Opticallimits

650D, 18-35 IS STM, 40/2.8 STM (pancack).



http://www.dpreview.com/news/2012/06/08/Canon-announces-EOS-650D-Rebel-T4i

• AF in LV and video
  
  
• Touchscreen
  
  
• Master built-in flash
  
  
• Digic 5 processor
  
  
• All AF points are cross-type
  
  
• Built-in stereo microphone
  
  

Bearing in mind it's a Rebel and not XXD or XD I think they did a fine job.



http://www.dpreview.com/news/2012/06/08/Canon-creates-EF-S-18-135mm-F3-5-5-6-IS-STM-EF-40mm-F2-8-STM



When considering the overall size of lens and camera I'm struggling to see the allure of pancake design, especially with the existence of the significantly faster 35/2 and 50/1.8. Maybe the STM will find lovers in the video realm but for stills?



BTW, based on what is currently known, does anybody understands how STM is better than Ring-USM?

[quote name='Yakim' timestamp='1339138397' post='18761']

650D, 18-35 IS STM, 40/2.8 STM (pancack).



http://www.dpreview.com/news/2012/06/08/Canon-announces-EOS-650D-Rebel-T4i

• AF in LV and video
  
  
• Touchscreen
  
  
• Master built-in flash
  
  
• Digic 5 processor
  
  
• All AF points are cross-type
  
  
• Built-in stereo microphone
  
  

Bearing in mind it's a Rebel and not XXD or XD I think they did a fine job.



http://www.dpreview.com/news/2012/06/08/Canon-creates-EF-S-18-135mm-F3-5-5-6-IS-STM-EF-40mm-F2-8-STM



When considering the overall size of lens and camera I'm struggling to see the allure of pancake design, especially with the existence of the significantly faster 35/2 and 50/1.8. Maybe the STM will find lovers in the video realm but for stills?



BTW, based on what is currently known, does anybody understands how STM is better than Ring-USM?

[/quote]



as far as one can tell from sentences like this:" However, while hybrid AF is available with all lenses, smooth and quiet AF for video is dependent on the use of the latest STM lenses.".

STM:

1) silent compared to normal micromotors.

2) STM uses a stepper motor. Presumably this will allow precise smooth movement control, while a micromotor might take a bit to get to speed, so maybe the later is a bit more jerky.



regarding USM. USM is also silent, but how is the movement? As far as I can tell it's fast and accurate, so STM shouldn't really have an advantage over USM with respect to point B.



So, I presume the main difference is still cost. STM is now in the new pancake 40mm lens, which is a cheap lens.

ring USM could also be a bit larger, since it's around the whole lens. There is a disassembly, you can see it's actually not that small:

http://www.photoscene.com/sw/tour/inside.htm

Surprisingly the MTFs of the 18-135 IS STM look improved compared to the old model - quite a bit actually.

[quote name='Klaus' timestamp='1339151973' post='18767']

Surprisingly the MTFs of the 18-135 IS STM look improved compared to the old model - quite a bit actually.

[/quote]



New:

http://www.usa.canon.com/cusa/consumer/products/cameras/ef_lens_lineup/ef_s_18_135mm_f_3_5_5_6_is_stm



Old:

http://www.usa.canon.com/cusa/consumer/products/cameras/ef_lens_lineup/ef_s_18_135mm_f_3_5_5_6_is



Note: the wide MTFs of the STM are to the right

[quote name='Yakim' timestamp='1339138397' post='18761']

When considering the overall size of lens and camera I'm struggling to see the allure of pancake design, especially with the existence of the significantly faster 35/2 and 50/1.8. Maybe the STM will find lovers in the video realm but for stills?



BTW, based on what is currently known, does anybody understands how STM is better than Ring-USM?

[/quote]

The STM is a must for fast live view contast AF. That is why all mirrorless cameras choose stepper motors over USM-style motors.



The 40mm f2.8 is still a lot more compact than the 35mm f2 and the 50mm f1.8. The 50mm f1.8 anyway is awful with its AF. The 35mm is noisy, and has 5 sided non-rounded aperture blades, the 40mm is better in that respect. It is also much cheaper.



Whether this pancake has the so-so bokeh of most other pancake lenses or not still has to be seen.

[quote name='Klaus' timestamp='1339151973' post='18767']

Surprisingly the MTFs of the 18-135 IS STM look improved compared to the old model - quite a bit actually.

[/quote]

I am not too surprised about that... It is the only STM zoom they offer. If they want to make a big point of the hybrid AF system for live view, it is the only option, and it would be stupid to have the only option have the not so great performance of the old 18-135mm.



The optics have changed quite a bit:

Old 18-135mm:



New 18-135mm STM:





The 40mm f2.8 TSM does not have half bad MTFs either (for a pancake):



Here is the lens construction:

[quote name='Brightcolours' timestamp='1339153014' post='18770']

I am not too surprised about that... It is the only STM zoom they offer. If they want to make a big point of the hybrid AF system for live view, it is the only option, and it would be stupid to have the only option have the not so great performance of the old 18-135mm.



The optics have changed quite a bit:

Old 18-135mm:



New 18-135mm STM:







[/quote]



Maybe one reason for the substantial redesign was the need to have minimal mass (small lens/lens group) for focusing, like in the case of the Olympus redesign that you posted in the other thread http://www.olympus.com.au/Learn---Explore/Core-Technologies/MSC-lens-technology.aspx

Alas, no information given here which parts are moving during focus.

Quickly skimming through the dpreview preview, I note the phase part of the hybrid AF is only effective in the centre region with a coverage area smaller than the 9 point diamond. Of course still an improvement over what was there previously, but it is no mirror killer (yet).



Also they say the STM lenses are focus-by-wire. Let's just say I'm not a fan of that...

[quote name='popo' timestamp='1339158155' post='18774']

Quickly skimming through the dpreview preview, I note the phase part of the hybrid AF is only effective in the centre region with a coverage area smaller than the 9 point diamond. Of course still an improvement over what was there previously, but it is no mirror killer (yet).



Also they say the STM lenses are focus-by-wire. Let's just say I'm not a fan of that...

[/quote]

They "have" to be focus by wire, as the lens has no traditional gearing system due to the stepper motor.

[quote name='Brightcolours' timestamp='1339152166' post='18769']

The 40mm f2.8 is still a lot more compact than the 35mm f2 and the 50mm f1.8. [/quote]



That's hardly a surprise as it is a lot slower.



[quote name='Brightcolours' timestamp='1339152166' post='18769']

The 50mm f1.8 anyway is awful with its AF. [/quote]



In my 20 years of shooting I had two copies of it and have used several others. With all due respect, that is nonsense. I was actually quite amazed to witness how good it performs, especially when one remembers its super-cheap price and primitive design. In his test Klaus also [url="http://www.opticallimits.com/canon_eos_ff/415-canon_50_18_ff"]noted[/url] : "The AF speed is pretty fast".



[quote name='Brightcolours' timestamp='1339152166' post='18769']

The 35mm is noisy, and has 5 sided non-rounded aperture blades, the 40mm is better in that respect. [/quote]



Very likely.



[quote name='Brightcolours' timestamp='1339152166' post='18769']

It is also much cheaper.[/quote]



Again, that's hardly a surprise as it is a lot slower.