Frame sizing

In case you are new to photography I would like to make some observations on frame sizing as my brother and I will be be referring to sensor and frame sizing at times and this will fill you in on what we mean when we say a certain thing.

Lets start small shall we.. so i’ll start with Digital

Digital camera CMOS Sensors are what captures the light in a digital camera, it converts the light from it’s natural form to a series of 1’s and 0’s.

Digital camera sensors are typically quite small. very small in fact most consumer digital SLR sensors are about, or less than half the size of a 35mm Film frame. Does that mean that only half the image information is recorded? you bet. Take any random image, then draw a border inside it that cuts the equivalent of half of the outer part of the image away from it, That is all lost information. In the Photography industry we call this the “Crop factor” Ken Rockwell has a very interesting article on this that details the different crop factors for well known Digital SLR’s it’s really worth the read.

Here is a table compairing digital sensor crop factor to popular film sizes

crop factor 35mm 120 film(6×6) 4×5 film
Canon 1.3 1.255 63% 23.51% 14.39%
Leica M8 1.33 57% 18.64% 11.41%
Nikon DX 1.523 43% 10.84% 6.64%
Canon 1.6 1.622 38% 8.43% 5.16%
Sigma 1.7 35% 6.98% 4.27%
3:4 System 2 25% 3.65% 2.23%

135 film, or (35mm film) as it’s popularly known is what we call “Full Frame.” Some professional digital SLR’s offer Full Frame sensors, this is all well and good but lets get into some technical details. A 35mm frame of film is 36mmX24mm and this size film was first introduced by Kodak in 1934 specifically for still photography. Despite some people’s beleifs 135 film is still very popular among professional photographers and serious amateurs. By now you are probably thinking, wait a minute! you forgot to mention APS!! Well yes i did but APS (Advanced photo system) *Read: Amateur Photo System* was not the most popular of formats and there for i won’t go into its details in this article.
You may also ask why is it called 35mm film if it’s 36×24, it’s simply the film width.

Now we will step up to medium format, we call it this because there are several different frame sizes available in medium format film, of which i will cover the two most popular, 120 film and 220 film.

120 film is the most popular of the medium format films, some cameras that shoot 120 film can be adjusted with the use of masks to shoot different size frames, this can be accomplished as 120 film doesn’t have the sprocket holes of 135.
frame sizes range greatly with the most popular being, 6×4.5, 6×6, 6×7 and 6×9. of course these are just the names given to each frame size, 6×6 is actually a 56mmX56mm square frame common place in most medium format camera’s. The legendary Rolleiflex’s and Hasselblads use this frame size as the standard many coming with masks to drop the frame size to a 6×4.5 to increase the amount of exposures on each roll to 16, up from 12.

220 Film is another less popular size of medium format film and is the same width as 120 film however twice as long giving 24 6×6 exposures on one roll as opposed to the 12 of 120 film. Many medium format cameras are capable of taking both 120 and 220 film.

This brings me to Large Format, the grand daddy of film. This film is so big it comes in sheet form. you can also get varying sizes in sheet form but for the purpose of this article i will only detail 4×5 sheet film.
4×5 sheet film is in fact 4inchesX5inches, these frames are quite large and are required to be stored in light tight backs that fit onto the View or Field camera’s that it’s used in. These camera’s are large and cumbersome but take the most technically superior photo’s in the world. when you have a frame this large you are capturing a huge amount of detail that nothing digital could even come close to reaching. Magazines such as National Geographic still use large or medium format film camera’s for the main images as it is unrivalled for lanscape photography. Large format camera’s use a bellows system for focussing and have pan and tilt functions allowing very strange planes of focus to be acheived, it’s an awesome look to have.

The above information is a simple breakdown of frames sizes in photography for those who either haven’t heard of them or have yet to understand the differences. for more information check out the below links.

Large Format Film
Medium Format Film
135 Film

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