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10-31-2008, 09:43 AM   #61
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Yep! +1 Someone buy this man a beer!

QuoteOriginally posted by RBellavance Quote
That retarded system (micro-motor) is what Pentax SDM is
How can you not care for USM? It's FAST, it's quiet, and it's VERY accurate. And they tend to put USM in their nice lenses anyway.

10-31-2008, 09:50 AM   #62
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There is "ring USM" and then there is "micromotor USM" (USM~HSM~SWM although not sure if Nikon has any micromotor SWM lenses)

Most Canon USM lenses are true ring USM motors (some "fake" USM lenses include the 70-300mm IS and the 50mm f/1.4). ALL Sigma HSM lenses have ring motors (except for a few consumer lenses which had to get a "motor" inside to be compatible with the Nikon D40/D60 such as the 17-70mm, so the HSM is really a marketing gimmick) And I believe all Nikon SWM lenses are ring motors.

AFAIK all the "dual focus" SDM lenses (ones that work with pre-K10D bodies) are micromotor SDM (such as the DA* 50-135 and 16-50). Don't know about the 17-70 or the 200/300 primes.

And going from the 50-135 (micro USM) to the Canon 70-200mm f/4 IS (ring USM) is like night and day. Both were quiet, but the Canon was MUCH "snappier" especially when traversing the entire focus throw.


QuoteOriginally posted by stevebrot Quote
I don't think so. Pentax does not make any micro-motor lenses. The Pentax Supersonic Drive Motor (SDM) is similar to the Sigma HSM, Nikon SWM, and Canon USM technologies.

Steve
10-31-2008, 12:03 PM   #63
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QuoteOriginally posted by egordon99 Quote
Yep! +1 Someone buy this man a beer!



How can you not care for USM? It's FAST, it's quiet, and it's VERY accurate. And they tend to put USM in their nice lenses anyway.
I care for picture quality and the dollars I have to spend to get there. If that means the lens makes a little noise while focusing, whatever, I don't care.
10-31-2008, 12:05 PM   #64
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QuoteOriginally posted by Class A Quote
Do you have a pointer to something that explains why read-out noise is lower with higher pixel density?
I don't remember the reference. The above is my conclusion from an experiment posted on some website comparing P&S noise vs. DSLR noise. The only explaination is that read-out-noise per pixel is relatively constant and if you are able to combine many small pixels to emulate a larger pixel, you actually reduce the noise level. Of course, this won't affect shot noise which is a first order effect.

11-03-2008, 08:26 AM   #65
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Venturi,
I agree that keeping the orginal setup is a real plus for everyone.

Dave

QuoteOriginally posted by Venturi Quote
I fully realize that it was intentional and planned from an engineering (AND marketing) standpoint by Pentax.
But, for you and I (consumers) and thousands of eBay sellers - it's luck.
11-03-2008, 09:23 AM   #66
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QuoteOriginally posted by kristoffon Quote
I care for picture quality and the dollars I have to spend to get there. If that means the lens makes a little noise while focusing, whatever, I don't care.
its obvious you have not held a camera and lens combintion that focuses faster than your brain can think, without you havening even the slightest clue that it just did that.

i tested the DA*16-50 at a store one time.. and i thought it was broken, because it wasnt moving and it wasnt making any noise,

i was so focused on trying to see the lens focus that i didnt realize for the first minute that the images where in fact in focus!
11-03-2008, 10:01 AM   #67
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Full frame is the real deal.. too bad it's expensive..
11-03-2008, 10:06 AM   #68
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QuoteOriginally posted by throndor Quote
Full frame is the real deal.. too bad it's expensive..
in that case go for MF...

11-03-2008, 10:36 AM   #69
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QuoteOriginally posted by egordon99 Quote
There is "ring USM" and then there is "micromotor USM" (USM~HSM~SWM although not sure if Nikon has any micromotor SWM lenses)

Most Canon USM lenses are true ring USM motors (some "fake" USM lenses include the 70-300mm IS and the 50mm f/1.4). ALL Sigma HSM lenses have ring motors (except for a few consumer lenses which had to get a "motor" inside to be compatible with the Nikon D40/D60 such as the 17-70mm, so the HSM is really a marketing gimmick) And I believe all Nikon SWM lenses are ring motors.

AFAIK all the "dual focus" SDM lenses (ones that work with pre-K10D bodies) are micromotor SDM (such as the DA* 50-135 and 16-50). Don't know about the 17-70 or the 200/300 primes.

And going from the 50-135 (micro USM) to the Canon 70-200mm f/4 IS (ring USM) is like night and day. Both were quiet, but the Canon was MUCH "snappier" especially when traversing the entire focus throw.
I guess I was led astray by Pentax marketing. Thank you everyone for setting the record straight.

For the record...Pentax apparently does not use ring motors.

Steve
11-03-2008, 10:43 AM   #70
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QuoteOriginally posted by Gooshin Quote
its obvious you have not held a camera and lens combintion that focuses faster than your brain can think, without you havening even the slightest clue that it just did that.

i tested the DA*16-50 at a store one time.. and i thought it was broken, because it wasnt moving and it wasnt making any noise,

i was so focused on trying to see the lens focus that i didnt realize for the first minute that the images where in fact in focus!
I actually consciously experienced the difference for the first time over the weekend. I was shooting Nels' daughter's wedding and I'm in the dressing room taking shots of the girls getting ready. I had the K20D w/ DA*50-135 and the PZ-1 w/ Tam 90/2.8. When I switched over to the PZ-1 to get some closeups of the rings and when the AF kicked in (wicked fast AF combo btw) you'd have thought I set off a fire cracker in the room. It was a little unnerving, as suddenly I wasn't "invisible" anymore.
This has nothing to do with FF vs APS-C. Just wanted to interject my own revelation at the difference SDM makes.
11-03-2008, 11:15 AM   #71
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QuoteOriginally posted by stevebrot Quote
For the record...Pentax apparently does not use ring motors.
Nor do the new Sigma HSM lenses for Pentax. Unfortunately. The HSM Sigmas are even slower than Pentax SDM because of requiring more steps to aquire focus. Tried them at Photokina.

I am still curious to try a ringmotor lens on a Pentax some day
11-04-2008, 01:35 PM   #72
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QuoteOriginally posted by Gooshin Quote
in that case go for MF...
MF? as in "manual focus"?.. Already got 5.. But what is the relationship between FF being the real deal and MF lenses..
11-04-2008, 01:43 PM   #73
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QuoteOriginally posted by throndor Quote
MF? as in "manual focus"?.. Already got 5.. But what is the relationship between FF being the real deal and MF lenses..
Think he meant medium format as in 645D.......... maybe..
11-04-2008, 02:04 PM   #74
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i did mean "medium format" (MF)

focal length is constant, ie 55mm giving the same magnification as human vision, anything less shrinks the image compared to human vision, and anything larger magnifies it compared to human vision.

you cannot change this.


therefore, theoreticaly, its best to get as much into the frame as possible given what you have.



however the problem with that is ofcourse, lens size (which ahve to account for a larger image circle) and the fact that now these larger lenses have to be corrected for barrel distortion, making them much more difficult and thus expensive to produce

anyway...
11-04-2008, 02:58 PM   #75
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QuoteOriginally posted by Gooshin Quote
ie 55mm giving the same magnification as human vision
I, sincerely, do have to correct you here.

The magnification is a combined function of focal length and view finder magnification. It is by convention only that with a focal length about 50mm, on a 35mm camera, the resulting magnification is about 1. On a camera like the Pentax LX, you can actually change this.

The convention isn't even well founded. It is just a compromise.

The human's field of view approaches 180 and a 12mm focal length would be more appropriate.

On the other hand, the FoV for sharpest vision is a few degrees only and 200mm focal length would be more appropriate.

45 is the compromise adopted by convention, i.e. 50mm for 35mm film. But it is a convention for view finder makers only.
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