Pentax smc Pentax-DA 40mm f/2.8 Limited User manual

smc PENTAX-DA
INTERCHANGEABLE LENS
OPERATING MANUAL

FOREWORD
Thank you for purchasing the smc PENTAX-DA lens.
This smc PENTAX-DA lens features a “Quick-Shift Focus System” that lets you finely
adjust the focus manually after the focus has been adjusted in addition to allowing
you to enjoy taking pictures using autofocus or manual focus by mounting on the
PENTAX -series digital SLR camera. For further information on the use of this
function, refer to p10.
This lens can be used only with PENTAX -series SLR cameras. It is not
compatible with film SLR cameras.
Please read this operating manual carefully before using the lens to ensure that it is
used properly. In addition, also refer to your camera’s operating manual.
In this operating manual, “smc PENTAX-DA lens” is shortened to “DA lens.”
Illustrations shown herein may differ from the actual appearance.

FOR SAFE USE OF YOUR LENS 1
Although we have carefully designed these lenses for safe operation, please pay special
attention to items marked with the following symbols when using this product.
WARNING This symbol indicates precautions that if not followed,
could result in serious injury to the user.
CAUTION This symbol indicates precautions that if not followed,
could result in minor or medium injury to the user or
damage to the equipment.
WARNING
•Never look at the sun through the lens or camera. Serious damage to the retina or
total loss of eyesight may occur.
CAUTION
•Do not leave the lens in direct sunlight without lens caps. Direct sunlight passing
through the lens will be intensified, and should it focus on flammable materials, fire
may occur.

PRECAUTIONS AND LENS MAINTENANCE
2
1. Storage and mildew prevention
• Take the lens out of the protective case or camera bag, and store it in a dry, well-ventilated place.
• Avoid storing the lens in a poorly ventilated location such as a closet, wardrobe, drawer, vehicle, or
where insect repellent or medicine is kept.
• Avoid storing the lens in areas of high temperature and humidity, where there is a risk of mildew growth.
Store the lens with a desiccant in a dry cabinet, airtight container, or plastic bag. (Leaving a saturated
desiccant in the storage container can cause damage to the lens. Be sure to read the instructions that
come with the desiccant before use.)
2. The lens is not waterproof. When using the lens in a rain or mist, be careful not to allow it to get wet.
3. Never use any organic solvent such as thinner, alcohol, or benzine, etc. to remove dust on the lens.
4. The lens is a precise optical instrument. Be careful not to let it fall, or subject it to strong shocks or
pressure. Use a cushion or similar pad to protect the lens from the vibrations of motorcycles or other
vehicles, boats, etc.
5. Avoid subjecting the lens to rapid changes in temperature, otherwise condensation can occur on both
the inside and the outside of the lens. Put the lens in a plastic bag or camera bag, and take it out after
the lens has reached ambient temperature.
6. When the lens is not attached to the camera body, attach both the supplied lens cap and lens mount
cap to protect it from dust.
7. Do not leave the camera with the lens cap off attached to a tripod or other rigid camera support. The
inner parts of the camera can be damaged by direct sunlight.
8. Have the lens inspected by a dealer every one or two years to maintain its high performance.

CONTENTS 3
°FOREWORD
°FOR SAFE USE OF YOUR LENS ···························································································· 1
°PRECAUTIONS AND LENS MAINTENANCE ········································································· 2
°smc PENTAX-DA LENS ·········································································································· 4
•About the DA Lens Mount ····································································································· 5
°MOUNTING AND REMOVING THE LENS ·············································································· 6
°LENS CAP ······························································································································· 7
°FOCUSING ······························································································································· 8
•Changing the Focus Mode ···································································································· 8
•Using Autofocus ···················································································································· 8
•Using Manual Focus ··············································································································9
•Using the Quick-Shift Focus System ( -series cameras only) ································· 10
•How to use the Quick-Shift Focus System ·········································································· 10
•Precautions on close-distance scale ··················································································· 12
°ZOOM LENS··························································································································· 13
•About the zoom ring·············································································································14
°ATTACHING THE LENS HOOD ····························································································· 15
•Screw-on Type····················································································································· 15
•Bayonet Type······················································································································· 15
•About the PL filter window ··································································································· 16
°FILTERS ································································································································· 18
°PRECAUTIONS WHEN USING THE LENS WITH A FLASH ················································· 20
•Built-in Flash ························································································································ 20
•External Flash ······················································································································ 20
•Compatibility of DA Lenses with the Built-in Flash ······························································ 21
°MAIN SPECIFICATIONS ········································································································ 22

smc PENTAX-DA LENS
4
Focusing ring
Distance scale
window
Depth-of-field scale
Mounting index
Lens hood
attaching index
Distance scale
Distance index
Depth-of-field scale
Note:
The DA lens does not have an aperture ring. Aperture settings are controlled
automatically as if set to the auto “A” position, so accessories without an auto “A”
setting cannot be used with this lens.

5
AF coupler Lens-information
contacts
About the DA lens mount
The DA lens is an interchangeable lens specifically designed for the PENTAX - series
digital SLR camera.
The KAF -mount of the DA lens is similar to conventional SLR lenses, but the DA lens cannot
be used on 35 mm SLR cameras.
KAF-mount
CAUTION
Be careful not to damage or dirty the lens-information contacts and AF coupler
on the mount surfaces of the camera and lens. Otherwise, failure or
malfunction may result.

1. To mount the lens on the camera body
Align the red dots on the lens and camera body, and then turn the lens clockwise until
it clicks into place.
✍Memo:
•Do not hold down the lens unlock button while mounting the lens, otherwise the lens will
not be properly mounted.
•After mounting the lens, gently turn the lens counterclockwise to make sure it is locked
in place.
2. To remove the lens
Hold down the lens unlock button on the camera body and turn the lens
counterclockwise.
MOUNTING AND REMOVING THE LENS
6
1 2

1. Take off the lens cap by pressing the two tabs inward as shown above.
2. Attaching the dedicated lens cap to DA 40mm f/2.8 Limited
First screw the dedicated hood onto the front of the lens, then screw on the lens cap.
✍Memo:
•When not using the lens, be sure to attach the lens cap.
LENS CAP 7
1
22

FOCUSING
8
1
Changing the Focus Mode
Use the camera’s focus mode switch to change between the autofocus mode and manual-
focus mode. For details, refer to your camera’s manual.
1. Using Autofocus
Set to autofocus with the camera’s focus mode, and press the shutter button halfway or
press the AF button of to autofocus. Above left illustaration is for .
CAUTION
During autofocusing, the focusing ring of following lenses will rotate.
•To prevent malfunction, do not touch the focusing ring during autofocusing.
- DA 16-45mm f/4ED AL
- DA 18-55mm f/3.5-5.6 AL
- DA 40mm f/2.8 Limited

9
2
2. Using Manual Focus
Set to MF with the camera’s focus mode, and turn the focusing ring to focus manually.

Using the Quick-Shift Focus System ( -series cameras only)
If you use the lens with an -series camera and the focus mode is set to autofocus,
you can focus manually after autofocus is achieved. Just turn the focusing ring to manually
touch-up the focus. You can do this without changing the focus mode to MF.
How to use the Quick-Shift Focus System
1. Using Autofocus
Set the camera’s focus mode switch to autofocus, then press the shutter button halfway
to autofocus.
With the , you can also focus with the AF button. With the , you can
focus by pressing the OK button. (Assuming that the “OK btn when shooting” in the
“CCustom Setting” menu is set to “2Enable AF.”)
2. Hold down the shutter button halfway (or press the AF button or OK button),
then turn the focusing ring to focus.
3. Finally, press the shutter release button fully to take a picture.
10

11
CAUTION
During autofocusing, the focusing ring of following lenses will rotate.
•To prevent malfunction, do not touch the focusing ring during autofocusing.
- DA 16-45mm f/4ED AL
- DA 18-55mm f/3.5-5.6 AL
- DA 40mm f/2.8 Limited
•When using the Quick-Shift Focus System, keep pressing the shutter button (or AF
button) after you achieve focus and before taking a picture. If you let go of the shutter
button before taking the picture, you will have to focus all over again when you press
the shutter button again.
In the following cases, you can take the picture without autofocusing after letting go
of the shutter button.
•With the , set the “AF with Press Halfway” Custom Function to off. To
autofocus, press the AF button.
•With the , in the “CCustom Setting” menu, set “OK btn when shooting” to
“3Cancel AF.” While you press the OK button, you can focus manually.
The setting procedure and more details are explained in the camera's instruction
manual.

12
Close-distance scale
Precautions on close-distance scale
(For DA 16-45mm f/4ED AL, DA18-55mm f/3.5-5.6 AL)
In the close-distance scale range (the distance scale in the orange area), when shooting at
the maximum aperture, image quality deterioration in the picture corners may result
because of the optical characteristics of the lens.
When taking a picture in this range, we recommend that you use a smaller aperture,
stopping down from wide open.

ZOOM LENS 13
Focusing ring
Distance scale
Zoom index
Mounting index
Zoom ring
Focal length scale
Focusing index
Lens hood
attaching index

14
The zoom lens has a focusing ring at the front and a zoom ring behind it.
Turn the zoom ring to set the desired angle of view (lens focal length).
✍Memo:
•The focusing point may shift slightly by changing the focal length. First adjust the zoom
and then adjust focus.
About the zoom ring
Turn the zoom ring clockwise for telephoto and counterclockwise for wide-angle.

ATTACHING THE LENS HOOD 15
Lens hood
attaching
index
1. Screw-on Type
If the lens hood is dedicated to the DA 40mm f/2.8 Limited, screw it onto the front of the
lens.
2. Bayonet Type
When attaching the lens hood, align the index on the lens hood with the attaching index
on the lens, and push both parts straight toward each other. Attach the lens hood on the
lens by turning the hood in the clockwise direction to lock it as viewed from the front of
the lens until it clicks into position.
✍Memo:
•When attaching the lens hood, hold the focus ring and zoom ring securely to prevent
them from turning.
•When the lens hood is not in use, it can also be turned around and attached in the
reversed position.
In order to avoid the deterioration in image quality from internal reflection, use of the lens
hood is recommended.
12

About the PL filter window
If a polarizing filter is attached to the DA lens, you can easily turn the filter via the PL filter
window on the bayonet-type hood.
How to use the lens hood with polarizing filter window
1. Remove the PL filter window cap by sliding it in the direction as shown above.
2. Turn the outer rim of the circular polarizing filter from the PL filter window as shown
above.
16
12

17
3. Attach the PL filter window cap.
✍Memo:
•When shooting, be sure the PL filter window cap is in place to make that the lens hood
is being used to maximum effect.
3

FILTERS
18
Mount the filter into the screw thread in front of the lens.
✍Memo:
•The compatible filter size for all the lenses are listed on pages 22-23.
Precaution on filters
•Since the filter becomes a part of the optics when attached on the lens, handle it in the
same way you handle the lens with care to dust, dirt and scratches. Normally, attaching
two or more filters on a lens is not recommended. However, attaching a circular polarizing
filter and another filter would not be a problem.
•Use a circular polarizing filter with Autofocus camera for proper exposure and
autofocusing.