[unfocused]

P.S. I see Hoya is selling the Pentax Camera Div to Ricoh. I'll drink to that. Ricoh knows what it's about. I still have my old XR7, a really nice camera of its time, and have long fancied their GR Digital III.

[Class A]

Agree, to disagree

From the Wikipedia article on "Lens Speed":

For controlling depth of field, especially in portrait photography[1], lens speed is a key variable in combination with other variables such as focal length and camera format size.

I understand completely the mathematical model that Falk is talking about. I even understand why you - and, as you quote him, he - make counter-factual claims.

What?
So the mathematical model is wrong according to you?
If it is correct (Hint, it is. Hint, Falk is a physicist; he understands more than "basic physics"), how can one derive "counter factual claims" from it?

That is what I'd like for you to explain, in context. How the same 8.5mm lens can pass a certain amount of light on ONE format, but a different amount when mounted on another.

I never claimed that. I claimed that the 8.5/1.9 Q-lens passes less total light than a 47/1.9 FF-lens.

A 8.5/1.9 Q-lens will pass the same total amount of light to an FF-sensor as it passes to a Q-sensor. But try mounting the 8.5/1.9 Q-lens on an FF camera. It won't produce the image circle required for the FF-camera. OK, let's enlarge it with extra optics. This, however, will spread the same amount of photons over a larger area. This will reduce the exposure. In other words, the exposure will not be the same as that from a 47/1.9 FF-lens that doesn't need enlarging of its image circle.

If the Q-lens passed through the same total amount of light that is produced by the 47/1.9 FF-lens then I wouldn't call it slow. Note that for this to have any relevance for the Q-system, the Q-lens would have to concentrate all these photons onto the size of a Q-sensor. In order to be able to collect all the photons required for that, however, it would have to be a lot faster than f/1.9. It would have to be a f/0.3.

Smaller pixels have smaller full-well capacities.

Yes, but that doesn't matter if you have more of them.
Pixel-pitch does not determine dynamic range. Sensor size does.

If you did concentrate all the light that falls on the larger sensor onto the smaller sensor of, say, the Q, you'd have nearly every pixel pegged to max, because they have lower full well capacities. You would have to change to a different (currently unknown) technology to make this happen.

Yes, you'd need very low ISO values (or neutral density filters). This is part of the limitation of the Q-system. It doesn't have fast lenses and it wouldn't be able to cope with them either.

So while I understand the mathematical concept expressed, it doesn't fit the real world.

If you think it doesn't fit the real world then you don't understand it.

Additionally, the standard model of exposure isn't faced with absurdities like claiming that I could, say, focus all the photons used by a 6x6cm back onto one molecule and get the same image quality as the 6x6cm image

Strawman.

But to make claims like "The lens passes less light because it's attached to a camera with a smaller sensor" is just absurd.

Strawman.

[jstevewhite]

From the Wikipedia article on "Lens Speed":

For controlling depth of field, especially in portrait photography[1], lens speed is a key variable in combination with other variables such as focal length and camera format size.

Also from wikipedia:

A lens with a larger maximum aperture (that is, a smaller minimum f-number) is a fast lens because it delivers more light intensity (illuminance) to the focal plane, allowing a faster shutter speed.

(emphasis mine)

What?
So the mathematical model is wrong according to you?
If it is correct (Hint, it is. Hint, Falk is a physicist; he understands more than "basic physics"), how can one derive "counter factual claims" from it?

Because he was speaking of "equivalence" only. My point has been to illustrate that "equivalence" is an analogy. Besides, I'd really be interested in Falk's input, but he's chosen not to become involved. And second, this is called "appeal to authority".

I would LOVE to hear Falk explain how an 8.5mm f1.9 lens passes less light to the FF sensor than a 47mm f1.9 passes to the same FF sensor.

I mean, I get that there can be slight variance due to angle of incidence, and that lens designers have struggled to control vignetting because of that, but that's a lens design problem; an ideal lens, regardless of focal length, will pass the same amount of light to the same sensor at f1.9, and ideal lenses with the same image circle will pass the same TOTAL light (even light that doesn't end up on the sensor) at f1.9 regardless of focal length.

I suspect that Falk would agree with that - because it's true; otherwise you'd have to tell your hand-held light meter what the focal length of your lens was.

I never claimed that. I claimed that the 8.5/1.9 Q-lens passes less total light than a 47/1.9 FF-lens.

A 8.5/1.9 Q-lens will pass the same total amount of light to an FF-sensor as it passes to a Q-sensor. But try mounting the 8.5/1.9 Q-lens on an FF camera. It won't produce the image circle required for the FF-camera. OK, let's enlarge it with extra optics. This, however, will spread the same amount of photons over a larger area. This will reduce the exposure. In other words, the exposure will not be the same as that from a 47/1.9 FF-lens that doesn't need enlarging of its image circle.

There you go again. This is the ENTIRE root of the counter-factual claim. A FF sensor at ISO 100 requires a certain total amount of light to create an exposure, as you have insisted over and over - and I agree with. If I put that 47mm f1.9 lens on the camera and meter it at f1.9, I get a reading. If I remove it and replace it with an 8.5mm f1.9 lens with appropriate optics and image circle, it will pass the same total amount of light to the sensor, giving me the same exposure at ISO 100 and the same shutter speed. Can we agree on that? Or do you believe that you get DIFFERENT total exposures from two different focal lengths @ f1.9?

If the Q-lens passed through the same total amount of light that is produced by the 47/1.9 FF-lens then I wouldn't call it slow. Note that for this to have any relevance for the Q-system, the Q-lens would have to concentrate all these photons onto the size of a Q-sensor. In order to be able to collect all the photons required for that, however, it would have to be a lot faster than f/1.9. It would have to be a f/0.3.

Right - it would be the SENSOR size, not the f-stop of the lens. See, I *understand* that you're saying that 1) if you had a sensor with sufficient capacity and 2) sufficient pixels at that capacity, you could concentrate the total light from the larger sensor onto it and achieve the same total SNR; the problem with that is that no such sensor exists, period. You could build the fastest glass in the world, but you couldn't USE it this way, because the SENSOR couldn't sink that many photons. It would require a DIFFERENT KIND OF SENSOR.

Yes, but that doesn't matter if you have more of them.
Pixel-pitch does not determine dynamic range. Sensor size does.

LOL. Yep. You're right. So a larger sensor must have higher SNR, therefor, it *is* about the sensor size, not the lens, right?

Yes, you'd need very low ISO values (or neutral density filters). This is part of the limitation of the Q-system. It doesn't have fast lenses and it wouldn't be able to cope with them either.

Which would reduce your exposure, negating all of the relevance of "equivalency" except for DOF.

If you think it doesn't fit the real world then you don't understand it.

There's this concept that is foreign to many people. "I understand, but disagree."

Strawman.


Strawman.

The fact that equivalency doesn't work in the real world because no such sensor exists - because no such sensor *can* exist - is a straw man?

Look... Let's say you invent a sensor that can accept enough light at the size of the Q to use your f0.3 lens. You get the same SNR as a current FF sensor, same DOF, same noise floor. Great. But NOW we can use that same technology to build a FF sensor that has *exactly* the same improvement in SNR over your Q that a current FF has over the Q now.

That's not a straw man, it's a *fact*.

[jstevewhite]

If you think it doesn't fit the real world then you don't understand it.

So I spent a lot of time looking at optical charts and equations and exposure charts trying to figure out why a seemingly perfectly reasonable person such as yourself would make claims like that. And I think I finally got it.

I think you're saying that, because the subtended subject angle is the same between our 8.5 f1.9 lens and the 47mm f1.9 lens, the 8.5mm lens passes *less total light for the subtended subject angle*. I believe this is what you - and Falk - mean, and if so, I agree (and would have done so at any time had it been phrased properly).

If you make an 8.5mm lens with a 36mm image circle, and a 50mm lens with a 36mm image circle, and then put a photon counter at the aperture blades, they will both pass *the same number of photons* (assuming, say, a 15% gray target that covers their subject angle of view). But the number of photons from any specific subtended subject angle will be less. This is true regardless of format of the sensor. In the case of the q, the subtended angle of the sensor receives fewer total photons from the same subtended subject angle. The lens could pass the same total number of photons, though, and it would make no difference, because it would be increasing the image circle beyond the borders of the sensor (wasting the light, essentially).

Even if I have finally understood what you mean, it doesn't address certain contextual issues. As you say, SNR depends on sensor size, not pixel size, if we're talking about the same size enlargement. This should be a clear clue that you don't even accept equivalence globally, because, as Falk said, if you put the same amount of light on the sensor, the SNR is identical. But you know, and I know, no current sensor exists that would allow you to do that, if you *did* have the 8.5mm f0.3 lens - and if it did, they same technology would exist in larger sensors, which would restore the difference in SNR between small sensors and large ones.

Saying "it's the lenses, not the sensor" is still misleading IMO, because even if that 8.5mm f0.3 lens existed, the sensor *could not accept the same total photon count* as the FF sensor, as it would be massively overexposed.

[Designosophy]

As froeschle suggested, let's not quibble over what "fast" means.

I don't see it as quibbling. There's no communication and no understanding unless there is agreement on what terms mean, especially terms about which there is controversy. I'm pretty sure there's some controversy in this thread. No?

[sebberry]

I'm not sure I understand what target market this camera is aimed at.

There are plenty compact cameras that take excellent photos that have good wide to tele lenses built in.

[Ash]

There are plenty compact cameras that take excellent photos that have good wide to tele lenses built in.

But they don't all have 5fps continuous shooting speed and the high ISO performance (potentially) of this system. Granted, the specs may have been better with a larger sensor, but this is a novelty camera focusing on miniature size and weight. So it fits nicely between P&S and hybrid/APS-C systems.

[froeschle]

Still discussing? There are lots of ways to happiness and all roads lead to Rome . Sometimes different points of view can lead to the same conclusion.

Sticking to

If you want to see something that looks kinda like what you might get from the Q, possibly, try setting your APS-c camera to ISO1600 and put on a 30mm lens and set the aperture to 7.1 and shoot some pictures.

is perfectly fine to me and imho also serves the major purpose of this thread .

[abacus07]

But they don't all have 5fps continuous shooting speed and the high ISO performance (potentially) of this system. Granted, the specs may have been better with a larger sensor, but this is a novelty camera focusing on miniature size and weight. So it fits nicely between P&S and hybrid/APS-C systems.

This is still the important question imo (not the pissing match going on). I'm not sure if there is a market for a miniature non-zoom anywhere close to this launch price. If you really care about IQ then you're going to need a m4/3's, NEX, dSLR level camera. And most will still want a compact P&S (with zoom) for versatility.

Which part of the market wants a 3rd system that requires a lens investment?

[froeschle]

Complicated lighting conditions, K-5 - 31mm, f/7.1, ISO 1600, upper inset: 100% crop

[Laurentiu Cristofor]

This is still the important question imo (not the pissing match going on). I'm not sure if there is a market for a miniature non-zoom anywhere close to this launch price. If you really care about IQ then you're going to need a m4/3's, NEX, dSLR level camera. And most will still want a compact P&S (with zoom) for versatility.

Which part of the market wants a 3rd system that requires a lens investment?

Funnily, I just met a friend who is a casual shooter that was interested in the Q. His current compact got its telescopic lens stuck - it doesn't extend anymore. One of my previous compacts died the same way - the telescopic lens mechanism broke. This is the part that annoys me the most about compact cameras - their telescopic lenses - they do take less space, but they add complexity and a critical point of failure, besides making camera startup much slower. I want a compact camera, but I've been holding on getting one because none fit my list of wanted features - the Q, however, is the closest.

The market for cameras like the Q is not targeting people that want IQ above anything else, but people that want small size (and build quality) above anything else, with IQ being a secondary consideration. It's supposed to be a high end compact system, for people that aren't happy with the cameras that form the high end of the compact market today.

Of course, if compact cameras are already fulfilling your needs or if you're ok with larger systems, the appeal of the Q will be lost on you. At its price, it is clearly a niche product. Hopefully, the tech improvements made for Q will show up in less expensive compact camera models that will target larger segments of the market.

[abacus07]

The problem is that once it loses its pocketability (when adding the zoom) it becomes less useful. So the market is for people that want a normal prime compact. And it appears that the NEX isn't that much larger with the pancake prime and it offers a sizeable increase in IQ.

Why the Q and not the NEX at a lower price and better IQ? Is it because it says Pentax?

edit - forgot to mention that we haven't seen image comparisons between the Q and a few of the better compact zooms. I'm really hoping that the Q has substantially distanced itself from that category.

[Laurentiu Cristofor]

The problem is that once it loses its pocketability (when adding the zoom) it becomes less useful. So the market is for people that want a normal prime compact. And it appears that the NEX isn't that much larger with the pancake prime and it offers a sizeable increase in IQ.

Why the Q and not the NEX at a lower price and better IQ? Is it because it says Pentax?

edit - forgot to mention that we haven't seen image comparisons between the Q and a few of the better compact zooms. I'm really hoping that the Q has substantially distanced itself from that category.

No one has managed to produce a compact zoom lens yet, so for portability we need to use primes. Which isn't so limiting considering other cameras ship only with a fixed lens, like the Sigma DP series and the Fuji X100. At least, with the Q you get to choose between the standard prime or the other toy lenses which seem to be equally small.

Why the Q and not the NEX? Size, weight, SR/DR, and flash are some of the reasons that come to my mind. Frankly, if you can give me an even smaller compact with interchangeable lenses (or even with a good fixed prime lens), I will consider it - brand is irrelevant to me once a new mount is introduced (or none at all).

The Q compares well against the S95 at ISO 3200 - how well it compares at lower ISO I don't know, but the S95 is supposed to be the best high ISO compact, so I take that as a good sign.

[abacus07]

So are you saying that the market for the Q is not only experienced dSLR users but experienced prime users?

Because I see the more typical potential customer frustrated by using a prime only camera despite its compactness. Adding the zoom not only limits the portability but it's also substantially more expensive.

Do the Fuji/Sigma models sell well? Because I see them struggling for the same reasons that I mention.

[eddie1960]

The fuji has been an order and wait for it camera since it came out
And it has pretty good distribution as far as i can see
The sigma is highly regarded but has poor distributipn so i imagine the sales reflect that
The Q is a fofferent animal again quirky maybe but i think it will do pretty well (but nothing like a kx for volume)
It will be interesting to see what Ricoh does with it since they likely were involved in tha background
I imagine we will see at least 2 more lenses eventually - a fast wide angle for the street shooters and a longet tele zoom for the ps crowd
And maybe a q module for the gxr (or the rebranded Pentax gxr that is likely to appear