is the mount the only difference in a 3rd party lens

[jann1033]

ie is a nikon 70-300 sigma the same lens as a canon 70-300 sigma except for the mount? wondering as sometimes i can find a reviewed lens for nikon but not canon...would there be a difference in the way they work between brands? ie if a sigma has a focus problem would that carry over to all brands? comprende?

 

[ukcatfan]

I asked the same question once and was told that it sort of applies. B/c each brand handles them a different way, they can give different results. I believe it is b/c the manufacturer of the camera does not supply the 3rd party with the framework of the software handling communication and they sort of hack into it to make it work. Sometimes they do well and other times not so well. And it could vary between camera brands for the same lens. I would not expect dramatic differences though.

Kevin

 

[gruZ]

Sort of off the point, but for what it is worth, there are adapters to allow certain mounts to work with other camera models. I know there are Nikon lens to Canon body adapters, such as this one here. I don't know if there are reverse adapters. I have not used these, don't know anyone who has, and can't vouch for their effectiveness.

 

[handicap18]

From what I understand jann, yes. The mount is the difference. I could be completely wrong, but from looking at photo's sorted by lens at flicker.com the pics from both Nikon and Canon with various Sigma and Tamron and Tokina lens are great. I've noticed when pricing lenses out that there is a slight difference in price. Usually only a few dollars, though for Pentax camera's I've seen Sigma prices about $50 more. I guess the only real way to find out is to ask the particular lens maker. The auto focus might work differently as Nikon, Canon and Pentax auto focus isn't the same (though the HSM Sigma lenses will use the lens to focus). I'm guessing that the metering wouldn't differ as its the same glass and metering is done in the body, though each companies sensor might record the image differently with the same 3rd party lens using the same settings and similar meter mode. But I would think that is not a lens issue.

With the reviews I've seen on different 3rd party lenses, both Canon users and Nikon users say pretty much the same things about each particular lens. So that is a good start to go by anyway.

 

[MarkBarbieri]

For a third party lens to work on different manufacturers bodies, more will be different than just the mount.

With some manufacturers, the body does the focusing work. With others, the focusing motor is in the lens. Some can do it either way.

Every modern lens system invovles communication with the lens to report back things like focal length and focus distance. The communication protocal varies from manufacturer to manufacturer. To make matters worse, the manufacturers don't provide specifications for the communications protocol. The 3rd party lens makers must reverse engineer them. That's why some new bodies don't work with some 3rd party lenses.

Aside from the mount, the focusing, and the communications, I can't think of anything else that would be different.

 

[jann1033]

For a third party lens to work on different manufacturers bodies, more will be different than just the mount.

With some manufacturers, the body does the focusing work. With others, the focusing motor is in the lens. Some can do it either way.

Every modern lens system invovles communication with the lens to report back things like focal length and focus distance. The communication protocal varies from manufacturer to manufacturer. To make matters worse, the manufacturers don't provide specifications for the communications protocol. The 3rd party lens makers must reverse engineer them. That's why some new bodies don't work with some 3rd party lenses.
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Aside from the mount, the focusing, and the communications, I can't think of anything else that would be different.

(my bold)..that might be enough this was why i wondered...i know everyone does not have this problem but i had a terrible problem with a sigma lens and jsut wondered if it could be just with canon or just that lens and if it was worth attempting to get the lower cost lenses or not since i do see some rave reviews of ie tamron...

 

[MarkBarbieri]

I may have overstated the differences. Optically, they should be the same or very, very similar. The focus accuracy might differ between models. The same is true for focus speed, noise, and the ability to manually override focus while staying in auto-focus mode. Once focus is matched, I would expect things like sharpness, color, contrast, CA, optical distortion, etc to be identical.

 

[Anewman]

(my bold)..that might be enough this was why i wondered...i know everyone does not have this problem but i had a terrible problem with a sigma lens and jsut wondered if it could be just with canon or just that lens and if it was worth attempting to get the lower cost lenses or not since i do see some rave reviews of ie tamron...

Well the way I see it from personal experience(no scientific testing), if a SIGMA gives below desired results on with a Canon mount results have always been similar with the same EXACT model nikon mount. The same model tends to get either rave reviews or bad reviews among the different mounts.

But your last sentence seems to be a different question, maybe I am misreading it. Just because ONE Sigma model was terrible does not mean all Sigma models will be. The same way you hearing good things about a Tamron, does not mean different Tamron lenses(models) will be good.