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Author Topic: A Small Sigma 180 f/2.8 OS Macro Issue  (Read 16919 times)

Ellen Schmidtee

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Re: A Small Sigma 180 f/2.8 OS Macro Issue
« Reply #30 on: August 13, 2012, 05:25:37 AM »
But a basic problem remains: Canon doesn't do lens specific processing for fun, but because advanced techniques work only with certain lenses or at need specific data for others. That was a problem in the past when Sigma lenses only reported AF parameters for consumer bodies but lacked the second set for area-type sensors. Most of the time only the pro bodies were affected, and the 7D is using the center of most lenses, but if the 5d3 is an indicator for upcoming high end prosumer bodies...

I think it would be appropriate to distinguish between two cases:

1. Lens specific processing is not applied, because 3rd party manufacturer did not pay for the benefit.

As long as the 3rd party manufacturer does not falsely advertise that the lens would benefit from lens specific processing, e.g. automatic illumination correction or area focus, I see no problem here. The consumer would make a conscious between features (price, IQ, lens specific processing), and do what he sees fit.

2. Lens specific processing is misapplied, because 3rd party manufacturer had it's lens ID itself as an other lens.

IMHO, both the OEM and 3rd party manufacturer should cooperate to avoid this case. When a consumer buys a lens, he does not know which lens specific features would be introduced in future cameras, and how much effort it would take to circumvent it's misapplication.

In other words, I expect manufacturers to apply defensive design to avoid this cases.

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Re: A Small Sigma 180 f/2.8 OS Macro Issue
« Reply #30 on: August 13, 2012, 05:25:37 AM »

Mt Spokane Photography

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Re: A Small Sigma 180 f/2.8 OS Macro Issue
« Reply #31 on: August 13, 2012, 11:53:15 AM »
So Canon doesn't provide a proper way for other manufacturers to make EF lenses without paying horrendous licensing fees. Then it purpously breaks compatibility with existing 3rd party lenses with new bodies. That doesn't sound good to me. All Canon would have to provide would be a proper way to ID the lenses. A simple manufacturer ID + item ID would be sufficient.
Third party manufacturers can assign their own lens ID, they do not need to use a Canon ID.  They are merely trying to be clever, and it backfired.

However, the only way for a camera to know the optical and capable characteristics of a lens, is for the lens to be in the internal table that resides in the camera.  So, Canon would have to maintain data for all the competitors lenses and issue camera firmware updates for them, and get complaints when problems occurred.
Thats like saying car makers should design cars to work with all transmissions from other makes. Then, whenever they want to make a change or improvement, they must get everyone else to change.
Its not so simple as one might believe.
But, the lens correction feature is not mandantory, if a user wants to use a third party lens, he can turn it off.  Canon has actually provided for third pasrty manufacturers, you merely cannot use the lens correction feature in camera.
« Last Edit: August 13, 2012, 11:59:05 AM by Mt Spokane Photography »

Lawliet

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Re: A Small Sigma 180 f/2.8 OS Macro Issue
« Reply #32 on: August 14, 2012, 05:37:48 AM »
e.g. automatic illumination correction or area focus, I see no problem here. The consumer would make a conscious between features (price, IQ, lens specific processing), and do what he sees fit.

2. Lens specific processing is misapplied, because 3rd party manufacturer had it's lens ID itself as an other lens.

That works only if specific processing is optional. But those cases are only the tip of the iceberg, the real trouble starts when the camera needs the processing to work properly. Sure, you could set the AF to "dumb as a rock" as long as there is no proper ID, which likely would result in accusions of deliberatly crippeling 3rd party lenses. Or you shift it down as needed - looks fine on paper, but some of the Sigma lenses either front- or backfocusing depending on the orientation of the test target is uncomfortably unpredictable. And thats with just the center point at constant distance, more fun if you introduce real life variables.
Some cosmetic changes that have no impact on RAW files wouldn't justify to much worrying, I'm more scared of hidden troubles creeping up. ???

Ellen Schmidtee

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Re: A Small Sigma 180 f/2.8 OS Macro Issue
« Reply #33 on: August 14, 2012, 06:15:41 AM »
e.g. automatic illumination correction or area focus, I see no problem here. The consumer would make a conscious between features (price, IQ, lens specific processing), and do what he sees fit.

2. Lens specific processing is misapplied, because 3rd party manufacturer had it's lens ID itself as an other lens.

That works only if specific processing is optional.

IMHO, illumination correction is optional, e.g. the user can turn it off.

Furthermore, what would happen if a customer would mount a new lens without upgrading to a firmware version that knows how much illumination correction to apply?  What if the firmware version that knows that happens to have a bug?

I think it's reasonable for the firmware to fallback to no illumination correction for lenses it doesn't recognize.

But those cases are only the tip of the iceberg, the real trouble starts when the camera needs the processing to work properly. Sure, you could set the AF to "dumb as a rock" as long as there is no proper ID, which likely would result in accusions of deliberatly crippeling 3rd party lenses.

If that happens, Canon should reply those are unrealistic expectations, same as expecting it to buy such 3rd party lenses, invest man hours to measure it's light falloff, & add the appropriate illumination correction to the cameras's firmwares.

Ellen Schmidtee

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Re: A Small Sigma 180 f/2.8 OS Macro Issue
« Reply #34 on: August 14, 2012, 06:21:25 AM »
So Canon doesn't provide a proper way for other manufacturers to make EF lenses without paying horrendous licensing fees. Then it purpously breaks compatibility with existing 3rd party lenses with new bodies. That doesn't sound good to me. All Canon would have to provide would be a proper way to ID the lenses. A simple manufacturer ID + item ID would be sufficient.
Third party manufacturers can assign their own lens ID, they do not need to use a Canon ID.  They are merely trying to be clever, and it backfired.

As long as Canon doesn't set aside those numbers (before or after the fact), it's possible Canon would happen to reuse that ID for one of it's own lenses later on, causing the problem to arise at that time.

However, the only way for a camera to know the optical and capable characteristics of a lens, is for the lens to be in the internal table that resides in the camera.

That's not what I've suggested. My suggestion is to set aside lens IDs, then not perform any illumination correction. That would avoid the problem with practically zero effort and expense for Canon.

danski0224

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Re: A Small Sigma 180 f/2.8 OS Macro Issue
« Reply #35 on: August 14, 2012, 06:42:12 AM »
Does Canon offer licensing options to 3rd party lens manufacturers?

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Re: A Small Sigma 180 f/2.8 OS Macro Issue
« Reply #35 on: August 14, 2012, 06:42:12 AM »