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Cosina CT-10: manual and user guide

The K-mount Cosina SLR with aperture priority. Its original manual, then the essentials for using it.

View the manual on butkus.orgScanned CT-10 and CT-20 manual · 20 pages in English, 64 pages in English, German, French, Italian and Spanish

Manual scanned and put online free of charge by Mike Butkus, whose library runs on donations. The link opens his model page, where you can download the PDF.

Getting started

Batteries Open the battery compartment cover with a coin, turning it anticlockwise. Insert two 1.5 V S-76 batteries (A-76, G-13 or equivalent) following the marked polarities, then screw the cover back on fully. With the selector on AUTO, press the shutter button halfway: if no LED lights up in the viewfinder, change the batteries.
Loading Out of direct sunlight, pull the rewind knob until the back opens. Put in the cartridge, push the knob back down while turning it, slide the film leader into the slot of the take-up spool and wind on until the teeth catch the perforations. Close the back, take up the slack with the crank, then wind on and fire until 1 shows on the counter.
Sensitivity Turn the film speed ring to your film’s value, from ISO 25 to 1600 (ASA). It clicks into place at the engraved values.
Your first photo Set the selector to AUTO and choose the aperture: the camera sets the shutter speed by itself. Focus, press the shutter button halfway and look at the LEDs on the left of the viewfinder. Green, take the shot. Yellow, open up the aperture or use a tripod. Red, stop down.
Rewinding Press the rewind release button: it stays pressed in. Unfold the crank and turn it in the direction of the arrow until it suddenly becomes lighter, then pull the rewind knob to open the back. If the lever has locked halfway, keep the button pressed throughout rewinding.

What it can do

Aperture priority: you choose the aperture, the camera sets the shutter speed between 4 s and 1/1000 s. The more you stop down, the slower the shutter speed.
Four-position selector: AUTO for everyday use, X for flash (1/100 s), B for an exposure that lasts as long as you hold the shutter button down, OFF to lock the shutter button between sessions.
In the viewfinder, three LEDs and an F lamp: red for overexposure, green from 1/30 to 1/1000 s, yellow below 1/30 s, F when the dedicated Cosina flash is ready.
Focusing in the centre of the viewfinder: a horizontal split-image rangefinder surrounded by microprisms, on a Fresnel focusing screen. It’s sharp when the two halves of the image line up and the microprisms stop shimmering.

Which lenses?

K bayonet mount: all K-mount lenses fit it.
To remove the lens, press the release button and turn it anticlockwise until it stops.
To mount it, line up the red dot on the lens with the one on the body and turn clockwise until it clicks. If it isn’t properly locked, the exposure will be off.

The flash

With the Cosina Auto 160 and Auto 220, designed for the CT-10 and CT-20, stay on AUTO: at full charge, the F lamp lights up and the shutter speed switches to 1/100 s by itself.
With another flash, set the selector to X.
In both cases, set the aperture according to the flash’s instructions.

Good to know

Below 1/30 s, watch out for camera shake: hold the camera firmly and press slowly, or use a tripod and a cable release, as for B exposures. Don’t force it when screwing on the tripod.
The batteries last about a year in normal use. Wipe them before inserting them and remove them if the camera is stored for a long time.
Never open the back before rewinding is finished. If it’s stored for a long time, fire the shutter from time to time. Keep it away from heat, salty air and insecticides.
The manual also covers the CT-20: the self-timer, backlight button and audible signal exist only on that model.

CT-10 specifications

Format: 135 film, 24 × 36 mm frames
Mount: K bayonet, 45.44 mm flange focal distance
Shutter: focal-plane curtains, magnetic control, from 4 s to 1/1000 s and bulb, X flash sync at 1/100 s
Viewfinder: fixed pentaprism, 93% coverage, 0.9× magnification with a 50 mm lens
Focusing: horizontal split-image rangefinder and microprism collar on a Fresnel screen
Metering: through the lens, at full aperture, centre-weighted, aperture priority, from EV 2 to EV 19 at ISO 100 (ASA)
Sensitivity: ISO 25 to 1600 (ASA)
Flash: accessory shoe, dedicated Cosina Auto 160 and Auto 220 flashes
Power: 2 S-76 batteries of 1.5 V (A-76, G-13 or equivalent), silver oxide or alkaline, checked via the viewfinder LEDs
Dimensions and weight: 133 × 85 × 48 mm (body only), 450 g