Mamiya/Sekor 
1000DTL / 500DTL

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Click here to PDF version made from the above file

Parts manual


(posted 4-5-02)

(this is the exact duplicate for the 500DTL except it's top speed is 1/500 sec.)

TABLE OF CONTENTS

Description of Reference Points ..3

Section 1. Specifications ..5

Section 2. Insert the Silver Oxide Battery ..7

Section 3. Film Loading ..8

Section 4. Setting the Film Speed ..11

Section 5. Selecting the Shutter Speed ..12

Section 6. Focusing and Viewing ..13

Section 7. Setting the Exposure ..14

Section 8. Depth of Field ..17

Section 9. The Automatic Lens ..19

Section 10. Changing the Lenses ..20

Section 11. Holding the Camera ..21

Section 12. Self Timer ..22

Section 13. Flash Photography ..22

Section 14. Rewinding the Film ..23

Section 15. Helpful Hints ..24

Section 16. Troubleshooting Your Camera ..25

Section 17. Meter Cut Off Points ..27


Description of Reference Points for the Mamiya/Sekor 1000DTL
1. Self Timer Activating Button

2. Self Timer Cocking Lever

3. Neck Strap Eyelet

4. Automatic Reset Exposure Counter

5. Meter " Off " Locking Button

6. Shutter Release Button with Threaded Cable Release Receptacle

7. Single Stroke Rapid Film Advance Lever



8. Shutter Speed Dial and ASA/DIN Window

9. Film Plane Reference Point

10. Penta-Prism Housing

11. FP & X Flash Terminals

12. Rewind Knob with Rewind Crank

13. Film Compartment Door Slide

14. Focusing Ring

15. Depth of Field Scale4www.butkus.org

16. Aperture Ring

17. Spot/Average Meter System Selector Switch

18. Film Chamber

19. Battery Compartment Cover

20. Tripod Socket

21. Automatic/Manual Selector Lever

22. Viewfinder Eyepiece

23. Rewind Release Button

24. Film Advance Sprockets

25. Film Take Up Spool

26. Film Pressure Plate

27. Hinged Film Compartment Door

28. Film Cartridge Pressure Plate4www.butkus.org



SPECIFICATIONS:
Mamiya/Sekor 1000 DTL Camera With Spot and Average Metering System

CAMERA TYPE:
35mm Single Lens Reflex with two separate behind-the-lens metering systems--one for spot readings, one for averaging type readings.

FILM SIZE AND CAPACITY:
35mm film (perforated) in 20 or 36 exposure standard cartridges.

STANDARD LENSES:
55mm f/1.4 Mamiya/Sekor. 7 elements in 5 groups. Angle of acceptance: 43 degrees.
55mm f/1.8 Mamiya/Sekor. 6 elements in 4 groups. Angle of acceptance: 43 degrees.

LENS MOUNT: 
Praktica-Mamiya/Sekor, 42mm universal threaded mount.

LENS ACCESSORY SIZE: 
55mm f/1.4 Lens: Acc -55 mm threaded filters and other lens accessories.
55mm f/1.8 Lens Acc 52mm threaded filters and other lens accessories.

SHUTTER: 
Focal plane type with speeds from 1 to 1/1000 of a second and " B" for time exposures. Built-in variable delay self timer.4www.butkus.org

EXPOSURE CONTROL: 
Two separate metering systems with one CdS meter cell positioned on the back of the reflex mirror (spot system), and one cell located on each side of the viewfinder eyepiece, in the penta-prism housing (averaging system).  Both metering systems are cross coupled to camera shutter speeds and diaphragm mechanism of all automatic lenses with Praktica-Mamiya/Sekor universal mounts. Film advance lever switches metering system on and actuates diaphragm of automatic lenses. Metering systems also accurately measure light transmitted through non-automatic lenses, bellows, extension tubes, filters and other lens attachments. Spot/Averaging selector switch on camera body allows use of either the spot or averaging system of exposure calculation.

FILM SENSITIVITY: 
ASA 25 to 3200 DIN 15 to 36

* NOTE: Patent pending on Mamiya/Sekor Spot/Average Metering System.

VIEWFINDER: 
Penta-Prism type with micro diaprism center spot on fresnel lens for rapid focusing. Brackets visible in finder indicate location of spot meter reading area (6% of field). Pointer and "S" and "A" symbols visible in finder indicate whether the spot or the averaging metering system is being used. Exposure needle and reference points indicate necessary exposure adjustments.

FLASH SYNCHRONIZATION: 
With Focal Plane bulbs: 1 to 1/1000 second. With Class " M " bulbs: 1 to 1/30 second. With Class "F" bulbs: 1 to 1/30 second. With Electronic flash: 1 to 1/60 second.

The Mamiya/Sekor 1000 DTL has two separate sets of flash contacts, marked " FP " and " X ". Proper selection of terminals allows correct synchronization for all types of flash exposures.

REFLEX MIRROR: 
Instant Return Type.

FILM ADVANCE: 
Ratchet type film advance lever transports film, cocks shutter and advances exposure counter in a single stroke (160°) or by a number of shorter strokes.

EXPOSURE COUNTER: 
Progressive type, from " S " (start) to 36. Counter automatically resets to " S " when film compartment door is opened.

DIMENSIONS: 
Width: 5.8 inches (148mm)
Height: 3.7 inches ( 95 mm)
Thickness: 2 inches ( 51 mm) without lens.4www.butkus.org

WEIGHT: 
Body only: 1 lb. 9-1/2 ounces (725 grams)

INSERT THE SILVER OXIDE BATTERY:
The Silver Oxide battery supplied with the camera is especially designed to operate the two metering systems of the Mamiya/Sekor 1000 DTL camera. No substitutes, other than those listed below can be used. Install as follows:

TO OPEN THE BATTERY COMPARTMENT, place the tip of your thumb or forefinger on the knurled surface of the compartment cover (19), and twist counterclockwise until all threads have been disengaged. If the cover is too tight, use a coin to start the operation, but remove the coin after a quarter turn and complete the removal of the cover using only your thumb or fore finger.

Insert the battery negative 1 - ) side down (refer to Figure A). Replace cover carefully, making sure that the threads are properly engaged. Again use only your thumb or forefinger, this time using a clockwise twist until the cover is tight. DO NOT tighten cover with a coin.4www.butkus.org

The battery will last for approximately a year, depending upon use. To replace, use one of the following Silver Oxide batteries: Eveready S-76E, Mallory MS-76, or Ray-O-Vac RS-76.


FILM LOADING
CAUTION! When the camera is not in use, or when changing lenses, always LOCK the meter in the OFF position. To do this, depress the button (5) on top of the film advance lever. This causes the film advance lever to retract inward toward the camera body and prevents accidental switching " on " of the meter. If the meter is " on " during the changing of an automatic lens, serious damage may result. Also, when the camera is in its Eveready Case, the meter should be locked " off " to prevent accidental drain on the battery. The meter " OFF LOCKING BUTTON " automatically pops up again into the unlocked position when the film advance lever is pulled away from the camera body.

DO NOT LOAD IN BRIGHT LIGHT. Open film compartment door (27) of camera (refer to Figure B) by pulling upward on the slide lock (13).


Pull up the rewind knob (12) as in Figure C. Place film cartridge into film chamber (18), and return rewind knob to its former position.
Draw out the film leader (refer to Figure D), and insert the end of the film into one of the slots on the take-up spool (25). If no slot is in the correct position for insertion of the film, the take-up spool may be rotated by hand until the slot is accessible.
NOTE: The film must pass under the take-up spool when advanced (refer to Figure E).
Advance the film with the film advance lever (refer to Figure F), while noting the reverse rotation of the take-up spool. Make sure that the sprockets are engaged as the film passes over them, and that one complete wind of film is around the take-up spool. Close film compartment door, making sure that it is locked.

Refer now to the exposure counter (4) window. The letter " S' should appear opposite the triangular index mark in the exposure counter window. Next, Gently turn rewind knob in the direction of the arrow just enough to take the slack out of the film. Depress the shutter release button (6), and advance the film again by rotating the film advance lever as far as it will go in the direction of the arrow. The shutter is automatically cocked when the film advance lever is moved to its farthest point. Repeat this action until the figure " 1 " appears opposite the triangular index mark in the exposure counter window. The camera is now ready for taking the first picture.

NOTE: As the film is advanced, the rewind knob will periodically rotate in a backward direction. This indicates that the film is being transported correctly in the camera.

SETTING THE FILM SPEED:
Lift the outer ring of the shutter speed dial (8) (refer to Figure G), and rotate it in either direction until the ASA number of the film you are using appears opposite the reference line between the letter " S " and the ASA window (refer to Figure H). When using film which is rated by DIN speeds, set the DIN number opposite the line which is located between the numerals " 30 " and " 60" for the shutter speed. You will note that in Figure H the ASA setting is 100 and the DIN setting is 21. Dots located between ASA and DIN numbers on the film speed dial represent the following film speeds:

SELECTING THE SHUTTER SPEED:

The 12 numbers on the outer face of the shutter speed dial are speed settings, and represent fractions of a second. For example, (refer to Figure D, the number 125 on the dial (opposite the engraved reference mark) represents 1/125 of a second. Hence, the higher the number the faster the shutter travels during an exposure.

When hand holding the camera for taking a picture, always use a shutter speed of 1/60 or faster if possible (see instructions for using the exposure meter). For speeds slower than 1/60 second, the use of a tripod or other support is recommended.

With the shutter speed dial set at " B " the shutter will remain open as long as the release button is depressed. When the button is released, the shutter closes. For exposures utilizing the " B " setting, the use of a cable release is recommended. In the case of long exposures, a locking cable release will allow exposures of any duration. The cable release is attached to the camera through the threaded receptacle on the top of the shutter release button.

Shutter speeds may be changed before or after the film has been advanced and the shutter cocked. The shutter speed dial may be rotated in either direction when setting the desired speed. However, as indicated by Figure J. the dial cannot be rotated past the 1000 position or the B position.

NOTE: When selecting a new shutter speed, never pull up on the dial for the film speed settings (ASA/DIN) will be altered.


FOCUSING AND VIEWING:

The Mamiya/Sekor 1000 DTL is a Single Lens Reflex. This means that you view the subject through the taking lens. Since the same image is transmitted to the eye as to the film, parallax is eliminated. The subject is registered on the film exactly as it is seen by the photographer.

Focusing (Refer to Figure K) the 1000 DTL is made easier by the micro diaprism focusing grid in the viewfinder. This is the small round area in the center of the finder which exaggerates the difference between the " in focus " and " out of focus " image. By rotating the focusing ring (141 on the lens barrel, the micro diaprism can be made to disappear. When this happens, the image is in focus for both the eye and the film. For subjects with irregular outlines, like wooded hillsides. the entire ground glass area of the viewfinder may be utilized for focusing. In any case (except with infra red materials} when the image appears to be sharp in the finder, it will be sharp on the film.

When using infra-red film, first focus the image as above. Then note the distance as represented by the number which appears opposite the footage index mark on the lens barrel. Rotate the focusing ring until this number is opposite the small red mark, and the lens will be correctly focused for infra-red photography at that distance. This is necessary because infra-red film is sensitive only to infra-red light rays, which focus on a plane slightly behind that of ordinary light rays.4www.butkus.org



SETTING THE EXPOSURE:

There are two ways of determining correct exposure with the Mamiya/Sekor 1000 DTL. Whether you use the- Spot or the Average system will depend upon the type of picture you are taking. In either case, before taking the reading, set the Automatic/Manual selector lever (21) on the lens barrel to the letter " A" so that the automatic diaphragm feature of the lens is activated.

"SPOT" Reading:
The "Spot" method of exposure calculation is especially valuable when the most important area of the picture is either much lighter or much darker than the general picture area, or in landscapes, where sky light would register a much higher reading than trees or buildings at ground level. Such a situation would cause under exposure if the subject were to be measured with a conventional, averaging meter from the camera position.
" Spot " reading is also useful for subjects under insufficient lighting such as indoor shots or night scenes, because the exposure meter needle reacts faster under these conditions than during average reading.
To obtain a spot reading, set the shutter at the speed at which you wish to take the photograph. Move the Spot/Average selector switch (17) toward the letter " S " as far as it will go (Refer to Figure L).




Looking through the viewfinder you will notice that the small pointer at the bottom of the field is now on the letter " S " between the meter area brackets. These brackets outline the area of sensitivity, about 6% of the total picture you are viewing. Focus the lens so that the subject area is critically sharp. Then aim the camera so that the bracketed area falls upon the most important part of the picture you are about to take (Refer to Figure M). Make sure that the brackets do not include any part of the picture that is either lighter or darker than the section you are reading (Refer to Figure N).


Press the film advance lever (refer to Figure O) toward the camera body as far as it will go. (NOTE: If the film advance lever is in the meter Off-Lock position, move lever away from body until locking button 15) snaps up.) While pressing the film advance lever toward the camera body as far as it will go, rotate the aperture ring 116) Located on the lens) until the needle at the right of the finder is centered between the open ends of the reversed letter " C " (refer to Figure P). The exposure is now set, with the selected area of the picture being correctly exposed. You may now release the pressure on the advance lever and make final composition changes before tripping the shutter.


"AVERAGE" Reading:
When the scene to be photographed is made up of areas of equal importance, an overall, average reading will result in the best picture. To accomplish this, set the desired shutter speed, and push the Spot/Average selector switch toward the letter " A ". The pointer in the lower section of the viewfinder now for moves outside the Spot Meter bracketed area to the letter " A ", indicating that the whole picture is being measured by the meter. Focus on the subject area. Center the needle on the reversed " C " as above, by rotating the aperture ring while pressing the film advance lever. When taking an " Average " reading, the picture should be composed before the exposure is adjusted.4www.butkus.org


Exposure Setting When Using Non-Automatic Lenses and Close-Up Accessories:
When using pre-set lenses, non-automatic extension tubes, bellows, microscopes, or other close-up accessories, the lens diaphragm must be manually operated until the correct exposure setting is determined. The 1000 DTL meter requires no special calculations or compensations to read correctly through extension tubes, bellows or other attachments. The meter reading must be obtained after final focus, since exposure is influenced by distance between the lens and the film. Activating the meter and setting the exposure is accomplished as referenced above.

NOTE: You may reverse the above procedure if you wish to take a picture at a particular aperture for any reason. In this case, instead of choosing the shutter speed first, select the lens opening desired before taking the reading. Then, center the needle in the reversed " C " by rotating the shutter speed dial.


DEPTH OF FIELD:

When a camera lens is focused to give a sharp image of a particular subject, some objects slightly behind, as well as some objects slightly ahead of the subject focused on, will appear to be sharp. The distance between the nearest and farthest objects, which are in focus, is called Depth of Field.

Depth of Field changes each time the focusing distance changes, becoming greater as the lens is focused on points farther from the camera position, while decreasing as the point of focus becomes closer. Other factors influencing depth of field are the focal length of the lens and the diaphragm opening at which the picture is taken. The shorter the focal length and/or the smaller the lens diaphragm opening, the greater the depth of field for any given focusing distance, and vice versa.

Proper use of depth of field can enable the photographer to utilize the principles of "selective focus," which often means the difference between ordinary snapshots and pictures of quality. For example the proper selection of a "sharp" zone of focus can eliminate an unwanted object in the background. The same could be true for foreground objects.

When you wish to view the depth of field before taking a picture with the 1000 DTL, set the lens diaphragm on " automatic". Focus with the micro diaprism as explained before. Then press the film advance lever as if taking a meter reading. This causes the lens diaphragm to close le. g. stopped down). If you have already taken the meter reading, the lens is now at the diaphragm opening at which the picture will be taken.

The depth of field now appears in the finder exactly as it will be in the finished picture. By changing the focus while the lens diaphragm is stopped down, you can select the area of sharpness in your picture. When using non-automatic or pre-set lenses, the diaphragm must be closed manually, but the same results can be achieved.

You may also determine depth of field by checking the scale 115) on the lens barrel (Refer to Figure Q). Numbers representing lens apertures appear at the near and far limits of depth for any given focus distance and lens opening.

For example, if the standard lens is focused at 30 ft., one of the lines representing f/11 appears at the 15ft. mark. The other line [again representing f/11) is at the infinity symbol. What this means is that if a picture is taken with the lens focused at 30 ft., and the diaphragm is set at f/11, all objects in the picture between 15ft. and infinity will be in focus. This method is extremely valuable when the lens diaphragm is stopped down too far to allow enough light for the picture to be viewed through the viewfinder and depth of field set visually.


THE AUTOMATIC LENS:

The standard lens on the Mamiya/Sekor 1000 DTL is equipped with a fully automatic diaphragm. This means that you may view a scene with all light passing through a wide open lens, but actually take the picture through a stopped down aperture as indicated by the meter.

In order for the automatic features of the lens to operate, set the Automatic/Manual selector lever 121) on the lens barrel on " A" (Refer to Figure R). You will notice that after taking a meter reading in the normal manner, releasing the pressure on the film advance lever causes the lens diaphragm to open up to its widest aperture. However, when you press the shutter release button to take a picture, the lens automatically stops down again to the aperture indicated by the meter. The diaphragm remains stopped down only for the instant it takes for the exposure to be made, and reopens itself immediately, so that the eye has almost no sensation of having been " blacked out."

The automatic feature of your lens does not work when used on non-automatic bellows or on extension tubes. In order to read the meter in this case, proceed as explained in the earlier sec

CHANGING THE LENS

CAUTION! PLEASE READ THIS SECTION CAREFULLY BEFORE ATTEMPTING TO REMOVE OR INSTALL A LENS.

To remove an automatic lens from your camera, first depress the meter " OFF " locking button. Set the Automatic/Manual selector lever on the lens to " A ". Support the camera (refer to Figure S) body in the palm of the left hand with the lens projecting upward. With a firm grip on the camera body, use the right hand to turn the lens barrel counterclockwise until all threads have been disengaged.

To mount a lens on the camera, reverse the above procedure, turning the lens barrel clockwise until it stops. Always be sure the meter is in the " OFF " locking position, and that the threads are properly engaged. No resistance should be felt when mounting a lens. If excessive pressure is necessary, remove the lens completely, and inspect the threads for dirt or other foreign matter.

If slight resistance is met when removing a lens, grasp the lens barrel as close to the camera body as possible to avoid accidental damage.

Do not touch the reflex mirror after removing the lens. Dust particles may be removed with a blower or a soft camel hair brush


HOLDING THE CAMERA

Support the camera (Refer to Figure T) on the palm of the left hand with the thumb and forefinger curled lightly but securely around the bottom and sides of the focusing ring. Place the palm of the right hand against the end of the camera body. The right forefinger automatically rests near the release button, and the thumb is on the film advance lever. Bring the camera up to eye level, and rest it against the forehead with the viewing eye close enough to the viewfinder to see the complete subject area. The forehead is now helping to steady the camera. The left elbow should be held as close to the body as possible.

You may compose the picture either vertically or horizontally and the viewfinder shows the exact format of the picture. As a general rule, the camera should not be held at shutter speeds slower than 1/60 of a second. This becomes particularly important when using lenses of longer than normal focal length where it may be necessary to use even faster speeds to eli minate hand movement. At speeds slower than 1/60, use a tripod or other support to eliminate camera movement.4www.butkus.org

The release button should be gently squeezed when taking a picture. Never use a plunging or pushing motion.


SELF TIMER

The self timer (2) provides a method of taking delayed action pictures, thus allowing a photographer to be in his own pictures. 

When the self timer lever is rotated clockwise (refer to Figure U) , 8 it full travel of approximately 180 degrees, a delay of ten seconds is provided before the shutter position is released. Shorter intervals may be accomplished by rotating the lever for shorter distances anywhere between 90 and 180 degrees. The self timer activating button (1) is located behind the lever, and is visible only when the p timer is set for use.

Since the self timer operates independently of the shutter releases button, the camera may be operated in the usual way, with the' release button, even when the self timer has been set.

NOTE: If the self timer lever is not rotated to at least 90 degrees, timer will not function properly.

 

FLASH PHOTOGRAPHY

The flash terminals, marked FP and X (11) (Refer to Figure V) allows for a choice of flash synchronizations. The selection of a terminal depends upon the type of flash used, as well as shutter speed. The following table shows the correct combinations to be used in various flash situations. These combinations must be rigidly followed to insure correct synchronization.


Flash synchronization chart is not included since flash bulbs are no longer available.

REWINDING THE FILM:
When you have finished taking all the pictures in a cartridge, either 20 or 36, you must rewind the film back into the cartridge.

To do this, push in the rewind release button (23) located on to,. bottom of the camera body. (Button will remain inset without pressure until film advance lever is advanced a couple strokes) Wind the rewind crank (12) in the direction of the arrow until you feel t tension in the film lessen. That indicates that the film has left the take-up spool. If for any reason you are not sure that the film has been totally rewound back into the cartridge, continue to hold tension on the rewind crank and at the same time advance the film advance lever a full stroke. Trip the shutter and advance again.  Repeat this at least 3 times. If you do not feel a tension or pulling on the rewind crank when advancing the film advance lever, film has been completely rewound. Open the back of the camera and remove the cartridge.

AVOID DIRECT LIGHT WHEN UNLOADING/LOADING THE CAMERA.

HELPFUL HINTS:

STORAGE
When the camera is not to be used for an extended length of time, store with the shutter uncocked.

This relieves tension on the spring. Lock the exposure meter "Off." Remove the battery.

Never store in areas where temperatures exceed 100 degrees F. or go below freezing (32 degrees F).

Protect against excess moisture by using silica gel or other desiccant.

Never expose the camera to direct sunlight for extended periods of time.

Avoid areas where exposure to salt water or salt air occurs.

CARE AND CLEANING

Always use a blower or camel hair brush to clear film chamber and area around take up spool before loading film into camera.

Clean lens with lens tissue and regular lens cleaning liquid only. Do not clean lens at all unless you notice that it needs it. Avoid rubbing the surface of the lens if there is any loose grit or dirt present. Never rub lens with tissue alone. Always use a lens cleaning liquid. Never touch the lens with your bare fingers.

Never rub the surface of the reflex mirror. If there are foreign particles of any kind that cannot be removed by blower or camel hair brush, leave them alone until a factory approved serviceman is avails able. Dirt on the mirror can have no effect on the picture.


TROUBLESHOOTING YOUR CAMERA:

The proper operation of a precision instrument like the Mamiya/Sekor 1000 DTL camera requires strict attention to the correct manipulation of controls. In many cases, the camera may appear to malfunction simply because some small detail was overlooked, or not operated in the proper sequence. Before you decide the camera is broken, there are some things you can look for if you should experience any type of camera failure. A few of the problems and their probable causes are listed below.4www.butkus.org

Problem: NOT ENOUGH LIGHT IN VIEWFINDER.

Possible cause: Diaphragm closed. Lens Automatic/Manual selector lever set on " M " instead of " A " Correct this by moving lever to "A " setting.

Problem: EXPOSURE METER NEEDLE WILL NOT MOVE TO TAKE READING.

Possible cause: Improper shutter speed for film and light conditions. Try changing shutter speeds until needle moves. Or, be sure there is a battery in the camera. Use only specified type of battery (silver oxide. Or silver oxide battery may have been inserted wrong. Check to see that terminals are in the positions indicated in the instructions.

Problem: FILM COMPLETELY BLANK WHEN PROCESSED, INDICATING NO EXPOSURE HAS BEEN MADE.
Possible cause: Improper loading. Review the section on film loading and be sure you are loading the camera correctly, with the film being securely attached to the take up spool and winding in the CORRECT DIRECTION, that is, UNDER the take-up spool. Film may not have gone through camera at all.

Problem: SELF TIMER DOES NOT OPERATE SHUTTER. 
Possible cause: Timer not rotated full 90 degrees. Timer must be rotated to some point between 90 and 180 degrees.

Problem: FLASH PICTURES EITHER BLANK OR ONLY PARTIALLY EXPOSED. 
Possible cause: Improper shutter speed for the type of bulb used. Or improper cord receptacle used for the type of bulb or shutter speed. Check Flash Synchronization tables carefully.

Problem: LENS VERY HARD TO REMOVE FROM CAMERA. 
STOP IMMEDIATELY! 
Possible cause: Pressure on Film Advance lever causing automatic diaphragm actuating plate to press against pin on back of lens. THIS CAN CAUSE SERIOUS DAMAGE TO LENS. Check to be sure that the meter is turned " OFF." DO NOT USE FORCE.  (Webmaster - the lens should screw on and off very easily.  Two other possible problems, dirt on the screw part of the lens or the lens has been "cross threaded"  It was not put on straight and is ruining the threads of the lens.  Check the lens for any "white areas" around the threads. They are painted black, and white threads can be an indication that the  metal is being cut.)

Problem: SHUTTER WILL NOT RELEASE.
Possible cause: Film Advance lever not advanced far enough. A full stroke is necessary for cocking the shutter. However, a ratchet incorporated within the advance mechanism will allow you to accomplish a full wind in a series of short strokes.

If any problem listed above cannot be solved in the manner suggested, do not attempt to repair your camera. Take it, or send it, instead, to your nearest service station. A minor problem could possibly be aggravated by tampering.

METER CUT OFF POINTS
The Mamiya/Sekor 1000 DTL incorporates automatic disengagement or cut off points for the metering system at varying ASA/shutter speed settings. When a certain combination of shutter speed and ASA points is reached, both metering systems (spot system and averaging system) are disconnected, and in turn the needle immediately moves upward above the plus (+) reference symbol (refer to Figure W). Changing the shutter speed or ASA setting will reengage the metering system.

(Webmaster - This means that certain combinations of film ASA and shutter speeds can not correctly determine a correct exposure. The manual gives no reference points for this but as I remember: ASA 400 film would meter down to 1/8 of a second.  ASA 800 to 1/15 a second)