Letus 35 mini User manual

A Word of Welcome
Thank you and congratulations on your purchase of the Letus35 Mini! This
manual covers the basic installation and operation of your 35mm adapter
along with additional information on Troubleshooting and Technical Support.
35mm Lens
(user provided)
Front
Tube
Condenser
Lens
Prism
Casing
Interchangeable
Lens Mount
Ground Glass (GG)
& GG Holder
Achromat
Lens
Interchangeble
Connection Ring
Getting to Know the Letus35 Mini
Below is an image of the dierent components of the Letus35 Mini for refer-
ence throughout this user guide.

Letus35 Mini User Guide 1
TABLE OF CONTENTS
Understanding The Letus35 MiniI. ................. 2
Package ContentsA. ................................... 2
Optional AccessoriesB. ................................ 2
Main FeaturesC. ....................................... 2
Installation and SetupII. .......................... 3
UnpackingD. .......................................... 3
Connecting The Letus35 Mini To The CameraE. . . . . . . . . . . 3
Aligning The AdapterF. ................................ 3
Focusing The Camera Lens To The Ground GlassG. ....... 4
Attaching The Lens Mount And LensH. .................. 4
Powering Up The Letus35 MiniI. ........................ 5
Happy ShootingJ. ..................................... 5
Changing The Lens MountsIII. ..................... 5
Measuring FocusIV. .............................. 6
Adjusting Back FocusV. .......................... 6
Testing The Focus:K. ................................... 6
Adjusting The FocusL. ................................. 6
Cleaning The SystemVI. ........................... 8
Trouble Shooting And Technical SupportVII. ......10
WarrantyVIII. ...................................10
NotesIX. ........................................12

Letus35 Mini User Guide 2
Understanding The Letus35 MiniI.
This section provides information about the Letus35 Mini, package contents,
optional accessories and its main features.
Package Contents:A.
Letus35 Mini 35mm DOF Adapter»
Lens caps for the Mini (one for each side of»
the adapter)
Lens mount (which you specied with your»
order)
Your choice of a connection ring (37mm or»
43mm).
Allen wrench»
Optional Accessories:B.
Support Bracket»
Rod Support System (this system includes the support bracket)»
Rod Extensions»
Custom case»
Additional lens mounts for dierent types of lenses. We oer:»
Canon FD Mount»
M42 Screw Mount»
Nikon Locking Mount»
Canon EF/EOS Locking Mount»
Minolta MD Locking Mount»
Zeiss Contax (C/Y) Mount»
Leica-R Mount»
Pentax-K Mount»
Olympus OM Mount»
PL Mount»
OCT19 Mount»
For the current list of accessories, please visit our website:»
www.letus35.com
Main Features:C.
A half (1/2) Stop of Light Loss»
IOC Prism System to correct the image so it is right side up»
Virtually Quiet: The Vibrating Ground Glass emits nearly no operational»
noise.
Highest Optical Grade Achromatic lens custom-made for the Letus35»
Mini 35mm DOF Adapter.

Letus35 Mini User Guide 3
Custom Condenser specially tailored for the Letus35 Mini 35mm DOF»
Adapter optimizing Image Quality.
New and improved Ground Glass Design: Beautiful Film-Like Bokeh, ac-»
curate color reproduction, absolutely no vignetting and the best Edge-
to-Edge Sharpness in the industry.
A sleek On/O indicator with LED.»
Easy alignment»
Fully Enclosed batteries secured by tough magnets for ease of replace-»
ment in the eld.
Extreme Durability, Professional Look: Casing milled from Solid Alumi-»
num and nished in black.
Installation and SetupII.
Unpacking:A.
Remove the aluminum rear cap.1.
Remove the plastic front cap.2.
Connecting The Letus35 Mini To The Camera:B.
Using the Allen Wrench Tool included with1.
your package, loosen the three (3) screws
located on the Back of the Letus35 Mini
35mm DOF Adapter and carefully remove
the Camera Connection Ring.
Hand tighten the connection ring onto the2.
camera lter thread (Caution: Do NOT over
tighten the ring to the camera threads as
doing so may cause damage to your cam-
eras threads).
Aligning The Adapter:C.
Turn on your camera and zoom all the way1.
out.
Fit the adapter into the ring and look at2.
the LCD screen.
Align the adapter until you have all edges3.
of the Ground Glass (GG) parallel with the
edges of the LCD screen (you may want to
zoom in until the edges of the GG are close
to the edges of the LCD screen for better
alignment).

Letus35 Mini User Guide 4
Tighten the 3 allen head screws around4.
the thread ring once you are happy with
the alignment of the image on the LCD.
Zoom in until the edges of the Ground5.
Glass (GG) disappear and there are no
signs of vignetting (dark corners or sides).
This will be your outmost zoom level. From
your outmost zoom level you may zoom in
further to achieve a dierent Field of View
(FOV).
Focusing The Camera Lens To The Ground Glass:D.
Point the adapter (Without a Lens attached) toward a well illuminated1.
surface (white wall, sheet of paper) and by using your Camera’s IRIS AD-
JUSMENT or DIAL until the Ground Glass
(GG) Grain Pattern appears. Then, use your
Camera’s FOCUS ADJUSTMENT or DIAL to
focus on the grain until the pattern is dis-
tinct. You may also use the AUTO FOCUS
function of your camera to focus on the
Ground Glass (GG) Grain Pattern. Once the
Grain is in focus, switch your camera back
to MANUAL FOCUS. Your Ground Glass
(GG) is now in Focus.
Once you get your camera focused on the2.
GG properly, lock this focus setting down
(depending on your camera, you may
need to use tape to lock the focus ring in
place). You may want to write this number
down for future reference.
Note: For each Field Of View (FOV) chosen3.
you may need to set your Camera’s Focus once more. It may be desirable
to keep a log of ZOOM and FOCUS settings for each camera being used.
Attaching The Lens Mount And Lens:E.
Using the Allen Wrench Tool included with1.
your package, loosen the three (3) screws
located at the very front of your Letus35
Mini 35mm DOF Adapter.

Letus35 Mini User Guide 5
Insert the lens mount into the front tube2.
of the unit. Make sure to seat the mount
ush against the tube.
Tighten the three (3) set screws to rmly3.
lock the Lens Mount in place.
Now, attach the appropriate Lens to your4.
Lens Mount.
Powering Up The Letus35 Mini:F.
Open the battery cover located on the side1.
of your Letus35 Mini 35mm DOF Adapter.
Insert 2 New AA Batteries.2.
Replace the Battery Cover.3.
Turn on the Letus35 Mini 35mm DOF4.
Adapter by pressing the red LED button
on the back. When in operating mode, the
LED will glow Red.
Happy Shooting:G.
You may want to readjust white balance for»
your camera according to taste. Do so by
following normal operations for your cam-
era to manually white balance.
Happy Shooting!»
Changing The Lens Mounts:III.
The Letus35 Mini 35mm DOF adapter will allow you
to use dierent lens types for your project. Each
lens type will require a unique lens mount. Here
are the steps to swap in/out the lens mounts:
Using the Allen Wrench tool included with1.
your package, loosen the three (3) screws
located at the very front of your Letus35
Mini 35mm DOF Adapter.
Remove the current lens mount.2.
Insert the optional lens mount into the3.
front tube of the unit. Make sure to seat
the mount ush against the tube.

Letus35 Mini User Guide 6
Tighten the three (3) set screws to rmly lock the Lens Mount in place.4.
Measuring Focus:IV.
The Film Plane for the Letus35 Mini 35mm DOF
Adapter is 28.2mm from the front of the tube to-
ward the main body. If you have the optional sup-
port bracket, the back of this bracket is the Film
Plane; attach your tape measure to this section on
the adapter.
Adjusting Back Focus:V.
The back focus is set at the factory, so it should not need adjusting. In the event
that back focus for your Letus35 Mini 35mm DOF Adapter needs to be adjusted,
refer to this section. Generally, if your lens achieves Innity Focus, your shoot-
ing situations will not be aected. Some operators may also want to further ad-
just for accurate barrel markings on Still Camera Lenses. Follow these steps:
Testing The Focus:A.
Setup your camera with the Letus35 Mini 35mm DOF Adapter using1.
the preceding instructions, and attach a 50mm lens. (Any lens will do,
we’ve used a 50mm Lens because it is the easiest to use and widely
available amongst users).
Place a Siemens Star (available in the inside back cover of this manual)2.
in front of the lens at a predetermined distance. For this example we
will use a four (4) foot distance from Film Plane to the Siemens Star. To
determine the distance of the star you will need to measure from the
Film Plane to the star. (See: IV. Measuring Focus).
Using the lens, focus on the Siemens Star. The focal markings should3.
correspond to your focal distance appropriately. Example: At four (4)
feet the Siemens Star should be the focus point of your image or in
focus. If it is not, you may need to adjust back focus.
Adjusting The Focus:B.
There are two (2) cases where you may want to adjust the back focus:
Case 1: If your lens can achieve innity focus at less than the innity marking,
subsequently, the barrel markings are slightly o. This is how to x it:
Gently loosen the three (3) set screws holding the lens mount.1.

Letus35 Mini User Guide 7
Remove the lens mount and lens from the tube.2.
Located on the back of the lens mount3.
are three (3) small screws. Carefully, one
at a time, loosen each one a small amount.
Each screw should be loosened an even
amount. About 0.2mm may do.
Re-insert the lens mount and attached4.
lens into the tube.
Tighten the three (3) set screws.5.
Re-peat the6. Testing The Focus step,
checking your focal marks for accuracy.
If yes, you are done. If not, repeat this step until back focus is correct-7.
ed.
Case 2: If you cannot achieve innity focus at all, follow this method:
Remove the four (4) Allen Screws holding1.
the front tube to the body of the adapter
VERY carefully and VERY gently remove the2.
tube from the adapter. At this point you
should see the Ground Glass (GG) which is
mounted on three (3) Aluminum Posts.
VERY gently, and evenly, pull the three (3)3.
Aluminum Posts outward away from the
Body about 0.2mm one at a time.
Replace the front tube.4.
Repeat the5. Testing The Focus step.
If you do get innity focus, then see if the6.
other markings are correct. If the markings
are also correct, you are done. If you can
get innity focus but the marking is not
correct, go to the steps in Case 1 to x it.
If you are still unable to achieve Innity7.
Focus repeat these steps. Once you are
able to achieve Innity Focus, next, repeat
1. Checking The Focus for accuracy of your
lens Focal Marks. If the lens Focal Marks
are inaccurate, follow Case 1 adjustment
steps.
NOTES: Be VERY careful pulling the Ground Glass (GG) posts away from the
adapter body. Avoid touching the Ground Glass (GG) with bare ngers as it will
transfer oils to the Film Plane and may cause unwanted eects in your image.

Letus35 Mini User Guide 8
If, by accident, you happen to pull one of the posts
from its socket DO NOT PANIC! Remove the Rub-
ber Boot from the post VERY carefully, then, with
a toothpick or the allen wrench you received with
your adapter, gently tuck the Rubber Boot back
into the mounting hole. Then, carefully re-insert
the Aluminum Post into the rubber boot. DO NOT
attempt to force the Aluminum Post with Rubber
Boot attached into the mounting hole for risk of
damaging the boot and Ground Glass (GG) mount-
ing system. Take your time and be very careful.
Cleaning The System:VI.
We try our best to ship each unit free of dust in the
Optical Path. However, the Magic of Dust Particles
is always surprising. In which case you may need
to clean the optical path, refer to the steps listed
below: NOTE: If the dust moves when the unit is
operating it will more than likely be located on the
Ground Glass (GG) and you will only need to per-
form steps 1 – 3.
Open the front tube of the Letus35 Mini1.
35mm DOF Adapter by removing the four
(4) screws and VERY carefully remove the
tube. You will see the Ground Glass (GG).
Clean the ground glass if you nd the dust2.
there. Only go on to next step if the speck
is stationary when the ground glass is ro-
tating, if it is clean, put the tube back on. If
not, continue to step 3.
Clean the top surface of the condenser3.
(the glass right below the ground glass). If
the speck goes away, you are done clean-
ing, put the tube back on. If not, continue
to step 4.
Through the 2 holes on the ground glass4.
holder, unscrew the 2 Allen screws hold-
ing the enclosure cap to the body of the
adapter. Use a at object to pry o the en-
closure cap from the body of the adapter.
Clean the other side of the condenser.5.