Evaluating Focus Shift with the Sigma FE 28mm f/1.4 DG HSM Art

I had hoped to evaluate the Sigma FE 28mm f/1.4 DG HSM Art, which I previously tested on the Nikon D850 in DAP. The Sigma 28/1.4 is a very high performance optical design, but it seems that build quality is highly variable, and not just with the 28/1.4*.

But after two brand-new samples of the Sigma FE 28/1.4A with both unable to make a fully sharp image on the left side even at f/5.6, it’s clear that Sigma MTF is a marketing claim bereft of validity. Computed fantasy MTF is just marketing bullshit as compared to MTF testing a real lens with real light, as Zeiss does (only company in the industry to do so, AFAIK).

I am not going to try a third sample at this junction.

* I had similar quality issues with the Sigma FE 85mm f/1.4 DG DN Art, the Sigma FE 35mm f/1.2 DG DN Art, and the Sigma FE 14-24mm f/2.8 DG DN Art—all of which are terrific lenses *if* you can magically obtain a sample without optical build-quality problems. I’ve talked to other skilled photographers who went through ten (10!) samples of the 35/1.2 and just gave up, and others who have had to try multiple samples to get a satisfactory one.

Focus shift

However, I have evaluated focus shift on the Sigma FE 28mm f/1.4 DG HSM Art and it is an eye opener.

Sigma FE 28mm f/1.4 DG HSM Art: Focus Shift

Includes two different examples.

Sigma FE 28mm f/1.4 DG HSM Art

In Depth Study: How Shutter Speed and Aperture Mangle Bokeh with Electronic First Curtain Shutter (vs electronic shutter and mechanical shutter)

I was vaguely aware of bokeh differences with fast lenses at high shutter speeds, but since I usually shoot the sweet light whenever I can, it was never much of an issue.

The use of electronic first curtain shutter can mangle lens bokeh at very high shutter speeds—even stopped-down to f/4 (with some effects even at f/5.6). The article suggests various mitigations.

...

In Making Sharp Images, I show how shutter speed and aperture mangle bokeh with electronic first curtain shutter versus electronic shutter and mechanical shutter. These findings will apply to all lenses of any brand on modern digital cameras with only slight variation.

This page takes a thorough look how bokeh changes depending on aperture, shutter speed, and type of shutter:

Making Sharp Images: Effect of Shutter Type on Bokeh vs Shutter Speed and Aperture

Includes 48 frames at up to full camera resolution from f/1.4 to f4 at 1/8000, 1/4000, 1/2000, 1/1000 shutter speeds using mechanical shutter, electronic shutter, electronic first curtain shutter.

Also added:

Striping from Electronic Shutter with Artificial Light

Clipped bokeh shapes (right) from electronic first curtain shutter

f1.4 @ 1/8000 sec, ISO 100; 2020-09-24 11:28:08
Sony A7R IV + Sigma FE 85mm f/1.4 DG DN Art
RAW: LACA corrected, push 2 stops, +10 Whites, +15 Clarity, Luminance NR {20,50,0}, Chroma NR {20,50,50}

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Looks Like the Eastern Sierra Fall Color Season is Toast

With the Creek Fire* only 30% contained and till making a huge stinking and dangerously unhealthy mess over near Mammoth Lakes in the Eastern Sierra Nevada, much of the prime fall color season is toast unless we get a nice dousing storm soon—which is also what tends to rip all the leaves off the aspen around the first week in October in many areas. Still, I’ll take the rain and wind any time over the unpleasant and unhealthy smoke.

Creek Fire Sept 22: Weather conditions encountered over the past 2 days will continue. Warm and dry air with southwest winds will continue. Daytime heating and southwest winds will continue to push the smoke upslope towards the Sierra Mountains. Nighttime cooling in the higher elevations will continue to push the smoke back down into the valleys with light down-sloping winds from the northeast

* Being still “under investigation” 18 days later, I’m betting that it was started by human stupidity.

I’m waiting for a break in the conditions, to see the smoke clear out of the White Mountains, where there are some gorgeous stands of aspen known to few—maybe I can get a few days or even a week there with a little luck, and if the Inyo National Forest reopens (closed until Sept 25).

View air quality near Bishop, CA—there are PurpleAir sensors on White Mountain Peak (14252 ft) and Barcroft Research Station (~12200 ft), just to the east. [note: Safari won’t display the map, but Chrome does]

On my to-do list are the Sony FE 12-24mm f/2.8 GM and comparison with a bunch of alternatives. It’s going to to a tricky job to get right given pronounced focus shift with several of the lenses along with field curvature, but when done I hope that my readers will be able to shortcut a steep learning curve and immediately get the best out of the 12-24mm or its alternatives, by understanding the behavior.

I’ve also received a 2nd copy of the Sigma FE 85mm f/1.4 DG DN Art and it seems slightly better than the first sample. So I’ll give it a workout, though I’m still stunned at its godawful pincushion distortion, which is inherent to the optical design. Shame on Sigma for cutting corners so badly and marketing sharpness that cannot be achieved in reality, once distortion correction is applied.

Lloyd on Pine Creek Trail, 2019

f8 @ 1/30 sec electronic shutter, ISO 100; 2019-10-10 09:06:50
Sony A7R IV + Sigma FE 14-24mm f/2.8 DG DN Art @ 14mm
ENV: Pine Creek Trail, altitude 7600 ft / 2316 m, 28°F / -2°C
RAW: Enhance Details, LACA corrected, push 1.3 stops, +100 Shadows, -100 Highlights, +33 Whites

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Voigtlander FE 35mm f/1.2 NOKTON Aperture Series: Madrone Leaves

This scene of green evaluates the Voigtlander FE Nokton 35mm f/1.2 Aspherical for rendering style and bokeh. Green subject matter is highly favorable to lens performance.

Voigtlander FE 35mm f/1.2 NOKTON Aperture Series: Madrone Leaves

Includes images up to full camera resolution from f/1.2 through f/8.

See my Voigtlander FE wishlist page.

Madrone leaves (Arbutus menziesii)

f1.4 @ 1/200 sec, ISO 50; 2020-09-20 17:50:00
Sony A7R IV + Voigtlander FE Nokton 35mm f/1.2 Aspherical
RAW: Enhance Details, LACA corrected, +30 Whites, +15 Clarity

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Voigtlander FE 35mm f/1.2 NOKTON Aperture Series: Last Smoky Sun on Persimmon Tree

This scene of green evaluates the Voigtlander FE Nokton 35mm f/1.2 Aspherical for rendering style and bokeh. Green subject matter is highly favorable to lens performance.

Voigtlander FE 35mm f/1.2 NOKTON Aperture Series: Last Smoky Sun on Persimmon Tree

Includes images up to full camera resolution from f/1.2 through f/8.

See my Voigtlander FE wishlist page.

Persimmon Tree, heavily loaded with fruit

f1.2 @ 1/500 sec, ISO 50; 2020-09-20 18:21:47
Sony A7R IV + Voigtlander FE Nokton 35mm f/1.2 Aspherical
RAW: Enhance Details, LACA corrected, +30 Whites, +15 Clarity

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Voigtlander FE 35mm f/1.2 NOKTON Aperture Series: Oak Tree Trunks

This near-to-far scene focused at medium distance evaluates the Voigtlander FE Nokton 35mm f/1.2 Aspherical for field curvature and focus shift and sharpness across the frame.

Voigtlander FE 35mm f/1.2 NOKTON Aperture Series: Oak Tree Trunks

Includes images up to full camera resolution from f/1.2 through f/11.

See my Voigtlander FE wishlist page.

f2 @ 1/60 sec, ISO 50; 2020-09-20 17:53:33
Sony A7R IV + Voigtlander FE Nokton 35mm f/1.2 Aspherical
RAW: Enhance Details, LACA corrected, pull 0.35 stops, +40 Whites, +15 Clarity

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Reader Comment: Magnifying Eyepiece for DSLRs

See my Voigtlander FE wishlist page.

Eyepiece items in general

Nikon offers a range of eyepiece and eyepiece accessories, including diopter-correction eyepieces and other. See my list of eyepiece and eyepiece accessories.

Below are a few that are particularly useful. Not shown below are various anti-fog eyepieces, very helpful under some conditions.

Nikon DK-17M magnifying eyepiece

The DK-17M eyepiece screws into D3/D3s/D3x and similar Nikon bodies, providing 1.2X magnification, which I find helpful for manual focusing.

Be aware that on the D3/D3s/D3s and other models there is a eyepiece locking mechanism; you must close the eyepiece shutter to allow the eyepiece to unscrew. Don’t force it!

Get the DK-21M for other Nikon models (D200, D300, D40, etc). I've found both of them a plus for my use.

Eyeglass users might not like either magnifying eyepiece because it could cut off things like focus confirmation and other data at screen bottom.

Viewfinder Assist

Nikon wish list • Deals on Nikon

$27 Nikon DK-17F Fluorine-Coated Finder Eyepiece in Accessories: Photo Accessories

$38 Nikon DK-17M Magnifying Eyepiece for Select Nikon Cameras in Accessories: Photo Accessories

Lefteris K writes:

This may help readers still using Nikon DSLRs.

Chicago Botanic Gardens yesterday. 70 images, 64 were 100% in focus with manual viewfinder focusing without using the confirmation dot, with long lenses (125 and 135). Three samples attached (in the second one, it’s the far away flower). What helped to achieve this:

a. One of my D850 bodies happen to have perfectly aligned optical paths (mirror and sensor). That is a matter of luck of course, because in my experience only about one third of the bodies are precisely aligned in DSLRs for satisfactory high-res images, and that includes Canon bodies as well.

b. The viewfinder piece Nikon DK-17F Fluorine Coated Eyepiece is phenomenal! I could clearly see (with my presbyopic eyes) through the viewfinder, where the lens was focused exactly, as if I were using a loupe! With my daughter carrying the Z7 with her, I compared viewfinders (sunny day), and the D850’s with that new eyepiece seemed more “high res” to me than the Z7 at full view (not magnified).

c. Lenses used were Apochromatic (Zeiss Milvus 135mm and Voigtlander 125mm). It really makes a huge difference. I have kept no lenses with chromatic aberrations.

No “DOF preview”, no tripod, and no “Liveview” were used. I think that the percentage of hits is so unusual for using just viewfinder without confirmation dot, purely by what I was seeing in the viewfinder, and since this is the second session of mine with such high hit rate through the viewfinder with long lenses, that it is worth mentioning and even highlighting. Because the results were equally good even in the darker parts of the park where the flash didn’t fire (sample no. 003). At any rate, the focusing results are “great enough for nice family prints”.

DIGLLOYD: the first think I added to my Nikon DSLRs was the DK-17M.

Voigtlander FE 35mm f/1.2 NOKTON Aperture Series: Dolls

See my Voigtlander FE wishlist page.

This page evaluates the Voigtlander FE Nokton 35mm f/1.2 Aspherical at very close range, a reproduction ratio of about 1:11.3, or roughly a very tight head and top-of-shoulders shot.

Voigtlander FE 35mm f/1.2 NOKTON Aperture Series: Dolls

Includes images up to full camera resolution from f/1.2 through f/11.

Separately, I show a distortion example: Voigtlander FE 35mm f/1.2 NOKTON: Distortion.

f1.2 @ 1/320 sec pixel shift, ISO 100; 2020-09-19 14:08:23
Sony A7R IV + Voigtlander FE Nokton 35mm f/1.2 Aspherical
RAW: LACA corrected, +30 Whites, +15 Clarity

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Sony FE 12-24mm f/2.8 GM: Usage Notes

See my Sony wishlist page and Voigtlander FE wishlist page.

I’m not prepared to post images just yet (lousy subject matter, being confined to home by forest fires), but I’ve added some brief usage notes that are important to understand when working with the Sony FE 12-24mm f/2.8 GM.

Sony FE 12-24mm f/2.8 GM: Usage Notes

It’s going to be a 'bear' comparing this lens to the Sony FE 12-24mm f/4G and the Sigma FE 14-24mm f/2.8 DG DN Art, because they all behave so differently in terms of field curvature and focus shift—trusting “quick tests” is ill-advised. A key part of my review work will be how to best use the lens to exploit its sharpness, given the land mine of focus shift.

That said, the Sony FE 12-24mm f/2.8 GM might be the finest lens of its kind ever produced.

Extreme Wide Zooms for Sony Mirrorless

Sony Mirrorless wish list • Deals on Sony

$1399 Sigma 14-24mm f/2.8 DG DN Art in All Other Categories

$2998 Sony 12-24mm f/2.8 FE GM in All Other Categories

$1773 Sony 12-24mm f/4 FE G in All Other Categories

$2098 SAVE $100 = 4.0% Sony 16-35mm f/2.8 FE GM in All Other Categories

Voigtlander FE 35mm f/1.2 NOKTON Aperture Series: Bicycles

See my Voigtlander FE wishlist page.

This page evaluates the Voigtlander FE Nokton 35mm f/1.2 Aspherical at close range from f/1.2 through f/11, discussing sharpness, focus shift, and correction for secondary color.

Voigtlander FE 35mm f/1.2 NOKTON Aperture Series: Bicycles

Includes images up to full camera resolution from f/1.2 through f/11.

This series will give you a very good idea of how the Voigtlander FE 35mm f/1.2 NOKTON might apply to work where its pleasing rendering might apply, but also its potential for landscape photography.

f1.2 @ 1/125 sec electronic shutter pixel shift, ISO 100; 2020-09-15 18:40:30
Sony A7R IV + Voigtlander FE Nokton 35mm f/1.2 Aspherical
RAW: LACA corrected, push 0.9 stops, +20 Shadows, -80 Highlights, +30 Whites, USM {6,50,0}

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Voigtlander FE 35mm f/1.2 NOKTON: Examples at f/1.2

See my Voigtlander FE wishlist page.

This page shows examples at full aperture, and assesses sharpness, secondary color, and bokeh with the about $999 Voigtlander FE 35mm f/1.2 Nokton Aspherical SE.

If you want a 35m lens that offers a lot of 'character', this might be your lens.

Voigtlander FE 35mm f/1.2 NOKTON: Examples at f/1.2

Includes images up to full camera resolution.

f1.2 @ 1/125 sec handheld, ISO 100; 2020-09-15 19:01:40
Sony A7R IV + Voigtlander FE Nokton 35mm f/1.2 Aspherical RAW: LACA corrected

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Forest Fires: All California National Forests are Closed, BLM Lands Appear to Remain Open

Last night the air started to clear—what joy to have AQI back below 40, and now it is near zero (ultra clean) because it is actually raining today at my place, a light drizzle... hooray! But whether any of it makes it over to the Livermore CA area or the Creek Fire area in the Sierra foothills... unlikely.

Later in the day, it cleared up to sunny skies in icky humidity with normal season AQI of around 40, but I’ll take that over the godawful smoke. I enjoyed my first bike ride (2.5 hours) in about two weeks—a double joy since I had decent physical energy and clean air! Being holed-up for 2 weeks inside the house has been a real downer. But my legs let me know that I’ve lost a lot of conditioning.

...

So much for photographing in the mountains! I wasn’t aware of this until today, so I am sure glad I didn’t head out. Even the Inyo National Forest is closed (White Mountains and Eastern Sierra), and that is a mainstay for me. However, the order for Inyo NF expires in 9 days, on September 25.

UPDATE Sept 18: the National Forest Service announced that permission to access certain national forests is granted again, see Forest Service to Increase Access to National Forests in California 9/18/2020. However, Inyo National Forest (entire Eastern Sierra and most of White Mountains) remains closed until September 25 (TBD what happens).
Nine National Forests in California remain closed: Angeles NF, Cleveland NF, Los Padres NF, Inyo NF, Klamath NF, San Bernardino NF, Sequoia NF, Sierra NF, and Six Rivers NF. This decision will continue to be reviewed daily with evolving fire and weather conditions.

UPDATE Sept 26: Inyo National Forest and others remain closed through September 30. See the latest California National Forest orders.

As yet, I am unsure whether BLM (Bureau of Land Management) lands are closed other than a few localized areas (such as the Slink Fire near Coleville), but it appears that BLM lands near Bishop CA remain open, with certain restrictions. However, at this time of year, BLM lands are generally hotter than a pistol.

Accordingly, I may head to Utah for my autum work and shoot the Canyonlands National Park, Zion National Park, Bryce Canyon National Park, Capitol Reef National park, and other areas this year—if they’re open... gotta check on that. Would be a nice change of pace.

See also:

• Regional Orders for National Forest Closures for California
• Bureau of Land Management Spotlight page

Forest Service Temporarily Closes All National Forests in California

Contact(s): Jonathan Groveman, (707) 562-8995

VALLEJO, Calif., September 9, 2020—Due to unprecedented and historic fire conditions throughout the state, the USDA Forest Service Pacific Southwest Region is announcing a temporary closure of an additional ten National Forests, meaning all eighteen National Forests in California are now closed. The closure of the additional ten forests will be effective at 5:00 pm today. These additional forests include the Eldorado National Forest, Klamath National Forest, Lassen National Forest, Mendocino National Forest, Modoc National Forest, Six Rivers National Forest, Plumas National Forest, Shasta-Trinity National Forest, Tahoe National Forest, and Lake Tahoe Basin Management Unit. This decision will be re-evaluated daily as conditions change.

We had closed eight National Forests on Monday evening, Sept. 7, 2020. Explosive growth of fires throughout California during the day and late evening of Sept. 8th led to this updated decision.

“The number of large fires and extreme fire behavior we are seeing across the State is historic," said Regional Forester Randy Moore. "These temporary closures are necessary to protect the public and our firefighters, and we will keep them in place until conditions improve and we are confident that National Forest visitors can recreate safely. I ask all Californians and visitors to take these closures and evacuations seriously for their own safety and to allow our firefighters to focus on the mission of safely suppressing these fires."

The Forest Service thanks our partners and the public for their cooperation and understanding of this monumental fire threat. It is critical that all Californians and national forest visitors follow these important closures and restrictions for their own safety and the safety of our firefighters. Citizens with specific questions within their area may call their local forests for more information.

The Forest Service manages 18 National Forests in the Pacific Southwest Region, which encompasses over 20 million acres across California, and assists forest landowners in California, Hawaii and the U.S. Affiliated Pacific Islands. National forests supply 50 percent of the water in California and form the watershed of most major aqueducts and more than 2,400 reservoirs throughout the state. For more information, visit www.fs.usda.gov/R5.

Reader Comment: Zeiss Milvus 15mm f/2.8 Distagon

Get Zeiss DSLR lenses for Nikon and Canon at B&H Photo.

See my in-depth reviews of Zeiss DSLR lenses.

John H writes:

I wanted to pass along another thank you note regarding your work with the 15mm Zeiss. I’ve owned this lens (pre-Milvus) for about a year now, and I spent quite a bit of time puzzling over the issues of sharpness that you’ve aptly mapped to field curvature. One of the first days I owned this lens I put it on my D810 and went for a walk through central Tokyo, just shooting handheld, getting a feel for the lens and its perspective, etc..

Zeiss Milvus 15mm f/2.8 Distagon

The attached cityscape image was shot at f/8 and ISO100, I’ve done some tweaking in Adobe Raw to bring up shadows and bring down highlights. Of course I instantly fell in love with the look and perspective that this lens can deliver. On the D810 it is a wonderful tool.

But I couldn’t help pixel peeping and seeing what the lens was doing. Like some others, I thought…f/8 + 15mm means huge depth of field and everything sharp. But as you say, it never turns out that way, more effort is required to get the best results.

In this photo I can see the field curvature that you’ve presented, the crosswalk offers a nice guide, but you can actually see focus creeping closer going away from the center, and then moving back again toward the edges. This is another confirmation of everything you’ve written on the lens…it is spot on. Of course, it works very nicely for this particular scene, but I wasn’t always that lucky.

Keep up the nice work, it is very helpful and valuable to get the most out of this gear…which is very much worth doing.

DIGLLOYD: the Nikon D810 still takes some of the best images available.

The Milvus 15/2.8 is interesting in always making its owners happy.

Top-Notch Zeiss DSLR Wides and Normal

Zeiss DSLR Lenses wish list • Deals on Zeiss

$2699 ZEISS 15mm f/2.8 Milvus ZF.2 in Lenses: DSLR

$2299 ZEISS 18mm f/2.8 Milvus ZF.2 in Lenses: DSLR

$1843 ZEISS 21mm f/2.8 Milvus ZF.2 in Lenses: DSLR

$4990 ZEISS 28mm f/1.4 Otus ZE in Lenses: DSLR

$1999 ZEISS 35mm f/1.4 Milvus ZE in Lenses: DSLR

Ancient Bristlecone Pines, White Mountains

f8 @ 1/60 sec, ISO 64; 2014-09-22 17:16:09
NIKON D810 + Zeiss Distagon T* 2.8/15 ZF.2

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Sigma FE 85mm f/1.4 DG DN Art Aperture Series: Dolls

This series is at close range at a reproduction ratio of 1:14.7 (measured it). It evaluates all aspect of lens performance including distortion correction vs without.

Sigma FE 85mm f/1.4 DG DN Art Aperture Series: Dolls

Includes images from f/1.4 through f/11 plus crops and with and without distortion correction so that readers can see the effects across the entire aperture range.

Reader James K suggests that my loaner sample of the Sigma FE 85mm f/1.4 DG DN Art could be underperforming. Though I have not detected any obvious issues that would indicate lens skew, I also have been homebound due to horrible smoke, so I have no distance shots which are the easiest way to see it.

It is perfectly possible that this sample is at issue—I had sample-quality issues (lens skew and underperformance in general) with the Sigma FE 35mm f/1.2 DG DN Art. I have requested a 2nd sample, but do not yet know if I will get one. Sigma’s claims of MTF testing prior to shipment for quality control are IMO totally unsatisfactory, but that’s true of all brands these days.

A superb optical design means nothing if it cannot be built to strict tolerances!

Update Sept 17: a 2nd sample is definitely better and focuses spot-on as well. The first sample simply never focuses quite right with AF.

Cropped image

f4 @ 1/4 sec pixel shift, ISO 100; 2020-09-11 17:48:34
Sony A7R IV + Sigma FE 85mm f/1.4 DG DN Art
RAW: LACA corrected, +40 Whites, +15 Clarity

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Sigma FE 85mm f/1.4 DG DN Art Aperture Series: Kitchen Countertop

This series is about evaluating secondary color including violet fringing and magenta/green color bokeh. It alsos evaluates focus shift and sharpness across the frame as well as which aperture for optimal performance.

Sigma FE 85mm f/1.4 DG DN Art Aperture Series: Kitchen Countertop

Includes images from f/1.4 through f/11 plus crops.

f1.4 @ 1/10 sec pixel shift, ISO 100; 2020-09-11 17:57:18
Sony A7R IV + Sigma FE 85mm f/1.4 DG DN Art
RAW: LACA corrected, +40 Whites, +15 Clarity, USM {6,50,0}

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Sigma FE 85mm f/1.4 DG DN Art Aperture Series: Glass Vase

This series is primarily about evaluating secondary color and bokeh, but also evaluates focus shift and sharpness across the frame at a distance of approximately 8 feet / 2.5 meters.

Sigma FE 85mm f/1.4 DG DN Art Aperture Series: Glass Vase

Includes images from f/1.4 through f/11 plus crops.

f4 @ 0.5 sec pixel shift, ISO 100; 2020-09-11 17:52:07
Sony A7R IV + Sigma FE 85mm f/1.4 DG DN Art
RAW: LACA corrected, +40 Whites, +15 Clarity, USM {8,50,0}

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