3rd party lenses and the "Focus Problem" : your op

[fntzlnd]

Howdy all,

I sent in my 10D for almost a year of fighting, what I thought was a back focus problem. Focus test after focus test, until I was about to lose my mind.

I started with the 10D and a Tameron 28-300 lens. Not super happy with the results unless I was shooting at f8 or smaller. So, I went and bought the 17-40L. I was happy, but not super happy. I still wasn't getting the results I was expecting... and yes I am fully aware of the unsharpened image the 10D creates.

So, I drove to Irvine and asked them to calibrate..

Today I called to get a status, and the person on the phone told me this: Not to use my Tameron lens. That the lens will actually cause the 10D to lose focus calibration. I asked if this was a sales ploy, and was told no. That is was perfectly fine to use the Tameron lens on a film body all day long, just not on a 10D.

Wierd.

Anyway, they calibrated my camera and 17-40. Here's hoping...

[CyberDyneSystems]

We will be VERY interested to see how this turns out...

Although even a repair that leaves you 200% satisfied will not confirm the "Third party focus" story.. I am hopefull that your problem dies get sorted.

No.. in all the stuff I've heard from various sources this is a completely new one on me. I've never heard anyone blame a lens for changing the calibration of a Camera.

I hate to say,.. but it really sounds like a load of BS....

Anyway.. the important part is.. it sounds like they are admitting that the Camera needed work.. and they are going to rememdy it... that's a good thing :)

[Cadwell]

When you next talk to this person I would ask for a more technical explanation of why they say this will happen. Get some details. I am not going to say it is impossible but it does sound improbable.

[Canuck]

When you next talk to this person I would ask for a more technical explanation of why they say this will happen. Get some details. I am not going to say it is impossible but it does sound improbable.

Well this is truly odd...the loosing calibration bit. Both Cadwell and myself use the Sigma 120-300mm F2.8EX and neither one of use have had issues with focusing. If you have, you have, it hasn't been brought ot the attn of this forum. In other words whatever that person tried to sell you, don't buy it. There are many of use that use Sigma lenses, even CD when he had the 70-200mm F2.8EX and now the 500mm F5.6EX monster. I rtuely don't see how it could cause that problem.

[Cadwell]

Well if it comes down to it I also have the Tamron SP AF28-75mm F/2.8 XR Di and that hasn't stuffed up my focusing either... that's why I am curious to hear a more technical explanation.

[defordphoto]

A lens will cause change/loss of focus calibration within the camera? Ludicrous. A lens not compatible with a certain camera? Yup. With all the electronics these days that's very possible.

[mwinog2777]

This defies understanding. I agree with the other respondents.

The laws of physics as we know them in this universe do not allow for this problem to occur. Now, if we lived in a different universe with different laws, who could say?

[Guillermo Freige]

Never had that problem with the DRebel and my Sigma lenses. I don´t buy the story either.

[CoolToolGuy]

Strange, very strange.

I would get in touch with Tamron and ask them what they know about it.

And I would ask Canon Service to put what they told you in writing. That may help if you want to take it further.

[robertwgross]

We will be VERY interested to see how this turns out...

Although even a repair that leaves you 200% satisfied will not confirm the "Third party focus" story.. I am hopefull that your problem dies get sorted.

No.. in all the stuff I've heard from various sources this is a completely new one on me. I've never heard anyone blame a lens for changing the calibration of a Camera.

I hate to say,.. but it really sounds like a load of BS....

Anyway.. the important part is.. it sounds like they are admitting that the Camera needed work.. and they are going to rememdy it... that's a good thing :)

What I suspect they meant was that the Tamron lens makes the entire camera (body and lens) seem out of cal. It is difficult for a user to sort out whether a focus problem is a result of a funny lens or a funny body or some even weirder mismatch at the mount. The funny Tamron lens would not cause anything inside the body to fail, but it could make the whole kit look bad.

A chain is only as strong as its weakest link.

I just try to make sure the weakest link isn't me.

---Bob Gross---

[quickben]

I've read in other forums that Tamron seem to have a problem with inconsistancies in their manufacturing. Some people have had bad lenses, sent an identical replacement and the problem disappear. You might want to see if you can find another lens to compare with.

Gary.

[ron chappel]

I could think of a few ways that a lens could make a body lose calibration-but i'd have to think about it to put it simply.I don't think that's exactly what the tech guy meant though-maybe he meant that a 'crude' lens like the tamron can never work right with the 10D?(ie the camera would work fine again with a better lens?)
Anyway i too would like to hear a full explanation

And a retorical question on a related subject-how is it that canon can make their newest bodies work perfectly on their oldest lenses but manage to not work on anything but the latest sigma lenses??
Do all lens models have a code that sigma AREN'T allowed to reverse engineer?
There are other explanations but they all point to deliberate laziness/tightarseness on sigma's part.

[Cadwell]

There are other explanations but they all point to deliberate laziness/tightarseness on sigma's part.

Nope, not all they don't. Since we are in the realms of pure speculation here, how about this one? "Canon may engineer their latest bodies to not work with third party lenses in order to retain lens market share". Probably not true but as valid and likely as your speculation. ;)

[RDKirk]

There are other explanations but they all point to deliberate laziness/tightarseness on sigma's part.

Nope, not all they don't. Since we are in the realms of pure speculation here, how about this one? "Canon may engineer their latest bodies to not work with third party lenses in order to retain lens market share". Probably not true but as valid and likely as your speculation. ;)

Canon doesn't "allow" Tamron, Sigma, or anyone else to use their actual design specs (that is, they don't license them out at all). The 3rd parties must reverse engineer the specifications and then change them just enough not to infringe on Canon patents (similar to what AMD has had to do with Intel processors to run Windows code as well as Intel). The communications from and to the lens has to look enough like genuine Canon to "spoof" the camera--but the means within the lens to do so must not be a perfect copy of a Canon lens.

'Way back in the Canon FD lens mount days, Canon had a pin in the mount of each lens intriguingly marked "Reserved." As far as I know, no FD camera ever used that pin. Because it was never used, the 3rd party manufacturers didn't put the pin on their Canon FD-mount lenses--probably because they couldn't figure out what it was for. But the Canon engineers must have had something in mind for the future of the FD mount--that was cut short when the corporate decision was made to go to a completely new mount for autofocus.

I think Canon did something similar with the EF mount. When Canon made the drastic move from the FD mount (which mightily torqued off me and many others who had a considreable investment in FD lenses), it also gave them a wide space in which to "future proof" their specifications. It's a fact that the very earliest EF lenses work as well on the very newest EOS cameras as they ever did. In fact, they work even better--the focus faster and more accurately than they did on the EOS cameras for which they were designed.

I think Canon designed the EF lenses from the beginning with capabilities the early cameras weren't able to use--but in directions Canon engineers knew they would someday go. These may be things like response speed or signal amplitude ranges: Say, a certain lens signal ("amount of rear element motion") has always ranged in amplitude capability from 1 to 10 in the early EF lenses, but early EOS cameras only used and "asked for" a range of from 4 to 8.

If the 3rd party engineer examined only what the camera "asked for," he'd come up with a reverse-engineered lens that provided only an amplitude range of 4 to 8. Or perhaps he noted that the EF lenses could produce an amplitude of 1 to 10, but that was expensive considering the cameras were only asking for 4 to 8.

But then the new EOS cameras, with expanded abilities, now asked for the amplitudes at those extreme limits, and when the lens didn't deliver, the cameras locked up.

Whether the 3rd party lenses had problems depended on how faithfully (read: expensively) the engineers reproduced all the capabilities of the early EF lenses.

Now, granted, all the above is speculation on my part, but notice that when 3rd party lenses have run into trouble, fixing them has only required a "re-chipping" that took no more than a few months of firmware re-design--really just tweaking something that was already there, rather than some major design effort.

I'd hope and expect that they have learned their lessons and are doing a much more faithful job in reproducing all EF lens capabilties--even the ones they don't see presently being used.

[CoolToolGuy]

On this forum, when somebody brings up problems with Sigma lenses, there is often a chorus of 'Yea, yea, me too!' from other users that have had the same problem. You don't see the same thing when Tamron problems come up. That tells me there is not a generic 'Tamron' issue like there is with the other brand.

A few weeks ago there was a thread that discussed the test procedures that the Canon Service Centers use, and it talked about reference bodies and tool lenses. The lenses are checked with these tools, and adjusted if necessary. Is it possible that there is something wrong with this Tamron lens that could be causing the camera to act as if it is out of calibration? And the person at the Canon Service Center might not want to be too specific, just advise the customer to be a good doobee and only use Canon lenses?

Ask Tamron to take a look at the lens. Maybe it can be adjusted or fixed.

[Cordell]

It amazes me how SPECULATION can run so wild.

[robertwgross]

And a retorical question on a related subject-how is it that canon can make their newest bodies work perfectly on their oldest lenses but manage to not work on anything but the latest sigma lenses??
Do all lens models have a code that sigma AREN'T allowed to reverse engineer?
There are other explanations but they all point to deliberate laziness/tightarseness on sigma's part.

Years ago, in a different industry, my job was to reverse engineer another company's products. I could study the product and figure out what 98% of the components did and how we could (legally) copy that function. However, there was always about 2% that didn't make any sense. As a general rule, that 2% is what we decided to leave out when we made our product. Later on, if that 2% became something important to the original manufacturer, then it would have left us with a slight compatibility problem.

If you translate that to Sigma and Canon. Sigma may have reverse engineered the Canon EF lens and mount system, and they figured out 98% of it, so they made their lenses based on the 98%. Later on, Canon "enabled" the other 2% in the body, and that left the old Sigma lenses slightly incompatible. But then Sigma figured out that last 2%, made some firmware changes, and the frustrated Sigma lens customer sends his lens back to Sigma for a firmware upgrade. It makes perfect sense.

---Bob Gross---

[CoolToolGuy]

If you translate that to Sigma and Canon. Sigma may have reverse engineered the Canon EF lens and mount system, and they figured out 98% of it, so they made their lenses based on the 98%. Later on, Canon "enabled" the other 2% in the body, and that left the old Sigma lenses slightly incompatible. But then Sigma figured out that last 2%, made some firmware changes, and the frustrated Sigma lens customer sends his lens back to Sigma for a firmware upgrade. It makes perfect sense.

---Bob Gross---

It doesn't make much sense if your Sigma lens is too old for a firmware upgrade - and I believe there are some of them like that.

And what is to say that Sigma really only figured out 96% and didn't know it? After the 2%, there is still room for lens failures with Canon's next evolution.

Sigma should pay the freight for the EF technology. Otherwise they are cheating their customers by selling them a lens that they cannot guarantee is compliant with the EOS system.

[Cadwell]

Sigma should pay the freight for the EF technology. Otherwise they are cheating their customers by selling them a lens that they cannot guarantee is compliant with the EOS system.

As "RDKirk" pointed out, Canon don't license the EF mount technology to anyone so reverse engineering is the only approach Sigma, Tamron etc. have if they want to sell into the Canon market.

Now Canon is under no obligation to license its technology, that is true, but if the third party manufacturers didn't sell into the Canon market place then Canon would have a monopoly of supply. I wonder how much lenses would cost then? I suggest that even the people who buy solely Canon brand lenses have cause to be grateful for the competition brought by the third party manufacturers.

[CoolToolGuy]

Sigma should pay the freight for the EF technology. Otherwise they are cheating their customers by selling them a lens that they cannot guarantee is compliant with the EOS system.

As "RDKirk" pointed out, Canon don't license the EF mount technology to anyone so reverse engineering is the only approach Sigma, Tamron etc. have if they want to sell into the Canon market.


I don't have any industry knowledge of this, but I don't think that is the case. We don't hear nearly as many complaints about Tamron, Tokina, or Quantaray lenses on this forum as we do about Sigma. If RDKirk or anyone else has evidence that Canon keeps the EF technology to itself I think many of us on the forum would like to know about it. :?

This is intellectual property, and while it is in Canon's interest to protect it, it is also in Canon's interest to provide it to other lens makers - for a price. Canon (or any other camera maker) cannot be a leader in the SLR market without participation from the other vendors. The trick is to give them just enough to allow them to widen the market, but keep the biggest piece of the pie for themselves. This is business, after all. :wink:

Have Fun,

[ron chappel]

And then there is the middle option....

It's common knowledge that camera makers get others to make items for them to sell as a genuine item(tamron making many pentax kit zooms for example).Not a thing wrong with it of course.

I have zero proof but damn,those new series of canon kit zooms look like tamron's through and through!
I'm refering to such lenses as 28-90II,90-300,28-105(4-5.6),etc
The cosmetic style,build materials,cheap aspheric optics and most of all they're image characteristics all scream tamron

Everyone wins-canon get someone to make their lenses at a competitive price,consumers think they have something special and we get to bag them as steaming piles of doo doo :lol: :lol: :lol:

[CoolToolGuy]

Ron brings up an interesting point - it has been rumored that someone else makes some of Canon's lenses for them, and while that may seem like heresy, you don't have to look far to see the trend - Canon made the early Kodak DSLRs, now Sigma does. In other industries the practice is common - DVD players, even cars. So sharing technology is common. Why it hasn't happened with Sigma and Canon is anyone's guess, although the new Kodak (made by Sigma) might have gotten them over the hump.

Have Fun,

[CyberDyneSystems]

FYI Canon DOES NOT license the EOS mount to anyone.

Sigma just clearly that had a design that was more susceptible to the EOS electrical changes that Canon has implemented.

Many Quantaray AF lenses are Sigmas... (not all) and have the same issues.

[robertwgross]

It doesn't make much sense if your Sigma lens is too old for a firmware upgrade - and I believe there are some of them like that.

And what is to say that Sigma really only figured out 96% and didn't know it? After the 2%, there is still room for lens failures with Canon's next evolution.

Sigma should pay the freight for the EF technology. Otherwise they are cheating their customers by selling them a lens that they cannot guarantee is compliant with the EOS system.

If the old Sigma lens design had the firmware in a socket, then it would have been more easily replaceable. But then chips in sockets can be unreliable if they get loose. The newer Sigma lenses might have sockets that are reliable and still be upgradeable.

Yes, we don't know who it was on the Sigma reverse-engineering team that day, and we don't know what cost compromise descisions they made. Sigma is mostly "paying the freight" for EF by upgrading the firmware in the semi-new Sigma lenses. I have one that they did. Of course, they aren't offering much hope to the old Sigma lens customers who were told that an old lens can't be upgraded. Maybe somebody could beat them into submission, though.

---Bob Gross---

[CoolToolGuy]

FYI Canon DOES NOT license the EOS mount to anyone.

Sigma just clearly that had a design that was more susceptible to the EOS electrical changes that Canon has implemented.

Many Quantaray AF lenses are Sigmas... (not all) and have the same issues.

Just two points to think about:

1. I would think that Kodak would have to have a license for the mount to market their new DSLR. Not for legal purposes, but for practicality purposes. Otherwise they might run into the same issue.

2. If someone else is making lenses for Canon, Canon would have to provide the specs for the mount.

But, I could be wrong... :?

Have Fun,

[CyberDyneSystems]

I was about to make a statement about assumptions being made.. then i realized that I am just as guilty.. so let me rephrase my post and take out any wording that may result from an assumption.


FYI Canon SAYS it does NOT license the EOS mount to anyone. :)

[RDKirk]

[quote="CyberDyneSystems"]Just two points to think about:

1. I would think that Kodak would have to have a license for the mount to market their new DSLR. Not for legal purposes, but for practicality purposes. Otherwise they might run into the same issue.

2. If someone else is making lenses for Canon, Canon would have to provide the specs for the mount.

But, I could be wrong... :?

Have Fun,

According to one source I can locate at the moment, and others that I've read over the last couple of years, Canon actually sold the bodies to Kodak (as did Nikon) and Kodak refitted the bodies with their sensors.

http://www.imaging-resource.com/PRODS/D30/D30A.HTM

[CoolToolGuy]

Just two points to think about:

1. I would think that Kodak would have to have a license for the mount to market their new DSLR. Not for legal purposes, but for practicality purposes. Otherwise they might run into the same issue.

2. If someone else is making lenses for Canon, Canon would have to provide the specs for the mount.

But, I could be wrong... :?

Have Fun,

According to one source I can locate at the moment, and others that I've read over the last couple of years, Canon actually sold the bodies to Kodak (as did Nikon) and Kodak refitted the bodies with their sensors.

http://www.imaging-resource.com/PRODS/D30/D30A.HTM

I am referring to the Kodak DCS SLR/C, as seen here:
http://www.dpreview.com/reviews/specs/Kodak/kodak_dcsslrc.asp

The older ones were made as a joint venture with Canon, but the latest models (Canon mount as well as Nikon mount) seem to be made by Sigma. It would seem like Kodak would want to have an agreement that the camera is compliant with the lens mount, don'tcha think? :wink:

It seems like every few months we run through this mine field - does Canon license the mount, to who, and why they would or wouldn't want to do it. I don't think anyone on the forum really knows, and until we get Chuck Westfall or some other blessed one from Canon to come here and settle it we will have history repeat itself again and again. For me, I will avoid Sigma lenses until I see a statement (from them) that they are fully compliant with the EF lens mount protocols. As for Tamron and others, I will try them out on all of my bodies before I buy them to insure they work with what I have. I might run into a problem in the future, but they don't have the history of problems like Sigma does. (I did not mention Quantaray for fairly obvious reasons) :roll:

OBTW - you had the quotes slightly out of whack, so I fixed them. I'm sure CDS doesn't want my words put into his mouth. :wink:

Have Fun,

[RDKirk]

The older ones were made as a joint venture with Canon, but the latest models (Canon mount as well as Nikon mount) seem to be made by Sigma. It would seem like Kodak would want to have an agreement that the camera is compliant with the lens mount, don'tcha think? :wink:

Have Fun,

Hmm. However, the mount and mirror box form a single module, so it's possible that's all Canon provided. But I would seem to me that such a Frankenstein's Monster must have some kind of integration problems.

As you say, though, we only know what Canon will reveal--but the only thing they've revealed is that they don't license their EF specifications.

[CyberDyneSystems]

I'm Sure Kodak would WANT there body to work with Canon lenses in the future.. but that doesn't mean a thing.. Ironic that it is Sigma they turned to to get the bodies.. and not Canon.

Are you suggesting that the Body that Sigma is making IS Licensed and fully functional,. while Sigma's lenses are not?

Now why would Sigma have the proper specs in the Body dept.. and not the lens dept.?

This does not sound right to me :)

[robertwgross]

Canon EF lens specifications are "in the lens department" and Sigma had to reverse engineer it to get that semi-figured out.

Sigma obviously makes their lenses to be compatible with what they think the EF specification is. Sigma also makes bodies, but they write their own specifications there and don't have to match anybody. And with a Foveon sensor, they sure don't match much.

---Bob Gross---

[CoolToolGuy]

I'm Sure Kodak would WANT there body to work with Canon lenses in the future.. but that doesn't mean a thing.. Ironic that it is Sigma they turned to to get the bodies.. and not Canon.

Are you suggesting that the Body that Sigma is making IS Licensed and fully functional,. while Sigma's lenses are not?

Now why would Sigma have the proper specs in the Body dept.. and not the lens dept.?

This does not sound right to me :)

What I am suggesting is that Kodak would not enter into a venture to market a camera with the Canon mount without having some assurances that it is compatible with the electronics. They are marketing to professionals - who may, on the one hand see their lenses as tools they need today, not two years from now, but would likely pitch a royal fit if a lens doesn't work on their $5000 body. Kodak has noted in the marketing info that the camera is software-upgradeable, so maybe that covers it.

In another post someone suggested that the mount and mirror box might be made by Canon, but I haven't seen any evidence of that and the 'secret stuff' is not necessarily there - it is probably in some circuit board(s) buried deep inside the body.

Have Fun and keep those cards and letters coming,

[CyberDyneSystems]

Canon EF lens specifications are "in the lens department" and Sigma had to reverse engineer it to get that semi-figured out.

Sigma obviously makes their lenses to be compatible with what they think the EF specification is. Sigma also makes bodies, but they write their own specifications there and don't have to match anybody. And with a Foveon sensor, they sure don't match much.

---Bob Gross---

I agree Bob.. but we were talking about the Kodak DCS pro14 C.. which is a Kodak body that has the EOS mount for Canon lenses but the Body is in fact made by Sigma.. 8) for Kodak.. to mount Canon lenses.. :? :shock:

.... er... simple isn't it? :?: :wink:

[fntzlnd]

Wow! I did't think this would spark such a thread.

Anyway, I got my camera back ...

... and ...

(Drum roll please)

... they DIDN'T FIX IT!

[robertwgross]

I agree Bob.. but we were talking about the Kodak DCS pro14 C.. which is a Kodak body that has the EOS mount for Canon lenses but the Body is in fact made by Sigma.. 8) for Kodak.. to mount Canon lenses.. :? :shock:

.... er... simple isn't it? :?: :wink:

The thread was on a Canon 10D body with third party lenses. I don't think Kodak makes the body.

---Bob Gross---

[RDKirk]

[quote="CyberDyneSystemsI agree Bob.. but we were talking about the Kodak DCS pro14 C.. which is a Kodak body that has the EOS mount for Canon lenses but the Body is in fact made by Sigma.. 8) for Kodak.. to mount Canon lenses.. :? :shock:

.... er... simple isn't it? :?: :wink:[/quote]

Or perhaps it's a matter of a very restrictive license for the Kodak/Sigma/Canon camera by which Canon stills says, "If we see our identical circuitry in a 'Sigma' lens, we'll see you in court."