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Ultra-high speed with high sharpness

Ultra-high speed with high sharpness

The Nikon Nikkor Z 58mm F0.95 S Noct is an ultra-high speed manual focus lens for Nikon’s Z series of full-frame mirrorless cameras. The new Noct references the old manual focus AI and AIS Noct-Nikkor 58mm F1.2 from the mid-70s and early ’80s, a “special” lens designed to reduce coma particularly from bright light sources at night and in poor light. However, that’s where a good number of the similarities end.

While all S-type Z lenses are intended for pros and serious amateurs, the faster lenses appear better made than that of the other slower models. The Noct features an all-metal outer and eschews autofocus for manual focusing using a huge, finely machined focus collar, with close to a long 350-degree focus throw. It also features a highly complex optical system with no less than 17 elements arranged in 10 groups and has a 0.5 m (1.64 ft) minimum focusing distance.

Of those 17 elements, the Noct has three aspherical elements with one being an expensive large-diameter and ground type rather than molded to help with correction of coma and spherical aberration. In addition, it has four ED (extra-low dispersion) elements to help mitigate chromatic aberration. The lens also has Nikon’s full complement of Nano, Arneo and SIC coatings to improve ghosting and flare, as well as a fluorine coating to help when cleaning.

It also has slightly different cosmetics and features including a small OLED panel that can display the aperture setting, as well as the option to display focus distance with a depth-of-field scale below. There is also a customizable control ring to select exposure or compensation setting and a L.Fn button that allows access to the camera-based Fn functions, found on the camera body.

You can view the results for all tested lenses and create your own comparisons and in-depth analyses using our interactive image lens comparison tool.

Key specifications:

  • 17 elements in 10 groups
  • Three aspherical and four ED elements
  • 11 blade, rounded aperture
  • Manual focus only
  • Programmable control ring and Fn-button
  • 82 mm filter thread
  • Minimum focus distance: 0.5 m (1.64 ft)
  • Weight: 2000 grams (4.4 lb)

Test results

We tested the Nikon Nikkor Z 58mm F0.95 S Noct on the 45.7MP Nikon Z 7 where the camera and lens combined achieved a very high score DXOMARK score of 55. Indeed, it’s the highest score achieved by any lens and camera combination that we’ve ever seen.

This unique lens in the Z system has very high center sharpness even at the initial aperture which, given that it’s F0.95 is, frankly, a remarkable result. There is some fall off in sharpness starting in the mid zones and out to the corners, but let’s not forget this an F0.95 lens. By F1.2 the central zone of sharpness seen at F0.95 has expanded substantially beyond the mid zone/mid field and the corners have improved dramatically. From F1.8 onwards sharpness becomes more consistent and by F5.6 this is apparent across the field, albeit at the expense of central sharpness.

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Geometric distortion is very low (below -0.2%) with some pincushion evident at the edges of the frame where it’s generally more noticeable. The Noct also has very good transmission, measured at 1.1 T-stop, some 0.3 EV behind the reported F-stop. Even though the lens is enormous vignetting is noticeable at the initial aperture but that’s not really a surprise, at least it doesn’t persist much beyond F1.8/2.

Where this lens shows some weakness is in its levels of lateral chromatic aberration. However, even that is debatable given the challenge of producing a ultra-high speed lens like this. We measured the fringing at up to 9 µm wide in the extreme corners, though it has very low levels across the frame, so even then it could be said that it’s well-controlled generally.

All things considered then, this Nikon Nikkor Z 58mm F0.95 S Noct has the optical performance to match its company’s credentials.

As always though, it’s well worth looking through the more detailed data to see how the lens performs at individual aperture settings and various focal lengths.

In-depth comparisons

We’ve compared the Nikon Nikkor Z 58mm F0.95 S Noct on the 45.7 MP Nikon Z 7 with arguably the most serious rival model from Nikon’s DSLR days the manual focus Zeiss Otus 55mm F1.4 ZF.2 mounted on the 45.7 MP Nikon D850, one of the best performing Nikon DSLRs ever made. At around $3,999, the Zeiss Otus 55mm F1.4 in F-mount is half the price of the Noct.

We’ve also compared the enormous Noct with one of the most svelte of Nikon’s current Nikkor Z lenses, the Nikon Nikkor Z 50mm F1.8 S similarly mounted on the Nikon Z7. This combination allows direct comparison with its far pricier sibling, the Noct. While seemingly quite modest with an F1.8 maximum aperture, the Nikon Nikkor Z 50mm F1.8 S has a high-grade optical system and a price of around $599 today.

You can see an overview of this comparison in our database.

Sharpness

In years past, ultra-high speed lenses like this usually weren’t particularly sharp at the maximum aperture, however with what could be called “over designed” lenses like this that trend has been reversed. The new Noct is very sharp wide open. Admittedly there’s a drop in sharpness from the mid-zone and onwards to the corners but even at F0.95 it’s sharper than either the Zeiss Otus 55mm F1.4 ZF.2 or the Nikon Nikkor Z 50mm F1.8 S at their respective initial apertures. At least that’s the case in the center, it’s only the Otus that can claim slightly higher sharpness in the outer zone though even that displays some astigmatic behavior.

Stopping down the Noct maintains superior sharpness over rivals’ respective F1.4 and F1.8 settings, including in the mid- and outer-zones. At F2.8, however, rivals’ center sharpness is on a par with the Noct, though the more affordable 50 mm F1.8’s edge weakness is still apparent. It’s not until F4-F5.6 that the Noct exhibits its most homogenous and uniform performance, with the edges closest in sharpness to the center. However, that is at the expense of overall sharpness. Even then the Noct has the best edge performance of the three. After that, the performance of all three is very similar with the most affordable just trailing the Noct and Otus, in that order.

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Chromatic aberration

Lateral chromatic aberration appears in the image plane and the effect, shown as colored fringing, increases out towards the edges and particularly into the corners. While this effect is usually mitigated in software without loss in image quality, the separating of wavelengths reduces sharpness in the first place. High-grade optical designs can be used to overcome this, but this is reflected in the complexity, and thus, size, weight and price.

In this respect, the Noct performs very well over most of the frame even at the initial aperture. However there are quite high levels, peaking up to 9 µm in the extreme corners (90-100% field position) at F0.95, which is higher than that found on either the Zeiss Otus 55mm F1.4 ZF.2 or the Nikon Nikkor Z 50mm F1.8 S. While in the mid-zone (30-60% field position), levels are generally lower or at least no worse, higher levels of fringing remain throughout the aperture range.

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Geometric distortion

Geometric distortion correction is another aberration that’s best corrected optically, and although the Noct has practically unnoticeable levels (measured at -0.2%) it may well be noticeable with certain subjects, such as normally straight edges that end up parallel with the image frame. Both the Zeiss Otus 55mm F1.4 ZF.2 and the Nikon Nikkor Z 50mm F1.8 S show similar levels, however, they both display barrel distortion whereas the Noct exhibits pincushion type. This is typically associated with longer focal lengths.

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Vignetting (corner shading)

We were promised that vignetting would be mitigated by mirrorless designs. Be that as it may, the Noct displays quite high levels at the maximum aperture, with it peaking at around -2EV in the corners. This compares to around a maximum -1.6 EV for the two rivals in this comparison. However, just looking at the peak results can lead to erroneous conclusions. When looking at the vignetting profiles or field maps, the Noct’s visual weighting at F0.95 is not dissimilar to the Otus’ at F1.4. And it’s the “slower,” more accessibly priced Nikkor Z 50mm F1.8 S that shows a smaller central core, and arguably “heavier” visual weighting out towards the corners.

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Transmission

High transmission is not only a highly sought-after characteristic it aids IQ with regards to noise levels, as a lower ISO setting can be selected for any given exposure level. It, therefore, has quite a bearing on our DXOMark score. Although the Noct measured T1.1 at the maximum aperture, which is some -0.3 EV from the reported F-stop and ‘worse’ than the more accessibly priced Nikkor Z 50mm F1.8 S at just -0.1 EV, it is still ahead of the Otus. The Zeiss, with a T1.7 maximum aperture, is some -0.5 EV behind the reported F-stop.

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Conclusion

Like the original Noct-Nikkor was showcasing Nikon’s optical expertise back in the ’70s and ’80s, so too is the new Nikkor Z 58mm F0.95 S Noct. It has a phenomenal optical performance. Indeed, the new Noct on the Nikon Z 7 achieved the highest score by any lens and camera combination that we’ve seen to date. However, at close to $8000, it’s pricey and both the size and weight, not to mention the long-throw manual focus, are all sure to limit its appeal. Movie studios and rental houses won’t flinch though, nor will the well-heeled seeking the signature look of a highly-corrected ultra-high-speed lens, but for everyone else, it’s the kind of lens that people only dream of.

In this review, we have compared the Nikon Nikkor Z 58mm F0.95 S Noct mounted on a Nikon Z 7 to its closest rivals from other brands. Remember that the lenses may be used on various cameras with different sensors, or in some cases on different camera systems using different mounts, so the results will vary between them.

As usual, you can create your own comparisons and in-depth analyses using our interactive image lens comparison tool.

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dark_lord’s latest blog : diffraction ? the enemy of sharpness

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Diffraction – the Enemy of Sharpness

11 Oct 2021 9:41PM  
Views : 83
Unique : 74

Using small apertures is good for obtaining large depth of field, but go too small and image quality worsens. How bad is the effect and is it worth being concerned about?

Let’s take a look at what diffraction is. I recall physics experiments at school creating waves in a water tank passing through various sized slits in a metal barrier and observing the patterns produced. The waves spread out from the slit, more so the smaller the slit. The observation applies to water waves, sound waves and electromagnetic radiation. It’s this spreading that causes the softening in an image.

During my experiments with depth of field, looking closely, that is at 100% on screen, there is a noticeable softness at smaller apertures. It’s not a lot, and it depends on how large you’re going to print an image and how far away are you going to view it. With higher resolution sensors this softening will be more apparent if you look closely enough. The result may just give the impression that you’ve shot on a lower resolution camera, and for web size images or small prints may well not be a concern for some.

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The full image at f/32 as displayed on the web looks fine.

The effect is much more noticeable when I use an extender and extension tube on the macro lens below f/11, but then the lens was never designed for that extreme use. I’ve found apertures down to f/11 are fine, and as depth of field is so minimal at such close quarters I’ll forego that fraction of a millimetre for better overall sharpness.

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I used my macro lens for these images which is designed to hold up well at these smaller apertures. I have to say I’ve very rarely gone below f/16 in normal use or noticed anything untoward on earlier lower resolution sensors. That said, all lenses are different so you need to do your own tests. Zooms, particularly at the cheaper end of the market, are much more likely to suffer image quality reduction at the small apertures. I have come across images online that even at that reduced size (from the original capture) do show a marked softness, while at the same time ruling out as far as possible camera rigidity and ISO effects.

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Look closely and the detail isn’t as crisp as it is at f/8, but are you going to look this close?

Small apertures and diffraction effects are the reason you won’t find apertures below f/8 on small sensor cameras, and indeed f/8 will, on those cameras, give as much depth of field as you’re likely to need.

Are there good things about diffraction? When you’re down to X-ray wavelengths diffraction patterns are created by the arrangements of atoms which allow molecular structures to be determined. That’s important in areas such as novel drug development. So some diffraction is not all bad.

All text and images © Keith Rowley 2021

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How Aspherical Lenses Fix Aberrations and Improve Sharpness

How Aspherical Lenses Fix Aberrations and Improve Sharpness

What is an aspherical lens and what does it do? Canon has shared a video that explains the problems engineers face in lens design and how the company solved them using aspherical lenses.

Canon recently celebrated the 50th anniversary of its aspherical lens technology through a new exhibit in its virtual Canon Camera Museum. The aspherical lens exhibition has multiple articles and videos on aspherical and fluorite lenses as well as interviews with project members who discuss the development of the EOS and EF lenses.

Canon says that aspherical lenses have long been known to effectively correct for the various types of lens aberrations that can occur in optical design as well as improve overall image quality. These days, aspherical elements are pretty ubiquitous and can be found in lenses ranging from entry through professional-level optics from a range of manufacturers.

Below are two photo exapmples, one that is shot with a spherical lens and the other taken with an aspherical element:

How Aspherical Lenses Fix Aberrations and Improve Sharpness 7
Image shot with spherical lens element
How Aspherical Lenses Fix Aberrations and Improve Sharpness 8
Image shot with aspherical lens element

Canon explains that conventional lenses have a curved surface that is like a slice of a sphere, hence the name “spherical” lens. There are issues with this design, however.

“Compared to light rays passing through the center of a spherical element, rays entering from its peripheries must travel a longer distance in order to reach the image plane, resulting in the light rays converging at different positions,” Canon explains. “This causes an effect known as spherical aberration, where point light sources “blur” instead of being rendered as points.”

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Spherical aberration on a spherical lens element
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An aspherical lens element ensures light rays converge at the same position.

Spherical lenses also have issues with distortion.

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Aspherical lenses were known to correct these issues, but even though the supposed benefits of aspherical lenses was known, manufacturing such lenses was considered extremely difficult for a very long time. Canon says that it was challenging to achieve the precision needed in order to control the curvature at the submicron level (1/10,000th of a millimeter). Aspherical lenses were so hard to make that they were referred to as “dream lenses.”

Over half a century ago in 1971, Canon finally released an interchangeable lens for SLR cameras that included aspherical lens elements. Since then, the company has continued to refine processing methods and precision technology and says that it has been part of spearheading the constant improvement of image quality via aspherical lenses.

A great deal more information about aspherical lenses and Canon’s implementation of them in its lineup over the years can be found in the special exhibition on aspherical lens technology in the digital Canon Camera Museum. Within, Canon also has a great explanation of the capabilities of fluorite glass. All the information and videos are free to peruse.


Image credits: All images provided courtesy of Canon.

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johnriley1uk’s latest blog : in pursuit of sharpness

johnriley1uk's latest blog : the cameras with the wonderful lenses

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In Pursuit of Sharpness

9 Jul 2021 9:19AM  
Views : 214
Unique : 196

When we used film, the sharpest results would be obtained with agonisingly slow stock such as Kodak Technical Pan (ISO 16), Kodak Panatomic-X (ISO 25) or Ilford Pan F (ISO 50), and that’s just the black and white. For colour Kodachrome 25 (ISO 25) would be the choice. In reality, I would use Kodak Tri-X (ISO 400) and most of my friends would use Ilford FP4 (ISO 125), but then, as now, I prefer sharp, crisp grain to mushy grain free images that suffer from camera shake.

Frankly, digital is sharper. Edges can be as sharp as a razor blade edge, ISO can be incredibly fast without too much compromise and Shake Reduction makes nonsense of the usual guidelines on shutter speed. Failing all else, we can even use a tripod. And I often do as most of the images for lens reviews are shot using a tripod. Sharp images can be a joy in themselves for their pure technical quality, quite the opposite of perhaps ethereal, soft images that can also be something to aspire to. But for today I’m going to see what sharp images I have shot recently that I like.

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How to Focus Stack for Perfect Sharpness From Start to Finish: Part One

How to Focus Stack for Perfect Sharpness From Start to Finish: Part One

As you progress in landscape photography, you might find yourself wondering how others get everything in focus within their images. In this article series and video, I’ll go over how to focus stack while in the field and what to do once you sit down to process your images.

Focus stacking could be considered a more advanced technique within photography, but many times, it’s not all that difficult to accomplish. Within this article, we’ll go over what I consider to be a more complicated edit than your standard focus stack, but I will include resources at the end for other types you might encounter. Focus stacking is relatively the same in execution, but you might find different challenges depending on the image you’re trying to create. Here are a few I’ve personally dealt with:

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  1. Gradual focus shift: This is what you’ll encounter the majority of the time in landscape photography. Imagine you’re shooting with a wide angle lens in portrait orientation. You’re placed relatively close to your foreground subject, but you’d also like to have the background in focus. The focal plane from the bottom of the composition to the top moves gradually as the distance of subjects moves farther away from the lens. This is typically the easiest type of focus stack to edit together.
  2. Large focus shift: The composition includes foreground elements with a large distance between the background. This large distance causes a big shift in focus between your foreground and background that is difficult to blend together. This is the type of focus stack we’ll be editing within this two-part series. The biggest challenge is getting a cohesive edge between your elements that looks natural.
  3. Object separation: This is typically a mix of the above two scenarios. Imagine you’re taking the same shot as the gradual focal plane example, but it’s of a tree with many branches sticking out in the composition. This causes large separations of focus between branches and background and can be extremely challenging to edit, but there are options to make our lives easier.

Understanding that you’ll encounter different types of focus stacks is important, and I highly recommend starting out by trying to find a composition similar to the one described in the gradual focus shift to get your feet wet. Speaking of, let’s get our feet wet and jump into what you’ll need to do in the field.

In the Field

As with many techniques in landscape photography, you’ll definitely need a tripod and access to either a cable release or a self-timer on your camera. Unlike exposure bracketing, you can’t really get away with a quick handheld focus stack, as you’ll be shifting the focus between each image yourself. As for your in-camera settings, it will vary depending on your model and camera. That said, you’ll want to shoot at the lowest ISO your camera will go, an aperture between f/8 and f/16, and your shutter speed shouldn’t matter as long as you’re on a tripod and there isn’t anything moving in your composition. You might need to adjust your ISO accordingly if you need a faster shutter speed to capture something moving, like flowers.

You might be wondering why I don’t strictly recommend f/16 as your aperture to get as much in focus as possible in a single shot. Every lens has a sweet spot at where it is the sharpest and that typically falls within the range I recommended. If this isn’t something you know, just stick with f/11 and you’ll probably never notice the difference.

How Many Shots Do You need?

Once you have your composition set up and you’re ready to start taking photos, the biggest question you’ll encounter is just how many shots you need to take. Data is inexpensive, so you can never take too many focal points, but sometimes, you might end up taking so many that you overwhelm yourself in editing. The best way to decide roughly how many points you need is to focus on your foreground subject, whatever the closest object you want in focus is. While using live view on the back of your camera, you should have a magnification tool to zoom into the image. Once you have zoomed in, navigate through your image to where the focus starts to visibly fall off and refocus to that point and take a shot. Continue to do this through your image, mentally noting where you shifted focus while taking shots through the process.

The shots you just took likely won’t be the images you use to do a final edit because there may be too much time in between causing shifts in light, but it’s good to take them to refer back to. What is important is knowing a rough estimate of where you shifted focus and how many points you’ll need. Once you know this, you can go back through your image quickly with very little time in between shots to help prevent any changes in your environment.

The example we’re using throughout this tutorial could have used an extra focal point. Actually, it could have used three more if I wanted to get every single element in focus. I wanted to take as few images as possible to get the edit as simple as I could, but in the end, I should have taken at least one more image, which you’ll see in greater detail in part two of this tutorial once we get into edit the image. 

Shifting Focus

All that’s left to do is take your photos. I’m assuming most readers here have a camera that has autofocus and live view, but it’s entirely possible you might be using a manual focus lens. If you’re using an autofocus setup, all you’ll need to do is navigate through your image by either touching to focus on live view or moving the focal point with your camera’s controls if you don’t have a touch screen. Do this as quickly as possible through your image, as sudden light shifts can make blending much more difficult.

If you’re shooting with manual focus, you’ll just need to use the magnification tool in live view and move through the image just like you did when you were finding all your focal points in the step above while manually focusing on each point. Keep in mind because you’ll be touching the lens, you might have more movement between images, which can be even more exaggerated at longer focal lengths. Do your best to shift focus without moving the framing of the shot.

Conclusion

That wraps up what you’ll need to do in the field to capture a focus stack. Thankfully, no matter what type of image you’re trying to focus stack, the methods in the field remain the same. Post-processing is where you’ll encounter different obstacles, as you’ll see in part two of this tutorial. 

I’d love to know if you have any other tips when you’re in the field, taking images you plan on stacking later on. Or, simply share the images you’ve already captured. As always, thanks for reading, and be on the lookout for part two of this tutorial next week!

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Panasonic Lumix S 85mm F1.8 Lens review: Good sharpness

Panasonic Lumix S 85mm F1.8 Lens review: Good sharpness

Designed for Panasonic’s Lumix S series of full-frame mirrorless cameras featuring the L mount, the Lumix S 85mm F1.8 is a medium-speed fixed focal length lens for portraiture and indoor events such as sports or press calls.

The optical design features 9 elements arranged in 8 groups, including two ED (extra-low dispersion) elements to help control chromatic aberration.

With the idea of also appealing to videographers, the 85mm is the first of four f/1.8 primes from Panasonic that will share a number features, such as physical and filter size and control placement. In addition, the lens has a mechanism to mitigate focus breathing.

This Lumix S-series prime also features a dust- and moisture-resistant design and is relatively compact and lightweight.

You can view the results for all tested lenses and create your own comparisons and in-depth analyses using our interactive image lens comparison tool.

Key specifications:

  • Nine elements in 8 groups
  • Two ED elements
  • Nine-bladed rounded aperture
  • Linear AF motor
  • Dust- and moisture-resistant
  • 67 mm filter thread
  • Minimum focus distance: 0.8 m (2.62 ft)
  • Weight: 335 grams (12.5 oz)

Test results

We tested the Lumix S 85mm F1.8 on the high-resolution Panasonic Lumix S1R; the camera with its 47 MP sensor and the lens together achieved a DXOMARK score of 41. This new lens has very high sharpness at almost all apertures, especially wide open at f/1.8.

Short telephoto lenses like this rarely display distortion and this isn’t so very different, with relatively low levels measuring -0.2% — in other words, some slight barrel distortion.

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Vignetting generally is well controlled throughout, albeit with a maximum of -1.5 EV at the initial aperture in the extreme corners. It also has excellent transmission, measured at just 1.9 TStop. Where this lens is a little weak is in its control of lateral chromatic aberration, especially over the f/5.6 to f/22 range, where the fringing measured up to 9 µm on average.

Overall this lens is a a very good performer. As always, though, it’s worth looking through the more detailed data to see how the lens performs at different aperture settings.

In-depth comparisons

In this review we’ve compared the Panasonic Lumix S 85mm F1.8 with rival model Sony FE 85mm F1.8 on the 47 MP Sony A7R II, an older model but akin to the Panasonic Lumix S1R in pixel count. The Sony is competitively priced and includes a customizable button which is a useful feature found mostly on higher-end models. We’ve also compared the Panasonic lens with the Nikkor Z 85mm F1.8 S on the 47 MP Nikon Z 7, which is priced at around the same level as the Panasonic.

You can see an overview of this comparison in our database.

Sharpness

On the high-resolution Lumix DC-S1R, the Panasonic Lumix S 85mm F1.8 performed very well in our sharpness (acutance) testing. It has excellent sharpness at virtually every aperture and has very high sharpness at the initial aperture of f/1.8, achieving just over 80% acutance in the center, falling to just under 75% out to the corners. However in the outer field, starting at the 70% field position (shown in the graph below), some astigmatism-like behavior is noticeable. At that aperture it’s similar in sharpness to the Nikkor and the Sony in the center. At the edges it’s sharper than the Sony, though still not quite at the Nikkor’s level there.

Stopping down to f/2.8-f/4 sees the Panasonic’s sharpness improve slightly to its peak. It’s also more uniform in sharpness across the field, albeit with the astigmatism-like behavior still visible. Stopping down further sees the uniformity improve, though with a slight incremental decrease in sharpness (acutance) at each aperture. It’s mostly on par with its rivals in this comparison, though the Sony’s slightly higher central sharpness persists through the aperture range all the way to f/22.

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Chromatic aberration

Lateral chromatic aberration (LaCA) appears in the image plane usually starting mid-field (around the 60% field position in our graph) and progressively widens in the outer field and corners. In this regard the Panasonic is generally well controlled, with LaCA more noticeable from the 80% field position and outwards. In our tests this fringing becomes noticeable at around f/5.6, but is easily corrected via software. The best of the three is the Nikkor, but even the Sony with its single ED element is somewhat better controlled than the Panasonic.

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Geometric distortion

Correcting geometric distortion in-camera or via software can stretch an image and affect the sharpness, so it’s best to have a well-corrected lens in the first place rather than rely on a correction profile. The Panasonic Lumix S 85mm F1.8 keeps distortion well under control with just slight barrel (-0.2%). With some slight pincushion distortion, the Nikkor is lower still, which goes to show how well corrected this lens is. And even though the Sony is a little higher than the others in this comparison, all three still exhibit very low levels.

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Vignetting (corner shading)

While seemingly innocuous, vignetting can be troublesome to correct, especially at high ISOs, with large adjustments leaving unwelcome noise. Shading in the Panasonic peaks in the corners at -1.5 EV wide open, though that’s in the extreme corners — at around the 80% field position it’s just -1 EV. Visually, the effect is similar to the Nikkor Z 85mm and Nikon Z7 combination, though the Nikkor’s maximum shading is lower at just -1.1 EV in the corners. The Sony exhibits the heaviest vignetting with up to -2 EV into the corners, and with a usually less desirable, smaller central core left unaffected by shading.

By f/4, all shading is mitigated compared to the Nikon at f/2.8, however, it never really clears up at all in the Sony.

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Transmission

This is useful to know if you’re using your lenses for videography, but knowing the transmission isn’t much of a concern for photographers. Even so, it’s interesting to know how effective the coatings are, and it may even impact how a lens handles flare and ghosting. The Panasonic lens has good transmission and is at the same level as the Nikkor on the Z7 at T1.9. However, the best performer of the three here is the Sony, measured at T1.8 on the A7R II.

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Conclusion

Panasonic is well known for its Micro Four-Thirds system but less so for its full-frame models. It will take time to become established, but introducing a range of relatively affordable f/1.8 lenses seems sound. As for the optical quality, this 85mm F1.8 model is notable for its high sharpness at most apertures, especially the initial aperture. But there’s more to optical quality than that. In our tests we found it’s not quite as well-corrected as some of its closest rivals — it has high levels of lateral fringing, for example. Still, it’s a reasonably priced lens and a solid performer overall.

In this review, we have compared the Panasonic Lumix S 85mm F1.8 mounted on a Panasonic Lumix DC-S1R to its closest rivals from other brands. Remember that those lenses may be used on different cameras, or in some cases on different camera systems using different mounts, so those comparisons are not strictly applicable.

As usual, you can create your own comparisons and in-depth analyses using our interactive image lens comparison tool.

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dark_lord’s latest blog : sharpness, does it matter?

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Sharpness, Does It Matter?

7 May 2021 9:14PM  
Views : 65
Unique : 50

Sharp images are what most of us strive for and indeed are encouraged by a variety sources from advertisements of the latest lenses to picture library editors.

On the whole I like to see something sharp in an image as the focal point to draw me in as I explore the image. Not all of an image necessarily needs to be sharp (think differential focusing for example). Unsharp images produced by poor equipment or bad technique are no substitute for carefully considered and crafted soft images (something produced by a Lensbaby for example). Light and composition are still the important elements.

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There are times of course when sharpness is a prerequisite. Scientific and technical photography rely on detail and clarity. NASA took the hit on weight by taking medium format cameras to the moon in the 1960s and 1970s. Faultless technique and competency with good equipment is necessary. Advertising photography makes use of top quality gear, such as Phase One and Hasselblad cameras. With most advertising being viewed on small screens such as phones ultimate sharpness isn’t of any benefit or great concern except for high end products. A soft and dreamy result may be what a client is looking for and that can be added later (it’s easy to make a soft image from a sharp original than the other way round). For those of a certain age the Cadbury Flake adverts of the 1970s epitomise that look (though for some the chocolate was a secondary attraction!).

Before the internet, photographic magazines would regularly publish lens test results. I guess they still do but I don’t buy them. Amateur Photographer would use the view from their offices in south London, placing one particular building at the centre and edge of the frame and showing enlarged sections of the frames for comparison. There were some truly awful lenses. With many enthusiasts shooting on colour print film and having nothing larger than small prints made I doubt edge softness wasn’t a huge concern. Stopped down somewhat and with solid technique acceptable results were possible with most lenses.

Old lenses (or ‘legacy’ lenses) are enjoying a revival for some of their optical qualities and imperfections as photographers look for something less clinical and more individualistic than the cold and clinical rendition of modern lenses. Landscapes and portraits are ideal subjects for them.

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In the days of film you could choose to develop your monochrome film with ‘Acutance’ developers. What they did was increase the edge contrast between dark and light tones which gives the impression of greater sharpness. Useful with technical and architectural photography for example. There was no equivalent for colour film.

For any image that’s digitised (so that includes scans from film and print originals) there are various methods of sharpening an image. They all have their merits. The ‘Unsharp Mask’ which seems inappropriately named does in fact have its origins in the darkroom. An unsharp copy of a negative would be sandwiched with the original negative when producing a print. The result would be an apparent increase in sharpness. All to do with edge contrast. And the ‘Unsharp Mask’ tool does just that, increasing edge sharpness. Details stand out more clearly.

With this increased control over sharpness there is the spectre of over-sharpening. I think spectre is a good description as the result of over-sharpening is the stuff of nightmares and something you don’t want to see. Images take on a wiry look with halos around the edges of subjects. It’s often seen in poorly taken (or heavily cropped) images that someone has tried to rescue. Even a soft image looks better than on over-sharpened one.

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So in most cases sharpness is an important consideration. What about those situations where nothing is sharp? Or at least critically sharp? There are some very successful images that fit this description and I don’t profess to be able to do such things well though I keep trying.

ICM (in-camera movement) where the camera is deliberately moved during the exposure produces impressionistic images. I do find it works better if you are sharply focussed on the subject to start with so there is some structure to the streaks and patterns.

Lensbaby lenses produce dreamy and blurry images and even the ‘sweet spot’ maybe isn’t crisp. But that’s to miss the point, it’s not about the ultimate detail.

Panning with moving subjects is used to obtain a sharp subject against a blurred background to give the impression of speed. If you take the shutter speed even slower you’ll come to a point where even the subject isn’t sharp but you can still end up with something that embodies the atmosphere.

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It may seem counter intuitive, or even perverse, that a sharply focused, or at least as accurately focused as you can, will result in a better soft image than an image that’s unsharp to start with.

All text and images © Keith Rowley 2021

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