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Rumours: Canon 40mm pancake and STM motor
#1
I wont hotlink the pics but Canonrumors show two new lenses as well as the T4i/650D:

http://www.canonrumors.com/



Pancake is EF 40mm f/2.8 and looks small enough. Enter the usual arguments about the need to make DSLRs smaller and it being slow for a prime. Would you use one on a 5D3 for example?



Other lens is EF-S 18-135 IS STM which is described as a silent motor. I assume it wouldn't be either form of USM, so have they done something cheaper but still silent? Could make sense for budget video usage, especially as the 650D is currently rumoured to have full time AF in video and live view.



Rumoured announcement on Friday so not long to wait anyway.
<a class="bbc_url" href="http://snowporing.deviantart.com/">dA</a> Canon 7D2, 7D, 5D2, 600D, 450D, 300D IR modified, 1D, EF-S 10-18, 15-85, EF 35/2, 85/1.8, 135/2, 70-300L, 100-400L, MP-E65, Zeiss 2/50, Sigma 150 macro, 120-300/2.8, Samyang 8mm fisheye, Olympus E-P1, Panasonic 20/1.7, Sony HX9V, Fuji X100.
#2
Is USM actually expensive? Would it not be more expensive to machine a new motor than re-use the current technology or is there another issue with USM ? The 40 looks a little like the voightlander; anyways in canon land it just doesn't make sense unless - as you suggest - there is a smaller full frame body in the works.
#3
If USM (ring or micro) was cheap, wouldn't they put it in everything already? That they haven't means there is still some need for something else.



As for pancakes, they all look kinda the same to me. The Canon 40mm reminded me more of the Pana 20mm since I had that already.



My only fear is Canon end up "doing a Pentax" with a mirrorless that takes SLR lenses... I could only excuse them in that case only if it was full frame.
<a class="bbc_url" href="http://snowporing.deviantart.com/">dA</a> Canon 7D2, 7D, 5D2, 600D, 450D, 300D IR modified, 1D, EF-S 10-18, 15-85, EF 35/2, 85/1.8, 135/2, 70-300L, 100-400L, MP-E65, Zeiss 2/50, Sigma 150 macro, 120-300/2.8, Samyang 8mm fisheye, Olympus E-P1, Panasonic 20/1.7, Sony HX9V, Fuji X100.
#4
The STM motor may be s sign that Canon has developed a hybrid AF system. Meaning, the new 650D may sport fast contrast AF, and the new version has a motor and electronics that can handle fast contrast AF and phase detect AF. Olympus is not using USM motors for the very same reason... They are not the right type of motor to implement fast contrast AF with.



As for Canon doing the "Pentax thing", that is not going to happen. Canon is said to work on a mirrorless system with its own lenses, AND with full EF compatibility. That then means a compact camera without mirror box, but with an EF adapter that allows AF/IS/aperture control.
#5
[quote name='Brightcolours' timestamp='1339064316' post='18737']

The STM motor may be s sign that Canon has developed a hybrid AF system. Meaning, the new 650D may sport fast contrast AF, and the new version has a motor and electronics that can handle fast contrast AF and phase detect AF. Olympus is not using USM motors for the very same reason... They are not the right type of motor to implement fast contrast AF with.



As for Canon doing the "Pentax thing", that is not going to happen. Canon is said to work on a mirrorless system with its own lenses, AND with full EF compatibility. That then means a compact camera without mirror box, but with an EF adapter that allows AF/IS/aperture control.

[/quote]



As far as I know, USM seems to be very fast, faster than micromotors. Why would it not be fast enough for contrast detect, what else would be faster than USM?
#6
[quote name='photonius' timestamp='1339071654' post='18739']

As far as I know, USM seems to be very fast, faster than micromotors. Why would it not be fast enough for contrast detect, what else would be faster than USM?

[/quote]

USM does not react fast enough for the small steps contrast detect needs. It is not about speed but the way the motors are being used. USM is fine for PD AF use, where the motor does not have to stop moving for focus check.



As I said, this is the reason Olympus uses MSC motors in the contrast AF based MFT lenses, and not the SWD motors (USM clones) they used in PD AF DSLRs.



http://www.olympus.com.au/Learn---Explor...ology.aspx
#7
[quote name='Brightcolours' timestamp='1339073516' post='18741']

USM does not react fast enough for the small steps contrast detect needs. It is not about speed but the way the motors are being used. USM is fine for PD AF use, where the motor does not have to stop moving for focus check.



As I said, this is the reason Olympus uses MSC motors in the contrast AF based MFT lenses, and not the SWD motors (USM clones) they used in PD AF DSLRs.



http://www.olympus.com.au/Learn---Explor...ology.aspx

[/quote]



I suppose that contrast AF applies for motion picture recording? That new Canon body seems to emphasize motion picture recording ability with it's stereo microphones?
#8
[quote name='Brightcolours' timestamp='1339073516' post='18741']

USM does not react fast enough for the small steps contrast detect needs. It is not about speed but the way the motors are being used. USM is fine for PD AF use, where the motor does not have to stop moving for focus check.



As I said, this is the reason Olympus uses MSC motors in the contrast AF based MFT lenses, and not the SWD motors (USM clones) they used in PD AF DSLRs.



http://www.olympus.com.au/Learn---Explor...ology.aspx

[/quote]



If you look at the description of the Olympus technology, the key emphasis is put on a totally new lens design (compared to the previous lens), where now only a single small lens needs to be moved to reduce mass to an absolute minimum. "Low focusing optical mass for extremely fast moving speed and precise control".

This seems to be the most important aspect. Sure, there is also the "High speed drive motor with precise stop-start control characteristics". But I am wondering there if that motor is indeed faster than a USM motor.

The key question, as you put it, is what is the lag of the system. Does it take a while for the USM to get up to speed, so to speak. I actually don't think so. Piezo is extremely fast responding. The issue could be the "ring" USM, which may cause the whole system to have a larger mass since it's made as a ring around the lens. But a micro USM, like Canon uses in the 50mm f1.4 should do the job, if it's only a mass issue.
#9
Like I suggested, indeed the STM have been introduced to allow fast AF in live view. The type of motor used does make a huge difference.



So there you have it... STM for fast contrast detect in live view and in video mode. Not that I like AF in video.
#10
[quote name='Brightcolours' timestamp='1339133074' post='18759']

Like I suggested, indeed the STM have been introduced to allow fast AF in live view. The type of motor used does make a huge difference.



So there you have it... STM for fast contrast detect in live view and in video mode. Not that I like AF in video.

[/quote]



Actually, I think the key is the silent: " fast, quiet operation when shooting video", so the sound doesn't mess up the video.

So, all in all, I think it's just a micromotor that is silent (and fast enough), but it's still cheaper than USM. Otherwise, it wouldn't be offered as a 40mm pancake with STM.
  


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