Canon 40dcmos – with no Bayer-filter!

After long trials yesterday I managed to eliminate the complete Bayer-mask from a Canon 40d sensor. No scratches, no damage – just a beautiful golden mirror.

Next days I will have to mount it in a camera. Does anybody know, if the RAW files does contain the pixel images separately (so the native R G G B pixel information), and the softare does only the reconstruction of the RGB values of each pixel, or in the RAW there is the interpolated information already?

I have got this info:



Posted in General topics | 2 Comments

Canon 7d – ERR20 – again and again

This 7d has been repaired a few months ago with an ERR20 error code after each shooting. ERR20 could mean many different problems, here is he internal ode:

Interesting is, that, the internal error 215 is Mirror position problem, as possible case you find here the mirror OR the shutter phase switch.

I disassembled the mirror mechanism, the phase switch or brush was OK. I put some grease on the wheels, assembled – ERR20.

OK, let’s see the shutter,. On that unit they were no signs of any damage, but I ordered the ne shutter. Replaced – and ERR20 was over.

I made a few test shots, and gave back the camera to the owner.

After 2 months he called me: ERR20 again…

OK, I read out the error codes: ERR215

I disassembled the whole thing 3 times. Checked each socket and cable  – NOTHING. no corrosion, no damaged wires.

But: ERR20.

After a new disassembly of the  mirror mechanism, I observed, that the motor has –given by construction a relative big play, it is mounted on some rubber bumpers. When pushed in a certain direction, the gears were slightly blocked. Ouuups. I checked a disassembled 40d. That on has no bumpers, the motor is mounted on the plastic chassis.

The small “O”-rings are really very weak. So, I took some other screws, and I mounted the motor without any rubber rings (just the rubber base on motor side). Motor stands now rigid on the plastic base. To be safe, that the motor ill not get loose, I put some 2k glue on one side too (Poxipol)

Mounted it, checked: no error. 50 shoots: no error.

Wow, repaired!


And after this, i remembered, that in the past this happened me once. I checked on my blog …. Yes , it was exactly my own 7d – exactly the same failure, the same repair. (see below)

I think, this is a constructive given problem. Could happen by any other camera having the rubber dampers.

I should read more internet, before working a lot.


Canon 40d motor revival in the body of a 7d

This is a story about my own 7d, which has been flooded with water, before I have purchased it “as it is”, practically not working. I repaired it in a few hours -worked well after.
After a certain time stopped working, message was Exposure not possible, ERR20. Mirror moved up, but the curtain not. Other lots of hours of repair, disassembly-assembly. Normally I should change the shutter, but is really expensive. So i have rather bought the SPT software for the 7d.
I have read out the fault memory. And it was a problem regarding – the mirror motor position.!!!
Disassembled again – no sign of anything unusual.
Assembly – works. Second day in the morning – NOT working.
I resoldered MANY times a damaged cable socket, which was not so easy, as the former corrosion has damaged the contact surfaces.
Then I realized, that touching the motor, the camera works. Pushing it in another direction, the fault appeared immediately. Wow. The motor here is fixed to it’s frame only through 2 flexible points – 2 screws and two rubber collars. I disassembled a 99% similar motor from an old 40d – this has no flex joint, just two screws. No problem – I had no other solution anyway. So, i made both operations (out and in). And even after 3 days the camera is working perfect.
So, never give up!

7d h  7d-2h

Canon 7d – ERR20

After exposure, ERR20 – shooting is not possible message. This means some mechanical failure.

Official Canon advice:

“Err 20

Description: A malfunction with the mechanical mechanism has been detected.

Resolution: Turn the power off, then remove and re-install the battery. Then turn the power on again.”

Or say a prayer, whatever.

Reading out with SPT software:

2016-11-19_120133-err240_thumb  2016-11-19_120152-err216_thumb

This means, the mirror position sensor is not working. I disassembled the camera, and on the flex cable which comes from the sensor, I have found a tiny oxide dot (or what).

DPP_0001_thumb  DPP_0003_thumb  DPP_0004_thumb

I washed it away with normal water, then I treated it with some methanol, to take away the water.

And now it works, and no error code!


Posted in 7d, Canon camera | Leave a comment

AF problem? Adjust the zoom-brush!

A lot of used (and repaired) zoom lenses have autofocus problems, front focus or back focus. Case the lens has been disassembled before, the problem can be caused by the non-adjusted zoom-brush.

What does the zoom-brush have to do with auto-focus? The answer is in the working principle of the AF measuring of the DSLR-s.

Read the whole article – but for us at the moment is enough to know:

1. The autofocus is a secondary optical system – so, case the AF determines the correct focal position, the photo will be sharp ONLY if the primary optical system, the lens/CMOS  is correct adjusted to the AF system. This can be done in some cameras through the camera menu too (fine adjustment)

2. In the AF system we take two light-beams coming from the same point: one which goes through the right side of the front lens, and another one, which goes on the symmetrical opposite point (red and blue on the picture). Case the object is focalized, the two images will fall on the same point on the AF sensor. case out of focus, they will be physically separated. As more out of focus, as bigger the distance. This distance can be measured electronically by the AF chip..


Case you know this distance (the error), with simple geometry the camera can calculate the correct AF sensor/lens distance.

But for this, you will need one mode data: the focal distance of the used lens. This is no problem in case of a prime (fix focus) lens. But what about zoom lenses?

Yes, in this case the camera needs the momentary value of the zoom position.This i captured with a simple conductive flex cable with some lanes, connected through a metal brush. Normally this is a 5+1 lane flex, in this way you can make a 5 bit number (32 discrete values)  which gives the position of the zoom lens.

The cable must be clean, the brush must be aligned with the lanes – and HAS TO BE adjusted in position – to give the correct lens focal distance in any position.



Case the lens gives wrong focal distance value to the camera, the calculation will be wrong – the camera will give you the green dot in the viewfinder, as picture is in focus – but this will not be true!

How to adjust it?

There is a probably not very precise, but very simple method: use the external system strobe to display the zoom position. the method is good even to determine (without disassembly!!!) if the brush has contact problems).

  NewImage_800_451_90(18)   NewImage_800_451_90(17)

So mount the strobe, put on auto-zoom, and follow it’s display and the real lens position.

Case there is a difference, just readjust the brush.


Try it!

(the individual lens data are stored in the EEPROM of the lens, and they are also used to make the correct calculations.  This is the explanation, why you cannot change the electronic board from one lens to the other. But that is another story …)

Posted in 17-55 F2.8 IS, lens | 10 Comments

Nikon SB-24 flash repair

I have bought a Nikon SB-24 for a bargain price. I checked it, worked well.


…excepting the fact, that after 30 seconds the flash always went sleep.  From this mode was easy to wake up: just a short impulse on the middle pin in the hot shoe.

On the net you can find the repair manual

This flash has some settings in the inside: you can set the security voltage (the maximum after which it will shut off to protect the capacitor and the circuits)), the monitor voltage, which is that threshold, on which the ready light  goes on, and others, for example the light quantity for a Manual or an Auto flash.

On my flash the ready light on the back  was NEVER on – and for this flash is a normal behaviour, that case he can not observe the ready light (better to say, the capacitor can not reach a predefined voltage (ca. 330 Volts) after 30 seconds goes to sleep.

 So, be careful: a flash is not a joke. Works on 300-350 volts, can KILL YOU.

Before repairing it, always CHECK the capacitor, case it is charged, discharge it through  a small power 230 volt lamp, or a 1 kohm /5 W resistor.


This is the normal behaviour after 5-10 seconds



And this is mine, with NO ready light. The flash worked – but disconnected after 30 sec.


Case you open the body, begin with the bottom, then the red front cover. More is not necessary for this operation..

WP_20171005_22_21_07_Pro  WP_20171005_22_21_22_Pro

Under that cover you will find the measuring point of the capacitor voltage (deep under the plastic, so you will need a long multimeter probe), GND is on the front, in a 3 pin socket, under a cover, and the 5 different potentiometers. VR2 is the right one, if you watch it from the front (see the picture with the screwdriver).

Turn it clockwise (CW), and the monitor voltage limit is lower. Conterclockwise (CCW) – will be higher.

And worked. Imade a setting fo 320 volts. Lower,  than official (so will have a little bit less power) – but I will use it only as an auxliary flash with a radio remote control in Manual mode. 

2017-10-06_001644  2017-10-06_001748


For the whole description see the link

By the way: the hot shoe middle pin voltage is +4,50 volt, with the GND on the side pin of the hot shoe.

Posted in flash/strobe | 6 Comments

24-105 F4 IS – damaged stabilizer


A few weeks ago I repaired a used 24-105 for myself. I have purchased it in a box in thousand pieces for a bargain price. Everything was ok – excepting a strange noice from the stabilizer when switching on and off. Does it work – yes.  Does it have any fault symptoms – not.

Excepting the fact, that the photos were blurred.

When I checked it thoroughly, I observed, that stabilizer was working only within  a tiny moving field. The brake didn’t engaged the moving of the stabilizing lens element. Checking this is not too difficult, and IS A MUST AFTER ANY REPAIR. Watch through the lens and the camera to an object, and move the body (like small oscillations with the lens up and down, or left to right. Case the shutter is not pressed, the object will move in the field of view. Case the IS works (button halfway depressed), the image will not move in the viewfinder, better to say, only after making a bigger amplitude.


My one moved always, just after switching on the IS movement was a little bit less..

After disassembly of the lens: I have seen nothing. After disassembling of the IS unit, I had a feeling, that the small motor for the bake moves sticky.

  WP_20170409_11_31_30_Pro  WP_20170409_11_30_37_Pro

And watching through my favourite 20x stereo microscope, i have seen, that the small white gear has been damaged. One teeth is deformed. And that was enough to stop the brake ring.

Fortunately I had an another bad unit in a box (electronic failure). So I changed the electronic/cable on them.

WP_20170409_11_49_40_Pro  WP_20170409_11_41_56_Pro WP_20170409_11_45_16_Pro 

Is not too easy to get out the flex from this type of socket – I used some adhesive tape on the cables back, and I pulled then the tape, not the cable.

But be careful – the upper lens element has to be centrated after disassembly and assembly.


Just an another trick: the aperture flex cable always brakes in the same position.


At first, as I told in another post, cut the sharp edge of the last lens element to a round form.


Then put some textile-base adhesive tape on the flex cables back side.



Never forget to check on a repaired lens:

– the aperture on any zoom position
– the focusing on any zoom position
– the zooming
– the stabiliser switched off/on.

Posted in 24-105 F4 IS, EF lens, EF-S lens | 5 Comments

Dust blow gun – compressed air

I know, that there is possible to work with a hand-pump too – but trust me, the difference is HUGE. If You work with 2-3 bar, or special cases 5-6 bars, any solid contamination will be eliminated.

At first, You will need an oil-free compressor, if possible a silent one. After this, a filtering – there are cheep and expensive solutions. then a flexible hose, and of course a dust blow gun too. (Before I had a normal one – placed in the basement because of the 97 dB (!!!) noise.)

Here You see, what I use at the moment, this is as noisy as a washing machine:

HBM 25 kompresszor   kompresszor









Unfortunately the air gun is not a Swiss quality Mosolygó arc, so at first I had to disassemble and reassemble it.

Posted in dirty, dust, tools | 3 Comments

The PH00 screwdriver – the MOST impotant tool for us

Theoretically Canon uses a JIS standard screwdriver. I had bought one for a LOT of money, and… it was worst, that the PH00 screwdrivers. So – nevermore.

But which PH00 screwdriver, if you need one?


Kopiowanie i przetwarzanie bez pisemnej zgody firmy zabronione.

Kopiowanie i przetwarzanie bez pisemnej zgody firmy zabronione.

I can advice you this:  WIHA 00152  

Just to understand, in the last years I have tried a lot of different ones:
UNIOR – good price, small handle,
BETA – expensive, too harde, broken in a short time
some noname – nevermore
Neo-Tools – very good geometry, thick handle, but no possibility to by only the bit. The gibe 25 years of warranty 🙂 , and I changed back 2 times the bit after breaking it, which is a good sport, but too much time.

The WIHA has a good price – 5 EUR – and there is available in Conrad shops.

But for some special cases you will need a torque controlled screwdriver. Her is my newest tool – and it is WONDERFUL. You can adjust the max toque, when you reach that, will vibrate and will generate a beep sound, but if you turn more the screw, will display the maximum reached value. Is very helpful.


Sealey Torque Screwdriver Digital Readout 0.05 – 5Nm 1/4″ Hex Drive STS103


You will need a PH00 1/4″ bit too – try this:

Kopiowanie i przetwarzanie bez pisemnej zgody firmy zabronione.

Kopiowanie i przetwarzanie bez pisemnej zgody firmy zabronione.

WIHA 31961



Posted in General topics | 1 Comment