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Asphericallens vs spherical

The "Sonnar" name is for a lens design, while the "Otus" name is for a high-end lens line (with different lens designs, currently a Distagon and a Planar).

What they do depends on what the designer wants them to do: improve performance without adding elements, allow fewer elements without reducing performance, allow other elements to correct something other than spherical aberration (chromatic aberrations, astigmatism, etc.)

This requires additional glass elements that correct the error of the first element, but introduce their own aberrations, and more elements to correct those...etc. etc.. However, for quite a long time, it was still cheaper to pay for the extra bits of glass than to produce one-off aspherical surfaces.

Hi, Peter! In the BTS picture looks like you are using a 100mm filter system on a 7-14mm lens. I'm wondering how do you avoiding vignetting with wider shooting angles?

Very glad someone passed on the link to this article. What a great service you have provided to help us get started using this feature of our OMD cameras!

hello Peter, as all your articles very well liked by me. I was wondering: in your blog on "Exposure Bracketing" you use Sequential High so you can shoot without a tripod. Is this also a good idea for Focus Bracketing?

But since about 1990, better (cheaper, mass-production with a low loss rate) techniques have allowed the addition of aspheric elements throughout the industry. Leica and Hoya jointly developed a "blank-pressing" or molding process whereby soft hot glass is pressed against a metal mold already shaped to the aspheric curve. So that now even inexpensive P&S lenses often have aspheric elements.

Great tutorial. I've been wanting to try focus bracketing for landscape. I've done it once manually at Mt. Nemo on the Bruce Trail and it turned out well. Had to stack afterwards as it was the EM10i, which didn't have stacking nor did I have a lens that allowed it in camera. But, it definitely helps.

Inexpensive lenses reduce aberrations by adding lots of lens elements, but this increases flare. Using asphericals reduce the number of elements which may improve flare suppression

Peter, great article and timely for me as I want a "very near to far" in focus landscape image. Unfortunately, I do not get a far ridge line to come in focus (OM-1 &12-40/Pro, f8) using 8 shots - in camera stack at differential of 3. If I shoot a single shot at f8 and focus 10 feet away, everything is in focus. Any suggestions?

Thanks Peter for not just explaining the principles but giving the critical gritty details such as number of shots, focus band and apperture. VERY useful. Looking forward to trying it out with my Leica 8-18 mm soon!

Hi Peter, I am very happy that I found your blog and this article. I always wanted to try Focus BKT with my E-M1 Mark II, but now with this informations there is no more excuse not to do it. Very good explained, thanks a lot!

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Asphericallens elements

Erwin Puts says one aspheric surface does the work of two spherical surfaces, so two aspheric surfaces can eliminate one entire element (two sides, both spherical). Or improve the lens without adding one whole additional element.

Note that the APO Sonnar 135/2 is not part of the high-end Otus line, but it is in my opinion the best 135 lens ever made.

Peter Baumgarten is a professional photographer and educator. He is also an Olympus Visionary and NiSi Official Photographer.

In general, a double-aspherical lens is supposed to be better corrected than a single-aspherical lens. But this may not be the case. Technology always advances, and an improved/better design could use less asphericals for similar performance.

Asphericallens photography

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But since about 1990, better (cheaper, mass-production with a low loss rate) techniques have allowed the addition of aspheric elements throughout the industry. Leica and Hoya jointly developed a "blank-pressing" or molding process whereby soft hot glass is pressed against a metal mold already shaped to the aspheric curve. So that now even inexpensive P&S lenses often have aspheric elements.

When Leica first produced aspherical surfaces (Nocitlux f/1.2, 35mm f/1.4 "Aspherical," not "ASPH") they had to be hand-made one at a time, with a fairly large failure rate (toss the lens and start over).

Spherical lenses have a surface that is a section of a sphere. That is, they have a constant radius. This makes them easy to grind and polish, especially in mass production.

What they do depends on what the designer wants them to do: improve performance without adding elements, allow fewer elements without reducing performance, allow other elements to correct something other than spherical aberration (chromatic aberrations, astigmatism, etc.)

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Hi jip, Take a look here Aspherical so non spherical what is it actually?!. I'm sure you'll find what you were looking for!

Aspheric meaning

Thanks for all the easy explanations. Just of out of curiousity, can you please share your thoughts and analysis on Zeiss ones - more specifically Sonnar and Otus lenses. I know some of them are meant for DSLRs.

Erwin Puts says one aspheric surface does the work of two spherical surfaces, so two aspheric surfaces can eliminate one entire element (two sides, both spherical). Or improve the lens without adding one whole additional element.

When Leica first produced aspherical surfaces (Nocitlux f/1.2, 35mm f/1.4 "Aspherical," not "ASPH") they had to be hand-made one at a time, with a fairly large failure rate (toss the lens and start over).

Just to add a bit of personal experience about the magic of "asph"... in the automotive industry is normal to have aspherical surfaces in the reflectors of front lamps : the need to accord this with style-driven constraints makes the manufacturing of moulds for those components a very delicate and highly specialized job.... btw, CNC machines do not perform, mathematically strict speaking, aspherical tool paths, but very small arcs, continuosly tangent one to the other, with very small variations in radius... tolerancing fixes it all.

And when these lenses are compared, it is clear that what really matters is the overall lens design, rather than the number of asphericals.

Spherical lenses have a surface that is a section of a sphere. That is, they have a constant radius. This makes them easy to grind and polish, especially in mass production.

Hi Peter, This helped a lot … I’ve been struggling with different settings and been verry confused when I get some images in the series absolutely out of focus or no focus at close or distance objects. An other issue has been “double” objects from the merge process. I’ve been focusing a bit longer in to the motive and not as you are doing, closest object. I’ve also used focus differentiation settings closer to or at 10 to get the very distance sharp. I’ve used 4 – 6 shots in the series. I’ve used aperture settings to get a larger depth of field then you are, f 8 - f 11. I use focus bracketing mostly on my 7-14mm and 12-40mm lenses but sometimes also on my 40-150mm lens. I got the impression from your text that you use the same settings on all lenses also tele, is this correct? The issue with “doubled” objects can that be due to me using to large depth of field, aperture settings at f 11, getting overlaying sharp areas from different shots confusing the application? I’ve been using Helicon Focus but had trouble with it and found that Olympus Workspace is creating a better result. How do you see O. W. compared to PS? For me you nailed it with the way you described the process in detail, verry nice work! I will take a tour, already today, and test according to your recommendation, that obviously works. By the way you take amassing photos 😊

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Aspheric Lenses price

The 35 f1.4 "Aspherical" will cost you anywhere from $10,000 to $15,000 today. There are several on ebay if one is interested.

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Asphericallens vs normal lens camera

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Hi Peter, I just wanted to tell you how much I have enjoyed your amazing photos, videos and articles. And I have learned how to apply some of the parts of Olympus cameras that had been a little confusing. I am working my way through putting that knowledge into practice. I use the OM 1. After a few years of bird photography with the wonderful 300 mm lens, I shifting toward stars and landscapes and an am really enjoying the old primes, the 12, 25 and 75 and having light kit is divine. Look forward to reading and viewing more from you.

However, a spherical surface is not the best way to form a photographic image, especially with large-diameter (i.e. "fast") lenses. It introduces "spherical aberration" - light coming through the outer edges is not focused at the same point as light passing through the center.

Spherical lenses have a surface that is a section of a sphere. That is, they have a constant radius. This makes them easy to grind and polish, especially in mass production.

Disadvantages of aspheric lenses

Erwin Puts says one aspheric surface does the work of two spherical surfaces, so two aspheric surfaces can eliminate one entire element (two sides, both spherical). Or improve the lens without adding one whole additional element.

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A decade ago, I was lucky enough to get a 35 f/1.4 "Aspherical" and an "ASPH" together in the same place at the same time, and do a little test.

At f/1.4, the Aspherical was a bit sharper in the center and softer in the corners - the ASPH had more even sharpness over the whole image. Net - it would be hard to say one was "better" than the other overall, although the Aspherical might be a bit better for photojournalism (corners don't matter) and the ASPH better when the corners DO matter.

Aspheric lenses advantages disadvantages

I've now read and studied this tip and found it to be very helpful in understanding Focus Stacking on my M1.3. But, great information sometimes brings up an extra question or two. (1), when I look at the image files, it's hard to tell which frame is the "finished" one. With my camera set to record JPEG and Raw, there's quite a number of shots.After looking closely, I think it's the first one in the series of exposures, which if so, leaves me a little puzzled because (2) being a "stack" of all frames, there seems to be individual frames with better focus. BTW, I was shooting in the same area of your photos from Zion Canyon. Wonderful area.

This requires additional glass elements that correct the error of the first element, but introduce their own aberrations, and more elements to correct those...etc. etc.. However, for quite a long time, it was still cheaper to pay for the extra bits of glass than to produce one-off aspherical surfaces.

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However, a spherical surface is not the best way to form a photographic image, especially with large-diameter (i.e. "fast") lenses. It introduces "spherical aberration" - light coming through the outer edges is not focused at the same point as light passing through the center.