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Halide app developer says iPhone portrait smoothing is due to low contrast, noise reduction

4 Oct

The developer of the app, which is billed as RAW Manual Camera and has in one review been described as a “pro camera app”, suggests in this blog post that the smoothing observed (and previously described here) may be a consequence of smart HDR in that HDR always reduces contrast (hence high dynamic range) and therefore apparent sharpness, which may subjectively appear as smoothing. Read more here.

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Pentax licenses lens to Tokina, then lets them undercut the original price

30 Sep

I’ve referred to the HD Pentax D FA* 50mm f/1.4 SDM AW in stories several times. This lens is important because of the popularity of the 50mm focal length and hence the importance of such lenses to the industry. Optics companies measured their strength against another by the quality of their 50mm lenses in the 1950s, and they still do so today. Right now, there is a new iteration of this contest, in which lenses such as Sony’s Gold Master, Sigma’s Art, Zeiss’ Otus and Milvus, various Canon and Nikon versions, and of course, Pentax D FA* are tested against one another on various merits.

50mmPentaxAndTokina

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Whoa, what just happened to the camera industry?

28 Sep

So we’re nearing the end of Photokina now, and I don’t think quite as many record-breaking cameras and products have been announced in any previous year, especially at the high end, and especially on the mirrorless end. Two things are clear: the air is getting thin up there, and 2019 is going to be the year of the high-end mirrorless camera.

groupphoto2018

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Google open-sources extreme JPEG compression

18 Mar

I previously criticised JPEGmini, a commercial program that promised to reduce JPEG size by focusing on the way humans perceive colour. My repeated finding in using the program was that it was unable to provide better compression than GIMP’s JPEG export – and GIMP is free!

Now Google has fielded Guetzli, a new JPEG compression engine that Google describes as drawing on psychovisual research. So in that aspect, it doesn’t sound much different from JPEGmini. It is, however, open-sourced, and according to Google, promises 35% smaller files compared to the open source JPEG library libjpeg, which without much doubt must be the engine used by GIMP.

montage-cats-zoom-eye2

Original on the left, libjpeg, center, and Guetzli on the right. Google notes the paucity of blocky artefacts in the Guetzli output, but I would also note the loss in vibrance, a typical approach in noise reduction.

Guetzli, like other recent advances in imaging, is slow. So slow, in fact, that it sounds like its use case is currently limited to very frequently downloaded items like website banners, where spending a lot of time optimizing will considerably reduce traffic.

Alternatively, though, Google could put its weight behind FLIF, supporting it in Chrome/Chromium and thereby putting pressure on other browsers to also support it. FLIF promises to provide current-best lossless compression and is interlaceable – and open source.

Guetzli might give a smaller file than FLIF, but only with more lossy compression, and it sounds like it’s currently a lot slower (I have seen no figures comparing the two).

From photographers’ perspectives, Guetzli may have one further use case. Images with such highly optimised compression are unlikely to be very usable for further editing, so for showing off your work on the web while spoiling the fun for potential thieves, Guetzli or any higher-compression tool might be a good choice (but remember – Google can “guesstimate” the image back with RAISR).

Craving full-frame? Read this first.

3 Jul

Reading this article might save you some money. No, I’m not sponsored to write this, so you may safely proceed. All you’ll get is technical insight and honest opinion.

Perhaps like many photographers, you’ve thought about going for a full frame camera. Perhaps you’ve heard about shallow depth of field, low light shooting and noise. Maybe you’ve heard that full frame is “one stop faster” or “one stop brighter”.

In this article, I’ll cover one of the reasons for going full frame – more light, and how much sense it makes, especially for your bank balance.

Frontal product photo of a black camera against blueish white background.

Ever wanted a Nikon D800E? Read on. (Image credit: Jastrow)

By going from APS-C to full frame – probably the most common move – you gain approximately one stop of light, i.e. you get twice as much light over the whole of your sensor. It would be approximately true to say that shooting ISO 200 on full frame, you get the same noise as shooting ISO 80 on APS-C. So you can shoot faster shutter speeds and, over the whole sensor, get the same noise. However, if you shoot 16 megapixels on APS-C, then shooting 36 megapixels full frame, you will get the same PER PIXEL noise, at the same ISO. So far, so good.

Small rectangle denoted APS-C next to larger rectangle denoted

Relative size of the two major DSLR sensor formats (Copyright breakfastographer / Chriusha (Хрюша) / CC-BY-SA-3.0)

So if we shoot the same apertures, we gain a stop of light. So we can ask the question, how much does it cost to gain a stop of light?

If you upgrade from an 18-55/3.5-5.6 APS-C kit lens to a 17-50/2.8 APS-C premium zoom, you gain 1-2 stops of light, and it might cost you 150 Eurodollars if you buy used. Or for about the same price, you could upgrade to a 17-70/2.8-4.5, which gives you almost exactly one stop advantage over the kit lens, and a bit of extra range.

If you further upgrade to an 18-35/1.8 zoom, you might pay about 600 Eurodollars used or a good offer new, and you would gain a stop over the 17-50/2.8 or over two stops vs. an 18-55/3.5-5.6 kit lens. But you shorten your range by about one stop of teleconversion. Don’t worry if that sounds technical – just remember that 35mm is 35mm and not 50, 55 or 70mm.

Black zoom lens pointing upwards with hood attached, and lens cap lying next to it, label up. Zoom ring indicates 17-24-35-50. White background.

Another possible upgrade path? The Tamron 17-50/2.8 (Image credit: Christian Fischer/CC-BY-SA-3.0 Unported)

If low light shooting, reduced noise or faster shutter speeds are what you’re after, and you’re still shooting with an APS-C camera and kit lens, you owe it to yourself to first invest the 150 to see if the extra light is worth it. This will put you in a much better position to judge whether you want to invest about ten times that amount (or more) to get to a full frame camera and appropriate lens. (Note that a full frame camera with an f/4 lens offers no light advantage over an APS-C camera with an f/2.8 lens!)

There are other points to consider, of course, some of which I’ll touch on briefly. A full frame camera generally offers greater sharpness due to both an increase in resolution and easier manufacture and assembly of appropriate glass. The full frame format is more resistant to diffraction, typically tolerating f/11 rather than f/8 (APS-C) or f/5.6 (Micro Four Thirds) – note that these assumptions only hold for certain pixel pitch, i.e. a 36 megapixel full frame camera is just as sensitive to diffraction at the pixel level as a 16 megapixel APS-C camera. (Other assumptions apply, such as having comparable filter stacks in front of the sensor.) However, over the entire frame, the full frame camera is more tolerant. The flip side is that you need to shoot at those smaller stops to reach the same depth of field, meaning that in landscape shooting, there is no full frame advantage in available light, for the same positioning and framing.

Furthermore, full frame has greater limitations when it comes to designing zoom lenses – you may notice that a common superzoom lens specification for full frame is the 28-300mm lens, whereas on APS-C, the limit has been pushed to 16-300mm – the same versatility in focal length as a 24-450mm on full frame!

Similarly, compare the Sigma 18-35/1.8 to its full frame sibling, the 24-35/2. The smaller lens is both faster and, depending on your point of view, slightly more versatile. (The comparison is hampered by the full frame lens being the equivalent of a 16-24mm on APS-C – not an easy comparison!)

So a full frame camera is best suited to the shooter who knows what situations they want to cover and what their preferred focal lengths are. If you prefer spontaneous shooting and versatility, it is likely that a full frame camera will not make you happy.

Arguments about achieving shallow depth of field more easily on a full frame camera deserve a separate article.

Update 2/2/2017: Also check out my newer article, Low light photography? Affordable? Look no further! for the latest development, or check out a sample image.

Hasselblad Masters to wait eight months for their prizes

16 Jan

Hasselblad has announced the winners of its Hasselblad Masters 2016 competition, but they’ll have to wait until photokina in September to receive their prizes – a new Hasselblad medium format camera each. Perhaps this means that Hasselblad will announce a new camera at the trade show, which might be worth the wait – after all, we were promised that the time of whimsical management decisions at Hasselblad (Lunar, Stellar, HV) were over.

Timelapse/hyperlapse craze reaches saturation

11 Jan

I just watched Exhale, which was billed as some kind of revelatory experience. Within seconds of the video starting, my mind had drifted off to doing other things without me consciously realising it. I then watched it a second time just to understand how I had become so disconnected. The answer I came to is that the novelty of timelapse footage has faded. Crazy moving clouds, dangling flowerheads, changes from day to night and back – we’ve all seen it before, and in a variety of different landscapes, too, set to the same formulaic music as last time. It’s become hard to keep up the excitement.

Hyperlapse, meanwhile, to me is the pinnacle of making things banal. An entire weeklong trip can now be videographically condensed into just a few short minutes, with zooming replacing the experience of actually travelling from one place to another.

I, for one, am glad to be putting this need to “be amazed” at every new timelapse video that comes out, behind me, and getting on with more important, real stuff.

Yours,

Codger