a cool dry place. Keep out of the sun, stuffy cars, and away from radiators.

Always use the container supplied, this keeps dust and dirt out and spoils your film.

FILM BRANDS AND QUALITY

As with everything else in life, typically you get what you pay for. Big brands like Kodak and Fuji make very good films and you’ll pay a bit more than lesser brands for better quality. Ilford makes some excellent black and white films.

Kodachrome is number one for film archival. Its longevity is second to none.

Kodak color films typically are strongest in the red/yellow part of the spectrum. Rendering of reds, yellows, and skin tones look great. Fuji films traditionally are strongest in the green part of the spectrum. Great for nature and landscapes. Velvia 50 is superb, now discontinued, replaced by Velvia 100.

DX FILM SETTING

On most rolls of 35mm film, there is a pattern that looks something similar to a barcode. This is the film speed coded on the canister. It allows cameras that support DX-coded canisters to automatically set the film speed. Very useful if you often use different speed film and forget to reset the film speed. It also simplifies compact cameras to the point where they don’t allow manual setting of film speed.

 


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