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Why a camera can not be small AND have a deep grip

6 Aug

I keep seeing people clamouring for a system camera with a low depth, low width and a deep grip – see for example this recent thread on a popular forum. The hope, it seems, is that a mirrorless camera can provide this. Unfortunately, that’s not so. Mirrorless camera systems are designed on the idea that with the registration distance being shorter (because there need not be a space for the mirror), lenses can also be built to a more compact design. This comes with a number of challenges, one of which is illustrated below:

Sony A7R II with Vario Tessa 16-35mm f/4 lens.

Sony A7R II with Vario Tessa 16-35mm f/4 lens.

There physically isn’t space for a deeper grip, because it will not leave enough space for the fingers to fit between the lens and camera. I’d wager that for the same reason, it would be very difficult to design a similarly short 16-35mm f/2.8 lens, and equally this may be the reason why the A7 system’s 70-200mm lens is an f/4 rather than f/2.8. You quite simply have a problem if you want to fit a fat short wide aperture lens close to the camera body and have a deep grip for chubby man-fingers (no offence intended).

So there. I hope that covers that. Next time, I think I’ll include an X-ray of the fingers. 🙂

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The myth of the “cheaper mirrorless camera”

21 Jul

Having heard this more than once now, I think it’s time to speak out.

DSLRs and mirrorless both have their entry level price point at around $300 – that gets you a Pentax K-X0 or an Olympus E-PMY, for some value of X and Y corresponding to the current generation of camera systems. Then you have a typical enthusiast/semi-pro camera around $1000 body-only, and finally you might have a full-frame pro camera that’s $2k-$2.5k.

Now, that just gets you a camera, not a system. You also need some lenses. Let’s assume you want autofocus. Then you can forget about adapting DSLR lenses on a mirrorless system. You have to buy native. Well, native lenses haven’t been around for long, so there won’t be a real bargain on eBay yet for your mirrorless system. Likely you’ll have to buy new and pay in the region of $400-800 per lens, maybe more, depending on your needs. Well, for a DSLR camera, you may be able to buy a good used copy, and pay three quarters or even half, if you’re lucky, of the current new price. However, when you factor in that some DSLR lenses have been on the market for a while, allowing for new prices to also slide, you have quite a compelling value proposition on the DSLR side.

If you want a budget system, don’t buy mirrorless, or be very sure that you know exactly what you’re doing!

Why high resolution cameras don’t need an AA filter

17 Dec

Disclaimer: Unfiltered truth ahead.

Digital cameras used to have a problem, which was that their lenses were so sharp that images would show moire or aliasing if there wasn’t an additional anti-aliasing or low-pass filter placed directly in front of the sensor to add a small amount of blur. Side effects of this filter include a small reduction in light transmission and a slight distortion of the colour distribution.

As camera sensors got to around 16MP APS-C or around 40 MP full frame, it became apparent this problem wasn’t so much of a problem any more. Glass quality generally wasn’t good enough to still cause moire and other aliasing at this tight packing of Bayer array and photosites. The lenses themselves served as AA filters, and throwing in an low pass filter on the sensor only made images blurrier, without any particular benefit. So some smart executive or engineer at Nikon said, “let’s ditch the thing and see if our customers like it”. And the customers came, and they saw that it was good, and they bought it.

Around the same time, some Pentax execs likewise came together and said unto each other, “let there be unwavering sharpness”. But knowing full wele that the Nikon gods had spread their bets across two models, one with and one withoute AA filter, the good sirs of Pentax did likewyse, and thus there came to be the K-5 II and IIs, made in the D800E’s image.

So there you have it: the story of why you can buy a D800E or K-5 IIs without regret. And how, as an engineer, you can do something for very good reasons and completely fail to communicate this to the customers. Probably because upper management told you to keep your trap shut about the sharpness of the lenses. And the fact that the Ricoh GR and Fujifilm X100S take sharper pics than your monster-tea-bagging SLR.

So there you have it: the reason you can leave that K-3 AA simulation switched off, save battery power, and never worry. Woohoo!

Q: Who is the most collaborative camera manufacturer?

13 Sep

A: As of June this year, the answer would have to be Panasonic. They are working with Olympus on the Micro Four Thirds standard, with Leica on compact and bridge cameras, and now with Fujifilm on sensor technology. An honorable mention goes to Sony, who provide their sensors to a number of other companies, including Pentax, Nikon, and Olympus, but do not integrate others’ technology into their own products, with the exception of Zeiss lenses. Sony has also been allowing Hasselblad to rebadge some of its cameras as fashion accessories, in a move that many believe is ill-fated on Hasselblad’s part but carries little risk to Sony.

On the flip side, the title of least collaborative company may go to Canon, and there’s not much to say about that, really. Among other less collaborative companies, we find Samsung, Pentax, and Nikon. Samsung uses Schneider-Kreuznach lenses in some of its cameras, and has previously shared sensor technology with Pentax, prior to the latter’s move to Sony. Nikon has recently switched its sensor supplier from Sony to Toshiba, for the D7100. Pentax also apparently takes Tamron lens designs and rebadges them as its own.

Affordable DSLR that works great with video – or rather something else?

5 May

Someone recently asked about buying their first DSLR when their main interest is sports photography and video, at the entry level price-wise. The question also included Canon and Nikon as examples. I’ll try and answer that question here.

First things first – currently, all entry level DSLRs are capable of “professional” quality output. There may be specific applications where these cameras will not be competitive, but image quality is not typically a major problem.

Having said that, Canon is currently lagging behind in sensor technology, with higher noise levels and lower dynamic range. This will also limit the amount of light you need to take “reasonable” photographs, regardless of what personal criteria you may set for considering your output “reasonable”.

However, Canon is also generally held to be the better choice for video. The major challenges for video in a DSLR camera are continuous autofocus and noiseless operation (in terms of auditory noise). Panasonic is generally regarded as having the best video features, but they don’t currently sell any true SLR cameras, but rather opt for the mirrorless format, where your preview is indirect through the rear display or an electronic viewfinder (EVF). This may mean that your view of the scene is delayed, so it’s worth checking out reviews that have tested for this.

Principally, the characteristics of photographic output will feature again when recording video, so a camera with good dynamic range (DR) in still image output will also usually have high DR in video. This would be a considerable benefit from using a relatively affordable pro camera such as a Pentax K-5 or K-5 II. Remember that all DSLR cameras currently in production include HD video as an output option at upwards of 24 frames per second, so you won’t need to worry about that too much.

I will, however, add two more points for consideration. You should look not only at frame rates and resolutions when judging video, but also at the compression used. This will tell you how much you’ll spend on memory cards and hard disks to accommodate the length of filming you’re interested in, and it will also tell you whether there are situations where artefacts will show up in your movies. My experience comparing H.264 vs. Motion JPEG suggests that artefacts will occur with fast movement or sudden changes of lighting in the H.264 format, but will be absent from Motion JPEG. However, Motion JPEG will generate huge files by comparison which you should factor into your budget.

In terms of features, you should consider whether you’ll want to do time lapse or high speed video – for high speed in particular, there are no viable workarounds, so you’ll need a camera that can already do this. For time lapse capture, clunky external features may be required on various cameras including current Canon models.

Remember also that there are affordable video devices such as the GoPro Hero set of cameras that in a lot of ways, may be more flexible and fun than a big SLR setup, as well as all-in-one solutions such as Panasonic’s rather affordable FZ200, a superzoom bridge with plenty of video features. What a DSLR camera gives you is the ability to swap lenses, but each new lens will cost as much or more as a new or fairly new compact or bridge camera. If you think you have the discipline to stick with one camera and get really good at using it, then try leaning towards a DSLR, but if you think you’ll always want to keep up with the latest imaging technology, you’ll be far better off cost-wise looking at superzooms.

Eventually, only you can know whether your interest in video is strong enough to merit a choice of Panasonic over Canon, or whether even Pentax or Nikon might be viable choices due to the higher photo output quality, or whether you’ll want to pursue an alternate adventure with a GoPro-type camera or a compact/superzoom.

Why an electronic viewfinder (EVF)?

30 Apr

Much debate has surrounded the decision by some camera makers to replace traditional optical viewfinders with an electronic substitute, in which the user looks at an LED display rather than some direct optical projection designed to resemble the image captured.

Chief among these companies is Sony, who have gone as far as to implement such a system in a line of cameras that are direct successors to Minolta’s venerable film SLR business and early digital efforts (Sony continued the SLR legacy for a while after buying Minolta, then switched to its current “SLT” design). But why would you want a camera with an EVF?

As it turns out, there are a number of reasons, all controversially discussed at length among camera enthusiasts.

  1. An EVF protects your eyes. An EVF allows a manufacturer to completely control the spectrum emitted by the device. Therefore, UV radiation may be absent from such images, and there is no risk of blinding yourself by turning the camera at the sun – the image will never be brighter than the LEDs are capable of. Better to stress the sensor than your eyes, right?
  2. An EVF allows exact control of manual focus. While in SLR cameras, your eyes can compensate and thus give you a false sense of sharpness, an EVF gives you an image ”as the sensor sees it”. In this case, if the image is blurry, your eyes or brain can do very little to make it seem sharp. However, equally keep in mind that your assessment of the sharpness is limited by the resolution of the EVF, and small detail that would have been visible at the “retinal” resolution of your eye plus sharpness of your lens, may not be resolved by the EVF’s display.
  3. If sensor stabilisation is used, currently only an EVF can show you the image post-stabilisation, as it would appear on the sensor. So you’re getting a clear, jitter-free image. However, a brief excursion into stabilisation technologies is necessary here. Lens-based, “optical” stabilisation will give you a stable image no matter how you capture the image after it has passed through the lens – directly with your eye or through a display intermediary. Only with sensor-shift stabilisation technology does it make a difference where you capture the image. To give a full explanation of the pros and cons of lens- vs. sensor-based stabilisation, there will be another article in this series. What is important to remember is that image stabilisation never works perfectly. and so having to rely on it is always a flawed compromise. The combination of optical viewfinder and sensor-based stabilisation is perfect in at least this one sense, that it disciplines you to stabilise your camera properly, by giving you the means to learn how to do this. If the image is shaky, you will see it. And you will be able to counteract the shake – in fact, you will inevitably do so in an attempt to see the image better yourself. Additionally, keep in mind that sensor stabilisation drains your battery – this could lead to overall compromises such as a heavier camera with a bigger battery and bulkier grip, or the need for carrying spare batteries and swapping them out more often. In an OVF camera, the stabilisation will only be active during image capture, saving you battery life.
  4. An EVF allows displaying a brightened image in very dark conditions, where a “slow” lens on an OVF may not allow you to see much at all. However, this is counteracted by bullet point no. 4, as the above-mentioned alternate uses do not return the light for use by the sensor, but rather whisk it off to the side somewhere, in a little light prison. While an EVF may still not allow you to see in pitch darkness, it may be useful for older people whose night vision has declined. Also note that whatever noise the sensor generates will affect the EVF image, so younger people will likely prefer an OVF at night, especially with fast lenses.
  5. Compared to a through-the-lens optical viewfinder, which requires a mirror to be placed in front of the sensor to deflect the image towards the photographer’s eye, exclusive use of an EVF allows the mirror to be dropped from the design. This allows for a slimmer camera, but has several other benefits: (a) it eliminates camera shake that’s caused by the mirror, which is a major source of image blur at certain exposures (typically 1/100s), (b) it may allow lower shutter lag and higher frame rates because the mirror does not need to be used, and (c) it reduces the auditory noise emitted by the camera, useful particularly in street and wildlife photography. Additionally, in theory there does not need to be any blackout with an EVF; however, in practice, the image processing abilities of current-day cameras lag behind this theoretical tenet, for no particularly good reason.

Okay, that all sounds fairly good, so why wouldn’t you want an EVF? Disadvantages:

  1. We’ve touched on the lack of resolution.
  2. We’ve touched on the shorter battery life due to image stabilisation being permanently active except when the camera is already stable (e.g. tripod-mounted).
  3. Viewfinder lag. In the same way that we’re still waiting for blackout to be eliminated, we’re also being disappointed so far in that the transmission of video from sensor to viewfinder is not instantaneous with an EVF. Since there’s also no sufficiently large image buffer to allow shots to be recorded after they’ve happened, and panning decisions may have to be made instantaneously (or as close as you can get giving human reaction times) by the photographer, current-day EVFs can be frustrating to sports and wildlife photographers.
  4. No image when battery is drained. You can’t use your camera as a binoculars replacement. You may therefore have to additionally carry a pair of “binos”.

How does the Four Thirds (4/3) crop factor work?

9 Feb

A: The oft-cited 2 times crop factor of the Four Thirds (FT) sensor format is measured in the longer dimension. An FT sensor is 18.0mm wide, whereas a full frame sensor measures 35.8mm (Sony a99, RX1), 35.9mm (Nikon, Sony A900) or 36.0mm (Canon). In the shorter dimension, the crop factor is 1.78.