DIY sigma lens repair

In detail: do-it-yourself sigma lens repair from a real master for the site my.housecope.com.

Good afternoon.
On the occasion I bought a Sigma UC APO lens with a zoom of 70 - 210. When checking during the purchase, it turned out that the lens did not focus and the seller gave it for a little money.
At home, amateur diagnostics showed that:
The lenses are clean, free from damage or defects.
The contact of the diaphragm A is sealed with tape on the board (the tape was unsticked - the lens in position A began to correctly determine and work out the diaphragm).
The lens does not extend to the full up to the prescribed 210 mm, only up to 180 mm.
The factory paint on the screws is not damaged.
The lens has spacer rings, slightly rusty (total thickness up to 1.5 mm) - removing the rings did not give any results.
At the maximum closed aperture (f / 22), there is more or less sharpness, but at the fully open aperture everything is completely bad.
You can't see it sharply through the eyepiece, you can't focus on it.
Automation and autofocus work and even when the aperture is open, autofocus finds the best position with sharpness.

The question is - is it possible at all and how to return sharpness to the lens?

Carcass Pentax K100 super, before that there were a staff 18-55 and Granit-11.

Samples of frames (with minimum and maximum aperture) are attached.

Post has been edited Postman: 25 June 2009 - 11:44

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Sigmovtsy under Minolta do not make lenses with HSM as far as I know, otherwise there would be a reason to figure it out.

Video (click to play).

Well done. Respect!

From my own addition. As it seemed to me, the plastic of the case is ordinary polystyrene. At least the part where the flat contacts of the zoom position are glued exactly like him - I wanted to glue the edge with “Uranus” (butyl acetate based glue) - the body began to dissolve. Therefore, (most likely) the tooth could be carved out of polystyrene and glued in place with butyl acetate. Advantages - sits down "tightly", cannot come off, just break me. And the second - if suddenly (God forbid) the metal “tooth” comes off, then dangling inside can cause a lot of trouble (at least short-circuiting the contacts with incomprehensible consequences for the camera).

By and large, both topics should be drawn up in the form of an article and posted on the site

Well done. Respect!

By and large, both topics should be drawn up in the form of an article and posted on the site

Do not rush to post the article, I have not pulled myself up yet!
One of these days I will also disassemble Sigma.

[quot] Do not rush to post the article, I have not pulled myself up yet!
One of these days I will also disassemble Sigma. [/ Quot]
The process has begun!

Well, we are waiting for the results. If there is agreement between the authors of the topics, then I am ready to draw up the results of the experiments laid out here in the form of an article (maybe someone else will be interested)

Unfortunately, the photo with a drilled groove was not very successful, because I took it off my hands. In fact, the tooth is 2/3 lower than the edge of the surface, i.e. it is impossible to lower it into the groove flat, it must be inserted from the end. When fitting, I hardly picked it out from there.

As for the article, I am FOR, becauseservice in our country, to put it mildly - NO, and not everywhere, and the manufacturers have recently been saving on everything. Apparently, soon when buying a product, you will have to sign a paper that in the event of a breakdown of the product, I have no claims to the manufacturer.

I bought a lens. I took it without checking, it's good that it's not expensive.

Sold (so that the fagots fuck thee) assured that everything is fucking.

Autofocus turned out to be minimized. The engine whines and squeals and that's it.

Well, ok, let's open it. I want to note that I am taking apart the lens for the first time in my life, so do not swear.

... ATTENTION. first text then picture

We unscrew 4 large bolts and 5 small ones (they are not visible from this angle) indicated by the arrow. Remove the lens mount.

Next, remove the ring, there is another bolt under it.

Removing the switch strip.

We unscrew the two bolts holding the board and remove the board itself.

We remove the plate with a train, which is held by three bolts.

This plastic white gear was damaged ( photo above). The slots are licked, I restored them, because I xs where to get one.

I put everything back together, the defect has not disappeared. I had to derban again and look for what else the problem is.

I disassembled the gearbox completely and saw the sadness. The pin holding the left gear was broken off (in the second photo there is a small plastic pin next to the gearbox)

The gear dangled and did not give a good grip. Glue is not an option.

I had to make a new one. But the main problem was the thickness of this pin.

1.2 mm, it won't fit anymore, there is less backlash and makes a terrible noise when focusing. You can scare people around.

I had to drill through the gearbox to secure the pin. The pin was attached to the B-7000 glue

When reassembling, pay particular attention to the photocell.

If you put it crookedly, the lens will start to go crazy and not understand what it is doing and focus on everything in a chaotic manner.

Also, the bolt rod must be placed in the correct hole, otherwise it will jam in one position.

After all the manipulations, the lens worked like new with a pleasant sound.

Cool, informative! I repair manual glasses, the process itself and the result are a pleasure, but I have not climbed into focal glass yet)

I envy you. I like to buy “non-working” modern glass for a cheap price, usually there is a repair for a couple of minutes (insert a loop, glue a small plastic part that has fallen off, replace a gear, wash off the oil, etc.).

Once I got into the mechanical "jar", in which the focus was jammed, so in the end I could not assemble it normally - the thread of the focus is a hellish monster (about a hundred notches on both sides, such a thread does not turn out to be called), and could not combine correctly, so that the focal points match the markings and the minimum / maximum are correct.

My record holder is "kid" fifty dollars from 7d Minolta. The diaphragm is jammed, during disassembly there is a supply of rancid sunflower oil, this oil itself, scratches and dust everywhere, and a lot of fungus. I took it in 2011 for 500r, soaked it for a week in total, probably, it works now with a bang))

Here is a photo from the Internet of thread at the industrial, I had some kind of reunion (alas, at the next move I got lost somewhere, I can't show a photo of a live one).

It looked like it, only much thinner and longer at times. + the edge of the thread is not visible during disassembly, no mark is placed, and the offset is only a few degrees between adjacent installation points. Well, yes, they learn from mistakes, maybe I'll come across a similar one)

Unscrew the thread, and in the place where the thread breaks and the parts are separated - a mark directly on the thread and on the body. I did that. I put it together without any problems, I found the right place by the label)

I myself was so tormented with a 64-year-old lens) after the fall, the mechanism stuck and the focus did not spin

I was offered, I took it, there was nothing to check, the carcass was at home.

Sorry wildly, but can I find out where you are? =) I have a big sadness called Canon 24-70 2.8 lens. Dropped it long ago and put it off until better times. We need a body replacement and a diaphragm repair. Can you do that? Or do you need to do the adjustment later at the officials?

that's why I didn't bother too much, I just bought it.

Not bolts, but screws. And so a molder!

"Heat resistant repair mat"

it is heat-resistant, I solder phones and laptops on it

Recently I found one interesting specimen on Ibee - Nikon 300mm f / 4 AF-S. As the saying goes: “time has worn off the percussion mechanism”. It looks very shabby, but the optics are excellent. Autofocus does not work. According to the seller, he died smoothly. At first he began to “work poorly,” and then he completely died. The price for this device was 13,000 with delivery. Shop price for 75k.

I decided not to get involved, but now I even bite my elbows. I'm using the manual myself (300mm f / 4.5 AI-S). It was necessary to take and use it like a manual.

Question: how expensive would it be to repair such a device? I understand that it is difficult to assess, but at least approximately. What reasons could lead to such a smooth failure?

I do not repair photo equipment, I use phones and laptops.

so I am not competent to answer such questions.

This is not the first time I come across plastic gears in gearboxes and, in general, with plastic where it does not need to be, there is no gain in weight, it loses in strength, but the average person will buy new glass or take it for repairs.

The author is great, although if the wheels are not killed by "manual" focusing, then soon it will be necessary to make repairs again.

Author, what city are you from?

What prevented you from ordering parts and non-iron? If I respect the desire for poebazzo.

So it was used. But at times cheaper. Here is a toad strangling me to buy L optics for my canon for 70 thousand, when you can find one to be repaired for 5000, spend a couple of evenings with benefit, at the same time and figure out how it works inside and out.

I do not care that the technique is after repair, especially after my repair.

after I dug there, I already know for sure that everything is in order there and right now it works no worse than the new one, only the design has become a bit stronger.

It is very convenient to hammer nails with this Sigma. And the weight is large and the grip is convenient for this :)

There are three types of gluing: concave-concave, flat-convex, double-concave.

Theoretically, there can also be double-curved, but I do not know of a single optical scheme from the Soviet era, where they met.

So, we have a "conditional" gluing. The lenses are generally glued together, but not rigidly, they are movable relative to each other and we are not talking about any centering. Therefore, we need to center the gluing.

I got my hands on a Sigma 18-200 lens for Nikon mount. Symptoms:

The zoom ring rotates almost freely. In this case, no zooming occurs, and from the bowels of the lens comes a faint grinding noise and chips and dirt are poured.
The focus ring also seems to spin with no visible effect.
The mount is unscrewed, the bolts are in a bag and taped to the lens. Apparently, someone has already climbed there and despaired.
Front and rear lenses are dirty but not scratched.

Of course, I immediately thought that I would find inside the fragments of the focus drive gears, that is, the patient would not live. But I decided to take a look. It turned out that everything is not so bad.

Then I assembled the mount, wiped the glass with 99.99969% alcohol with microfiber and tested it on my semi-dead Nikon D70s. The trick works, there are no errors. It buzzes and lives. I hope the story was exciting and useful)

Thanks for the answer! The EXIF is definitely not affected by this contact, I checked - when the contact pad is removed, the information still gets the focal length into EXIF - maybe it's true, it's for the flash?

As I understand it, there are 2 more such contact pads in the sigma, but they are inside, probably there is also wear and tear and because of it it became worse to focus. It's just that I easily got to it, without disassembling the lens itself, only I took off the rubber ring and the paper tape, and I'm already a little afraid to climb in)))
I have an excellent camera focusing on the far end, but at a wide angle - somehow it does not work. If the angle is reduced from 18 to 24, then it is already normal. In general, I will think, maybe I will decide to make out. If I'm mentally ready to buy a new lens)))

it seems to me that this contact is responsible for the readings of the zooming scale, and not the focus. focusing contact on the inner ring. look at the EXIF value, where the effective focal length is written.
workshops don't want to get involved with these sigma models due to the fact that they are almost entirely made of plastic. some models even have plastic focus gears. these lenses are essentially disposable.It is risky to ensure that they work properly after repairs in the laboratory, especially if the laboratory is poorly equipped and cannot perform a complete calibration.
7-8 years is a decent period for this lens, I'm even surprised) sigma 18-200 is a glass with which you can learn to shoot while you are not confident in your abilities and finances.
if I were you, I would have saved up some money and tried to fix this glass. if possible, great. if not, buy a better glass, and this can be given to someone as a gift.
nothing can be done, a good zoom for Nikon costs about a thousand dollars. the only way to save money is to handle it.
or give up zoom altogether and buy native fixes for those focal points that you use most of all.

—–
I'll correct the answer: I now understand that you were looking at the focal value in EXIF, as I suggest. I don't understand how this happens without contact at all. Can the contacts really somehow manage the focus correction? I would fix it to check the sharpness. this one would be interesting) save the control frames before and after.

Edited at 2015-08-25 12:30 pm (UTC)

Professional service center "ReMobi" provides repair of Sigma lenses and electronic equipment. Highly qualified craftsmen of the company will perform any work in a short time. The company's goal is to carry out high-quality repairs, diagnostics of broken equipment, to do the possible and impossible so that you get a working electrical engineer at the exit. We have a network of service centers, services are available not only in Moscow, but also in Nizhny Novgorod, St. Petersburg, Yekaterinburg, Kazan, Novosibirsk and other cities. Contact ReMobi for help and you will certainly get it!

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Sigma lenses have gained popularity due to their high quality and affordable price, which makes them affordable for a wide range of users.

The reasons for Sigma lenses breakdown are no different from the reasons for the equipment breakdown of more eminent manufacturers. First of all, this is mechanical damage, due to which the vast majority of problems with cameras arise. It should always be remembered that the lens is the most fragile and delicate part of the camera and is the first to suffer from impact. No one is insured against the fall of the camera, and special cases, which also protect the lens from dirt, will help to protect it from impacts.

Another common cause of lens failure is water ingress into the lens, which is very difficult to remove from the lens. Salt water has a particularly negative effect on optics - it can break the protective layer of the lenses, as a result of which they will have to be replaced with new ones.

Like any technique, Sigma lenses wear out during operation, so individual parts have to be changed periodically simply due to the development of a resource. Owners are not recommended to carry out work on replacement of optics or its restoration on their own; it is best to entrust the repair of Sigma lenses to specialists who can be found in the Fotoblik service center in Moscow. Service technicians will quickly and efficiently perform diagnostics and replace the worn out part.

The most common reasons for contacting a photographic equipment repair shop:

zoom out of order;
autofocus does not work;
aperture problems.

Zoom stopped working, the ring scrolled and lost its reverse motion - these problems and not only bring customers to the service. As already mentioned, most breakdowns are caused by dropping the camera. A strong blow can provoke a tight rotation of the zoom or a complete loss of the function of approaching the object. Repair of Sigma lenses at the Fotoblik service center in Moscow includes comprehensive diagnostics and replacement of all necessary components. In a short time, your camera will work like new again.

In cases where autofocus does not work, it may be necessary to replace its motor, loop, or other restoration work.Qualified diagnostics will accurately indicate the source of the problem, which may manifest itself as follows:

focus "travels" from the closest to the maximum distance, but cannot be locked;
autofocus operation is accompanied by a characteristic buzzing, but focusing does not occur;
you can only catch focus in manual mode;
at the moment of focusing, the device emits uncharacteristic sounds - squeak, noise, clicks;
the photos are blurred.

Some models of Sigma lenses have the problem of gradual deterioration of focus in automatic mode, or they do not focus on a certain segment. Specialists of photo workshops successfully work with such shortcomings, depending on the specific case, performing repairs or replacing faulty elements.

Often, problems with the diaphragm can lead to the customer's service center when it either does not open or does not close. Aperture problems are also indicated by too light or too dark pictures. This means that the diaphragm is not adjustable.

If you lose the sharpness of your photos, it is most likely that you need to perform lens alignment, the meaning of which is to correctly adjust the lenses. The Sigma lens should never be adjusted by the camera owner. Especially in the absence of the necessary experience and special equipment. It is better to entrust such a responsible event in the hands of specialists. Otherwise, such savings can lead to the forced purchase of a new lens.

The optics in a camera is a fragile and delicate element, therefore the adjustment of Sigma lenses is a delicate process that does not allow the rude intervention of an amateur.

Sigma lenses are diagnosed and repaired by qualified technicians of the Photoblik service center. Depending on the problem, individual parts or whole working blocks are replaced. The center's specialists work only with original parts and components, therefore they vouch for the quality of their work. All repairs come with a 3-month warranty.

Both Muscovites and residents of other cities of the Russian Federation can contact the service center "Photoblick". For the first, courier delivery is provided, for the second - the "Remote repair" service. Thus, you can repair your favorite camera without leaving your home or being distracted from more pressing matters.

For more than 10 years "Photo-Master" has been repairing lenses of the Sigma company. But in Volgograd, practically no one undertook to repair these lenses.
Having accumulated vast experience, our engineers have succeeded in repairing Sigma lenses. We repair all models of Sigma lenses - both old and new.

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Speed. 70% of photo lens repairs are completed in a few days.
Quality. All of our engineers have vast experience.
Reliability. Repair warranty 0.5-6 months. We are responsible for our work.
Support. We will not only repair your photo lens, but we will also answer any questions that you do not understand.
Components. We only use original spare parts. This guarantees the reliability of further work.

Wide angle

Standard

30mm F1.4 EX DC HSM - Autofocus lens with an aspect ratio of 24 × 16 mm or less
30mm F1.4 EX DC - Autofocus lens with an aspect ratio of 24 × 16 mm or less
30mm F2.8 EX DN - Autofocus lens for mirrorless digital cameras
30mm F2.8 DN A013 - Autofocus lens for mirrorless digital cameras
30mm F1.4 DC HSM A013 - Autofocus lens with an aspect ratio of 24 × 16 mm or less
30mm F1.4 DC DN C016 - Autofocus Lens for Mirrorless Digital Cameras
35mm F2.8 YS Auto Flash - Non-autofocus lens for 36 × 24 mm frame
35mm F2.8 XQ - Non-autofocus lens for 36 × 24 mm frame
35mm F1.4 DG HSM A012 - Autofocus lens for 36 × 24 mm frame
50mm F1.4 EX DG HSM - Autofocus lens for 36 × 24mm frame
50mm F1.4 DG HSM A014 - Autofocus lens for 36 × 24 mm frame

Telephoto lenses

Macro lenses

50mm F2.8 Macro
50mm F2.8 Macro
50mm F2.8 EX Macro
50mm F2.8 EX DG Macro
55mm F2.8 YS Macro
55mm F2.8 XQ Macro ”
70mm F2.8 EX DG Macro
70mm F2.8 DG Macro A018
90mm F2.8 Macro
90mm F2.8 Macro
100mm F2.8 Micromacro
100mm F2.8 XQ Macro ”
105mm F2.8 EX Macro
105mm F2.8 EX DG Macro
105mm F2.8 EX DG Macro OS HSM
150mm F2.8 EX DG APO Macro HSM
150mm F2.8 EX DG APO Macro OS HSM
180mm F2.8 APO Macro
180mm F5.6 APO Macro UC
180mm F3.5 EX APO Macro IF HSM
180mm F3.5 EX APO Macro IF
180mm F3.5 EX DG APO Macro HSM
180mm F3.5 EX DG APO Macro
180mm F2.8 EX DG APO Macro OS HSM

Wide-angle zooms

21-35mm F3.5-4 Zoom-γ
21-35mm F3.5-4.2 Zoom-γ II
21-35mm F3.5-4.2 Zoom AF-γ
18-35mm F3.5-4.5 Aspherical UC
17-35mm F2.8-4 EX Aspherical HSM
17-35mm F2.8-4 EX Aspherical
15-30mm F3.5-4.5 EX DG Aspherical
20-40mm F2.8 EX DG Aspherical
12-24mm F4.5-5.6 EX DG Aspherical HSM
12-24mm F4.5-5.6 EX DG Aspherical
17-35mm F2.8-4 EX DG Aspherical HSM
17-35mm F2.8-4 EX DG Aspherical
10-20mm F4-5.6 EX DC HSM
10-20mm F4-5.6 EX DC
10-20mm F4-5.6 EX DC HSM
10-20mm F3.5 EX DC HSM
8-16mm F4.5-5.6 DC HSM
12-24mm F4.5-5.6 DG HSM II
12-24mm F4 DG HSM A016
14-24mm F2.8 DG HSM A018

Standard zooms

35-200mm F4-5.6 Zoom-π
28-200mm F4-5.6 Zoom-η
28-200mm F4-5.6 Zoom-η
28-200mm F3.8-5.6
28-200mm F3.8-5.6 Aspherical UC
28-200mm F3.5-5.6 DL Aspherical Hyperzoom Macro
28-300mm F3.5-6.3 DL Aspherical IF Hyperzoom
28-200mm F3.5-5.6 Compact Aspherical Hyperzoom Macro
28-300mm F3.5-6.3 Compact Aspherical Hyperzoom
28-300mm F3.5-6.3 Macro
18-125mm F3.5-5.6 DC
18-200mm F3.5-6.3 DC
28-300mm F3.5-6.3 DG Macro
28-200mm F3.5-6.3 DG Macro
18-200mm F3.5-6.3 DC OS
18-200mm F3.5-6.3 DC OS HSM
18-125mm F3.8-5.6 DC OS HSM
18-125mm F3.8-5.6 DC HSM
18-250mm F3.5-6.3 DC OS HSM
18-200mm F3.5-6.3 DC OS HSM II
18-200mm F3.5-6.3 DC HSM II
18-250mm F3.5-6.3 DC Macro OS HSM
18-250mm F3.5-6.3 DC Macro HSM
18-200mm F3.5-6.3 DC Macro OS HSM | C
18-200mm F3.5-6.3 DC Macro HSM | C
18-300mm F3.5-6.3 DC Macro OS HSM | C

Sigma lenses have gained popularity due to their high quality and affordable price, which makes them affordable for a wide range of users.

Like any technique, Sigma lenses wear out during operation, so individual parts have to be changed periodically simply due to the development of a resource. Owners are not recommended to carry out work on replacement of optics or its restoration on their own; it is best to entrust the repair of Sigma lenses to specialists who can be found in the “Photo-Master” service center in Volgograd. Service technicians will quickly and efficiently perform diagnostics and replace the worn out part.

The most common reasons for contacting a photographic equipment repair shop:

zoom out of order;
autofocus does not work;
aperture problems.

Zoom stopped working, the ring scrolled and lost its reverse motion - these problems and not only bring customers to the service. As already mentioned, most breakdowns are caused by dropping the camera. A strong blow can provoke a tight rotation of the zoom or a complete loss of the function of approaching the object. Repair of Sigma lenses at the "Photo-Master" service center in Volgograd includes comprehensive diagnostics and replacement of all necessary components. In a short time, your camera will work like new again.

In cases where autofocus does not work, it may be necessary to replace its motor, loop, or other restoration work. Qualified diagnostics will accurately indicate the source of the problem, which may manifest itself as follows:

focus "travels" from the closest to the maximum distance, but cannot be locked;
autofocus operation is accompanied by a characteristic buzzing, but focusing does not occur;
you can only catch focus in manual mode;
at the moment of focusing, the device emits uncharacteristic sounds - squeak, noise, clicks;
the photos are blurred.

If you lose the sharpness of your photos, it is most likely that you need to perform lens alignment, the meaning of which is to correctly adjust the lenses.The Sigma lens should never be adjusted by the camera owner. Especially in the absence of the necessary experience and special equipment. It is better to entrust such a responsible event in the hands of specialists. Otherwise, such savings can lead to the forced purchase of a new lens.

The optics in a camera is a fragile and delicate element, therefore the adjustment of Sigma lenses is a delicate process that does not allow the rude intervention of an amateur.

Sigma lenses are diagnosed and repaired by qualified technicians of the “Photo-Master” service center. Depending on the problem, individual parts or whole working blocks are replaced. The center's specialists work only with original parts and components, therefore they vouch for the quality of their work. All repairs come with a 3-month warranty.

Both Volgograd residents and residents of other cities of the Russian Federation can apply to the "Photo-Master" service center. For the first, courier delivery is provided, for the second - the "Remote repair" service. Thus, you can repair your favorite camera without leaving your home or being distracted from more pressing matters.

It's kind of by itself

Here's the software in action. !

It seems that so far no brand has an alignment of lenses for different focusing distances. At least for Canon and Nikon, adjustment is done only at one distance, such as 20-30-50-80 focal lengths and that's it.

The output of this device is very good. Competent step. Which can increase sales.

I hasten to upset the masters. This device will work only with new lenses, and versions for Canon, Nikon, Pentax, Sony, Sigma will be released.
That is, you will have to have a device for each brand.

Recently I bought myself a Sigma 35 F1.4 DG HSM. At first glance, the quality of performance is similar to the Canon Elka, and when you take it in your hands you remember the Best examples of Minolta. The lens hits the target in different ways, with careful testing, it can be seen that the correction is working out stepwise (that is, the problem that exists in Canon 50 1.4 and Sigma 50 1.4, Sigma 30 1.4 remained in constructive terms, but it was successfully solved programmatically). sharpness and geometry are not. This is a very decent lens.

On the old Sigma programmer, the lens is not readable. When next month when USB DOCK appears, I'll unsubscribe.

T99Alex, in some carcasses there is a similar adjustment.
This custom function is configured by blunt poking buttons without measuring the distance to the matrix.

Very handy thing

It has its drawbacks, for example, it is not possible to adjust the autofocus so that the zoom lens accurately hits at all focal lengths. In such cases, software lens alignment is required at a service center.

So now Sigma provides the ability to set up autofocus without the hassle of going to a service center. Moreover, now new lens models can be rebuilt in a way that no other service in the world could do! I think in a year or two, other brands will have similar opportunities. Probably, additional autofocus setting items will appear in the Nikon and Canon cameras menu.

in this regard, Sigma did not come up with anything new (apart from correcting at different distances). The difference from other brands is that the device is sold widely instead of being distributed among off services at a price of several kilo-bucks

Can you tell me where you can get hold of the old programmer and the program for it?

The new USB DOC came, but so far nothing has been brought from the new, and not one old lens is detected on it.

The lens is new, the jambs have not been fixed yet.
maybe updating lens firmware will help.
It is better to install the firmware of the beginning of the year or later on the camera.

(Canon actively interferes with Sigma's work, often when changing the firmware in the camera, the lens starts to work poorly)

So not in the camera, but in the lens, the firmware needs to be updated. If it is not possible to update in the lens, you need to roll back the firmware in the camera to an older one.

Sigma looks for holes in the Canon software, and writes its own software for them. Canon patching holes releases new firmware for cameras, after which third-party lenses stop working. Sigma looks for holes again and writes new firmware, after updating the firmware in the lens, they start working again.
And so in a circle.
=====
Now about your problem.
Canon carcasses have different autofocus systems (depending on the model). And the setting in Sigma is one universal, for all types of autofocus.

For example, if it hits 20d - 550d undershoot.
20d overflows - 550d for sure.

in the service software (not on sale), an amendment is usually set -20 Less often +20
adjusting the focus on the lens with the sigma utility should help.

In canon lenses, corrections are set for points 2.8, 5.6 cross or conventional sensors. also separate setting for units
sigma is simpler. One setting with no options.

I think unstable work due to the fact that sigma emulates the work of canon (not sure), and in parallel does what it needs.
e.g. Sigma 30 1.4 is defined by the Canon programmer as Canon 17-35 2.8

Why didn't Sigma support USB box 50 / 1.4?

Ps: If you check each AF sensor separately on the bundle and make a correction, then the stability will be slightly higher

Why didn't Sigma support USB box 50 / 1.4?

I think it will update soon, as updated 30 / 1.4

An exemplary carcass is a carcass set at 44,000mm and the more accurate its autofocus, the better (in fact, all kenons have 2.8). The units stand out from the rest by the magnesium body of the mirror system - those, more precisely, in time.
The carcass instructs the lens to “move 54 stops forward!” (already taking into account the adjustments of the body and the lens), and the lens simply does it. The carcass checks and, if everything is correct, confirms.
Only unfamiliar lenses for a carcass, or vice versa, "old sigma friends" work differently. the device realizes that it is wearing an “enemy lens” and deliberately introduces a huge error. The newer the carcass firmware, the more “old friends” it has.

If sigma made a normal SC network in Russia with a firmware update “for inexpensive”, everything would be fine. but getting her authorization or just buying a programmer from her is just some kind of trouble

((

Earlier, on the pages of our website, we reviewed the main malfunctions and repairs of the canon 50 mm 1.4 lens.

In the material of this article, we will analyze a fifty-kopeck piece from Sigma, we will also consider the main malfunctions, features, cost, repair time.

Externally, the portrait lens (see photo) from sigma looks impressive, but since appearance can be deceiving, we will analyze the owner's reviews and consider its main characteristics.

Owners of Sigma 50mm 1.4 optics most often refer to the advantages of the lens: aperture 1.4, 9 aperture blades, picture quality, sharpness, quality of the material from which the lens is actually made.

The owners of the fifty kopecks from Sigma complain mainly about the unstable operation of autofocus, the lens misses differently from shot to shot - both on crop and full frame.

Key Features of the Sigma AF 50mm f / 1.4 EX DG HSM Canon EF Lens:

Focal length: 50mm

Minimum Aperture: 16

Construction: number of elements / groups of elements - 8/6; the number of aspherical elements - 1; aperture blades - 9

Viewing angle: 46.80 deg.min

Minimum focusing distance: 0.45m

Filter thread diameter: 77 mm

Dimensions (D x L): 84.5 x 68.2 mm

Repair of Sigma AF 50mm f / 1.4 lenses in our workshop it is carried out in a period of 1 to 3 working days, the cost of repairs is from 3,500 to 4,000 rubles, including parts of general use.

The cost of maintenance, which does not require significant disassembly of the lens, can vary in the range of 750 - 2500 rubles.

You can get advice or other information from the specialists of our workshop by phone 8 (495) 518 54 93 or 8 919 775 74 55.

All types of services provided are guaranteed. Diagnostics - free.

It's time to disassemble the lens, find the malfunction and fix it.To do this, we will take a Sigma 50 mm 1.4 lens that came to our photo workshop with the err01 fault. You can read more about the error code err01 on the pages of our website for example here: https://my.housecope.com/wp-content/uploads/ext/3479/fotocamera/canon-err01-code.htm

It looks like we came across a lens during the repair, which got a fair amount of liquid, possibly sea water, as evidenced by traces of corrosion and a characteristic bloom with a greenish tinge on some parts of the electronic board, other parts of the lens, as well as dried spots on the lenses.

In the photo above, you can see that the greatest consequences from the ingress of liquid are in the area of \ u200b \ u200bthe connector of the loop from the contact group. In principle, this is not surprising the presence of liquid, voltages for powering and controlling the operation of the lens contribute to a chemical reaction, the presence of salt in the liquid, for example, in the case of seawater, accelerates the reaction (remember the chemistry lessons at school and experiments on how to get copper sulfate) ... Corrosion on the connector and the contact group cable is the cause of a malfunction, in which the camera generates the error err01 - an error in communication between the camera and the lens.

It is also easy to see corrosion in the photo on the ultrasonic AF motor and on the fine focus sensor.

In this case, the technician needs to conduct a thorough examination of all components and parts of the lens in order to determine at the preliminary stage of diagnostics how cost-effective the lens repair will be. A well-chosen inspection sequence strategy, refurbishment of lens assemblies and components can save not only time, but also avoid unnecessary financial costs.

- The manual focusing ring is jammed, this malfunction may be caused by wear of parts, deformation of the helicoid, tubes or corrosion in the focus lens drive clutch unit, such as in the case considered in this article.

- Automatic focusing does not work, a malfunction of the lens autofocus system can be caused by a number of reasons, there are no prevailing malfunctions in sigma 50mm lenses, as practice shows, each case is individual, malfunctions of the autofocus system can be caused by a failure of the HSM motor (hyperSonic Motor - ultrasonic motor) of the stator (see above in the photo on the left), the rotor, driver and control circuits for the automatic focusing circuit, including the fine focus sensor (see above in the photo on the right).

- The lens focuses, but the pictures are blurry - the reasons for this malfunction are mainly associated with the need to adjust the lens at the software level, the lens lens displacement as a result of mechanical stress or wear of the guide bushings. Above, we noted that many lenses were initially incorrectly adjusted, that is, before buying a sigma 50mm 1.4 lens, they must be checked, checked and checked again before buying. Then, without leaving the checkout, check again. This is not only our opinion, judging by the reviews on the Internet, most of the complaints are directed at this particular manufacturer.

Lens aperture does not work, the camera gives an error err01, the causes of the malfunction in most cases are associated with the ingress of liquid, a faulty stepper motor, problems with the position sensor. This lens model is not susceptible to plume disease.

Damage to the lens barrel due to mechanical damage, comments, in this case, will probably be superfluous, except that in most cases, even significant damage to the body parts, which, as it may seem to many users, cannot be repaired, are perfectly restored in the hands of our service engineers. The technology developed by our specialists allows gluing plastic parts at the molecular level, it is important that no attempts are made to glue with any glue before coming to our workshop.

Scratches, dust, dirt, other damage to sigma 50mm 1.4 objective lenses... Problems caused by incorrect and negligent use of the optics. If you can get rid of dust and dirt by disassembling and cleaning the lenses in the sigma 50mm lens, then scratches and other damage to the lenses can be solved only by replacing them. We have repeatedly considered this issue on the pages of our site, for example, here https://my.housecope.com/wp-content/uploads/ext/3479/remont/canon/carapiny-na-linzah.htm. If cobweb-like patterns are visible on the surfaces of the lenses, then most likely the lenses are damaged by a fungus that usually starts when traveling to exotic countries with a humid climate.

Fungus in lenses It feeds not only on dust that accumulates on the surfaces of the lenses, but also eats up a special coating of glass. In our country, the development of the fungus is inhibited. In this case, if the damage is not significant, then they do not affect the quality of photographs. To get rid of the patterns on the lenses damaged by the fungus, as in the case of scratches, it is possible only by replacing them.

Broken light filter, stuck threads on a Sigma 50mm lens. Removing the lens filter in our workshop takes 15-20 minutes. Our craftsmen will not only dismantle the frame of the light filter, but also remove the remnants of the fragments. They will check and, if necessary, correct the thread of the lens ring, where the filter is screwed. The cost of dismantling the lens filter is 750 rubles. If desired, the owners can purchase a protective light filter in our workshop.

Sigma 50mm f / 1.4 electronic board malfunctions
The electronics in the lenses of all manufacturers are quite reliable, malfunctions are usually caused by improper operation - the fall of optics or other mechanical influences as a result of which the printed tracks and electronic components are damaged, the ingress of liquid, such as in the case under consideration in this material.

In conclusion, we note that the lens considered in this article has been successfully repaired. During the check, no deviations from the norm were revealed, the focusing of the lens worked stably without misses throughout the entire range. The pictures turned out to be clear, not smeared. The photo workshop has met the price range indicated in the price list.

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