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Nice article, but I'd argue that it is, in fact, a DSLR. What makes it a DSLR is the mirror; that's what makes any DSLR a DSLR. The 'R' stands for Reflex, and this is still a reflex thanks to its mirror. The fact that the mirror does't move is another thing entirely ...

paulbradforth, on 25 August 2011 - 05:12 AM, said:

I agree completely. The article is clearly wrong and the author should have done his homework. If he did, he would notice that a TLR (twin lens reflex) camera does not have a moving mirror but is still a reflex camera. The use of a partially transparent mirror that doesn't move goes back to the Canon Pellix (ca. 1965). The Pellix was correctly called an SLR then too. Historically, *movement* of a mirror has had nothing to do with the use of the term "reflex". Also, all modern SLR mirrors are not fully reflective because some light needs to go to the AF system. The main difference here is not that the mirror system is "partially reflective" but that it is designed to allow a clear light path to the sensor while still having additional light paths to the viewfinder and AF system.

paulbradforth, on 25 August 2011 - 05:12 AM, said:

You guys (first two commenters) are correct. Reflex means the light path is bent with a mirror. The proof would be a TLR camera. Twin lens reflex cameras, such as the Rolleiflex. It has two lenses. One for images, one for viewing. There is no moving mirror. It is a reflex camera.

Now, as for this camera, I've been quite skeptical, but the author's arguments are pretty strong – in theory. This camera will add some pressure to Nikon and Canon to get their acts together. Luckily, for those who use Nikon's mid-range prosumer cameras (D300s and future D400 and D7000) this is likely the next sensor they're going to get. Most Nikon sensors in this level of camera are based on Sony designs (and modified by Nikon to their standards). But will Nikon get the video part? This camera's video capture is clearly better.

Autofocus continually while shooting is very compelling for sports/wildlife/street shooters. Nikon and Canon have this almost as good with their predictive autofocus. But it really only works well with their top-level cameras. And this kind of feature would improve on that by a long shot no doubt. My main concern is the amount of light lost in diverting some light to the viewfinder (via sensor or optically). Canon has done two cameras with the Pellix (non-movable) mirror. And they have not been successful because of the 1/3 stop light loss which doesn't sound bad until you realize you're only getting 2/3 of the light you could have. Higher ISO performance helps, but still cannot overcome that issue completely. And there is going to be some image quality reduction based on physics of light passing through a transparent medium. There's no way around that. It will be interesting to see how good the images are. Not to mention reports that the OLED viewfinder is hard to see when shooting in bright light.

In the end I don't think many pros will switch. They'll wait for such features to arrive on their cameras because Sony, for all it's innovation in this area, is not a pro camera system. Not enough lenses, not enough accessories, not enough history supporting pro photographers. That could change over time. But nobody with thousands of dollars invested in lenses and accessories is going to switch. For people looking for a camera system? This is very compelling, especially with the killer Zeiss lenses available for it.

Well done Sony. Too bad the other aspects of your business aren't as innovative.

This post has been edited by leicaman: 25 August 2011 - 06:35 AM

Maybe, as in other cameras, Sony has built in the sound effect of a mirror flipping. That could possibly make 'not a DSLR' snobs happier?

I want to see how good the viewfinder is, because I too have really valued the optical viewfinder in the (Pentax) DSLRs that I have used. But, if the viewfinder really does give sharp images, then this could be a huge advance.

Actually, the camera I am more excited about is Sony's NEX-7 (http://www.dpreview....ex7overview.asp), which supposedly shares the same eye-level viewfinder and APS-C CMOS sensor in a truly non-reflex (mirrorless) body. I am thinking that this is going to be the way that many amateurs and possibly even some pros will go in the near future.

paulbradforth, on 25 August 2011 - 05:12 AM, said:

Totally agree. A DSLR is a DSLR is a DSLR, translucent mirror or not. It doesn't move because it doesn't have to but it does reflect.

Is Chevy Volt not a car because it doesn't use internal combustion engine to move? Car = automobile - autonomous motion.

"Translucent-mirror technology isn't new." I'll say. It was either Canon or Nikon came out with a camera with the same kind of mirror in the Eighties. I think it was marketed for the pro sports shooter. The non moving mirrow allowed the photographer to get more frames per second.

ronparr, on 26 August 2011 - 07:24 AM, said:

The A77 is "not a DSLR" because the mirror does not reflect any of the light to an optical viewfinder. The A77 does not have an optical through-the-lens viewfinder, even though it has a mirror. According to my understanding, the presence of a mirror alone does not make a camera a DSLR. That mirror has to reflect the light to an optical viewfinder, which this camera doesn't have.

Thanks,
Tim

This post has been edited by Jason Snell: 26 August 2011 - 02:46 PM

tmoynihan, on 26 August 2011 - 11:27 AM, said:

Suppose I pointed a video camera in the optical viewfinder of a traditional SLR and then displayed what was shown on a screen. Would the SLR stop being an SLR then? Actually, people have made such devices. One was called the Zigview S2 and was made about 5 years ago before SLRs had sensors capable of high speed displays. Would clipping one of these things on an SLR make it not an SLR? That would seem to be consistent with the position you've taken. Your premise seems to be a human eyeball staring at the rays reflected by the mirror is necessary for something to be an SLR. Do you really believe that a human eyeball is what makes something an SLR? There's another piece of equipment called a reflex mirror lens. It turns out that it's still called a reflex mirror lens no matter what you point it at. The term "reflex" refers to the optics, not the thing at which they are pointed.

This post has been edited by Jason Snell: 26 August 2011 - 02:47 PM

ronparr, on 26 August 2011 - 07:24 AM, said:

No, and that's not what I said.

A mirror that allows you to look through the lens is what makes something an SLR. That's along the lines of every definition I've ever seen of an "SLR" or a "DSLR" camera. If you disagree, please supply some materials to back up your claim.

A shooter accustomed to using DSLRs would pick up this camera, look through the eye-level viewfinder, and say "Hey, this isn't a DSLR. This view is electronic!"

If I had called this camera a DSLR in the story, you can bet that there would be at least as many people calling me out for referring to it as a DSLR.

tmoynihan, on 26 August 2011 - 02:37 PM, said:

Of course that isn't what you said. I never suggested you actually said that. I was pointing out the absurdity of your position by highlighting the absurdity of the assumptions that would be required to give your position any logical coherence. I see now, there is another possible misunderstanding on your part that I hadn't considered before:

Quote

You almost have it right there. "A mirror that allows you to look through the lens" is what gives us the "R" in SLR. Such a mirror is still present in the A77; it's just that the light is directed to a sensor instead of your eyeball.

In my previous response, I concluded that your basic misunderstanding was some sort of eyeball chauvinism, but I see now that there is another possibility. You may be confused about two types of "mirror" systems in typical SLRs. One is the mirror that reflects light at 90 degrees from the lens up to the pentaprism (or pentamirror in cheaper designs). The other is the pentaprism assembly itself in the top of the camera which bends things another 90 degrees to hit your eye. The pentaprism is what gives SLRs their typical hump on the top.

As should be evident from the examples already given, the first mirror is the key thing. A twin lens reflex camera has no pentaprism, but it is still called a reflex camera. A reflex mirror lens has no pentaprism, but it is still called a *reflex* mirror lens. Clearly, it is the reflex mirror that puts "reflex" in the name of these devices.

You asked for links. I suggest you got to wikipedia and read up on these basic photography terms. Read about TLRs. Read about SLRs. Note the arrow pointing to the thing called the "reflex mirror" in the wikipedia page on SLRs. (This isn't just a Wikipedia thing; if you read up on SLRs, you'll see that that the mirror all SLRs have in common with the A77 is consistently called the reflex mirror and the other is consistently called the pentaprism.) For "reflex mirror lens" you should just use goggle because Wikipedia doesn't have an entry on that.

http://tinyurl.com/42a4jdf

http://tinyurl.com/3kwp4uh

http://tinyurl.com/3cmk3y6

Quote

That could well be true for readers with a poor understanding of basic photography terms. The great thing about modern photography is that many people can enjoy it and even produce great results with only a vague (and sometimes even incorrect) understanding of the technology and terminology. Nevertheless, there is a clear and consistent reason why there is an "R" in SLR and it's the same reason why the A77 is an SLR.

Thanks Ron,

I agree with everything you said, I just think that we're reaching our conclusions from different angles.

1. You are correct that the A77 has a reflex mirror, and I was wrong about what "reflex" referred to in the earlier version of this post. What led to the mistake wasn't confusion between a reflex mirror and a prism, but actually seeing diagram after diagram of the internals of a DSLR camera, seeing the label "reflex mirror" applied to a mirror that usually moves, and applying the "reflex" definition to the wrong part of that equation (the movement, not the mirror). Thanks for correcting me on that information. The post was amended, and I apologize for the error.

2. Yes, the A77 does have a reflex mirror as part of its internals, but it's employed in a different way than those found in traditional DSLRs. It's also used in a different way than the fixed-mirror Canon Pellix camera mentioned in leicaman's post, as the mirror in the Canon reflected light to an optical viewfinder. In the case of the A77, the mirror redirects light to an autofocus sensor, which adds (and subtracts) features that ultimately distinguish this camera from what you'd find in a traditional DSLR.

3. On the end-user side of the fence, there are certain expectations of how a DSLR works. One of those expectations is that the reflex mirror is ultimately used to provide an optical, through-the-lens display. Another common expectation is that the reflex mirror flips out of the way while shooting, interrupting the optical display during still and video capture.

This is where I think we're approaching "what it means to be a DSLR" from different angles. I think your stance is that, regardless of the way the reflex mirror is used, the A77 is a DSLR because it has a reflex mirror--a technical definition based on the presence of a reflex mirror. My stance is that, regardless of the fact that the A77 has a reflex mirror, the way in which it's employed differs greatly from the way it's used in every other DSLR camera, and that distinguishes the A77's features from those of a traditional DSLR--a definition based on end-user expectations and semantics.

... aaaaand the plot thickens (in case you still care).

According to several sources, including Encyclopedia Britannica, a dedicated camera Wiki (I usually wouldn't mention a wiki due to its crowd-sourced nature, but this one is both specialized and extensive), and CNET, the term "SLR" is tied to both the reflex mirror being used specifically for an optical viewfinder and the movement of the mirror:

Encyclopedia Britannica: "A 45° mirror reflects the image-forming rays from the lens onto a screen in the camera top. The mirror moves out of the way during the exposure and back again afterward for viewing and focusing the next picture. The image on the screen therefore temporarily disappears from view during the exposure."
http://www.britannic...gle-lens-reflex

Camera-Wiki.org: "Reflex -- Refers to the mirror and its movement that makes the use of a single lens possible."
http://camera-wiki.org/wiki/SLR

Camera-Wiki.org (again): "The term Reflex is used as a way of classifying types of cameras, based on their viewfinder system."
http://camera-wiki.org/wiki/Reflex

CNET Digital SLR buying guide: "...these types of cameras use a mirror positioned behind the camera lens to direct light toward the viewfinder when you're composing a photo. When you release the shutter, the mirror swings quickly out of the way..."
http://reviews.cnet....r-buying-guide/


So at the very least, I'm not the only one who is confused, and at the very most, I may be right about the A77 not being a DSLR in the technical sense.

I agree with you that it's a more difficult question than it may have seemed initially. There's plenty of incorrect and logically inconsistent information out there. We can just throw up our hands and says it's ambiguous or we can reason it through and see if there's a correct answer.

If we combine the following facts: 1) A TLR is a reflex camera without a pentaprism and without a moving mirror; 2) The Canon Pellix (and successors from both Canon and Nikon) are SLRs without moving mirrors, then I don't see any way to escape the conclusion that the A77 is a single lens reflex camera unless we were to revise history and say that TLRs should not be called TLRs and that earlier SLRs with Pellicle mirrors aren't really SLRs.

These sorts of confusions aren't that unusual in photography. When non-SLR camers with interchangeable lenses starting getting more popular, there was a wave of confusion among recent adopters about whether interchangeable lenses were an essential property of an SLR. This could be resolved by pointing that there were film SLRs with fixed lenses as well as film non-SLRs (rangefinders) with interchangeable lenses.

This post has been edited by ronparr: 30 August 2011 - 07:14 AM