CANON EOS 600D WITH STM 50MM F/,1.8

[Jimbak]

Hi i have Canon EOS 600d/T3i and i want to buy Canon 50mm f/1,8 STM will the len fits in my camera or not?

And the len have manual focus in video?

[jrhoffman75]

I don't have the pancake or zoom, but it seems to be a popular lens on non-gripped bodies for street photography. Compact package.

[ebiggs1]

To each his own.  Makes me happy. 

[TTMartin]

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@ebiggs1 wrote:

To each his own.  Makes me happy. 

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I understand constant aperture lenses are harder to design and build than variable aperture lenses, so they constant apertures lenses are typically higher end lenses.

What I never understood, was if you can make a constant aperture 70-200 f/2.8 lens, couldn't you make just as high a quality 70-200 f/1.4 - 2.8  variable aperture lens? And why wouldn't you want a lens like that?

[amfoto1]

What's really important here is that STM lenses (be they EF-S or EF mount)  use "fly-by-wire" focusing... In other words they require power supply to drive the focus motors and have no mechanical means of directly controlling focus manually. With the camera off or in sleep mode, you won't be able to manually focus. Also, when you first turn the camera on or awaken it from sleep mode, the lens will do a "reset" of the focus, which surprises some people. STM can be manually overridden (like USM), but once again requires the lens be powered on at the time to do so.

Newer cameras are optimized to work with STM. I don't have any myself, but understand that the STM lenses act a little odd on some older camera models that pre-dated the introduction of STM in 2012. No harm done apparently and it should work fine, but it might be a little noisier focusing and/or have some other minor quirks when used on earlier camera models.  I believe the Rebel T5i/700D and 70D were the first models optimized for use with STM.

So, in answer to your question... yes, it will fit and work. Just don't be surprised if the lens operates slightly differently than other Canon lenses you've used (micro motor or USM).

And, yes, one instance where you might want to operate the lens focus with power off would be when putting the camera away, setting focus to infinity in order to retract the lens fully for storage. With an STM lens, it's simply that the power needs to be on to do this.

Other points from the manual have to do with STM zoom lenses. Of course teh STM 50/1.8 isn't a zoom, so those don't apply.

***********

Alan Myers
San Jose, Calif., USA
"Walk softly and carry a big lens."
GEAR: 5DII, 7D(x2), 50D(x3), some other cameras, various lenses & accessories
FLICKR & EXPOSUREMANAGER 

[TTMartin]

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@amfoto1 wrote:

. . . 

Newer cameras are optimized to work with STM. I don't have any myself, but understand that the STM lenses act a little odd on some older camera models that pre-dated the introduction of STM in 2012. No harm done apparently and it should work fine, but it might be a little noisier focusing and/or have some other minor quirks when used on earlier camera models.  I believe the Rebel T5i/700D and 70D were the first models optimized for use with STM.

. . .

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i've had no issues using the 40mm f/2.8 STM with my Canon XTi. It makes a great little compact combination.

[ebiggs1]

"...  couldn't you make just as high a quality 70-200 f/1.4 - 2.8  variable aperture lens?"

Don't we wish it were that simple?  Remember f1.4 is two stops faster than f2.8.  And the lens has to be designed as a 70mm f1.4.  Make sense?  The cost of that alone would make the cost soar.  Lets consider a close comparison. The EF 50mm f1.4 is around $350 bucks.  But the EF 50mm f1.2L is about $1500.  This is less than a stop difference. And four times the price.   Granted it is an L vs a standard but the comparison is still valid.

I guess we can dream.

[ebiggs1]

Of course cost is only one of the factors.  A few others would be size and weight.  It would be huge and it would be heavy. Very heavy.  Add to that it is a zoom with all its problems.

[TTMartin]

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@ebiggs1 wrote:

Of course cost is only one of the factors.  A few others would be size and weight.  It would be huge and it would be heavy. Very heavy.  Add to that it is a zoom with all its problems.

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The lens is already designed to have an f/2.8 aperture at 200mm. Keeping that same aperture size works out close to f/1 at 70mm.  Making a constant aperture L lens variable aperture shouldn't increase the size or weight at all. It seems like more of a marketing issue than a technological one. But, then I could be missing something.

[RobertTheFat]

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@TTMartin wrote:

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@ebiggs1 wrote:

Of course cost is only one of the factors.  A few others would be size and weight.  It would be huge and it would be heavy. Very heavy.  Add to that it is a zoom with all its problems.

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The lens is already designed to have an f/2.8 aperture at 200mm. Keeping that same aperture size works out close to f/1 at 70mm.  Making a constant aperture L lens variable aperture shouldn't increase the size or weight at all. It seems like more of a marketing issue than a technological one. But, then I could be missing something.

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Since you seem to be more knowledgeable about lens design than most of us think we are, perhaps you could enlighten us (without the arm waving) as to how the specific issues that would surely arise (optics, autofocus motor, aberration control, size and weight, manufacturing, etc.) should be approached. Normally I wouldn't try to put you on the spot, but you seem so sure of yourself, and so resistant to others' cautionary comments, that I guess you won't mind in this case.

[jrhoffman75]

" It seems like more of a marketing issue than a technological one."

If it was marketing I would think marketing would favor the variable aperture. Folks would be all over a "70-200mm f/1.0-2.8" lens.