Tag Archives: Image quality

Enhancing Image Quality by Oversampling

Getting rid of digital noise in a single picture often leads to a loss of image detail. Noise is traded against smudge. On the other hand, astronomers have long been using computational imaging techniques for low-noise photography. What distinguishes the approaches in this area, versus techniques used on a single exposure, is the fact that adding and averaging data reduces noise without giving up on image detail.

Pantheon, Paris, France

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Posted in Architecture, Image quality, Photoessays, Travel photography Also tagged , |

Review: Fujifilm GFX 50S

Regular readers of this blog will know that I am lusting for larger formats. This is, of course, a matter of personal preference that results from my established shooting style and two Linhof view cameras waiting for a second life. In the film days the situation was easy; bigger was better. But in the digital world not everything scales with log2.

Fuji GFX 50S. Quite compact for its sensor size, but still best mounted on a sturdy tripod.

I could have created click bait by reviewing the hyped-up Hasselblad (X1D) and Fujifilm (GFX 50S) earlier, but wanted to wait until the initial bugs in the firmware are sorted out and Lightroom and/or CaptureOne support the RAW files. Now it’s about time to have a closer look because there is a new option: the 45 mega-pixel, Nikon D850 that is supposedly a leap further in almost all respects.

The question is if I would supplement my workhorse Nikon D810 with the D850 or replace it with a medium format system. There must be compelling reasons for a switch though; most importantly, an expanded shooting envelope in terms of handling and reliability (mainly high ISO capabilities and image stabilization), and image quality (resolution, dynamic range, and tonal separation).

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Printer Diaries: Preparing Images for Print

The truth is in the print; what looks good on the screen doesn’t necessary hold in print (and vice versa). Having gone through the first set of cartridges and pile of paper, I am glad that I haven’t deleted my original files. In a number of cases I had to return to the RAW files and process them with adjusted settings. Let me explain:

Look at prints, not megapixels.

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Posted in Fine art printing, Image quality, Software Also tagged , , |

Olympus OM-D Mk II and Fuji X-T2 versus Nikon D810: An unfair fight?

If all your equipment were stolen, the insurance settlement was generous, and you had to start all over, what would you procure? This question is actually not too academic, because it happened to a friend who had bought my Nikon D800e with the 70-200 f/2.8 VR-II as well as some other bits and pieces. All bygone.

Size matters; but not as much as you may think.

What is the best all-purpose camera in 2017, with the right balance of image quality, versatility and handling? One may argue that instead of learning to handle a new camera, it’s better to go out and shoot. And this is why I wouldn’t be tempted to change systems, unless this enlarged considerably  the shooting envelope on grounds of resolution, dynamic range, high-ISO performance, and image stabilization. But if everything was stolen?

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Fine-Art Printing Diaries: Setting up

This series of posts will be on getting serious (I hope) about fine-art printing. In the film days I didn’t bother developing and printing myself; first I didn’t have the space for a darkroom and then I was reluctant to deal with the chemicals. But more importantly, there were plenty of overnight development labs in town and professional print makers that had a certain affinity to art. Color rendition wasn’t really an issue to discuss over a 4×5 slide on a color corrected light table. And I had a lot of prints done, as they were the only way to enjoy images, except perhaps for 6×6 slide projections.

Look at images, not megapixels.

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Neutral Density Filters

Neutral density (ND) filters reduce the amount of light that enters the lens. ND filters are often used to achieve motion-blur effects with slow shutter speeds, blurring water or cloud motion, reducing depth of field in very bright light (when 1/4000 or 1/8000 of a second is not short enough for the large aperture), or to reduce the visibility of moving persons.

Iquacu falls. Fuji Velvia 50, f/32, 2 seconds. No ND filter needed.

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Have a Bokehlitious Christmas

In photography, bokeh* is the rendering of the blur produced by a lens in the out-of-focus parts of an image and is thus affected by the aperture, iris-blade construction, lens design (aberrations), and diffraction (Airy diffraction patterns). Photographing point-like sources of light such as Christmas-tree illumination is the best way to check the quality of bokeh, i.e., uneven or sharp luminance transitions, ni-sen (Japanese for double lines), irregular textures, and color fringes.

But there is no general consensus of what good or bad bokeh is. If you like it, it’s good, if you don’t like it, it’s bad. The same with Christmas celebrations, gifts and cakes. Some don’t like it at all. But if you had it, it might as well be smooth, round, and creamy rather than nervous, polygonal, and harsh.

And remember; to optimise bokeh keep reducing the distance between yourself and the subject while increasing the distance between the subject and the background.

In this sense, have a bokehlitious Christmas. SR

Christmas Tree Bokeh; Nikon Coolpix A, f/2.8

*The word bokeh is derived from a Japanese word, which means something like  “fuzzy” and is used to describe, among other things, the “flavour” of out-of-focus areas in photographs; “boke-aji.” Mike Johnston, Editor-in-Chief of PHOTO Techniques magazine from 1994-2000 and now running the website “The Online Photographer”, added the “h” because English speakers would mispronounce boke like “joke”, instead of the “bo” as in bone, “ke” as in Kevin, and with equal weight on each syllable.

Posted in Image quality, Philosophy+Opinion Also tagged |

Focus Stacking, Part 2: Artefacts

Now as part 1 of this post has had time to settle, let’s press on. Focus stacking is one of the techniques know as Computational Photography, which include panorama stitch, high-resolution sensor shift, multi-exposure HDR, and light field. All these techniques involve multiple images that are blended in post-processing to a new type of single image or scene representation; opposite to techniques in digital photography that work on a single capture, such as filtering and color adjustments.

These techniques may promt the question about ethics in photography. I have absolutely no problem with time-lapsing out people, for example. Over-saturation and over-sharpening, or turning the colors of a lake in Scotland to those of the waters at Anse La Digue is another matter. And nobody would consider the surrealistic photo-illustrations of David LaChapelle as dishonest work, while this is exactly what Steve McCurry, or his now fired assistant, are accused of producing. In my oppinion the problem lies not in the image itself, but its (incoherent) caption and the (false) message that the image is supposed to support. But I am digressing.

Focus stacking is particularly useful in situations where the scene has a large range of depths in the subject space compared to the shallow depth of field obtained for a given sensor size, focal length, and aperture combination. It will also be a way to make sense of the future FF sensors with 50+ megapixels, where diffraction will counteract the increase of accuaty by stopping down and compromise image quality for depth of field. Moreover, focus stacking can be useful to reduce noise in astrophotography. So there is nothing dishonest here; it is an attempt to optimize the conflicting elements of image quality:  noise, diffraction, lens-aberations, and depts-of-field.

There is, of course, the alternative of using tilt-shift lenses, but this is constrained to inclined focal planes (continuous depth maps), for example in landscape photography. The subject of the image below would also qualify.


Focus stack from 19 images. Automated capture using Helicon Remote and post-processed with Helicon Focus.

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Testing Lens Alignment

A year without new gear hasn’t been really successful. And although we have seen a lot of new equipment this year, there was nothing to merit a complete system change (to the Sony mirrorless or the Pentax 645, for example).


My target for testing lens alignment. Almost a nice image in the autumn fog.

After the disappointing test of the Nikon 24-70 f/2.8 VR, I thus treated myself to a Zeiss Distagon T* 25 mm f/2.0. Great deals can be had on these “classic line” Zeiss lenses, because they will be replaced by the Milvus lenses. The Milvus 50 f/1.4 and 85 f/1.4 are new designs, while the others are basically avatars in an Otus gestalt.

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Hands on review: AF-S Nikkor 24-70 mm f/2.8E ED VR

I love my holy trinity of Nikon f/2.8 zoom lenses covering a total range of 14-200 mm focal length. The mid-range zoom AF-S 24-70 mm f/2.8G ED N (short G-version) has become my workhorse and go-to lens with its most versatile zoom range; from wide-angle landscapes and panoramas, to portraits and events. Not that it is lightweight, but the built quality is excellent, the out-of-focus areas are smooth, and there are very little chromatic aberrations along the entire zoom range and at all apertures. The lens snaps into focus instantly and silently and it never hunts, even in most challenging lighting conditions.

The public library in Stuttgart, Germany. All you need to test corner to corner sharpness, lateral and longitudinal chromatic aberrations, flat field, out-of-focus rendering, and geometric distortions

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Why I Hold Out Against the Otus Lust – For Now

Yesterday I picked up some accessories at Euro-Photo Puig in Geneva, where they had on stock a Zeiss Otus 85 mm f/1.4 Apo Planar T*. This is a mouthful of a name, so I call it Otus 85 from now on. I had the opportunity to take a couple of sample images, however, not out the store’s door as originally planned. It had started snowing, which rendered the scene useless as test for sharpness and micro-contrast. So what else is there to photograph inside a photo store than a nice vintage camera?


Zeiss Otus 85 f/1.4 Apo Planar shootout. 100% crops, click to enlarge. From left to right: f/1.4, f/2.8, f/5.6. Top: Nikon PC-E 85 mm. Middle: Otus 85. Bottom: Nikon 85 f/1.4 G.

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Four Ways to 85 mm: Three Nikon Lenses and the Carl Zeiss Planar for the Hasselblad V-Series

Fighting hard against GAS (Gear Acquisition Syndrome), I still have four ways to arrive at 85 mm focal length. I may therefore check out some widespread myths about lenses: 1) Prime lenses are better than zooms. 2) Vintage lenses are ill suited for digital sensors because they are not telecentric, that is, the ray angles at the edges of the sensor exceed the acceptance angle of the microlenses, which results in reduction of color saturation, and color fringes. 3) The 35 mm lenses have a better resolution than medium and large-format lenses, simply because they need to cover only a smaller caputure area and can therefore be made from more expensive glass.


From left to right: Nikon AF-S 70-200 f/2.8 G ED VR II, Nikon AF-S 85 f/1.8 G, Nikon PC-E 85 f/2.8 Micro, Hasselblad Zeiss CF 80 f/2.8 Planar T* mounted on a Photodiox adapter.

The contestants

  • Nikon AF-S 70-200 f/2.8 G ED VR II
  • Nikon AF-S 85 f/1.8 G
  • Nikon PC-E 85 f/2.8 Micro
  • Hasselblad Zeiss CF 80 f/2.8 Planar T* mounted on a Photodiox adapter

I hated the Nikon AFS 70-200 f/2.8 and the Canon equivalent, because having set up my large format camera, I was more than once harassed by photographers carrying these lenses. Considering their form factor it does not need much to imagine what some guys are compensating for.

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