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02-14-2012, 05:08 PM   #76
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I don't know if it helps.

But I would like to thank Class A for his uphill battle to clarify things. Please, listen to what he says.

The original question by the OP makes me remember that I wanted to write a blog article about the issue. Maybe, I really should do it. Many issues have not even been mentioned yet in this discussion, like the various cost/performance curves wrt sensor size.

Without digging too deep now, I'd like to add that FF has a larger advantage for mirrored cameras than mirrorless ones. This relates to manufacturing tolerances and QC obstacles.

02-14-2012, 05:13 PM   #77
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QuoteOriginally posted by falconeye Quote
Without digging too deep now, I'd like to add that FF has a larger advantage for mirrored cameras than mirrorless ones. This relates to manufacturing tolerances and QC obstacles.
I'd like that expanded on when you get a chance.
02-14-2012, 05:14 PM   #78
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In my opinion the most important advantage of FF is the larger viewfinder. As far as the technical advantages, they are only relevant for the very small percentage of users who would be able to produce better images than could be captured with aps-c.

If I ever get to the point where I'm limited by my camera and want the best of the best, I'll go with the 645. Or, more likely (and financially feasible), wait a couple years for aps-c technology to improve.

IMHO for Pentax to develop full frame camera & lens lineup would be a waste of resources.
02-14-2012, 05:15 PM   #79
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QuoteOriginally posted by Ash Quote
Getting back to basics... why want a FF camera? Well, why would Nikon and Canon produce FF cameras if their APS-Cs were enough for all their photographer client base? After all, the D300 and 7D have very, very good autofocus and excellent results - 18Mp of it on the 7D. How many photographers, even pros, need more than 18Mp? Why are their FF sales so successful if these high end APS-C offerings were enough? That's the demand end of the argument for FF.

Teasing out some more of the practical reasons for the Pentax FF, we have the potential to gain a significant deal more DOF control and larger area for data collection, thereby creating smoother high ISO results - I believe jsherman999's thread on Full Frame shots and thoughts discusses the benefits well. So there is no doubt there are real and practical reasons for wanting a Pentax FF, but as we know, we just have to wait...
Well we live in a time where demands from professional photograps are getting hi-er every year. You don't get away with an avarage image anymore (unless something spectacular is happening in that image) when you want to sell a picture to a glossy. For a newspaper it is okay and for internet there is no problem.

In 2012 we think that shooting at iso1600 is normal. In the age of K20D that was for extra-ordanary pictures.

02-14-2012, 05:53 PM   #80
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equivalent images

QuoteOriginally posted by Class A Quote
They arrive at this conclusion because they are using the same f-stop for both sensor formats.

That's comparing apples to oranges, as the image on the larger sensor will have less DOF. It is a bit like saying "My image is brighter than yours (because I exposed 1.5 times longer than you)".

If you stop down the lens in front of the larger sensor in order to achieve the same DOF, this reduces the number of photons available to the sensor. Now both (small and large) sensors receive the same total amount of photons. The larger sensor has a larger surface but with the same amount of photons that only means that the photon density per sensor unit area decreases.

Larger sensors only have a noise advantage, if they receive more photons than smaller sensors. For instance, if they receive the same number of photos per unit area (i.e., if the exposure is the same). However, achieving the same exposure by using an f-ratio that yields shallower DOF is not fair. Using a different shutter speed would lead to a different image as well (in general). Hence the only way a larger sensor can make up for its need for more total photons, in order to achieve the same exposure, is to use a higher ISO setting.

There is still a low-light advantage to larger sensors as they can use lenses (e.g., 50/1.4) for which no APS-C equivalent (e.g., 33/0.9) exist. But it is the lens availability that creates the low-light advantage, not a property of the larger sensor.

Another way to illustrate what this means using a (hopefully) practical shooting example:

FF: 50mm f/4 1/200s ISO 1600
APSC: 35mm f/4 1/200s ISO 1600

The shutter speed is the same, the FOV is the same, ISO is the same, but the noise will be at least one stop better on the FF sensor, because that larger surface area is able to collect more light for the same amount of exposure.. But, the DOF will be different, so they won't be exactly equivalent images - the FF shot will have 1.3 stops less DOF, would look more like an f/2.5 shot on the apsc camera, in terms of DOF.

So, to make them equivalent, you would need to stop down the FF combo to f/6 or so - but then you would need about 1/80s shutter speed to get the same exposure. So, if you want equivalent images, you'd need to shoot the FF combo at about:

FF: 50mm f/6 1/200s ISO 4000

And this would show about the same amount of noise as (and be equivalent in every other way to) :

APSC: 35mm f/4 1/200s ISO 1600

Now - here's the kicker - in many practical shooting situations, you are not trying to create the exact equivalent image you'd get from aps-c. You're just not concerned with doing that. Thus, you could have left that FF shot at f/4, accepting (and probably enjoying) the "f/2.5 DOF" look, while retaining the f/4 sharpness at the plane of focus... and retaining that 1.3 stops better noise performance.

If you do find yourself in a situation where you want a bit more DOF for that FOV, where you really want that aps-c look, you can simply stop down the FF combo to take advantage of that nice aps-c camera embedded in your FF camera.


.

Last edited by jsherman999; 02-14-2012 at 06:13 PM.
02-14-2012, 05:57 PM   #81
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QuoteOriginally posted by ragingtornado Quote
IMHO for Pentax to develop full frame camera & lens lineup would be a waste of resources.
When every lens made for FF can be used very nicely on aps-c, when almost all the tech developed for a FF camera can also be used in an aps-c body (maybe a generation removed, for marketing reasons,) ... I don't see how anyone could consider it a waste of resources.

I think something like the 'Q' represents a waste of resources. FF is actually a very smart concentration and focusing of resources.

.
02-14-2012, 06:10 PM   #82
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QuoteOriginally posted by jsherman999 Quote
I think something like the 'Q' represents a waste of resources.
.
I'll agree with you there!

I just dont see how another entire line of lenses could possibly be sustainable given the amount of people who would actually buy a Pentax full frame. Yes much of the development work is done, but that's only part of the expense (stock, advertising, support, etc.) Lots of people talk about a FF camera on forums but I think few would actually buy it.
02-14-2012, 06:20 PM   #83
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QuoteOriginally posted by jsherman999 Quote
The shutter speed is the same, the FOV is the same, ISO is the same, but the noise will be at least one stop better on the FF sensor, because that larger surface area is able to collect more light for the same amount of exposure.
I just wanted to point out that this is only true if your assumption is that both the APS-C and FF sensors have the same number of pixels. A larger sensor with more of the the same size elements will still have the same noise behaviour. Some people who have responded to the thread have wanted a larger sensor with the same number of megapixels, and others have wanted a FF sensor with more megapixels.

02-14-2012, 06:28 PM   #84
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QuoteOriginally posted by RobG Quote
I just wanted to point out that this is only true if your assumption is that both the APS-C and FF sensors have the same number of pixels. A larger sensor with more of the the same size elements will still have the same noise behaviour. Some people who have responded to the thread have wanted a larger sensor with the same number of megapixels, and others have wanted a FF sensor with more megapixels.
Actually, when the image is represented at the same size on screen or in print, that won't really matter - you may see more noise at the pixel level with the higher MP FF sensor, but not at the representation level. 'More MP = bad" is sort of a myth. The only way it's really bad is with the processing overhead, throughput, disk space, etc. In every other way it's good, especially when it gives you the ability to crop to the aps-c FOV and still retain an amazing 15MP on the target. That's just pretty cool to me.

There are differences in quantum efficiencies that we haven't talked about - some sensors just have a better QE, and the read noise performance is better than a simple scale-up would suggest. (D3S has a higher QE than the D3/D700 for example. That's why many of us are hoping for a D700s in addition to the D800 - a D700 with the D3s sensor.)
02-14-2012, 06:33 PM   #85
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Of course, personally speaking, because my interest in the Q and K-01 is limited to their novelty, I'd have found a FF in place of those developments a more welcome addition to the dSLR lineup. I understand these things take time for a smaller company, though. Perhaps it may be wise to wait until at least until a K-5 and K-r replacement are on the horizon as well as some more FF compatible lenses before bringing out a flagship FF model.
02-14-2012, 08:04 PM   #86
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QuoteOriginally posted by jsherman999 Quote
Actually, when the image is represented at the same size on screen or in print, that won't really matter - you may see more noise at the pixel level with the higher MP FF sensor, but not at the representation level. 'More MP = bad" is sort of a myth. The only way it's really bad is with the processing overhead, throughput, disk space, etc. In every other way it's good, especially when it gives you the ability to crop to the aps-c FOV and still retain an amazing 15MP on the target. That's just pretty cool to me.
Assuming that the technology used in the individual sensor elements is the same, your APS-C crop would have exactly the same noise characteristics as an APS-C camera.

You said:
QuoteQuote:
but the noise will be at least one stop better on the FF sensor, because that larger surface area is able to collect more light for the same amount of exposure
This is simply not true if the sensor elements in the FF sensor are the same size as in the APS-C sensor. The light on each sensor element is exactly the same, and the element hardware is the same, so there's no improvement in signal to noise. I can see that having the same image represented in more mexapixels would mean that overall you could get a more accurate representation of the image, but I don't see why that would equate to a stop difference in noise. Larger sensors tend to have more problems with heat dissipation and that in turn leads to noise issues; another factor which I don't think anyone has mentioned.

And yes, I agree that some sensors are better than others, even with more megapixels - the K5 sensor versus the K7 sensor is a perfect example. However, that wasn't the premise of the point.
02-14-2012, 08:08 PM - 1 Like   #87
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I probably have no business entering into this discussion because I know very little about it. Nevertheless, when I was helping my daughter decide what to buy (she aspires to be a professional photographer), I came across an ad looking for photographers for a travel magazine (I forget which one). They were looking for photographers in different locations throughout the world, but what surprised me is that they required that you own a FF Canon or Nikon (they listed the permissable options). So if I wanted to shoot for this magazine, I couldn't shoot Pentax. I don't know how common this requirement might be in the world of professional photography, but if it is common then I would think that might be a good reason for Pentax to offer a FF. It's just a thought. (BTW my daughter bought a Kx because at the time it simply offered more bang for the buck than the competition.)
02-14-2012, 08:39 PM   #88
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QuoteOriginally posted by RobG Quote
Assuming that the technology used in the individual sensor elements is the same, your APS-C crop would have exactly the same noise characteristics as an APS-C camera.
Yes, you wouldn't realize any noise advantage cropping like that. You'd really be using it as an aps-c camera at that point - but one closer to the K-5 (if you were shooting a D800) vs. a K100DS (if you were shooting a D700.)

QuoteQuote:
QuoteQuote:
FF: 50mm f/4 1/200s ISO 1600
APSC: 35mm f/4 1/200s ISO 1600

The shutter speed is the same, the FOV is the same, ISO is the same, but the noise will be at least one stop better on the FF sensor, because that larger surface area is able to collect more light for the same amount of exposure
.
This is simply not true if the sensor elements in the FF sensor are the same size as in the APS-C sensor. The light on each sensor element is exactly the same, and the element hardware is the same, so there's no improvement in signal to noise. I can see that having the same image represented in more mexapixels would mean that overall you could get a more accurate representation of the image, but I don't see why that would equate to a stop difference in noise. Larger sensors tend to have more problems with heat dissipation and that in turn leads to noise issues; another factor which I don't think anyone has mentioned.
If by 'sensor elements' you mean sensels or pixels, and you're talking about an aps-c sensor and FF sensor with equal pixel pitch (meaning a very high MP FF vs a low-mid MP aps-c,) then the noise at the pixel level will be the same, yes, but the overall image noise will be lower, finer grained, etc, with the FF image.

.
02-14-2012, 09:37 PM   #89
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QuoteOriginally posted by falconeye Quote
The original question by the OP makes me remember that I wanted to write a blog article about the issue. Maybe, I really should do it.
Please do.

It would be very useful to be able to link to such an article in discussions like this one and it would touch upon more interesting aspects like the cost/performance curves.
02-14-2012, 10:08 PM   #90
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This is all starting to sound like a repeat of... "because I want it." Or "Because I'm so obssessive it would drive me crazy to know my picture could have been minutely better, technically."

But I'm really interested... who has a reason , that involves an area where APS-c is so deficient, you'd have to be crazy not to go full frame?
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