Why are super 8 film ISOs so low?

[joelanders]

This is one of those questions that I really don't want to ask... but I'm completely new to film movies. Dabble in 35mm SLR photography, some film, mostly digital... (again, I duck my head) But why are the speeds in super 8 all 25, 40, 64, etc. I'm used to 200, 400, 800, even 1600 occasionally.

Does it have to do with image size? Focusing a bunch of light onto an 8mm film instead of 35mm film?



Another dumb question: Why don't they use filmstocks that any reasonable photolab could process? Why require a new brew for developing? The drastic ISO difference? Back to the first question...


Thanks a ton in advance.

[BigBeaner]

Grain in the Super 8 image is bigger than it would be in 35 or 16mm so using a slower, finer grain stock such as 40 is prefered by most as opposed to a faster ISO with slightly/more grain. Regardless, There's Kodak Vision 2 200T and 500T.... but those are negative so you have to get them transfered or a work print. And it looks really good anyways.

You can also push/pull a stock.

also ektachrome 64 uses the E6 chemistry I believe which is easily available and also Tri-x and Plus-X is developable at home.

Best place for info is kodak itself: http://www.kodak.com/US/en/motion/s8mm/ ... 14.4&lc=en

I don't endorse nor have I ever used Pro 8 I simply am supplying the information that there are other stocks:
http://www.pro8mm.com/main.php

[Patrick]

The basic reason why the iso speed of super 8 film film stocks is generally so slow is because of the tiny frame size. Remember that when super 8 footage is projected, the grain structure of that tiny frame is being magnified hundreds and hundreds of times. Hence, a super 8 image will always appear more grainy than a 35mm image of the same iso speed. In order to get fine grained images in super 8 use, you must use very slow speed films. This is why you rarely see fast films in super 8 because they would usually be too grainy.

However in the last few years, Kodak has released Vision 200T and 500T negative film in the super 8 format. Both of these films are very modern film stocks so they take advantage of the unusually fine grain inherant in the latest film technologies. Even so, they would probably appear a little on the grainy side in super 8, particularly the 500T (I admit I have never shot these so I am only assuming.)

As for super 8 processing, the latest Kodak emulsion released in super 8 is Ektachrome 64T which is a slide film so this uses the familiar E6 process common to most slide films.

[BigBeaner]

Just search this forum for examples of Super 8mm 200T and 500T or maybe someone will be nice and put a few on here.

[joelanders]

That makes a lot of sense guys thanks a ton. I wasn't thinking of the huge impact that a grainy image would have in such a small frame. Gahhh I knew it would be an obvious answer....

But how is it that a super 8 camera can adequately expose such low speed film? If I tried to use 24 ISO film in a still camera... maybeee outdoors in the sun I wouldn't get a blurred image... Or the aperture and lens must let in a ton of light.

I'm guessing the monstrous 60-70 fps cameras need a higher speed film?

Thanks BigBeaner for the info on the film also, I'll definitely read up on those.


Thanks again, you guys are great.

[alpha.tango]

The main issue restricting range of exposure is the effective shutter speed - a function of filming speed and shutter angle - if this is in the range of 1/45 to 1/60 of a second then the use of films in the range of 25 to 160 ASA matches very well with normal aperture ranges.

For example with 200asa in a still camera you might happily use 1/250 sec at f11 on a sunny day - translate this into a cine shutter speed of 1/45 sec would require an aperture of f22- f32 or the use of ND filters.

Higher speed films are useful in particular situations but not necesarily best for general use - hence the suitability of the more common films.

I also have a vague recollection that some image blurring from subject movement (not camera shake) actually assists with the perception of movement from persistence of vision. I have only tried this with video where a higher shutter speed (electronic) does give sharper images by frame but seems to create a slight jerkiness of movement. Only a perception - I may be imagining it !

just found reference -see - http://en.wikipedia.org/wiki/Go-motion

[Angus]

Nope alpha.tango you are not imagining it.

When I first saw video images shot with a fast shutter (circa 1990) I thought they looked like animations. They're OK for sport where you might want to freeze the frame or go slo-mo but for regular motion a bit of blurring is useful.

So a typical super 8 shutter speed will be in the region of 1/40s, whereas one would try to shoot with a faster shutter for still photography, especially where motion is involved. Also remember almost all super 8 cameras have a wide aperture of *at least* f1.8, giving you a stop or two advantage over most 35mm SLR lenses.

With all that borne in mind, you can compare a 25ASA motion picture film with 100 or 200ASA still film. Such films are fine for all outdoor conditions from overcast dull days up to bright sunlight.

The Kodak neg films are very forgiving and 200T as a tight grain structure, bear in mind those films are designed to be telecined (converted to video) and not projected as film - though a projection print is possible it is costly.

I also found the then typica 25ASA speed for super 8 film a little surprising when I tried it first some 21 years ago, having come from 35mm and 120 photography.

[Blue Audio Visual]

Why don't they use filmstocks that any reasonable photolab could process? Why require a new brew for developing?

Motion picture and stills film are developed in different machines. One reason for this is the length of the film. A 36 exposure 35mm stills film is about 5ft long, 1/10th of the length of a 50ft Super 8 reel. A common type of 35mm processor is the "dip & dunk". Multiple rolls of film are clipped onto a holder, and the machine dips the films into different tanks of chemicals/washes to complete the stages of development. An advantage of this is that other than the ends, the film never comes into contact with the machine, reducing the rick of scratches etc.

Such a system would be impractical with a 50ft length of film. Motion picture machines use a different system. Films are spliced together into one long roll, and a series of rollers transport the film through a series of tanks of chemicals/washes etc. This method is also more consistent in terms of the amount of time each frame spends in each bath than "dip & dunk".

So even if a stills lab could handle the chemistry, their machines probably couldn't. I've never worked in a lab, and I'm sure there are people out there who can explain the differences in greater detail, but that is the reason why motion picture labs are few & far between compared to the stills labs.

[wado1942]

To add to all those fine answeres, I must state that there isn't a super-8 film on the market slower than 50ISO and that's special order from 3rd parties. Most super-8 film is 64-200 ISO. I started in a 35mm SLR background but I stuck with 100 ISO most of the time.

Also and believe it or not, until about 15-20 years ago, most motion picture film was generally lower than 200 ISO. Crap the Woodstock movie was shot on 16 ISO film and that was 16mm. In the 60s and early 70s, 100 ISO was considered high speed film. The reason for this of course being the film would be projected onto a HUGE screen that would really show the grain. Film stocks have gotten MUCH MUCH better in the last 10 years so 200 ISO is common and you can even get 800 ISO now. I don't know of anybody that shoots over 500 even in 35mm as a 6 meter wide image really shows the grain. Now remember the image on super-8 is only 5.3mm wide and it's typically going to be blown up to a meter or more to be viewed or 200x. Most 35mm still photography doesn't get enlarged much more than 10x. Now that I think about it, I think it's VERY strange that Kodak only offers super-8 negative in 200T and 500T. If I were to pick ONLY ONE super-8 stock, it would be 100T which would be good indoors with artificial lighting or outdoors with an 85B filter that'll effectively take it down to about 50 ISO. AT 50ISO, 1/48th sec shutter speed, you're talking F16 on a bright day and F8 on a really cloudy day. I've seen 500T super-8 and it's unwatchable. Plain and simple, there's more grain than image. I tried to convince one of the engineers at Kodak to make 50d in super-8 and she said they didn't think there was a market for it....hmmm, she must not shoot super-8 herself.

As for developing, the processing required for super-8 is standard for motion picture film. I would be rather upset if it was C4 because then I couldn't get it developed anywhere. Not at Walgreens (because of the machinery) nor AlphaCine (because of the chemistry).

[fogo]

If you want slow speed seems its a tough choice between Pro8s 10 and Kahl's 'Dokument 12'....ISO / DIN 12 / 12...

Ade

[Blue Audio Visual]

Pro 8 HI-CON ASA 10 B&W Reversal is re-manufactured from Kodak 5363. The same stock is available in the UK in STD8.

[T-Scan]

If I were to pick ONLY ONE super-8 stock, it would be 100T which would be good indoors with artificial lighting or outdoors with an 85B filter that'll effectively take it down to about 50 ISO. AT 50ISO, 1/48th sec shutter speed, you're talking F16 on a bright day and F8 on a really cloudy day. I've seen 500T super-8 and it's unwatchable.

I've had a lot of experience with 500T under tungston where the grain is not signifigant at all. I agree it's a little sloppy for daylight, but for tungston, you can hide the grain very well. 100T is a bit coarser than the new 50D. I'd like the idea of having the extremes of 50D and 500T.

[alpha.tango]

In comparing film speeds with still photography remember that in Super 8 films such as 64-T and Kodachrome 40 (still have a couple of cartridges ) are tungsten films - With filter in use in daylight their effective speeds are 40ASA and 25ASA respectively.

Angus may have found K25 slow coming from 35mm and 120 - but I started using colour in Standard 8 before I really got into still slide films and at that time Kodachrome was 12ASA and the new fangled KII just being introduced at 25 ASA was considered fast !

Certainly for colour reversal in cine it was not a case of choosing a slow speed film to minimise grain - that was as fast as it got....

Amazing how things change.

[wado1942]

50D has less grain but it's also less sharp by about 10%. Super-8 is very soft looking so I'd rather use 100T to maintain some of the clarity.

[T-Scan]

50D has less grain but it's also less sharp by about 10%. Super-8 is very soft looking so I'd rather use 100T to maintain some of the clarity.

Yes, the 100T has a bit more detail. I've only shot one roll of 100T in S8, but it's really not much different than the 200T in daylight, which we already have. A tad less grainy, but not a whole lot. 50D is still a very sharp film, but more like K40 and E100D for grain.