What is the different between EF-S IS II vs. EF-S IS STM lenses?

[jrhoffman75]

EF-S is the lens mount description. EF-S lenses are designed to only go on crop sensor versions of Canon DSLRs.

IS means the lens has Image Stabilization. You will find some lenses with IS and some without.

Most lens will have USM or STM next in the name. USM means Ultrasonic focusing motor and STM means Step-focusing motor. Some older lenses use and older type motor and don't have USM or STM. USM is more prevalent than STM. STM is generally considered better if you do a lot of video recording.

The II is the second version of the particular lens. If everything else is the same but the II (some have III and if I recall there may be a few with a IV) it means it is a later model of that lens.

[TTMartin]

STM is a type of focus motor. The STM focus motor focus faster than everything but a USM focus motor. It is one of the newer focus motors Canon has. This means that any lens that has the STM focus motor, is a more recent optical design. As a rule, the image quality from the STM version of the lens, will be superior to the non-STM version.

I may be wrong, but, I think you must be refering to the EF-S 55-250 IS II and the EF-S 55-250 IS STM. In this case the STM lens focuses faster, and has better image quality, and it the clear pick between the two.

[kvbarkley]

Usually what it means is that Canon redesigned the USM lens to give it the II designation. Then they redesigned it again with the STM and called it that.

[TTMartin]

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@kvbarkley wrote:

Usually what it means is that Canon redesigned the USM lens to give it the II designation. Then they redesigned it again with the STM and called it that.

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I can't think of any EF-S USM II lens. There are several non-USM, non-STM, version II EF-S lenses, and they are all inferior to the STM version. 

There is a new EF-S 18-135 IS USM which matches the STM version in image qualtiy. But, again, all the non-USM, non-STM lenses regardless of their version don't match the image quality of their STM counter part.

[kvbarkley]

Yeah, I think you are right about the USM part, but same idea. STM is an improvement over USM, too.

[TTMartin]

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@kvbarkley wrote:

https://www.usa.canon.com/internet/portal/us/home/products/details/lenses/ef/standard-zoom/ef-s-18-5...

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Yep, that is a perfect example of a non-USM, non-STM, Version II lens that is inferior to the 18-55 IS STM version of the lens.

[kvbarkley]

Which is why I cheated and edited, you are too fast.

[TTMartin]

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@kvbarkley wrote:

Which is why I cheated and edited, you are too fast.

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The reason why I emphasize the non-USM part, it that for EF IS USM the version II lenses are all the top of the line, like the EF 70-200 f/2.8L IS II USM,  or the EF 100-400 L IS II USM.

So version II in an EF USM lens is a good thing.

On an EF-S non-USM lens, version II, not a good thing compared to the STM version

[Waddizzle]

"There is a new EF-S 18-135 IS USM which matches the STM version in image qualtiy. But, again, all the non-USM, non-STM lenses regardless of their version don't match the image quality of their STM counter part." 

From the little slice of examples that I have seen, this opinion is indeed a fact.  The STM designs are newer than non-STM lenses.  I understand that the USM design is newer than the STM.  The glass used in some lenses could very well be old designs, but the focusing motors seem to have vastly improved since autofocus lenses were first introduced.  Ditto for Image stabilization.

I have no specifications on the motors used in the lenses.  Stepping motors are rated at how many steps, or incremental movements, the motor makes to complete a full rotation.  Motors are becoming more and more precise, capable of smaller and smaller steps, which naturally translates into more precise control over the movement of the focusing elements.