Kenko F8 Instruction Manual

This is a telephoto lens for a single-lens reflex

camera or interchangeable lens mirrorless digital

camera, adopting reflective optics to achieve a long

focal length within a compact body.

Instruction Manual

3-9-19 Nishi-Ochiai, Shinjuku-ku, Tokyo 161-8570

http://www.kenkoglobal.com

1. Name of Each Part

[Fig. 1 Lens with T-Mount Removed]

[Fig. 1]

10 12 15 20 30 50 100 ftMACRO

3 3.5 4 5 6 8 10 15 30 m1:3.5 1:4 1:4.5

10 12 15 20 30 50 100 ftMACRO

3 3.5 4 5 6 8 10 15 30 m1:3.5 1:4 1:4.5

② ③ ⑤①

④

⑦

⑥

⑧

(Inside)

⑨

＊ The shape of the T-mount varies among the different camera brands.

① Focus ring

② Distance scale (in feet)

③

Distance scale (in meters)

④

Macro magnification scale

⑤

Distance scale indicator mark

⑥

T-mount adapter (Sold separately)

⑦

T-mount attachment thread

⑧

Filter attachment thread (Inside of rear)

⑨

Filter attachment thread (Front)

2. Attaching the Lens to the Camera

Align the indicator marks on the T-mount and the camera,

and then turn the lens until you hear a “click.”

(For attachment and removal, refer to “Attaching the Lens”

and “Removing the Lens” in your camera's manual.)

Check the attached lens for any looseness.

CameraT-mount

10 12 15 20 30 50 100 ftMACRO

3 3.5 4 5 6 8 10 15 30 m1:3.5 1:4 1:4.5

3. T-Mount

⑨ Outer screw

(three locations)

⑩ Outer ring

⑪ Inner ring

You must adjust the position of the T-mount to adjust the

position of the lens. Remove the T-mount to attach rear

filters to the lens.

Use the following procedure to adjust the position of the

T-mount or remove the T-mount:

Turn the lens until the distance scale indicator comes to the
top center, and then securely tighten the outer screws ⑨
(three locations) as shown in Fig. 2.

Slightly loosen the outer screws ⑨ (three locations) as
shown in Fig. 2.

＊ Do not loosen the screws too much, because it may cause

the inner ring of the T-mount (⑪ in Fig. 2) to come off.

＊ Use a commercially available precision screwdriver to

loosen the screws.

2

1

Remove the T-mount from the lens by turning the T-mount
counterclockwise while holding the lens with the other hand.

Slightly loosen the outer screws ⑨ (three locations) as
shown in Fig. 2.

＊ Do not loosen the screws too much, because it may cause

the inner ring of the T-mount (⑪ in Fig. 2) to come off.

＊ Use a commercially available precision screwdriver to

loosen the screws.

2

Take the lens off the camera first.

3

1

Note: I f the o uter
screws ⑨are loos­ened too much, the
inne r rin g ⑪ may
come off.

If the distance scale indicator mark

(

⑤

in Fig. 1)
doesn't align at the top center of the lens when it is
attached to the camera, make an adjustment with the
following procedure:

Use the following procedure to remove the T-mount
from the lens:

[Fig. 2]

⑨

⑨⑨

⑩

⑪

＊ The shape of the T-mount varies among

the different camera brands.

Some cameras must b e set up to be to us e a manual lens
prior to l ens attach ment. Set up your ca mera by ref erring
to t he info rmat ion pro vide d be low. For det ails , refer to
your camera's manual.

4. Setting Up the Camera

As a g eneral guid e, the shutt er speed sh ould be in a range of
1/500 to 1/10 00 on a fine day when t he ISO sensitivity is s et to

400. If you're using a digital single-lens reflex camera, take your
photos while checking each image on the LCD monitor:

●

The image is too dark: Lower the shutter speed.

●

The image is too bright: Raise the shutter speed.

Tip

The lens can be used in the “Av (aperture priority)” mode and “M
(manual)” mode.

■

How to use the “Av (aperture priority)” mode

1. Set the exposure mode to “Av.”

2. Correct the exposure compensation if necessary.

If this lens is used with a Canon E OS series camera, the following
operations may be requi red on some models du e to the mecha­nism of the camera:

• When the lens is attached, the aperture is displayed as “00.”:

No action is needed in this regard.

• A value (e.g., F5 or 6) is displayed as an aperture wh en the lens

is attached:
Open up the aperture (adjust it to the smallest value).

●

Canon EOS Series

＊ Thi s len s can 't b e use d wi th the E OS-7 00, 7 50 an d 85 0

because those cameras h ave no aperture priority mode (Av) or
manual mode (M).

＊ If a conversion len s or an extension tube (ring) is a ttached, the

camera won't o perate normally. Do not c ombine this lens with
the above items.

＊ The Focus Aid can't be used.
＊ The aperture can't be adjusted in the aperture priority mode.
＊ The aperture value isn't displayed under “Exif.”

Set the sho oting mode to “M (man ual).” On th e α77 and certain
ot her mod els, the non -len s re leas e lo ck f unct ion must be
canceled.
Menu 󲰛 Setu p Menu 󲰛 Change the s etting for [ Release with out
Lens] to [Permit].

＊ The aperture can't be adjusted in the aperture priority mode.
＊ The aperture value isn't displayed under “Exif.”

●

Sony α

The “M (manua l)” mo de and “Av ( apertu re p riorit y)” sh ooting
mode can be used.

When us ing the built -in hand-shake correction fu nction, set t he
“Lens Focal Length” on the “Focal Length Entry” screen.

＊ The aperture can't be adjusted in the aperture priority mode.
＊ The aperture value isn't displayed under “Exif.”

●

Pentax

The suppo rted exp osure mo des are l imited d epending on the
camera model.
Refer to “Lis t of Supp orted No n-CPU Le nses” or other si milar
sections in your camera's manual.

To use this lens with any cam era listed above, set the sho oting
mode to “M ( manual) .” The s hutter won't re lease in any ot her
mode.
＊ The shutter spe ed must be adjusted dep ending on the condi-

tion in which photographs are taken.

＊ Set the focus mode to “MF.”
＊ The aperture can't be adjusted in the aperture priority mode.
＊ The aperture value isn't displayed under “Exif.”

●

Nikon

D100, D50, D70, D70S, D40, D40X, D60, D80, D90,
D5000, D3000, D3100

The non-lens release lock function must be canceled.
Menu 󲰛 Setu p Menu 󲰛 Change the s etting for [ Release with out
Lens] to [Permit].
Any shoo ting m ode c an be used , exce pt fo r tho se in which
priorit y is given to the shutter s peed. It isn' t recommended that
priority be given to the shutter speed (shutter priority mode).
＊ In the program mode, aperture pri ority mode or manual mode,

set the ISO sensitivity to AUTO.
Menu 󲰛 Brightness/Color 󲰛 ISO Sensitivity 󲰛 Set to [AUTO].

＊ The aperture can't be adjusted in the aperture priority mode.
＊ The aperture value isn't displayed under “Exif.”

●

Sony NEX (E-mount)

Any sh ooting mode can be used, except for th ose in which the
shut ter sp eed is given prior ity (s hutt er pri ority mode). It isn 't
recommended that priority be given to the shutter speed.

＊ Whe n usin g the progra m mode , ap erture prior ity mo de or

manual mode, set the ISO sensitivity to AUTO.
Setup Menu 󲰛 Exposure /Ligh t Measure ment/ISO 󲰛 Set t o
[AUTO].

＊ The aperture can't be adjusted in the aperture priority mode.
＊ The aperture value isn't displayed under “Exif.”

●

Olympus Micro Four-Thirds

The non-lens release function must be set to [ON].
Setup Menu 󲰛 Release without Lens 󲰛 Set to [ON].
Any shooti ng mode can be used, ex cept for those givin g priority
to the shutter speed (shutter prior ity mode). It isn't recommended
that priority be given to the shutter speed.

＊ Whe n usin g the progra m mode , ap erture prior ity mo de or

manual mode, set the ISO sensitivity to AUTO.
Setup Menu 󲰛 ISO Sensitivity 󲰛 Set to [AUTO].

＊ The aperture can't be adjusted in the aperture priority mode.
＊ The aperture value isn't displayed under “Exif.”

●

Panasonic Micro Four-Thirds

Brightness

Lens construction

Minimum focus distance

Macro magnification factor

Filter diameter
(diameter of filter at rear of lens)

Maximum diameter

Overall length (excluding T-mount)

Weight (excluding T-mount)

F8 (fixed)

2 groups, 6 lenses

1.15 m

1:2.5

67 mm

＊

(30.5 mm)

φ74 mm

82mm

340 g

5. Performance Table

＊ Before attaching a filter to the front of the lens, be sure the filter

won't contact the reflective part (black circle) at the center of the front
surface of the lens.

Specifications and exterior views are subject to change without notice for
the purpose of product improvement.

• This lens is small and light, but it's still a telephoto lens with a
long focal length.

Generally, telephoto lenses are associated with a small angle of

view and higher probability of the images becoming blurry due
to m ag ni fi ca ti on s of ever y mo ve me nt of the l en s kn ow a s

“camera shake”. It's recommended that you set your camera to
high sensitivity and a high shutter speed, or use a stable tripod
or monopod.

●

Preventing Blurry Images

6. Taking Photographs

You can prevent blurry images by using a cable release or self­timer function.
In this cas e, b e su re t o use a stable, stu rd y tr ip od . If your
cam era ha s a mirro r-up fu nction, use th e functi on to further
reduce the possibility of blurring.

Tip

• Whe n a te le p ho t o l en s i s u sed , t he mag ni f ic a ti o n fac tor
increases and therefore d ust , water vapor and ot her ma tter
suspend ed in the air will a ffec t the imag e quality. To capture
sharp images, ideally photograph s sh ould be taken on a fine
day with minimum wind following several consecutive fine days,
in a l oc a tio n n o t s ub j ect to ex h aus t g ase s , s mok e f ro m
chimneys, etc.

●

Photographing Conditions with a Telephoto Lens

It is difficult to capture sharp images in mountains and coastal
areas during the summer, because the air contains a consider ­able amount of gas and water vapor. However, your photogra­phy can be more enjo yable if you'll take adva ntage of unfavor­able conditions to create works of your own, such as capturing
the sea through vibrating air or shooting the ridgelines of moun­tains veiled in haze.

Tip

• This l ens isn't linked to the auto focus functio n, so the focus
must b e a djusted man ual ly. To b rin g the subje ct into focus,
simply turn the focus ring.

• With a telephoto lens, the depth of field (the range in which the
sub jec t can be brought in to focus ) become s shallo w (= the
focus range is small), so it's difficult to adjust the focus.

Use a stable tripod or monopod to adjust the focus carefully.

●

Adjusting the Focus

General ly, a super-te lephoto le ns with a range o f 3 00 mm or
more will hav e so me a llow ance in the position of the infinitely
symb ol

∞

. Th is i s because t he refra ctiv e index of ligh t in air
changes as the temperature in the mirror cylinder changes, and
the focus position may shift slightly as a result. Accordingly, be
sure to adjust the focus carefully by checking the image on the
finder screen, even when capturing a distant view, starry sky or
other very distant subject.

Tip

If you're using a digital camera with a live view feature, you can
use the zoom-in function to fine-tune the focus.

Tip

• This le ns emp loys refl ect ive optics, so th e a per ture i s f ixe d.
Accordingly, the amount of light must be adjusted by changing
the shutter speed. (If you're using a digital camera, you can do
this by c hanging the ISO s ensitivity.) However, a slow shut ter
speed tends to cause blurry images, so it's recommended that
you set your camera to high sensitivity and use a high-sensitivity
film (ISO400 or better).

• Auto exposure is possible on nearly any camera that offers an
AE function with aperture priority (except for certain Nikon and
Sony mode ls)(the program AE and shutter priority AE are not
possible). Set the camera without lens to the aperture priority
AE mode, and then try taking photographs in a bright area and
a dark area. If you notice that the shutter speed differs from one
condition to the next, auto exposure is enabled.

●

Adjusting the Exposure

This lens has no electrical contacts, so signals aren't exchanged
ele ct ri cally b et ween th e camer a an d len s. A ccord in gly, the
camera’s finder display or LCD scre en m ay n ot come on, but
this doesn't affect the camera or lens function. (It's the same as
tak ing p ho togra phs w ith a n ast ronom ical teles cope or fi el d
scope attached to the camera.)

Tip

Attaching the lens

❶

Attach the T-mount to the lens and then set the lens on the
T-mount to the camera.

❷

Provide a T-mount appropriate for your camera.

[Refer to 3, “T-Mount.”]

＊ Multiple types of mounts may be available depending on the camera

brand. For details, contact the camera manufacturer. (Four-Thirds, Micro

Four-Thirds, etc.)

❶

The T-mount isn't attached to
the lens.

❷

The T-mount doesn't match the
mount on your camera.

The lens can't be attached to
the camera.

❶

Securely tighten the outer screws using a commercially
available precision screwdriver.

[Refer to 3, “T-Mount.”]

❶

The outer screws (three
locations) on the T-mount are
loose.

The mount rattles.

❶

Loosen the outer screws on the T-mount and turn the lens until
the distance scale indicator mark comes to the top center, and
then tighten the outer screws on the T-mount.

[Refer to 3, “T-Mount.”]

❶

The lens and T-mount aren't
adjusted to proper positions.

The distance scale indicator
mark doesn't come to the top
center.

❶

The T-mount has a double-structure. Once the outer screws
(three locations) on the T-mount are loosened and removed,
place the outer ring on the T-mount again and tighten the outer
screws on the T-mount, and then remove the T-mount from the
lens.

[Refer to 3, “T-Mount.”]

❶

The inner ring of the T-mount
remains on the lens.

Other mount can't be
attached.

7. Troubleshooting

Condition Remedial action

Taking photographs

❶, ❷

Set the necessary items beforehand by referring to 4,

“Setting Up the Camera,” and your camera's manual.

❸

Set the camera’s focus mode to “MF” (manual focus).

❶

The shooting mode doesn't
support the attached lens.

❷

The camera isn't set correctly,
or the camera is set to disable
the shutter release when a lens
without electrical contacts is
used.

❸

The camera’s focus mode is
set to “AF” (auto focus). In the
AF mode the camera may not
be able to detect the focus
position of this lens, in which
case the shutter doesn't
release.

The shutter doesn't release.

❶

Neither the camera nor the lens function is affected.

❶

This lens has no electrical
contacts, so it doesn't send or
receive electrical signals
to/from the camera.

The camera’s finder display or
LCD screen doesn't come on.

❶

Turn the focus ring and manually adjust the focus.

[Refer to 6, “Taking Photographs.”]

❶

This lens is a manual focus
lens.

Auto focus doesn't work.

❶

Firmly secure the camera when taking photographs.

＊ The use of a tripod or monopod is recommended.

❷

Increase the distance from the subject.

❸

Take photographs in a place having less airborne dust, water
vapor, exhaust gases, etc.

❹

Wipe clean the lens using a soft cloth.

[Refer to 6, “Taking Photographs.”]

❶

The hand shakes when
photographs are taken.

❷

The distance to the subject is
too close.

❸

Effects of dust and water vapor
in the air.

❹

The lens is dirty.

Images become blurry.

❶

Adjust the exposure by changing the shutter speed.

[Refer to 6, “Taking Photographs.”]

❶

This lens has a fixed aperture.

The aperture can't be
adjusted.

This lens is a mono-focal lens.The camera doesn't zoom in.

Condition Remedial action

Cause

Other

❶

Check your camera for the type of mount, and consult the
dealer/retail shop where you purchased your lens.

❶

You can attach various
T-mounts sold separately.

I want to use my lens with a
camera of a different type of
mount (a camera from a
different manufacturer).

❶

When attaching a filter in front of the lens, first confirm that the
filter won't contact the center of the front surface of the lens.

❶

[Refer to 1, “Name of Each
Part.”]

A filter can be attached to the

filter attachment thread ⑧ or ⑨
as shown in the Fig. 1.

I want to attach a filter.

❶

Do not remove the black object. It's okay to take a photograph
as is.

❶

This is the part of the lens
structure that is used to reflect
images.

What appears to be a black
cap at the center of the object
lens (lens on the subject side)
doesn't come off.

❶

On cameras with aperture priority mode, this problem can be
compensated to some extent by correcting the exposure. On
models that only have the “M (manual)” mode, the lens is linked
neither to the AE function nor to the exposure meter in the
camera.

When using such a camera, refer to the instruction manual for

information on the appropriate shutter speed.

❶

The exposure is significantly
off.

Photographs are all white or
all black.

Condition Remedial actionCause

Cause