'We want to make lenses that can be used forever': Sony engineer discusses G Master lenses
'We want to make lenses that can be used forever,' says a senior engineer behind Sony's new G master lenses. At the launch of the ‘G Master’ range of high end lenses, we spoke to Motoyuki Ohtake, Distinguished Engineer in Sony’s Lens Design Department about the process and the philosophy behind the latest lenses.
The development process series involved re-thinking several parts of the design and manufacturing process, he says.
|Motoyuji Ohtake, Distinguished Engineer, Opto Design Department, Core Technology Division, Digital Imaging Business Group at Sony.|
To understand how the lenses came about, he explained the usual process of lens development. ‘Sometimes we propose a new lens but often it comes from the product planning department [the marketing department that assesses potential requirements and demands]. We then make a series of rough designs, some are big, with high optical performance, others are more compact but maybe not so optically strong. We discuss which design to proceed with, based on what we think is the optimal balance or cost, performance and size to make the perfect product.’
After deciding which of the initial designs to pursue, there’s a great deal of collaboration between teams, he explains: ‘we work with the mechanical team, the lens motor team, the lens control team, the lens element team and maybe the equipment team who will have to prepare the manufacturing process.’ Each of these team feeds its expertise into the design. ‘Maybe the optical team proposes a new lens design and the motor team tells us which motor is best. Or warn us if the focus will be too slow. They feed back about the mechanical aspects,’ he says.
The G Master series required many of these teams to re-think their parts of the process, from design to manufacture.
Re-thinking basic assumptions
‘For the G Master lenses we decided we would assess the spatial frequency at 50 lines per mm,’ says Ohtake: ‘Usually lens makers, including ourselves, evaluate lenses at 10 and 30 lpmm (or 10, 20 and 40 for Carl Zeiss-branded optics).’
‘At the start of the process we all agreed we should change the spacial frequency [to a more challenging target],’ he says: ’but which is best to get good performance? We could design for 100 lpmm but the lens would become very bulky and long - which might not be a very practical lens. A balance of the size and the optical performance was very important.’
The target of 50 lpmm wasn’t dictated by the company’s 40MP camera or 4K video, he says. ’All our FE lenses were designed for at least 40MP. Because we have an image sensor team within Sony, we get to see the sensor roadmap, so we’ve been designing for this all along with FE. With the G Master we’d like to make lenses that can be used forever.’
A focus on bokeh
But it’s not just the more stringent frequency assessment that was developed for the G Master lenses, Ohtake explains: ‘We had to discuss what good bokeh means. We have some designers from Minolta who understand that the spirit of the ‘G’ lenses was good bokeh in the background but we had no way to evaluate that.
‘We looked at what is considered good bokeh and how it affects not just the background rendering but also the transition from perfectly sharp to out-of-focus regions. We developed a way to evaluate bokeh and were able to make a simulation. This meant we didn’t have to build a lens to see how it performed, we could now computer model it before taking a design too far.’
This is a significant change, Sony says, as it means bokeh can be one of the primary design considerations, rather than being something that can only be adjusted later in the process, once the main aspects of the design have been settled upon.
Another piece of the puzzle - shape and smoothness
This analysis of the factors that affect bokeh showed that both the precision of the lens molding and the smoothness of the lens surface could have an effect.
‘Traditionally it was very hard to achieve both: current technology gives a roughness on the scale of 20-30nm on the aspheric surface. Improving this usually involved polishing, which can then lead to the lens element being slightly unevenly shaped.’
‘We developed a new way of making the lens element and a new molding process, including a new machine. Now we can get roughness down to around 10nm and get a more accurate shape to the aspherical surface.’
|Ohtake wouldn't budge when we asked which his favorite lens was, but immediately reached for the 85mm F1.4 when we took this group shot.|
The first three G Master lenses use three different AF motor technologies between them - emphasizing Ohtake’s point that different technologies work better in different contexts.
The 24-70mm F2.8 uses a Direct Drive SSM system (piezoelectric element). This is very fast, very quiet and very precise. We used a linear motor for the 24-70mm F4 but this lens has a heavier focus element, so direct drive was a better choice.
The focus element in the 85mm F1.4 was even heavier, however. ‘For the 85mm we use a ring type focus motor. This is very good for heavy lens elements and our lens software team developed a good algorithm so that it works well with contrast-detection autofocus' (a traditional weakness for ring-type designs).
Finally, the 70-200mm uses a combination of a linear actuator and a ring-type focus motor. ‘The focus group had become too heavy so we separated the two focusing lenses. One is very heavy, so we used a ring type motor for that one, then used a linear motor for the other. The ring type is used to quickly achieve approximate focus and the linear motor is used for the high precision aspect.’
Still correct to optically correct
Discussing the idea that bokeh and sharpness have previously been in conflict, we asked Ohtake about other trade-offs. We’ve been told that the ability to correct lateral chromatic aberration in software makes lens design easier, since you don’t have to correct it optically, which can quickly complicate the lens design and detract from other parameters.
Not for G Master lenses, he explains. ‘Light doesn’t separate nicely into red, green and blue' (the color channels that most cameras capture, and which can be adjusted, relative to one another, to correct lateral CA). It’s a continuum with each wavelength being displaced slightly differently. ‘To get the really high contrast we wanted in G Master, we had to suppress it in the lens.’
The future of APS-C
We also asked Ohtake about Sony's APS-C lenses for E-mount. His team likes designing APS-C lenses, he says: ‘The focus elements are light, so it’s easier to design. We have all these focus motor technologies in-house and we’d like to try them in APS-C lenses if that’s what the Product Planning team says is required.’
|Lost in cyber space by Jill Hancock|
from Your City - Look Down
|Bringing Home the Bacon by Domenick Creaco|
from My Best Photo of the Week
|I Think I Can? I Think I Can? by kjfrigo|
|ON THE TAXIWAY by DIM POL|
from Leaving on a Jet Plane
Well-known photography educators Tony and Chelsey Northrup recently won $40,000 from an Australian company who used one of their most popular portraits on product packaging without so much as asking permission. Check out the video for the full story.
The Sigma 105mm F1.4 DG HSM Art lens—colloquially referred to as the 'bokeh master'—will cost just $1,600 USD when it ships for Canon, Nikon, and Sigma mounts in 'late June.' That's $600 less than the Nikon 105mm F1.4E.
'Recall shooting functions' lets you recall previously saved exposure settings (including shutter speed and aperture) by simply pressing and holding specific controls. The function is designed to allow for quick shooting parameter changes in variable light conditions.
Zeiss has announced a new lineup of 13 'Supreme Prime' lenses for large format cinematographers who want smaller and lighter glass that still produces top-quality results. The kind of lenses that make your salivary glands work... and your wallet groan.
The new HP DesignJet Z6 and Z9+ supposedly offer "the fastest printing capabilities available on the market today," all while using fewer ink tanks, and featuring useful add-ons like a built-in vertical trimmer.
In an effort to streamline production and minimize confusion, RED has announced that it is simplifying its product lineup to three main cameras. As an added bonus, this change dramatically drops the prices for all three options.
Fujifilm's new X-T100 is an SLR-style mirrorless camera that takes the internals of the X-A5, including phase-detect AF, and adds a fully articulating LCD and high-res OLED viewfinder. The X-T100 is priced at a very reasonable $599/€599 body-only and $699/€699/£619 with a 15-45mm lens.
Panasonic's latest firmware update for its GH5S, GH5 and G9 series of cameras was leaked in Japan earlier today and is now being officially announced a week early. But don't get too excited – you still won't be able to download it until May 30th.
We've been saying for years that the term "lens compression" is misleading, but Lee Morris over at Fstoppers has put together a useful video that explains why this is the case, and demonstrates it with two easy-to-understand examples.
Last week, some 'leaked' photos were published online that purported to show a DJI Phantom 5 drone with interchangeable lens camera and several prime lenses. The rumor was widely reported, but DPReview has learned that those images do not, in fact, show a Phantom 5 at all.
The bezel-free Vivo Apex concept phone with its pop-up camera might be more than a concept. A new teaser video and ad seem to hint at a similar smartphone to be released June 12st.
Skylum has teamed up with its sister company Photolemur to create Skylum AI Lab, where the duo will work on AI-powered image solutions including image segmentation, tagging and upscaling.
Award-winning fashion and celebrity photographer Markus Klinko recently tested out the Godox EC-200 flash extension head. Actually, he tested out four of them, creating a quad-flash ring light alternative that works great for both beauty and close-up work.
According to a recent investor presentation, Sony intends to occupy the top slot in the overall camera market by the end of 2020, beating back Canon and Nikon by boosting its interchangeable lens systems.
HTC brings back the dual-camera on the newly-announced U12+, which features a secondary tele-camera with 2x zoom factor, as well as 4K video recording at 60 frames per second.
Google has finally added the ability to mark your favorite images in Google Photos, so they can be filtered into a dedicated album. The service is also planning to a social network-like "heart" button that lets you like other people's photos.
We've been messing around with Apollo, an iOS app that allows you to add 3D lighting effects to images using depth information, and have to say we're impressed with what it's capable of – but that doesn't mean we don't have a few requests for the next version.
The new lightweight laptop packs a whole lot of photo- and video-editing punch. The laptop can be specced out with a Core i9 processor, 16GB of RAM, 1TB of SSD storage, NVIDIA graphics with 4GB of GDDR5, and a 4K display with 100% Adobe RGB coverage.
It looks like Canon is getting into sensor sales. The three specialized CMOS sensors the company recently demoed—including a 120MP APS-H model and an ultra-low light sensor—have been listed for sale through a distributor in the US.
Instagram has finally launched a "Mute" button, and is testing an "All Caught Up" feature that will let you know when you've seen all new post from the people you follow from the past 48 hours.
45-year-old photography magazine Shutterbug announced today that it is shutting down its print publication, focusing instead on reaching its readers online as a web-only publication.
Kodak Alaris has launched a new single-use disposable camera in Europe. Called the Kodak Daylight Single Use Camera, this 800 ISO film camera is supposedly ideal for parties, weddings, and similar events.
Computer vision company Lucid and cinema camera maker RED have partnered to create an 8K 3D camera that can capture 4-view (4V) holographic images and video in real-time. The camera is designed to work with RED's upcoming holographic Hydrogen One smartphone.
If Canon and Nikon do get into high-end mirrorless, it's almost certain that they'll do everything they can to maintain compatibility with their existing mounts. But, asks Richard Butler, wouldn't it be more interesting if they built a small, niche system to live alongside their existing DSLRs?
It seems RED's Hydrogen One super-phone will make it into the hands of customers in the near future. The phone is now officially slated for a Verizon and AT&T release in the US sometime this summer.
You know that feeling when you're already all suited up and out on a spacewalk outside the International Space Station, and only then do you realize you forgot to put the SD card in your GoPro? No? Us either... but one astronaut on the ISS sure does.
From 2015 to 2017, filmmaker Macgregor and his crew spend many months traveling back and forth on the famed Mauritanian Railway—the so-called 'Backbone of the Sahara—to document the grueling journey endured by merchants who regularly travel atop this train. This beautifully-executed short doc is the result.
You can now insert another user's Instagram post into your own Stories as a customized sticker, the first official "regram" feature we've seen from the Facebook-owned photo sharing app.
Synology has added a new 6-bay NAS to its DiskStation+ series, and it's aimed squarely at photographers and medium sized businesses. The DS1618+ can handle up to six 12TB drives, giving it a max capacity of 72TB, or up to 60TB in RAID 5.
Our original gallery for Tamron's new 70-210mm F4 had portraits, slow-moving wildlife and city scenes, but was sorely missing fast action. We remedied that by photographing some motorcycles flying through the air.