Cause of Broken Zoom

———————— (Photo above, Right — Note a clack in the white nylon gear )

Yet again, this is about the same broken Sigma Zoom Lens.

While examining the mechanism, electronics, I’ve been puzzling why

this lens was not working.   It seems everything are functioning. —– ? ? ?

—– Then I noticed, when the AF motor was connected to the battery

and rotating, focus mechanism only moves a little.  In both direction,

gears rotates only short time even though the motor was kept running.  

—– On the end, I discovered,  a gear connected to the motor has a clack, 

so, it’s loose from the shaft and slipping.

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In theory, it is easy to replace the gear like this, which is not expensive.  

BUT in practice, in order to access this part of the mechanism, the whole

lens has to be disassembled. —– Considering the time and the expertise,

just  change a small gear which cost (to the Sigma) may not be more than 50P,

still the service charge would be more than £100.  

= good second-hand would be even cheaper. 

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In my life, I rarely paid a service charge to the camera company.

 1) I don’t brake a camera.   2) If it started malfunctioning, I repair myself.  

3) If it was beyond repair, I disassemble and use it for experiment. (and have a fun !)  

4) Being as a technical writer, the service engineers are my good friend and to keep

cosy relation, camera company wouldn’t charge us.  (often, broken camera is a bad

news which the company want to keep it  in secret.  

And our feed-back is indispensable for them. )

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In principal, the Gear shouldn’t break, still, as I saw the broken gear like this

only  the second time, it is rare occurrence.  = it should be OK

= and if it happened on you,  you are extremely unlucky.  

Have a pint or two and blame the God.  🙂

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F-Aperture / Iris Control (2)

This is the up-date of the post with the same title before.

The temporally test circuit of the Iris control then has been made to

a proper board.  Still, where to put the battery hasn’t yet fixed.

(At moment the power was connected through the cables.)

To make the drive circuit of Iris control was rather simple (= Just put the

necessary components on a piece of strip board.) though, where to put the

Open-Close Switches gave me a headache.  —– Ideally, it should be inside of the

Camera or make the Camera’s shutter button function for the trigger of this Iris

control too.  (Asking too much !)    Or, alternatively, put the Iris Close Button

right next of the shutter button and press both of them in the same time.

—– On the end, I decided to use the Camera’s remote trigger switch.  

Remote trigger switch is double switch.    First half press activates the

auto-focus then deeper press trigger the shutter.  Though, to the hand made

macro lens, auto-focus switch is no use.   I decided to use this switch to close

the Iris, and put a change-over switch to select  either Focus or Iris close.

(The button to Open the Iris was put the back of Remote trigger.)

In this setting, Focus and Framing can be done while Iris was fully open,

then the press of button, first close the Iris then expose the picture.  

With a use of  TTL Flash-light, almost automatically a photo was made !

—–  a short coming was, as the trigger was made by Remote Switch in the

left hand, camera was held almost right hand only. = a bit heavy.  😦  

Still, the Camera in the free-hand, then just click the shutter and enable

to take picture is a great convenience.  🙂  🙂

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F-Aperture / Iris Control

As I wrote in the previous posts, I have recycled rear element of the

broken Zoom lenses to use for the macro photography.  Both of them were

Canon EF type lens which has an electronically controlled Diaphragm / Iris.

Electronic Iris has an advantage, they  only needs electronic connection,

not a rigid mechanical connection though, this electronics is not just a cable.

—– If the recycled lens was maintained

all the electronics as before, Iris could 

be controlled by the camera side. 

But when the lens was stripped down

to Iris and its Pulse motor,  it is

necessary to create a driving circuit 

for the motor. = And this Pulse motor

needs to have a specific alternating pulse.  

So that a Pulse generator and a Full-bridge

driver would be needed.

(If you would like to know about those pulse motor and its proper control,

please Google  >>> Bipolar stepper driver schematic )

Electronics is a funny phenomena.  It can be elaborated to have Hi-Tech

sophistication but in the same time it still works in a very primitive way.

= Such as the Electro-Magnetic device could be as sophisticated as HDD, still,

if you wind a wire around an iron nail and connect it to the battery, it would

work as an Electro-Magnet and pull the other iron pieces. 

To drive such pulse-motor, there are many IC chips in the market though

most of them are for higher voltage.  I needed to make it using discreet

components = as long as it generates alternating pulses, the Iris works.

(The original driving circuit has a PWM = Pulse-Width-Modulation for

smooth and quiet operation, but here better not ask too much)

The photo above is a circuit to open-close the Iris in the cannibalized

rear element from a Sigma Zoom lens.   (Can drive Canon’s  as well !)   

(Circuit was too simple, I didn’t even bothered to use Prototyping Beloboard

—– just soldered together. = as long as it works, good enough to test)

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From the test, I found the circuit was just enough = no frill, bare minimum.

(Ideally the F-Aperture value indicator may be needed though, in practice,

I may not need more than “Fully open for focus — close down for shooting”

= I decided to put only  two switches, open and close. ~ ~ ~ When the building

work progressed, I’ll show the new photos.  🙂

———————————-

PS:   WP noticed me, this is not only my 602nd Post but this is also the

Anniversary of 5 years  on blogging. —– gosh.  😀

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Junk still a Macro Lens

This is yet another version of the post  “How to recycle / reuse a junk”  

So, you may visit the old posts,  Here and There.  🙂

The Lens here is the same Sigma Zoom lens I’ve used its front element

to make “Wide angle Pinhole” and I’m using its rear element here.

To utilize the rear element though,

I needed to disassemble whole

zooming mechanism to take it out

from the outer barrel.  But instead

to have a trouble to completely

disassemble it, I gave rather rough 

treatment to break a lens barrel.  

(To deal with even Precise Optical

instrument, some time, we need to

use quite a brutal force as well. 😀 )

So, I kept some zooming mechanism to use as a focus adjustment.

The core of the rear optics in the zooming barrel was mounted to

a  M42 to 49 mm thread = Pentax Reverse Adapter.  And mounted to

a Bellows, then to a Canon DSLR body.  = In this configuration, the

lens can give  x5 magnification in the view finder.

Obviously, this massive, awkward set-up is not suits to a field work

—– and anyhow, the subject would be pretty small, it is better to use

on the copy-stand.

This is a test shot on a tablet screen with F-Aperture / Iris fully open.

= This evenness of the quality is not too bad.  

—– In early 70s, Sigma Produced a lens called “Micro-Macro 100mm F4”.

To see the lens, I visited their “Company” in Komae near the edge of the Tokyo.  

It was turned out to be a wooden shack having many lens polishing machine

working on the floor = lots of mess with those lens polishing dark paste.

Sigma seemed to have a knack to correct the aberration in the close range and

the said lens was extremely sharp but also having extremely high contrast

almost like an industrial pattern projection lens.  (So, I didn’t buy.)   

This Butterfly wing became a standard test pattern.  🙂

(This image was clopped to a half = effectively x10 magnification here.)

It seems this lens was the sharpest lens I have in the  x5~x10  range so far.

The advantage is, since their diaphragm / Iris was electronically operated,

once I made a controller, it would be very convenient to use.  

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Good Lens or Cheap Lens

Some regular reader may remember, this lens has appeared here before.

But if you look inside, you may noticed that this one doesn’t have shiny

blue beer can.  = In deed, the front lens is the same though, the panel, and

the pinhole inside is different.  I did swap the panel to single pinhole hence,

it still has semi-fisheye wide angle view but the image doesn’t have a

hallasion created by the Double Density Pinhole.

The front lens came from an ubiquitous cheap Fish-eye Adapter, therefore,

giving fish-eye like distortion and wide-angle view, but being as low cost =

single lens structure showing the Chromatic Aberration.  = Part enlarged

bright-spot of Photo above, rainbow effect is quite visible.

Theory was the same = ” Place a strong concave lens before Pinhole would

creates [Wide angle Pinhole Image]” and this one has a concave lens from a

Canon Zoom Lens. = which is in deed the front element of the same lens I’ve

experimented with its rear element in the previous post.  

And I put the same Double-Density Pinhole panel behind of this lens.

This Canon’s Zoom was EFS type 18~55 mm hence, it was a kind of

medium wide-angle, so that even a front element concave lens was not too

strong = giving modest wide view.  (Though, still having quite a distortion.)

Yet still, the lens carrying the quality of the Canon = this front element

has an Achromatic design = no Chromatic aberration was visible. 

So that, thanks to this high quality Diopt-Pinhole Photo System, on a

full-frame 5D Mk-III camera, I can take high-quality Fuzzy image !

(I’m serious, believe me.   Ha ha ha  😀  😀  )

———————–

IN ADDITION:  This is the front element from a Sigma Zoom Lens.

Lens came from a friend of my friend who gave-up to repair the lens.

(The person managed to disassemble though, couldn’t put it back.)

It seems Sigma was used all sorts of clever tricks to produce the lens

“Reasonable”= not superb, still good enough, light and small, and

most importantly, not expensive for the people of this class.

The front lens seems to be plastic = easy to be scratched (Photo Left)

and the Photo Right shows funny reflection = this is an “Aspherical Lens “. 

You may have a fancy illusion toward the Aspherical Lens. = Yes, Aspherical

lens can give superb optical quality though, these days, it was used as a

magic bullet to save a cost !  (Instead to use many heavy and expensive

Grass, just one plastic Aspherical Lens could eliminates the aberration.)  

Because, Aspherical lens is no longer difficult to make nor expensive.

= Computer give the design and the laser curving can make a precise

die-cast, then the rest would be just a plastic mass-production work. 

As a rather ordinary  x3  Zoom, the strength of the front Concave lens is

similar to the Canon’s Zoom shown before.   The front element consists

two lenses hence it supposed to be an Achromatic design —– though

photo above shows the Chromatic Aberration. (See the rainbow color.)

(of cause, it might be corrected together with the rear element.)

And I put a single pinhole behind of this lens.

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Junk as a Macro lens

Camera lens is the optics = even if it was broken and ended-up in a bin,

lens can still function as an optics.  Convex lens can project an image.  

This lens was a Canon zoom lens which I got free from a camera shop.

Top left of the photo above, is the rear group of the Zoom lens which function 

as a convex lens to project the image.  Convex lens mean, it will work as a

magnifying lens and in reversed direction, it could be a good macro lens.

—– for a fun, I tested this lens unit to take macro photo.

(on the photo, you can see a L-shaped plastic bar on the lens-unit, there were

three of those which held the lens unit in the position though, such flimsy

plastic couldn’t survive a shock and easily broken but impossible to repair, it

was the end of the life ! — replace whole unit may cost half of the lens price.) 

For macro photo, lens unit was stacked on a mount adapter ring using sticky

plastic-pate, and it was mounted on

Canon 5D through 2 sets of Extension

tube. (total extension was 125mm) 

—– After few shots, I found the

sharpness wasn’t good enough,  

so that, I closed the Iris somewhere

half-way. (Photo left)  

This Aperture / Iris  has a

stepping motor built inside

= So, I’m going to make electronic circuit to drive it. 

And, this is how the photo was taken while using a small flash-light.

The photo wasn’t too bad —– considering the lens came from a bin.  😀

This lens unit act like a 38 mm lens, so that it can produce about  x5 macro

image on this extension.   The photo above was a clopped part-enlargement.

(effectively,  x10 magnification = 3.6 mm object was on the 36 mm frame)

Originally, this was a rear half of the good zoom lens. —– Think about, it

is a magnifying glass of £100 cost = it got to be high quality !

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Parts Box ?

To make, modify or repair something etc. what ever to do, it’s always need

to have all sorts of components or parts. —– strange urban myth was that

I’m a kind of professional, so, I have a professional class storage / drawer

box to sort the components.  And people are believing that I got a workshop.  

Wrong !   I’m a non of professional.  Therefore, I’m keeping the components in

the most unprofessional way.

= My storage box for the parts is “plastic Ice-cube tray” used in a fridge. = This is

the most compact and convenient way to keep the small parts in order.

(And cost virtually nothing.  🙂 )

Even just the screw, there are many different sizes, starting from  1mm~.  

About the same size but old  1/8″ doesn’t match to metric 3mm screw.  

So, they has to be kept separates, ETC, ETC !

Situation is far worse in the electronic front. —– if I got to store everything,

I need to have a space, size of a shop.  

So, I keep the items handy I most likely to use, in the Ice-cube Tray.   

I don’t remember when I got this and started to use. —– I might have

brought those from Japan = it’s mean, I’m using this, past  40 years !

For me, the matter is its function.  = as long as it fulfils my needs, that’s enough.  

And, even more crucial matter is  “What I do with those components”.

Parts are just a matterial.  Part wouldn’t creates anything. = Thousands tons of 

cement is not a building.   And the beautiful way to pile-up the cement neither

form a building. —– Building would be counted when it was elected.

So does the component here, when it became a part of a finished product,

it would be counted as a meaningful existence.  (but thousands end-up in a bin)

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Small Repair

In our daily life situation, when

something break down and need to

be repaired, in most of the case it is 

a loose screw or loose connection

kind of very simple fault.

In certain extent, it is true that the

everything break and lost = natural

were ant tear surely eat away its life

though, in the same time if we pay 

reasonable attention such as to give an oil or tighten the screws etc, the things

can last quite long time.  Like my Electric Kettle, it is more than 30 years old.  

In fact, there is little possibility of a Kettle to break down unless switch

it on without a water thence either whole Kettle melted down or burn-out the

heater element.   It’s mean, if we do “Always put only necessary amount of

fresh water and boil” = Kettle was designed to last for ever in this condition.

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But a kind of machine which has a motor inside, its vibration often cause a

break down.  The worst was the worn-out of the motor bearing (due to a rack

of care = dust,  and rack of oiling) otherwise,  a component became loose.

Photo on the top is a control board of a motor tool in which you can see an

exploded component called Triac.

The vibration caused a component to come loose and caused a short circuit.

The damaged parts was visible and the repair was simply to replace and fix them. 

The photo above is a control board of a back-up battery power supply.  

Right side in the left photo, you can see a yellowish box shaped component

was burnt and exploded.  From the shape and the size, it’s easy to see that it

was the same one in the left side, which said 100mF = It was a capacitor.

Remove the damaged one and test with equivalent component, if the whole

unit works (it’s mean no other component has been damaged), it’s the repair.

In this very case, the damaged capacitor was replaced by the equivalent

capacitor (in the photo right). —– But, if no obvious damage was seen, then

complicated trace and analysis game starts.  It’s mean, this  is not a small or 

simple repair. —– Some time it was called nightmare and often

it is cheaper to buy new one.  😀

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Too Early Magnolia

When I saw this Magnolia, I was even annoyed by it.

It is definitely wrong — gone too far.

Cherry can flower earlier but not this variety of magnolia.

Normally, this tree flowering after the Cherry — in May.

Without a reason, I have strange soft spot to ancient plants.

 Cycad, Tree-fern, Horsetail, Ginkgo, Yew, Monkey-puzzle, Magnolia, Lotus, etc.

For them to survive hundreds of millions of years,  they must

have a supreme wisdom printed in their gene ! —– I feel awe !

So, what’s wrong with she in this time ? ? ?

Those fuzzy images were taken by Wide-angle Pinhole on Canon 5D Mk-III.

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Moss

Wet but not too cold = who most enjoy this weather must be the Mosses.

And nobody would say otherwise.  So, no word here. 

(In fact, I do know them very little any way.  🙂 )

Three photos above were taken by Zeiss 85mm F1.4 with close-up lens.

Rest of photos were taken by Canon EF Macro 100mm F2.8 with Close-up lens.

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