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Comment by shawnz | Hacker News Reader

This is mostly unrelated, but I've had a longstanding question about the camera industry and maybe someone here will know the answer. Why do we keep investing in DSLR technology when mirrorless is obviously superior? Is it just a matter of professional photographers being hung up on old technology?

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There's a few reasons, but they're all becoming irrelevant. I'm going to focus on Sony as the exemplar mirrorless player because I'm most familiar with them.

Mostly, it's because mirrorless lenses were garbage compared to Canon/Nikon until recently. This is the biggest reason. Sony in in particular has been very aggressive in addressing this issue by releasing native lenses which compete with Canon/Nikon in terms of price and performance at the high end. This wasn't an innovation problem, this was just a matter of Sony catching up to the leading players. When they did this, 3rd party players like Tamron and Sigma responded by producing more mirrorless lenses as the market size grew.

Next was brand value and inertia. Despite those, Sony has gone from a prosumer toy to a serious consideration in the pro space over just a few years. I don't think this shift could have happened much sooner.

Finally, and this only applies to Canon, it's the firmware. Through a series of happy accidents, Cannon cameras ended up with a completely open sourced firmware package called Magic Lantern which unlocks functionality not found in any other cameras - functionality that enables some types of photography that simply weren't accessible without 6 figure budgets before. This hasn't happened in the mirrorless space, so there's a segment of Canon users who are ready to make the jump to Sony but are held back by its comparatively limited stock firmware.

Also, there is one limiting factor on mirrorless cameras that takes away their main advantage at the high end. Professional grade lenses are big and heavy, and mirrorless cameras do nothing to remedy that. It's just a physical limitation of optical systems, the performance of the lens is ultimately dictated by the diameter of the elements. So if you're a pro photographer with his 85mm/f1.4 or 70-200/f2.8 lens, the size of that lens isn't going to change, and it completely dominates the size of the camera body. This takes away one of the main advantages of mirrorless technology in the pro space.

Not even garbage necessarily, just a limited choice in lenses. The mirrorless lenses are being made by the same high quality established companies as the DSLR lenses, they just have fewer choices. To take MFT as an example, which is the biggest mirrorless lens mount by far, it has lenses by several different manufacturers but still doesn't have the same variety available of either the Canon or Nikon full-frame DSLR mounts. Here's the MFT lenses: http://www.four-thirds.org/en/microft/lens_chart.html

Professional grade lenses are big and heavy, and mirrorless cameras do nothing to remedy that.

In fact, I added a battery grip to my APS-C body for long days shooting with my 400/f4 to add grip surface & balance the weight. I was getting carpel tunnel before I added the grip.

> DSLR technology when mirrorless is obviously superior

There is no tech superior to another. Mirrorless requires extensive battery usage for previewing your pictures. A DSLR can take thousands of pictures continuously. That's why the Sony Mirrorless 35mm digital cameras have a some kind of weakness: their autonomy on a single charge is about 300-400 pictures. An equivalent Canon or Nikon DSLR can take easily 1500 pictures on a single charge.

This used to be true but the latest generation of mirrorless are competing well on the battery front. Flapping a mirror around vs EVF, while I wouldn't want to give up my optical viewfinder just yet I think it's only a matter of time until they become niche.

Because at the current time, mirrorless isn't entirely "obviously superior". It's been rapidly improving and gaining market share (for good reasons), but there's valid reasons to still have DSLRs too.

Also, parts of the market aren't buying "a camera", they bought into an ecosystem that's more than just camera tech. Someone in the Nikon or Canon ecosystem (the two only(?) important players that primarily do DSLRs) will stick with that even if they don't do mirrorless versions of their high-end cameras.

As there are more and more rumors about Nikon and Canon finally intoducing professional mirrorless cameras, they certainly would also support all their current lens systems.

Sure. But they might be making the jump now, when they can be very competitive with the DSLRs, instead of earlier, when it would have been a "why bother buying a worse product?" offering. (+ of course likely some amount of corporate inertia)

E.g. a large part of why Sony is so attractive right now is because their sensors are the best: Canon making a mirrorless isn't going to have that benefit - and if they had the tech, their DSLRs would gain it too.

The sensor is just one thing. There are numerous categories of lenses where the Sony offering is either inexistent or completely overpriced vs what Canon or Nikon offers. Sony cannot win just everywhere, at least right now.

Hopefully they also take advantage of the shorter flange distance of mirrorless, to redesign their lenses to be more compact too.

Being able to reuse existing glass is great (in fact, that's why Canon / Nikon adapters for Sony's mirrorless are so popular), but it always ends up being suboptimal (sure you save some weight on the body, but the lens is still massive).

Do you have some examples of lenses with comparable optical properties that are smaller in mirrorless mounts?

AFAIK demand for corner-to-corner sharpness wide open has made lenses huge NOT whether there is a mirror or not. I have a bunch of old school Nikon primes that are tiny compared to modern lenses but are essentially "portrait only" lenses until f/4.

I think the Zeiss Loxia (mirrorless) and Milvus (SLR) lines are an interesting comparison point, since they're both from the same manufacturer, both manual focus, and should both be comparable quality.

The Loxia 21mm/f2.8 is 72 mm long, and 394 g. The Milvus 21mm/f2.8 is 95 mm long, and 735 g (Nikon mount)

Once you go to a higher focal length, keeping the lens compact requires sacrificing something, i.e. slower glass:

The Loxia 35mm/f2 is 59 mm, 340 g. The Milvus 35mm/f1.4 is 125 mm, 1131 g.

The Loxia 85mm/f2.4 is 95 mm, 594 g. The Milvus 85mm/f1.4 is 113 mm, 1210 g.

So, I'd sum it up as, at wider angles, the lens designer probably has a bit more flexibility because of the absence of the mirror box, but at longer focal lengths it matters much less. It's also interesting to me that Zeiss is focusing more on slower lenses that retain the compact form factor. They do have a 35mm 1.4 FE mount, which is huge, and Sigma recently released their FE versions of the Art prime lenses (which are just as big as their SLR equivalents), but the bulk of the Batis and Loxia lineups are f2 and up.

Seems to indicate that while there was indeed a lot of demand for huge, extremely sharp f1.2 or f1.4 lenses in the SLR world, mirrorless customers generally seem OK with trading some of that speed for less weight.

The argument over DSLRs and mirrorless remind me of the endless SLR vs rangefinder debates among film users. Each side touts various advantages that exist more in their own minds than in the actual cameras.

Mostly yes, people are locked into their brand through the lens mount and it's pretty expensive to switch. In some ways mirrorless hasn't been considered as good as SLR, with focusing and battery life, though this has been improved a lot recently. Some others still talk about weather sealing, which Sony seems to be lacking - but this is not a inherent flaw in mirrorless systems, but a choice by Sony.

If Canon and Nikon start making full-frame mirrorless cameras, I think we'll start to see a switch, especially if they neglect their SLR bodies and lenses.

I could see silent shooting becoming a requirement in press & some sports, which would essentially accelerate a change to mirrorless in the pro market. Video is another driver for mirrorless, since it can't use the mirror anyway (except in SLT cameras).

I really like the Fujifilm X-Ex line in particular and use it more than my Canon 5Diii. (I mostly use the latter for action or if I need very tele or very wide angle lenses.) But the mirrorless lines are definitely sort of a niche. A lot of the potential customers are pretty locked into Canon or Nikon glass. Furthermore, for a lot of people, mirrorless doesn't fully replace DSLRs--though it increasingly can for many types of shooting. So you're left with expensive camera lines that aren't quite as versatile as a DSLR although they're significantly lighter and smaller.

I recently went from a Nikon D7000 to a Fuji X-T2. I've gotten used to the EVF (quite low latency, but crappy dynamic range), but the main annoyance is poor battery life, unless you're willing to have the additional grip attached 24/7, which sorta defeats the purpose of having a smaller mirrorless body. Also, the menu system is completely unintuitive.

I can't say I've had a particular issue with the X-E3's battery life even when using it to shoot lots of pics at an event. I do carry spare batteries but I can usually get through a day of hundreds of photos on just one.

I don't love the menu system either and I really wish they could have figured out a way to get ISO on a top dial.

That said, the X-E3 has a lot of appeal. Especially with its pancake lens, its feel reminds me a lot of various rangefinders I used to use and it's much more responsive than the X-E1 I used to use. I'm less of a fan of the more SLR-looking form factors.

ISO is bound to the front wheel under your pointer finger, press it in to select ISO mode. Have the back wheel on mine bound to shutter speed (top dial set to 'T') and the top function button to switch between the electronic and mechanical shutter. White balance is the only thing that seems a bit out of reach.

Sony's make mirrorless full-frame, they already able to replace SLRs for many photographers. It's not a trade off as you suggest, because Sony image quality is rated as one of the best, if not the best in the full-frame market. The new "iii" series cameras have much longer battery life than before.

The size of mirrorless cameras is only one benefit, and there's no particular reason that a mirrorless camera couldn't have a big Nikon D5 style battery if there was a market for it.

I don't see any particular reason that mirrorless cameras won't completely replace SLRs in time, a mirror is no longer neccessary, like it was for film. No one would make a new SLR system if they were starting now, and they haven't, all the new mounts are mirrorless.

A lot of it is due to lenses. Lenses contribute at least as much to image quality as camera bodies. Pros will often have tens if not hundreds of thousands of dollars invested in lenses, and glass doesn't go obsolete. But SLR lenses are only compatible with other SLRs with the same mount. So switching to mirrorless isn't just a matter of buying a Sony body instead of a Canon body the next time you want to upgrade. It's also a matter of replacing thousands and thousands of dollars of glass (and that's assuming there are equivalent replacements, which isn't always the case).

How come it wouldn't have been possible to develop a mirrorless camera that is compatible with the lenses of existing SLR cameras?

It is possible, but SLRs have a bigger flange distance to the sensor, because a mirror has to fit between the lens and the sensor. To be able to use SLR lenses with mirrorless cameras, the mirrorless camera needs to have the same flange distance as the SLR, which would make the camera body bigger. This kills one of the main mirrorless features.

Yeah but you can easily add a mechanical adapter, e.g. Nikon sells the FT1.

While you can easily add the adapter, you are using the lens in a way it is not designed for. It will work for various definitions of work, and casual users might never even notice the difference. But it will never be equivalent to its native usecase.

Some random issues of the top of my head..

1) Tiny tolerance/alignment differences between the target mount and adapted mount can cause the lens to become decentered or be mounted at a tiny angle to the sensor plane. 2) special mirrorless camera features might not work as well e.g. eye AF in sony / object tracking / etc 3) possible autofocus hunting issues on outer focus points or autofocus performance will be impacted 4) pro level lenses like the canon 500 F/4 combined with a 1Dx type body unlocks a faster focusing mode which wont be available with an adapted lens.

> Tiny tolerance/alignment differences between the target mount and adapted mount can cause the lens to become decentered or be mounted at a tiny angle to the sensor plane.

It is certainly possible to make an accurate mount adapter; see the Pentax m42 → K mount adapter. The "problem" is people don't want to pay for a good one; the Pentax adapter costs about 2x as much as the adapters everyone seems to buy.

I have had mixed results with the Sigma MC-11 adapter. Some lenses worked OK, and some didn't. I don't have the setup or the resources to do a thorough analysis. I attributed them to the 'slop' in the system - From the focus motor to the mount to the adapter to the AF system and sensor. I was probably unlucky and the +/- tolerances didn't cancel each other out.

It is possible. The Sony 35mm Mirrorless bodies can adapt Nikon FD lenses with an adapter.

It is, but lens mounts are largely proprietary and SLR lenses are big. Some wide angle lenses are also heavily corrected in order to accomodate a swinging mirror. Even if you can fit them with an adapter that retains most features, you wouldn't want to lug around a heavier lens, when you could just sell it and buy the native equivalent, which in some cases even performs better due to physics. There is no point in using a SLR mount for mirrorless as it's oversized and will negate the cost and size advantages of shorter flange to sensor mirrorless designs.

For specialty lenses of various kinds, some people find it makes sense. But in general, as you say, there are compromises in using adapters in terms of function, size, etc. and usually it makes more sense to sell the existing lens and buy a native one.

The adapters exist but are never quite as good as the "real thing".

They'll misbehave with certain lenses, or the autofocus performance will be poor, or...

Sort of like console emulators.

It is possible since 2012 with the https://en.wikipedia.org/wiki/Canon_EOS_M . There is a first-party EF/EF-S to EF-M adapter, and all Canon DSLR lenses work on the EOS M series of cameras with full functionality (aperture, focus, IS, etc.) and zero caveats. I'm not sure what motivated your question.

One reason is that with a mirrorless camera you have to have the sensor powered all the time. That means background heat in the sensor which traditionally been a source of noise. With a DSLR you only have to have the sensor on to capture your final image.

That seems to be less of a problem with modern sensors so it may become a non-issue as time goes by.

>Why do we keep investing in DSLR technology when mirrorless is obviously superior?

Are they superior for the same price?

I care very much for low light and high ISO performance. I get darn good performance with my Pentax ($500-1000 body). When I checked 2 years ago, the only mirrorless cameras that came close cost over $2000.

I have noticed the opposite, that Sony bodies run far cheaper than the comparable Canon (although I never even considered Pentax).

My 42MP A7Rii runs $2300 new compared to the Canon 5DS which is $3800. Same thing when I bought my Sony A6000 and original A7.

It's changed a lot. Check out the Sony mirrorless cameras now. The A7 III which just came out is amazing, and dominates any of the DSLR competition at the same price point.

Mirrorless cameras have reached the point in their development where their increased simplicity is winning out in terms of providing quality for the money. A mirrorless camera is really simple; there's one moving part (the shutter), and everything else is stationary sensors and screens. It thus benefits well from the exponential nature of silicon development. DSLRs, by contrast, are more complicated and have more moving parts, and we've reached the inflection point where mirrorless cameras are winning out at the same price point thanks to the simplicity of manufacturing they enable.

And hell, all mirrorless cameras have an electronic shutter feature too (for silent shots), so they can get away with zero moving parts in most situations. A DSLR has always got a mirror to move at the minimum.

> A DSLR has always got a mirror to move at the minimum.

I know very little about cameras, so this might be a question with an obvious answer, but is there a reason why a DSLR camera could not operate in a "mirrorless" mode as well? i.e. retract the mirror (thereby disabling the optical viewfinder) and use the sensor to show a digital viewfinder?

So there's a complete optical path from the lens to the viewfinder. Even if you retract the mirror, you still need to then insert an electronic viewfinder into the path somewhere that displays what the sensor is receiving. You could probably design something using a prism as film movie cameras have done in the past but it would be complicated and have its own set of compromises. Not a lot of reason to do it.

>The A7 III which just came out is amazing, and dominates any of the DSLR competition at the same price point.

It has not yet been released. I'll await reviews comparing it with, say, the Pentax K-1 Mark II.

My question: Is any Sony camera that is similarly priced to the 2016 Pentax K-1 better performing (mostly in terms of noise)?

(The amusing thing is that my older APS-C Pentax uses the same sensor as some of the Sony cameras - yet Pentax had lower noise).

Part of it is development priorities. You can't launch a brand new system and hope to immediately take on the whole existing DSLR ecosystem, so mirrorless started out inhabiting the niches that weren't so well served by DSLRs, because within those niches (at least) some people will be willing to overlook the shortcomings. And then you can build on that, and produce newer models with fewer shortcomings, and maybe start to capture a bigger market.

SLRs still have better battery life and an optical viewfinder

The optical viewfinder is the main negative of the SLR, and what is motivating the shift to mirrorless. It often doesn't give a great representation of the actual digital image that will be captured, it requires bulk for the mirror, and you can't overlay nearly asuch information on the viewfinder. Plus the mirror itself is loud and doesn't permit using the viewfinder while taking video.

The battery life problem is being solved. The Sony A7 III, which just came out, does much better on battery life. And personally I have an Olympus OM-D E-M5 II, use the viewfinder almost exclusively, and have never run out of battery, even after a full day of touristing. I have four spares I've never had to swap in. I'm not a professional though.

> The optical viewfinder is the main negative of the SLR

I'm going to have to disagree with you there. A 0 latency view of exactly what your composition will look like is what I need.

> It often doesn't give a great representation of the actual digital image

In auto modes your camera is clever enough to take a "good" exposure. In manual mode you should know how to expose a photo properly.

> requires bulk for the mirror

The mirror is a small part of the weight / size of a camera. The main disadvantage of an SLR always has been and always will be the flange focal distance.

> the mirror itself is loud and doesn't permit using the viewfinder while taking video.

Agreed

> you can't overlay nearly asuch information on the viewfinder.

Good! I want less information in my way, not more.

> The battery life problem is being solved.

Maybe, but the reality is still that even the A7 III has only half the battery life of a comparable DSLR. That is a problem for heavy shooting.

"The a7 III uses the Z battery, introduced in the a9 and also used by the a7R III. It's good for 710 shot per CIPA ratings with the a7 III, as its power requirements are less than the a9 or a7R III, both rated for 650 images per charge."

All of my Nikon DSLRs (D5000, D7000, D750) can shoot between 2-4k images on a charge, and I use a mix of official Nikon batteries and cheap eBay knock-offs. In general the cheap knock-offs perform better. If I had to change batteries every 500-600 photos, I would be constantly stressed during a job and probably flip batteries every time I had a minute free. If that's not enough juice for a photographer, the battery grip will get that number much higher (and provide stability when using heavier lenses).

It has taken a long time for mirrorless AF to catch up to the performance of high end sports cameras.

But is that due to the nature of mirrorless technology, or is it just that development of mirrorless cameras was not a priority?

There are some fundamental differences, which meant that initially mirrorless cameras were at a disadvantage, but that has started to turn into an advantage these days. Autofocus SLRs, digital or analog always focus via phase detection. This was done with a separate sensor module behind the main mirror, which has some transparency. This system can not only detect the exact focus, but also how far the camera is out of focus. This allows the cameras to directly tell the lens where to go in one big step, so focus this way is very fast.

Mirrorless cameras of course couldn't use that separate module, so they used "contrast autofocus" where the camera moves the lens and with the image sensor watch the contrast of the picture improve until focus is achieved. Initially this was very slow. But in the meantime, sensor readout and signal processing got much faster and lenses have been constructed, which can change their focus position much faster than traditional autofocus lenses. As a consequence, a good contrast auto focus is a fast or faster as a decent phase auto focus. More recently, phase detection systems were integrated into the sensors, giving the mirrorless cameras the best of two worlds.

Considering how long DSLRs have been out compared to how long mirrorless cameras have been out, I don't think it is a long time at all.

When digital became a reality, it also took plenty time to displace film. When I bought my first digital camera (a Canon D30), it had many drawbacks compared to the top-of-the-line 35mm film cameras of the time. A measly 3 MP resolution, a confusing crop factor (b/c the sensor wasn't truly 35mm), not great battery life, limited low-light performance. Yet it was clear digital was the future.

Sony and Fuji are making great strides, but Canon and Nikon have had decades to perfect their systems. And while mirrorless manufacturers are investing very heavily, Canon and Nikon have really only been putting out fairly iterative updates (especially Canon).

Professional photographers often have $10k+ invested in lenses so switching systems isn't something they'd be likely to do for an incremental upgrade. Some have switched to the Sony A9 though.

For me personally I had nowhere near that much money invested in Canon glass, so switching to Sony wasn't as painful (I pre-ordered the Sony A7iii but haven't received it yet).

Given that the $2000 Sony is out-reviewing the $3500 Canon 5D markIV, it's getting a lot of attention and I'm hardly the only one jumping ship. I think it's safe to assume that Canon/Nikon will respond with pro level mirrorless cameras as soon as they're able to.

Inertia and well established tech. Pros with money invested into lenses. Short sensor to mount distances have numerous advantages on the other hand.

Because mirrorless tech is not mature enough yet.

Because mirrorless isn't.

It's because SLRs are superior to mirrorless, since there are no advantages of a mirrorless camera over SLR tech.

SLRs don't have the latency that mirrorless cameras have, which is important for sports & journalism. If you're shooting still-life, then mirrorless is probably fine.

SLRs also have better phase-detect AF sensors available to them. Mirrorless phase-detect sensors are primitive, and eat up image sensor area, so they can't be as sensitive.

Also, mirrorless eats up batteries, since you now have to power the sensor and viewfinder full-time.

Really, companies need to stop making mirrorless cameras, since they're not useful. I don't know why anyone would buy them.

> Companies need to stop making mirrorless cameras, since they're not useful.

They sell, so they appear to be useful to people. Just maybe not to you.

> there are no advantages of a mirrorless camera over SLR tech.

Here are a few I can think of.

- Less moving parts, so increased reliability.

- Possibility of faster shutter time (assuming the autofocus issues with mirrorless can be resolved).

- No high precision SLR mechanism means more engineering budget to spend on better sensors, etc. Thus producing a better camera at the same price.

- Viewfinder shows a truer representation of the final image since it's reading from the same data as what will ultimately be captured.

- Shorter sensor to flange distances which allow for simpler design, more compact wide angle lenses, plus any kind of mirrorless to SLR adapter.

- Smaller body due to smaller mechanical footprint

- using image processing for focus rather than finicky focus sensors which only cover a small part of the image (and having to tune your lenses...)

I’ve been on the fence of getting the latest Nikon 850 or waiting to see if Nikon announces a full frame mirrorless compatible with DSLR lenses someday... I saw a rumor they may announce some kind of mirrorless this year.

> Less moving parts, so increased reliability.

I use Nikon and haven't heard of a mirror failing on its own. Ever! Dead cameras due to some electronic part that got wet or desoldered OTOH...

> No high precision SLR mechanism means more engineering budget to spend on better sensors, etc

I don't think the way the reflex mirror works has changed for ~50 years.

> I don't think the way the reflex mirror works has changed for ~50 years.

True, but integration of a complex mechanism still adds complexity, even if the mechanism itself has already been designed.

Furthermore (sorry, can't edit my post): A mirrorless camera would require strictly less electronic parts than a DSLR. So your experience with electronics failures supports the idea that a mirrorless design could be more reliable.

One huge advantage of mirrorless is the absence of mirror-slap vibration at shutter speeds. Finally i can do long fast bursts when panning at 1/60

Plus the removal of flappy mechanical bits improves reliability and offers even faster frame rates.

There's a Canon full-frame mirrorleas prototype in the hands of their "Explorers of Light" now, so expect a big advertising push next year.

So, instead of mirror-slap blur, you now have camera motion blur?

No worse than when panning with a DSLR.

Of course the keeper-rate drops dramatically in direct relation with shutter speed but that's the beauty of digital. Even one out of 20 keeps me happy and the rest go to the bitbucket.

At present I have to restrict my camera to about 5fps when panning at 1/60 and even slower when at 1/30; if non-slappy mirrorless boosts that two or threefold I'll be delighted.

There's also Sony's SLT system, where the mirror is translucent and stays put.

Not everyone is a photojournalist, so why should they lug the bulky SLR bodies and lenses around? And not every amateur photographer is happy with a point-and-shoot camera or a phone camera.

Mirrorless cameras are a good option for a lot of photography enthusiasts who like to travel light but also benefit from the advantages of interchangeable lenses. They wouldn't sell so well if people didn't find them useful.

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