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last modification: february 10th, 2012

Brightlight or Lowlight XL camera?   - the difference

Sorry, this page has almost only text....

at the end you will find my own view of this stuff...

Very often users ask me following questions:

Which type of camera shall I buy? Answer: To be flexible: both types, but it depends of.....

Can I expect sharp pictures from XL cameras? Answer: In general: Maybe, but it depends of....

Dependant from preferencies and conditions, see two excamples:

• panning - longer shutterspeeds can have some advantages if vertical objects like fenceposts ore also humans “moves” through your scene... it looks a little bit smoother due to blurrier frames - if you like this.....
• filming in fluorescent (neon or other) light - longer shutterspeeds can eliminate the flickering (60 or 50 Hz)

 It´s hard to give a definite answer! To give some clearance I have written some technical explanations.....

table of cameras ....

Fine grain Super8 films have a low film speed and needs a lot of light. In practice we do not have enough natural light often in winter time,  late afternoon, early evening or bad weather conditions for this films. Physical dependencies and corresponding camera construction determines the special qualities of a camera and your films:

• - sharp pictures are dependent from lens,  smaller aperture opening and short shutter speeds
• - low light conditions require open apertures, longer shutter speeds,  minimized light loss in camera construction
• Camera construction for bright AND lowlight condition is a little bit like to do a split......and is truely never realized.

 

Some basics and rules to understand the physics:

• 1. sharpness: in general the best sharpness also in edges of pictureframes is 3 or 4 fstops closed from maximum of the lens
• 2. Zoomfactor: ratio of max. focal length to smallest focal length (e.g lens: 6mm - 48mm;  factor= 1:8) . Zoom lenses with higher zoomfactor have more lenses (combined in groups) than fixed focal lenses or lenses with small zoomfactor .
• 3. Shutterspeed: Opening sector of the rotating shutter is responsible for the shutterspeed (see also...). Longer time allows smaller apertureopening -  Shorter speeds requires more open apertures. The limitation in lowlight is the max. possible lens opening.
• 4. Opening factor of a lens: ratio of focal length to max. effective lens/aperture opening (e.g. focal length of 6mm and aperture of 5mm = f1.2) This is only the theoretical possibility of a lens to pass light. Be aware: an optical system with many lenses in many groups but with good opening factor of 1:1.4 can pass fewer light to the film, than a camera with few lenses and opening factor of 1:1.8 The written factor on the zoomlens is only for the minimal focal length and varies for longer zoomlength. This is very often a misunderstanding!.
• 5. fstop: lenses are calibrated in a scale of fstops (1, 1.4, 1.8, 2, 2.8, 4, 5.6, 8, 11, 16, 22, ......64). Max open is the smallest number which is identical with the opening factor of your lens. Closing to the next fstop reduces 50%.of the light or in other words opening one fstop increases the light for 100%.
• 6. Light loss in an optical system rises up at every glass-to-air-surface due to light reflection. It can be from 1% to 4% loss for every surface. This is dependant from coating. One single lens has 2 surfaces, 12 lenses or 12 lensgroups have 24 surfaces, 16 lenses have 32 surfaces and so on.... Commonly zoom lenses with high zoomfactor have more glass-to-air-surfaces than fixed focal length lenses or zooms with a small zoomfactor. Due to marketing reasons unfortunately the important percentage of this loss is NOT described in any camera manual. But the internal lightmeter is constructed to consider this. An external lightmeter cannot do this and meters different (theoretical) fstops. (If you want to do this please read my technical tips....)

Objective for lowlight cameras: increasing the useable light !

a) decreasing light loss in lowlight camera construction

Light loss in a normal reflex camera with TTL feature:

• zoomlens: 20 - 50%
• beam splitter or pellicule for viewfinder and lightmetering 20 %

(Beaulieu´s guillotine shutter with his mirror do not reduce the light which can pass onto the film. But this cams have high shutterspeeds and are NOT lowlight cameras...)

b) longer shutterspeeds

• Shutter speeds of bright light Super8 cameras with rotational shutter range from 1/46 sec. to 1/36 sec (18fps). This is better for acceptable results for moving objects or filming out from your hand. In opposite: Longer shutterspeeds have a greater risk to get bad pictures...

 

Engineers started to construct cameras with extra low or existing light (XL) feature. At these years a zoom lens for Super8 cameras was common standard and requested by the market. Unfortunately (also today) a lens with a high zoomfacter 6:1, 8:1 and more was a status symbol but mostly not really necessary (only for wildlife or special zoom effects).

Features like parallaxfree reflex viewfinder, TTL metering and automatic aperture settings are very comfortable . But all of this features lowers the amount of light which passes to the film. Against better technical knowledge these features are also to find in XL Super 8 cameras to prevend the homeusers for overcharge .

Changements depending of model were made:

• 1. Zoomlens: some lenses were constructed with fewer groups of lenses to reduce light loss and they have zooms up to 42mm - enough for normal professional usage. Some few lenses have more.
• 2. Opening factor was increased (f1.1 to f1.4)
• 3. Fixed Shutter: openings between 200° and 230° to get shutter speeds around 1/30 sec.

In total these changements increases the light which passes through the filmgate. A "lightwin" - comparable like one or more fstop is realized. Due to marketing reasons manufactorers have combined also lenses with large zoomfactors together with XL-shutters.

Wow, a lot of technical stuff! Hope you are ready now to decide by yourself.

My personal view:

a) If you want to get a universal camera select one with a shutteropening of 180 - 200°.

b) If you want a camera with best lowlight possibilities select one over 200°. Have a look for your requirements: for zooming, select lenses with best opening factor and all other features you want to own.

c) If you want a camera for brightlight conditions  look for acamera with shutters below 180°. Keep in mind also your other requirements.....

But be aware: the overall "best" camera does not exist! Of cause the more expensive XL(S) Canons are fine universal cameras. But like any "universal" it must not be the best for a special tasks...

  Very fine lowlight "XL" Super8 cameras are made by BAUER (XL series), BEAULIEU (6008,6028), CANON (electronic: 814 and 1014), CHINON (pacific200/12XL), COSINA (professional series), ELMO (612, 1012), MINOLTA Nizo (integral, 1048 to 6080) and SANKYO. For special features and modifications please see ADAMS64.

Professionals who are familiar with all this technical stuff knows:  The best lowlight camera does not have any beamsplitter for TTL or viewfinder. But a lens with good opening factor (also interchangeable fix focus) with few lensgroups - like some 16 or 35mm professional moviecameras or old Normal 8 cams.

For making films in real lowlight conditions I own a budget KODAK camera without any beamsplitter and TTL metering. For sharp picturestanding  I have modified the filmpressure and also added a "+/- correction" for automatic aperture setting. With this camera I (and a friend) have made several fine filmscenes and had never  problems with a parallaxfree viewfinder!

If I need other features like fades, backward filming or different fps I currently use my modified BAUER A508 combined with  another XL lens f1.2 7-42mm (with only few lensgroups). This gives me some more light than the original A508 or A512 lens.

And of cause I own some other cameras for using in bright light condition. Each for a special task.....