don_b__south_africa_

>> I think that the 28/1.8 USM is a comparable lens to the 30/1.4 and is FF compatible to boot. Price is actually a little cheaper.....

 

Yes, but f/1.4 is nearly a stop faster than f/1.8. However, I think Canon has just about convinced me to get rid of the Sigmas, and I suppose the 28/1.8 is the best Canon option for a normal lens on a crop camera.

I've had excellent results with a 199A on a 300D, a 350D and a 30D. Sometimes I even think that the old thyristor auto flash exposes just as well as the fancy E-TTL II system.

 

I've got several vintage flashguns, and I've equipped them with optical slave triggers. Since some of the flashes have manual power adjustment, it makes for quite a flexible portable lighting setup.

>> "My conclusion was, that the AF on the 350D is not very consistent, especially not at f1,4. So I sold the 350D and my two f1,4-primes and bought a 30D."

 

Henrik, you may be right about the 350D. One of the reasons I upgraded to a 30D was because my most prized lens, the 24-70/2.8L, was a little iffy about focus on the 350D. Nothing serious, mind you -- it was just a little bit off, randomly either back or front, more often than I would have liked. Tests on a friend's 20D and a colleague's 1D showed that the lens focused perfectly on those bodies. And now it focuses perfectly on my new 30D. So far, so excellent.

 

Ironically, the Sigma 30/1.4 always focused bang-on on the 350D, even at 1.4, where the DOF is sliver-thin. I expected it to do just as well on the 30D, but instead it front-focuses by miles -- or by about 20ft over a 60ft distance. This is not "misfocusing". This is something seriously amiss.

>> "We don't really know how the Canon EOS / EF interface works. It may be a lot more complicated than we may imagine it to be. It is entirely possible and even likely that instead of this being an evil plot against Sigma et al, the lens / body issues are a side effect of the vast complexity of the system. With a total of 53 bodies, 127

lenses, 4 teleconverters, and 4 extension tubes available, the amount of possible interactions between these highly computerized components is huge."

 

Any sensible design engineer -- and we assume Canon employs sensible engineers -- would, when faced with the prospect of a system with so many components, design an interface to be rigorously standard and as simple as possible.

 

And, indeed, it seems Sigma is capable of making its lenses function flawlessly on all 53 Canon bodies. It's only when the 54th body comes out that Sigma lenses go haywire on it. Which smacks, if you prefer to call it such, of an evil plot.

 

Not that I think it's evil in any way. It's just a reason to wonder if Nikon isn't perhaps a better option if you want the widest possible choice of lenses.

Henrik, yes, a recognition algorithm is what would be required. However, it would have to be encrypted and appear different for each lens or else it could simply be copied. I tried earlier to give an over-elaborate account of how such a scheme might work.

 

To me, though, logic is increasingly suggesting that such a scheme might well exist. The occasional Canon lens might misfocus a bit, but by and large they are rock solid on Canon bodies. Sigma, on the other hand, has a terrible reputation for lenses being obsoleted by new Canon bodies. This fact is not disputed by most people.

 

And to labour the point slightly, I find it stretches credulity to think that Sigma is simply a stupid company that cannot reverse-engineer body-lens communication. What has to be transmitted, anyway? Surely nothing more than distance info from the lens and aperture info and focus-motor instructions from the body. Not rocket science, as I have said.

Well, Yves, a conspiracy requires more than a single party to it, so I don't think I have a conspiracy theory here.

 

I reckon it's perfectly possible that Canon, irked by loss of lens sales to off-brand makers in the FD period, decided to put something into the new EF lenses -- which now contained their own little computers, after all -- with which to make life difficult for third-party lens makers.

 

As I said in an earlier post, the information exchanged between lens and body for functional purposes must be be quite trivial and very easy to decode, certainly for a big company with Sigma's resources. If Sigma does keep on getting it wrong, either Sigma has a bizarre blind spot or something hidden in the Canon system is periodically being wheeled out to scupper the current generation of Sigma lenses.

 

In fact, it seems less a possible explanation than a probable one. Nothing paranoid involved.

Thieves and parasites! That's rather extreme. Look, there are degrees of reverse engineering, and some are certainly immoral, such as copying patented techniques and processes.

 

But, by your standards, it would be immoral, for example, to measure the output of a Ford's electronic ignition system so that you could design a compatible tachometer. And I think that's absurd.

 

And what "investment and research" of Canon's are off-brand lens makers actually exploiting? They're taking a signal from the camera's metering and focusing systems, certainly, but that's inherent in building a modern lens. For the rest, they're conducting their own perfectly respectable R&D on lens design, coatings, etc etc. And that's surely where the serious R&D is concerned in making a lens.

>> I bought Canon system because lenses quality is the most important factor to me. Cameras are almost disposable parts and can be exchange every few years. Mostly quality of photo is limited by glass not a camera.

 

Canon makes some brilliant glass but it also makes some horrible glass, and has peculiar gaps in its range. Sigma makes a lot of horrible glass but also some gems, such as the 70-200mm/2.8 and the 30mm/1.4. It is blind brand loyalty to suggest that only Canon glass is capable of producing top-quality pictures.

>> What amazes me is that there must be so many ways to reconfigure the connections but somehow Canon's own lenses do not become obsoleted by this practice.

 

Indeed, and I think you've hit the nail on the head -- it must be digital chicanery involving encryption. I doubt that those EF lens contacts are anything but a data bus (in other words, there's not one contact for focus, one contact for aperture and so on).

An even more plausible scenario for what Canon may be doing is this. The company may have taken a decision at the dawn of the EOS system to insert a different set of public-key-encrypted data into the firmware of every EF lens.

 

No third-party lens maker would be able to deduce its function, because it wouldn't have any overt function, and because every lens would have a different encrypted data block, it wouldn't be possible simply to reproduce it in third-party lens firmware and hope for the best.

 

Then, as Canon rolls out new bodies, it can have the algorithms in those bodies interrogate the encrypted data and make interesting decisions about what to do if everything doesn't add up.

 

This wouldn't explain why Tamron and Tokina lenses allegedly have no problems on new Canon bodies (although some say they do), but it should be possible to contrive such altered body algorithms to target a specific maker's -- such as Sigma's -- lenses specifically.

 

Sigma is getting a bad rep because of these difficulties and, if Sigma is Canon's biggest lens competitor, it might be in Canon's interests to keep most Tamrons and Tokinas working perfectly just to make Sigma look particularly bad.

 

A prediction follows from this hypothesis: If Sigma goes down and Tamron overtakes it as the biggest threat to Canon lens sales, one will expect to see Tamron lenses mysteriously failing to work on new Canon bodies.

>> Every single Canon camera's manual warns you against using 3rd party lenses / flashes.

 

Yes, well, and my Suzuki motorcycle manual warns me sternly against using any lubricants other than Suzuki-brand oils, which are, of course, three times the price. Does anybody take this kind of self-serving corporate warning seriously?

Neil, I salute your dedication to manual focus. I regard this new-fangled autofocus stuff with some suspicion myself, and I'd be delighted if my old FD lenses could be made to work on a digital body. Ten points off, Canon, for screwing all your old customers. I'd be even more delighted if digital bodies had proper focusing screens, but, alas, they don't, unless you spend the seriously big bucks.

 

>> Canon does not care because they want you to buy thier own lenses of course. Their angle is that their lenses have no compatitbility issues!

 

If Canon simply didn't care, I wouldn't be annoyed. What irks me is the strong suspicion that Canon keeps in reserve secret and fundamentally nonfunctional parts of the lens communication protocol so that it can invoke them now and again in new bodies to confound Sigma lenses. Sigma is the biggest off-brand seller, is it not?

 

I say nonfunctional because communication between a body and lens is hardly rocket science. Certain, very limited parameters need to be passed both ways, and it should be the easiest thing in the world to reverse-engineer all the functional aspects of such a protocol. I suspect that Canon itself is doing some reverse-engineering -- of Sigma lenses. Aha, says Canon after testing a bunch of Sigma lenses, Sigma is using such-and-such a parameter to do such-and-such arithmetic in a way that we don't -- so let's change the focusing algorithms to mess up Sigma lenses' focusing calculations! Plausible, no?

 

Don

>> My Ford Warrantee does not cover my aftermarket non-ford XM Radio.

 

No, of course not, but if your new Ford started putting out 10 volts instead of 12 on the accessory circuit and, as a result, your old radio wouldn't tune in, you'd have a legitimate beef against Ford. You wouldn't be much soothed by Ford's statement that all Ford-brand radios have stable tuning down to 9 volts, now would you?

Giampi, yes, you're right, I should calm down. Certainly I did accept the risks of buying Sigma: but supposedly, according to much of what I saw while doing my research, the dire problems of yesteryear were over. So I was wrong.

 

I wouldn't be at all surprised, though, if Canon were doing this deliberately with new bodies, as an earlier poster suggested. If that's true, then it's a monopolistic practice and it stinks. And since I harbour that suspicion, I'm afraid it's made me a little angry.

 

Now I will calm down. Promise.

In case you're interested, I unwittingly started up some parallel excitement about a front-focusing Sigma 30mm at

http://www.photo.net/bboard/q-and-a-fetch-msg?msg_id=00Gm4f

Yves, thank you very much for the pointers to those other threads. If nothing else, it's good for the soul to know that one is not alone.

 

Henrik, of course those pictures aren't "evidence". No picture could be. But do you seriously imagine I've determined that my Sigma 30mm front-focuses on the strength of a single pair of pictures?

 

And to those Canon loyalists who seem to imply that anybody who buys off-brand lenses deserves whatever misfortune he gets, I suggest you must be in favour of anti-competitive corporatism at heart.

 

As for why I chose Sigma: well, in South Africa there isn't much choice. In the old FD days, Tamron and Tokina were widely available here, but they seem to have vanished a decade ago or more. Tamron lenses have recently appeared again in a couple of shops, but afaik until recently it was a straight choice between Canon and Sigma. We don't all live in New York, you know. And Canon, in fact, makes no lens comparable to the 30mm/1.4, unless you count the 35L, which is a little too rich for my blood.

 

And as for Sigma's response to my problem, yes, I'm very pleased with their attentiveness and I'm crossing my fingers that when the calibration equipment arrives, I'll be sorted out.

 

Don

And, as a matter of interest, does any other maker, such as Nikon, publish its lens communication spec? Because, if there is one, I would be sorely tempted to switch brands to the "open source" one.

Ummmm, I think it actually *is* Canon's problem, in the sense that I might well not have bought the 30D if I'd known I was about to enter a world of pain with two of my existing lenses. And it's not as if I shun Canon lenses -- I've dropped tons of money on them.

 

If anything, Canon would do well in the eyes of users like me to make sure that new bodies DON'T derange off-brand lenses, if possible.

Hi

 

I have two Sigma lenses: a 30mm/1.4 and a 10-20mm/4-5.6. They worked perfectly

on my 350D, so much so that I sang their praises.

 

Then I upgraded to a 30D body. And the Sigma lenses started front-focusing. The

10-20 is not too bad, partly because of its huge DOF, but the 30mm -- a

favourite lens of mine -- has become unusable at anything brighter than f/11.

 

Anybody else had a similar experience, and how was it solved?

 

Sigma South Africa has been very responsive, and indeed claims to be importing

special calibration equipment from Japan to solve my problem. But I remain

perplexed as to why the lenses should perform so differently on the 30D and 350D.

 

My Canon lenses -- three "L"s -- are fine on both bodies.

 

All theories gratefully received.

 

See http://www.pbase.com/glassbottle/focus_problems

 

Don

See my message above. Sigma South Africa got back to me to say that Japan had looked at my sample pictures and decided that the focus on my Sigma lenses needed recalibrating. Japan is sending some special equipment to South Africa to enable the local agents to do the job. The equipment arrives on June 18.

 

If this sorts out the problem, I'll be impressed with Sigma's customer service.

 

I still can't understand -- and Sigma has not explained -- why the lenses should have been fine on a 350D but gone bananas on a 30D. Grateful for your ideas on the subject.

 

Don

Yowee, I'm having a serious problem with a Sigma 30mm on a new Canon 30D body. The Sigma front-focuses by miles, making it unusable. My Canon lenses focus perfectly on the same body.

 

Sigma in South Africa seems to disbelieve me and wants to blame the body. But why should Canon lenses be fine and Sigma ones not? Incidentally, I have a Sigma 10-20mm as well, and it also front-focuses on the 30D. The problem is less obvious because of greater depth of field.

 

Both Sigma lenses were spot-on when used on my 350D. Very puzzling.

 

Here are two 100% near-centre crops of pics taken with the Sigma 30mm and my Canon 24-70mm/2.8L. Both pics were taken with the same settings: 1/1500s, f/2.8.

 

http://www.pbase.com/glassbottle/focus_problems

 

In both cases the focus target was the edge of the roof of the house across the street. As you'll see, a fence about 20ft closer is what's in focus in the Sigma shot!

 

These results are typical, consistent and reproducible.

 

I wonder what the hell is going on. Anybody got any idea?

 

Don

Excella lights are made in Thailand by the same company that produces a line called Electra. I was sceptical myself, especially considering that a Google search suggests they are available only in the East, South Africa, Romania, Russia, Germany and the Netherlands.

 

However, the local distributor in South Africa claims in advertising that they are "used exclusively" by the National College of Photography, to which I duly sent an email. The reply:

 

Dear Don,

For more information on the manufacturing of the Electa brand please contact Interfoto directly on 011 403-1000.

 

I can tell you with confidence that in all my years of photography, having worked with numerous brands of studio lights, the Electra lights have proved to be exceptional value for money and extremely reliable. Furthermore the after-sales service from Interfoto is brilliant.

 

As a result, the College now exclusively uses Electra equipment.

 

Yours sincerely

 

Martin Osner

Senior Lecturer

NATIONAL COLLEGE OF PHOTOGRAPHY

 

<quote off>

 

I also spoke to the MD of the South African national distributor, who claims he gave up the local Elinchrom agency years ago because after-sales service was too troublesome and expensive. He says he's been distributing Electra for nearly 15 years and has very few comebacks.

 

Excella, he says, is a new line from Electra, intended as a separate brand with separate retail channels but which is basically Electra guts in a more modern-looking housing.

 

For what it's worth, I feel reassured enough to try a pair of the things, and I'm awaiting delivery of my order of two 500W-s Excellas.

 

Don