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06-28-2011, 03:57 AM   #166
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QuoteOriginally posted by Digitalis Quote
eh.

From a marketing perspective they should have taken that key ring shot with a Ferrari or Lamborghini key on it...not a Toyota- or has the "toy-ota" got something to to with those "toy" lenses?
I thought the same. Mercedes, a least. But Pentax is more of an engineering company than a marketing company, it seems.

06-28-2011, 04:01 AM   #167
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QuoteOriginally posted by snogglethorpe Quote
Er, a small sensor size most definitely hurts in low-light -- that's the main reason people don't like small sensors...
These people are confused about the source of bad low-light performance. A bigger sensor is not more sensitive. It has better dynamic range, that's all. Small sensor cameras typically come with small, slow lenses. The latter are the source of the problem.

You may want to read the "Low noise benefit of FF vs APS-C equals ... zero" thread.

QuoteOriginally posted by jstevewhite Quote
Wait... f1.9 is f1.9 as far as exposure is concerned.
No, exposure and DOF are tightly coupled. It is additional light (coming from more acute angles) that makes the OOF areas look fuzzy.

QuoteOriginally posted by jstevewhite Quote
The "47mm f10.5" is *only* in ref to DOF; you still get the same low-light EV (notice your meter doesn't have a "focal length" setting).
The equivalent f-ratio applies to both DOF and exposure.
Not sure about what you mean regarding the meter being focal length agnostic. The meter sees the effective aperture which is 8.5/1.9 (or 47/10.5 in full-format equivalent values).
06-28-2011, 05:33 AM   #168
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QuoteOriginally posted by Laurentiu Cristofor Quote
Where were all these theoretical discussions around diffraction and lens equivalence when Pentax was producing other compact cameras?
Two reasons, one factual, one emotional. People weren't falsely equating earlies p'n's with DSLRs so it was never required that someone speak the obvious truth. Also, I think it's a sign of disappointment that the Pentax mirrorless system is so far below the spec set by other manufacturers.
06-28-2011, 07:13 AM - 1 Like   #169
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QuoteOriginally posted by Class A Quote
It is additional light (coming from more acute angles) that makes the OOF areas look fuzzy.
I just can't keep up with all this new physics, it's not what it used to be before t'Internet

06-28-2011, 07:23 AM   #170
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QuoteOriginally posted by Class A Quote
These people are confused about the source of bad low-light performance. A bigger sensor is not more sensitive. It has better dynamic range, that's all. Small sensor cameras typically come with small, slow lenses. The latter are the source of the problem.
Dynamic range and low-light performance are tightly coupled. That's why the best low-light performers have the best dynamic range. Smaller sensors are noise limited; it's *not* just the lenses, and the lens on the Q camera is not 'slow'.

QuoteQuote:
No, exposure and DOF are tightly coupled. It is additional light (coming from more acute angles) that makes the OOF areas look fuzzy.
I'm well aware of that; you're missing my point. If the camera has an 8.5mm f1.9 lens, and your light meter says 1/50 @f1.9, *that's what you shoot at*. If you pretend instead that you have a 47mm f10.5, you'll overexpose by many stops. Aperture is aperture. It does indeed have an impact on DOF and diffraction and all else, but it's NOT a 10.5 when it comes to exposure, period.

QuoteQuote:
The equivalent f-ratio applies to both DOF and exposure.
Not sure about what you mean regarding the meter being focal length agnostic. The meter sees the effective aperture which is 8.5/1.9 (or 47/10.5 in full-format equivalent values).
The meter doesn't care what the focal length is, period. That's why you can use an external meter with no focal length setting and get accurate exposure. Your aperture for exposure is f1.9, NOT the "calculated based on format and DOF" 10.5; because, in the end, and 8.5mm lens is an 8.5mm lens, no matter what the format of the sensor; so if my meter says ISO100, f1.9, 1/250, that's the exposure regardless of the "effective" or "calculated aperture on FF".

It's also not a "slow" lens; it's f1.9. f1.9 is f1.9 is f1.9. If my 50mm meters at f1.9, so will that one.
06-28-2011, 07:28 AM   #171
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QuoteOriginally posted by jstevewhite Quote
Dynamic range and low-light performance are tightly coupled. That's why the best low-light performers have the best dynamic range. Smaller sensors are noise limited; it's *not* just the lenses, and the lens on the Q camera is not 'slow'.



I'm well aware of that; you're missing my point. If the camera has an 8.5mm f1.9 lens, and your light meter says 1/50 @f1.9, *that's what you shoot at*. If you pretend instead that you have a 47mm f10.5, you'll overexpose by many stops. Aperture is aperture. It does indeed have an impact on DOF and diffraction and all else, but it's NOT a 10.5 when it comes to exposure, period.



The meter doesn't care what the focal length is, period. That's why you can use an external meter with no focal length setting and get accurate exposure. Your aperture for exposure is f1.9, NOT the "calculated based on format and DOF" 10.5; because, in the end, and 8.5mm lens is an 8.5mm lens, no matter what the format of the sensor; so if my meter says ISO100, f1.9, 1/250, that's the exposure regardless of the "effective" or "calculated aperture on FF".

It's also not a "slow" lens; it's f1.9. f1.9 is f1.9 is f1.9. If my 50mm meters at f1.9, so will that one.
Exactly. DOF and Diffraction will of course suffer, but exposure is exposure. otherwise the system is useless

F stops are not the most accurate measurement of course, T stops are; but it's only the movie industry using that system now
06-28-2011, 09:42 AM   #172
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I'm not completely against this camera yet since I understand that it's not aimed at Pentax dSLR owners looking to step down.

But I'm wondering who it is aimed for? And if the IQ will be a big enough of an increase over the top compacts with zooms? It seems like a lot of hassle to use a compact with a fixed focal length (put the zoom on the Q and it no longer fits in your pocket) unless it does offer a huge increase in IQ.

And if someone wants the flexibility of a zoom lens then it will cost them an additional $300. I see a lot of disappointed buyers that don't get the zoom lens since prime shooting isn't for everyone and it's a HUGE change from a typical compact.

I would like to see more pictures though.
06-28-2011, 12:14 PM   #173
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QuoteOriginally posted by snogglethorpe Quote
Very odd, as the dimensions are very similar; from my previous comment:

Pentax Q:
Dimensions: Approx. 98.0mm x 57.5mm x 31.0mm (excluding the operation parts and protrusion)
Weight: Approx. 200g (loaded and ready with the dedicated battery and SD Memory Card)

Sony NEX-C3:
Dimensions: 110 x 60 x 33mm
Weight: Approx. 225g (7.9 oz, with batt and card)

[Sony dimensions from the dpreview preview; Q dimensions from the article linked to in this thread.]

Is somebody fudging...?
This is why an image is worth a thousand words Note that even the dimensions give you the right picture about the width being 10% smaller for the Q - 12mm less. What the numbers omit is the fact that in height, the Q gains a few mm just due to the flash mount but its body is less tall than the numbers show, while for the NEX its height really describes the body height.

QuoteOriginally posted by rparmar Quote
People weren't falsely equating earlies p'n's with DSLRs so it was never required that someone speak the obvious truth.
AFAICT, the only people that equated the Q with a DSLR were those that were criticizing it for not being one. This is called strawman argument.

06-28-2011, 12:38 PM   #174
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Ya know the Sony NEX-5 does look really appealing considering it is aps-c and has an adapter for virtually every lens made.. However with all this, they make a stupid decision to make it so the camera can only fire the cheap included flash and with NO WAY to turn off the pre-flash.. They should of offered a pc sync jack or hot shoe with the camera.. sigh. I won't get it just because of this stupid limitation. How could they be so out of tune with their target customers?

At least the Q has a hot shoe.. geesh.
06-28-2011, 12:51 PM   #175
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This Q is cater more to the Japanese as I see they are more people there that likes X-Pros type of pic/Toy camera etc. Thats the reason why Pentax brings out the Toy Lens. Its cater more to Lomographers as a fun camera since it doesnt care much abt grains n blur images. Thus the knobs at the front can be customize for quick dial for Xpros,toy etc.

I think this camera would be fun.

lomography - Google Search
06-28-2011, 01:21 PM   #176
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QuoteOriginally posted by kh1234567890 Quote
I just can't keep up with all this new physics, it's not what it used to be before t'Internet
You shouldn't stress over technicalities if the tool does what you want it to do
06-28-2011, 02:31 PM   #177
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QuoteOriginally posted by jstevewhite Quote
Dynamic range and low-light performance are tightly coupled.
In sensor technology they are. The lower the noise floor, the higher the dynamic range. Almost all of the DxOMark results basically measure noise. That is, however, completely independent of sensor size.

QuoteOriginally posted by jstevewhite Quote
Smaller sensors are noise limited; it's *not* just the lenses, and the lens on the Q camera is not 'slow'.
Smaller sensors are not intrinsically noise limited. Why would they be? Why would a sensel produce more noise just because there is less sensor around it?

The lenses on the Q camera are slow like hell.
A widest aperture of f/1.9 for a 8.5mm lens may sound fast, but if you express it in full-format terms, you see that a full-frame camera can take the same pictures with a 47mm lens that has a widest aperture of f/10.5.

QuoteOriginally posted by jstevewhite Quote
If the camera has an 8.5mm f1.9 lens, and your light meter says 1/50 @f1.9, *that's what you shoot at*.
Of course. I have never said anything else.
With a Q camera and the 8.5mm lens, you never shoot with a focal length of 47mm.

If you want to predict the kind of images you can get with the Q standard lens, it can be useful to hypothesise about an equivalent lens on a full frame camera. That lens would be a 47/10.5.

QuoteOriginally posted by jstevewhite Quote
...but it's NOT a 10.5 when it comes to exposure, period.
That doesn't make sense. You're right that it isn't an f/10.5. Nor is it a 47mm. That's why I said people should not refer to the lens as a 47mm f/1.9 lens. There is an equivalent full frame lens which is a 47/10.5. For this one f/10.5 counts for DOF and exposure. You cannot separate DOF and exposure.

QuoteOriginally posted by jstevewhite Quote
Your aperture for exposure is f1.9, NOT the "calculated based on format and DOF" 10.5; because, in the end, and 8.5mm lens is an 8.5mm lens, no matter what the format of the sensor;
Correct. Note however, that DOF and exposure of an 8.5mm lens at f/1.9 on the Q camera are identical to that of an 47mm at f/10.5 on a full frame camera.

QuoteOriginally posted by jstevewhite Quote
It's also not a "slow" lens; it's f1.9. f1.9 is f1.9 is f1.9.
Is it a wide lens?
The focal length of 8.5mm suggests that it is an ultra wide, provided you are using a full frame or APS-C sensor as a reference.

Of course you know that 8.5mm is not ultra-wide within the Q-system. You know that in order to judge its AOV in terms of the full frame "normal" reference of 50mm (or 43mm), you need to convert by the crop factor. You have to do the same to judge the lens speed. Just as "8.5mm" only sounds ultra-wide, "f/1.9" only sounds fast. The lens is slow, no arguing about that.

Ever wondered about the "fast" Olympus lenses for their small sensors? Well, they are not as nearly as fast as their sensor-relative f-ratios make them appear to be.


QuoteOriginally posted by Clicker Quote
You shouldn't stress over technicalities if the tool does what you want it to do
Sure, but in order to predict whether a tool would be able to do something for you, it is useful to resort to some technicalities.
06-28-2011, 03:25 PM   #178
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Class A, your argument that the aperture for exposure changes with sensor format is incorrect. The maximum aperture is always f/1.9. While the f/10.5 value is valid for evaluating depth of field, the smaller sensor does not reduce the exposure. The small sensor may mean that less total light is received by the sensor, but this is spread over a smaller area. The concentration of light on any one point of the sensor is the same, so exposure is no different. An aperture value such as f/1.9 depends only on the size of the entrance pupil (minimum diameter of front lens element) and focal length. Like jstevewhite said, an set of exposure parameters such as 1/250, f/1.9, ISO 100 represents the same exposure value regardless of sensor size or film format.

--DragonLord
06-28-2011, 03:47 PM   #179
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That was my understanding too. The smaller sensor though means loss of performance at high ISO, but whether it costs 5 stops or some lesser amount I'm not sure. It certainly does seem true of APSC vs FF where APSC loses a stop in high ISO performance to FF.
06-28-2011, 04:06 PM   #180
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QuoteOriginally posted by DragonLord Quote
Class A, your argument that the aperture for exposure changes with sensor format is incorrect. The maximum aperture is always f/1.9. While the f/10.5 value is valid for evaluating depth of field, the smaller sensor does not reduce the exposure. The small sensor may mean that less total light is received by the sensor, but this is spread over a smaller area. The concentration of light on any one point of the sensor is the same, so exposure is no different. An aperture value such as f/1.9 depends only on the size of the entrance pupil (minimum diameter of front lens element) and focal length. Like jstevewhite said, an set of exposure parameters such as 1/250, f/1.9, ISO 100 represents the same exposure value regardless of sensor size or film format.

--DragonLord
Class A is just saying that the image you get from the 8.5mm f/1.9 ISO 100 1/250 shot taken with the Q would be identical in all respects to a shot taken with a 47mm f/10.5 ISO 3200 1/250 using a FF camera. Sensor technology differences and other issues being assumed negligible (it's theory, not practical comparison). That is the lens equivalence point he is making.

All I can say about this is that I am impressed by the performance that FF cameras get at ISO 3200 and I am happy to be able to reproduce it with a small compact
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