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09-04-2008, 08:29 AM   #1
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What does AL mean on a lens designation?

The DA18-55 AL and DA18-55 ALII lenses both have the AL designation. I believe that the new DA17-70 AL SDM also has the designation.

What does it mean?

For example,
DA= Digital "only", no aperture ring, designed to work on a digital image circle

I believe the 17-70 has aspheric elements, but I don't think the 18-55 does.

Any help?

09-04-2008, 08:43 AM   #2
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Right out of the Pentax Lens Catalogue:

AL - (Aspherical Lenses) Contrary to spherical, aspherical lenses do not have a uniformly curved spherical shape. The form of an aspherical lens is adapted to a specific task and the curvature of each is individually computed. The production of these lenses is accordingly complex. The greatest advantage of aspherical lenses: several types of optical aberrations can be corrected at one time. They are used particularly in high-quality lenses allowing for the use of fewer lens elements so that a high luminous intensity is attained.
09-04-2008, 08:45 AM   #3
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AL can be detrimental to bokeh ... visit some leica forums and they refer to some lenses as pre-ASPH
09-04-2008, 08:47 AM   #4
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Pentax abbreviations

SMC: Super Multi Coating
FA: fits full 35mm sensor(film cameras), also fits digital cameras
FA-J: budgetlenses made for full 35mm sensor, no aparture ring
FA Star: Top serie for 35mm film cameras
DA: made for the reduced sensor in digital cameras, does not work with film-slr
DA*: Top serie for digital cameras, weatherproof, does not work with film-slr
D-FA: Adjusted to digital cameras, but also works on film-slr
SDM: Super Direct-drive Motor (ultrasonic autofocus)
ED: Extra-Low Dispersion-glass
IF: Internal Focus
SP: Super Protect coating
AL: Aspherical Lenses

09-04-2008, 12:43 PM   #5
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Thank you all!
09-04-2008, 12:52 PM   #6
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I think this is what you're talking about. Notice the "rings" around the out-of-focus highlights (taken with my Sigma 30mm f/1.4 on a Canon 40D)

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QuoteOriginally posted by k100d Quote
AL can be detrimental to bokeh ... visit some leica forums and they refer to some lenses as pre-ASPH
09-04-2008, 02:34 PM   #7
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QuoteOriginally posted by throndor Quote
Pentax abbreviations

SMC: Super Multi Coating
FA: fits full 35mm sensor(film cameras), also fits digital cameras
FA-J: budgetlenses made for full 35mm sensor, no aparture ring
FA Star: Top serie for 35mm film cameras
DA: made for the reduced sensor in digital cameras, does not work with film-slr
DA*: Top serie for digital cameras, weatherproof, does not work with film-slr
D-FA: Adjusted to digital cameras, but also works on film-slr
SDM: Super Direct-drive Motor (ultrasonic autofocus)
ED: Extra-Low Dispersion-glass
IF: Internal Focus
SP: Super Protect coating
AL: Aspherical Lenses


thanks for this info... valuable future reference.





Neil
09-04-2008, 04:33 PM   #8
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QuoteOriginally posted by egordon99 Quote
I think this is what you're talking about. Notice the "rings" around the out-of-focus highlights (taken with my Sigma 30mm f/1.4 on a Canon 40D)

Not sure if that a result of aspherical elements or not. The FA31 features aspherical elements and doesn't seem to make those sorts of highlight rings.

Just speculation though.


K.

09-04-2008, 05:02 PM   #9
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QuoteOriginally posted by egordon99 Quote
I think this is what you're talking about. Notice the "rings" around the out-of-focus highlights (taken with my Sigma 30mm f/1.4 on a Canon 40D)

Attachment 18192
Well that's interesting! Do you get the concentric rings often? I wonder if it's an artifact specific to the light source rather than specific to the lens. . .

Here's an article from Nikon that sort of explains the relationship between bokeh and correction of spherical aberration:

Nikon | Imaging Products | Nikkor - The Thousand and One Nights, Tale 32 : Ai AF DC Nikkor 135 mm F2S
09-04-2008, 05:26 PM   #10
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This should be a sticky.

QuoteOriginally posted by throndor Quote
Pentax abbreviations

SMC: Super Multi Coating
FA: fits full 35mm sensor(film cameras), also fits digital cameras
FA-J: budgetlenses made for full 35mm sensor, no aparture ring
FA Star: Top serie for 35mm film cameras
DA: made for the reduced sensor in digital cameras, does not work with film-slr
DA*: Top serie for digital cameras, weatherproof, does not work with film-slr
D-FA: Adjusted to digital cameras, but also works on film-slr
SDM: Super Direct-drive Motor (ultrasonic autofocus)
ED: Extra-Low Dispersion-glass
IF: Internal Focus
SP: Super Protect coating
AL: Aspherical Lenses
09-04-2008, 05:36 PM   #11
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QuoteOriginally posted by egordon99 Quote
I think this is what you're talking about. Notice the "rings" around the out-of-focus highlights (taken with my Sigma 30mm f/1.4 on a Canon 40D)
that's definitely a bit distracting

QuoteOriginally posted by thePiRaTE!! Quote
Not sure if that a result of aspherical elements or not. The FA31 features aspherical elements and doesn't seem to make those sorts of highlight rings.

Just speculation though.


K.
the FA31 is said to be surprising because of it's good bokeh even with aspherical elements
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