What does ASPH mean to you?

[markbakovic]

I don't mean "Is the Leikor Bloktron 42mm 1.3 ASPH a good lens?", I mean what do you understand about "aspheric" *photographic* lenses? What are they for AFAYK? Are there pros and cons? What level of insight would you need to part with 2x the cash? 4x? Shut-up-and-take-my-money... umm... 'times'?

 

[michaelwj]

It simply means that one surface of one element doesn’t have a single radius of curvature. As in, it’s not spherical.
As far as better? It usually means the lens designer can replace multiple elements with one element and therefore make a lens simpler and or smaller.
As for your poll, it’s is so misinformed that none of the choices make any sense. Is there a “none of the above”?

 

[Ko.Fe.]

Since it is not posted in Leica Lens subforum.
CV ASPH lenses are not x2. 7A 28 f1.4 ASPH is less expensive than non ASPH CV 28 f2. And CV 35 f2 ASPH is less expensive than Biogon 35 f2 non ASPH.

It is shut-up-and-learn-before-posting "times". 🙂.

 

[Rayt]

Easier to design and produce lenses?

 

[Rob-F]

I didn't see an option that reflects my understanding, either.

To me, the ASPH lens has the potential to perform better at the widest apertures. Stopped down to around f/8, not much difference. Or if there is one, the ASPH may render the image a bit sharper, but the image might look "harsh," less pleasing, depending on what I'm photographing. If I want to shoot at f/2 or f/2.8, I'll likely use a Summicron ASPH. At 5.6 or 8, I might use my Summaron or Zeiss c Biogon, or my non-ASPH Summilux. The latter is, IMHO, useless at f/1.4, but stopped down the images are just fine.

Apart from that, you have to go on a lens-by-lens basis. It's a matter of which lens, not ASPH vs. non-ASPH.

 

[Ko.Fe.]

Forgot to mention, my new 35 2.5 ASPH Leica lens cost me less than averagely priced used and worn out Cron. It was one of the reasons I purchased it. 🙂 .

 

[Archlich]

The very basic Canon and Nikon 18-55 kit lenses both have an aspherical element. Your phone's lens has several. In fact it's rarer for you to see a spherical design than aspherical today, since the later has become so cheap to manufacture.

So the term does not guarantee anything but (mostly) marketing. Which in fact is a Leica (of which the path is followed by CV) specialty. Most of the Japanese manufacturers didn't even bother with it and other terms like FLE (in Nikon's literature, CRC) anymore after the 1980s', during which these technologies became widespread. They've got more posh words to play with now.

 

[kyte]

To me it means a computer designed lens that has modern characteristics, not necessarily meaning better.

 

[lawrence]

To me, the ASPH lens has the potential to perform better at the widest apertures.

Yes, that plus you tend to swap some barrel distortion for pincushion.

 

[markbakovic]

well that was... bracing.

Thank you to the honest respondents to a poll about what camera equipment consumers glean from camera equipment manufacturers' branding.

To the others, thank you for offering your opinions as well.

I look forward to learning more of what readers of the Optics Theory subforum have to say on this topic.

 

[Mackinaw]

My experience? Aspherical surface usually means a sharper, more contrasty image wide-open, especially with a high-speed lens. Comparing an ancient Canon FD 55/1.2mm with a FD 55/1.2 aspherical wide-open, the difference is dramatic, with the aspherical being much better. Of course many will argue that the signature of the non-aspheric is better. But that’s a personal choice.

Jim B.

 

[bayernfan]

If the element count is kept low, an aspherical lens can offer nice correction and wide open performance without that clinical/flat look. I think the Summicron 35/2 ASPH is an example of this, in that it has some 'character' despite the aspherical element.

 

[David Hughes]

In some cameras it means a plastic lens. Those I've seen were no better and no worse than normal lenses. OTOH I've been very pleased with "proper" glass ones in various lenses.

I won't mention the technical bit as it's been covered.

Regards, David

 

[willie_901]

ASPH is one of several optical designs purposed to minimize spherical aberration artifacts. The primary symptom is haloing caused by light ray refraction differences between the edges and centers of spherical lens elements. It is impossible to focus the rays to a single point.

The refraction artifacts decrease as aperture decreases since the lens edges become blocked.

Spherical aberration is also associated with focus shift.

Some very fast ASPH lenses have magenta color casts for foreground out of focus objects and green casts for those in the background (spherochromatism). The optical refraction compensation is not the same for all wave lengths. This is different than chromatic aberration.

 

[raid]

ASPH ==> extra cost.

 

[aizan]

It usually means onion-ring bokeh to me.

 

[Phil_F_NM]

It usually means expensive, harsh and boring to me.
Phil Forrest

 

[nightfly]

It means it will be several times the price of the older iteration of the same lense which will henceforth become known as the "non-ASPH" version.

 

[pgk]

Aspherical lens surfaces are used in all sorts of applications, some expensive, some not. Most are now molded but in the past they were ground which was far more expensive. They have advantages for the design and build of lenses in terms of optical improvements, size, simplicity and so on. The poll is far too simplistic to have any value.

 

[michaelwj]

well that was... bracing.

Thank you to the honest respondents to a poll about what camera equipment consumers glean from camera equipment manufacturers' branding.

To the others, thank you for offering your opinions as well.

I look forward to learning more of what readers of the Optics Theory subforum have to say on this topic.

"ASPH" or "Aspherical" on a lens denotes it contains an aspherical surface. You can't just brand a lens as such without an aspherical surface (you can I suppose, but it'd be lying). It used to be a big deal, but now it isn't. You phone most likely has the most aspherical lens you've ever used, yet it doesn't mention it, and doesn't conform with many of the above perceptions of what aspherical surfaces have on image quality.