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06-28-2013, 02:08 PM   #1
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What do ED AL [IF] DC WR mean?

Probably a dumb question, but what do all the designations at the end of the model name mean on Pentax lenses: ED AL [IF] DC WR

WR is weather resistant. Can't figure out the rest, and can't seem to find any explanations.

06-28-2013, 02:34 PM   #2
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ED = Extra Low Dispersion - features some elements to manage chromatic aberrations
AL = Aspherical Lens - one or more elements have an aspherical surface to reduce spherical aberrations wide open
IF = Internal Focusing - the front element does not extend from the body when focusing
DC = Digital Crop - A Sigma term, it means that the image circle covers the APS-C sensor size and was designed for the sensors of digital cameras
06-28-2013, 02:44 PM   #3
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AL = Aspherical element.
ED = Extra Low Distortion glass.
DC = DC motor for focusing
SDM = Supersonic Direct Drive Motor
SMC = Super Multi Coating
HD Coating - High definition coating
SP = Super Protection Coating
IF = Inner Focusing.
QS = Quick shift focusing system
WR = Weather Resistant
AW = All weather

See the Pentax Lenses and Accessories booklet.
Or search for CATALOGUE_EN_resized.pdf
06-28-2013, 02:45 PM - 1 Like   #4
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QuoteOriginally posted by icywindow Quote
DC = Digital Crop - A Sigma term, it means that the image circle covers the APS-C sensor size and was designed for the sensors of digital cameras
Almost everything good.

Since all of them are from Pentax lenses DC is also for Pentax i believe and not for Sigma.

Anyway for Pentax a DC stands for Direct Current motor i believe, it means there is a little motor inside the lens for autofocusing.
SDM and HSM are also in the lens motor but they are different type of motors.
SDM use vibration and frication to create motion, DC is your standard electro motor and use a magnetic field.

06-28-2013, 02:50 PM   #5
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QuoteOriginally posted by Anvh Quote
Almost everything good.

Since all of them are from Pentax lenses DC is also for Pentax i believe and not for Sigma.

Anyway for Pentax a DC stands for Direct Current motor i believe, it means there is a little motor inside the lens for autofocusing.
SDM and HSM are also in the lens motor but they are different type of motors.
SDM use vibration and frication to create motion, DC is your standard electro motor and use a magnetic field.
Thanks for the correction. I learned something too.
06-28-2013, 02:58 PM   #6
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QuoteOriginally posted by Kobayashi.K Quote
AL = Aspherical element.
ED = Extra Low Distortion glass.
DC = DC motor for focusing
SDM = Supersonic Direct Drive Motor
SMC = Super Multi Coating
HD Coating - High definition coating
SP = Super Protection Coating
IF = Inner Focusing.
QS = Quick shift focusing system
WR = Weather Resistant
AW = All weather

See the Pentax Lenses and Accessories booklet.
Or search for CATALOGUE_EN_resized.pdf
What about FREE
2 pentax lenses that are on sale have that, probably even more.
06-28-2013, 03:17 PM   #7
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QuoteOriginally posted by Anvh Quote
What about FREE
2 pentax lenses that are on sale have that, probably even more.
FREE = Free-Form (Progressive) lens.
06-28-2013, 03:36 PM   #8
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I thought SP = Super Protect, not Super Protection? Just being hideously pedantic today.

Jack

06-28-2013, 03:50 PM   #9
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QuoteOriginally posted by jbinpg Quote
I thought SP = Super Protect, not Super Protection? Just being hideously pedantic today.

Jack
The Pentax Lenses and Accessories booklet says:
SP (Super Protection) Coating.
A special coating on the external lens element, based on a fluorine coating and it prevents the contamination of the lens by water-based or oily substances.
06-28-2013, 06:21 PM   #10
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OK, thanks.
06-29-2013, 10:48 AM   #11
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QuoteOriginally posted by Kobayashi.K Quote
FREE = Free-Form (Progressive) lens.
Fixed Rear Element Extension (FREE): a lens whose last cell i remains fixed during focusing. FREE lenses achieve low field curvature and low spherical aberrations not only when focused close to infinity but also at very short distances. For normal applications the FREE system leads to small physical extensions, and thus allows the design of physically smaller and lighter lenses. For macro applications FREE lenses exhibit non-proportionately long extensions which aid precise focusing. However, to achieve these positive effects, the FREE design causes the lens focal length to decrease as the focus distance decreases. Pentax has listed FREE as a feature only for prime lenses even though there are zooms that also have a fixed rear elements


The DFA 50 and 100 mm macro have this and probably more
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