Ring USM ???

[Ron Wilson]

I am looking to buy a 100mm F2.8 Macro. I see that some are advertised with a Ring USM motor while others just say USM. Is there a difference? Is the ring USM bwetter/faster/quieter?

[Cadwell]

"Ring USM" is the better of Canon's two USM mechanisms. It is faster and quieter than the cheaper "Micro USM".

[Ron Wilson]

Thank you for your quick response. Does the 100mm Macro come in both varieties?

[Tom W]

It comes with ring USM only, but I believe that in the past, an earlier version may have had the micro-USM system instead.

[Cadwell]

The EF 100mm f/2.8 Macro USM only comes with a Ring type USM.

http://consumer.usa.canon.com/app/pdf/lens/EFLensChart.pdf

[weasel]

The ring USM on Canon lenses is a primary advantage over 3rd party lenses.

[Tom W]

I checked the Canon museum - there was a previous 100 mm macro lens, but it was not listed as USM. The present version is ring-type USM and has been on the market since 2000.

[Ron Wilson]

Excellent answer, thx Tom.

[ScottE]

The ring USM on Canon lenses is a primary advantage over 3rd party lenses.
Most Sigma HSM lenses are comparable to Canon Ring USM. I believe only the older Sigma 17-35/2.8 HSM was non-ring type.

The advantage of ring type USM or HSM is that manual focus override will not harm the auto focus mechanism. With other types of lenses, autofocus must be disengaged to focus manually or the gears in the auto focus mechanism can be damaged.

[Cadwell]

Some Micro-USM motored lenses have the ability for full time manual focusing. The EF 50mm f/1.4 for example.

[Citizensmith]

The older 100 macro had an AFD focus motor and a tendancy to spend longer hunting than a redneck in duck season. The new 100 macro noted as having USM has ring-USM and is much improved. It is still pretty slugish when compared to something like the 85 1.8 due to the wide range over which it looks for focus. However its a lovely lens, amazing optics, and one you'd never regret picking up.

[tim]

Often stores appreviate the abbreviate the names of lenses, I don't know of any lens currently in production that comes with different types of motors - although just because I don't know something it doesn't mean it's not true ;) Maybe the kit lens comes in a fancy USM version, not that many people should buy it.

[grego]

I know the 15mm f/2.8 fisheye doesn't come with USM. Damn noisy. Only thing i can find wrong with that great, beautiful lens.

[Tom W]

Some Micro-USM motored lenses have the ability for full time manual focusing. The EF 50mm f/1.4 for example.

I think that the 50 is the only one with full-time manual & Micro-USM. It's the only one with a focus scale.

[Cadwell]

I think that the 50 is the only one with full-time manual & Micro-USM. It's the only one with a focus scale.

According to Canon the following lenses also have Micro-USM with full time manual.

EF 28-90mm f/4-5.6 II USM
EF 28-105mm f/4-5.6 USM
EF 28-200mm f/3.5-5.6 USM

[Tom W]

According to Canon the following lenses also have Micro-USM with full time manual.

EF 28-90mm f/4-5.6 II USM
EF 28-105mm f/4-5.6 USM
EF 28-200mm f/3.5-5.6 USM

The best I can extract from my copy of Canon's "Lensworks III" book shows that the only Micro-USM equipped lens with full-time manual is the 50/1.4. Others must be placed in manual. I've not seen any evidence to the contrary in the lens descriptions provided in the Canon camera museum located here:

http://canon.com/camera-museum/camera/lens/f_lens.html

[Cadwell]

The best I can extract from my copy of Canon's "Lensworks III" book shows that the only Micro-USM equipped lens with full-time manual is the 50/1.4. Others must be placed in manual. I've not seen any evidence to the contrary in the lens descriptions provided in the Canon camera museum located here:

http://canon.com/camera-museum/camera/lens/f_lens.html

Information taken from this Canon publication that I linked to in my earlier post

http://consumer.usa.canon.com/app/pdf/lens/EFLensChart.pdf

where "*2" next to the AF actuator type indicates "Mechanical full-time manual focusing built-in".

[Tom W]

Information taken from this Canon publication that I linked to in my earlier post

http://consumer.usa.canon.com/app/pdf/lens/EFLensChart.pdf

where "*2" next to the AF actuator type indicates "Mechanical full-time manual focusing built-in".

Ahhhh - a discrepancy. The chart in the book is different, giving FTM only to the 50/1.4. The Canon USA web site is clearly different.

[Tom W]

Here's another source. It appears that Canon needs to do a little proofreading:

http://www.brochures.canon-europe.com/pdfs/EF_Lenses_-_Range-p7267-c3841-UK-1094621892.pdf

[Tom W]

Just noticed that you're going to the Canon US site and I'm going to the Canon Europe site. :)

[Cadwell]

Mmm... seems Canon doesn't know it's arse from it's elbow over this one. Now I guess we need a member of the forum with one of the disputed lenses to see if it's happy to have it's focus ring twiddled whilst set to AF or not! :lol:

[Ron Wilson]

TY all for some interesting talk on the Ring USM. I did not know the 50mm had a full time manual override. I got that lens. I will check it out tonite. The feature is probably not as important as on the 100mm Macro.

[MrChad]

According to Canon the following lenses also have Micro-USM with full time manual.

EF 28-90mm f/4-5.6 II USM
EF 28-105mm f/4-5.6 USM
EF 28-200mm f/3.5-5.6 USM

I had the 28-105mm f4-5.6 USM, it was not FTM.

[Jon]

I have the 28-90 II USM. It can be ground back and forth while set to auto, but that hoses the AF until you shift it back into manual, rack it in and out, and then put it back into auto. Not what I'd call FTM.