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12-03-2011, 06:31 AM   #1576
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QuoteOriginally posted by Class A Quote
This is a common misconception.

Please read the article "DxOMark - More pixels offset noise!".
It is irrelevant how big photosites are. The only thing that matters is the size of the sensor (assuming sensor implementation details being kept constant).

FF sensors are larger, hence they carry the potential for less noise (provided you obtain the same exposure, which either means lowering the shutter speed or raising the ISO setting, compared to APS-C setttings).
No, I read the article as being quite supportive to my notion in the post you refer too. I took the liberty to emphasize the key message with bold lettering. I'll quote a few key sentences from that article, though one should also be careful and mistrustful about the equations DXO give, because they obviously need to justify the processing they apply, as they don't make a living out of education, but out of the products they sell:

>> For a given exposure time, each smaller pixel receives four times less light than a large pixel—the equivalent of reducing exposure time by a factor of four. So to get the same sensor response, exposure time needs to be multiplied by four, which means that the ISO sensitivity of the high-resolution sensor is four times less than the low-resolution sensor.

Now assume that the same exposure times and identical ISO settings are used with a low-resolution camera and with a high-resolution camera having four times as many pixels. Since each high-resolution pixel is intrinsically less sensitive, a higher gain (either analog or digital) is applied to the signal, yielding more noise.

However, the four high-resolution neighboring pixels can be averaged out to form a low-resolution pixel.

The loss of resolution produces a better SNR. We now have two images at the same resolution and shot in similar conditions. When printing with the same printer using the same format, it is more relevant to compare sL(I ) and sH(I ) + 6dB. << etc. etc.

DxO introduce a kind of reference ISO and resolution (which is base for their own processing, I would guess). But they only compare FF cameras. Relevant to our thread here would be to compare a FF camera to an APS-C modell of the same pixel count.

Resolution is not a good measure anyway, as it is dependend on many factors and not the pixel count alone. Indeed a lower res. camera may mask noise, buy introducing blurr. But that is hardly a measure to increase quality. Also, it is hardly a measure to reduce noise by pixel binning. It can be helpful, if applied properly, but than this is a tedious apporach by combining high res (un-binned) images (usually only luminance images) with binned low res (colour) images. In that case you can keep the sharpness provided by the luminance information with the reduced noise of the resolution reduced colour images. That is not, what is done in our DSLRs as far as I am aware off.

Also, the DxO article does exaclty what I wrote about: it refers to the final printed image and not to a 1:1 inspection of single pixels.

Ben

12-03-2011, 12:41 PM   #1577
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<p>
QuoteOriginally posted by falconeye Quote
It is my strong impression that you don't work hard to gain a better understanding of what you are talking about. I know, I sound arrogant by saying this, but it is my strong impression.</p>
<p>&nbsp;</p>
<p>E.g., the two sentences above: It is the meaning of equivalent body/lens/ISO combinations that no difference is visible. But if you can't find an equivalent combo, then you face a factor 2 of difference which you personally may be able to see or not. I don't say you need this extra factor. But it is there.</p>
<p>...</p>
<p>And the 70-200/4 on APS-C would become a 100-300/5.6 equivalent. The latter kind of lenses typically have no corner probs, so what are you talking about?</p>
<p>...</p>
<p>And I won't talk about photons with you...
</p>
<p>&nbsp;</p>
<p>:[ in asking questions and saying these things because I want to know more. And is shooting at 200 f/5.6 on FF goimg to give the same results as 135 f/4 on APS-C? If not then they aren't equivalent surely? </p>
<p>&nbsp;</p>
<p>And don't patronise me. I've studied in a masters degree in Physics, so you're free to tell me all I need to know about photons. Electronics and software however, I have no idea about, so save telling me what I already know about light and tell me something useful. Thank you for contributing to me learning though. I'll read the DXO article when I get home.</p>
<p>&nbsp;</p>
<p>I left my physics course to become a photographer, and never leaent about diffraction limits and all that because its never made my shits any better knowing stuff like this. But I'm interested anyway, so rather than dismissing me help me learn. WOULD a normal person sew the difference in FF if they were looking at it on a 20inch widescreen HD monitor?, or a 6x4 300dpi print? I want to know that, and then in happy. I now understand that people want full frame because lenses are made to full frame specifications (aperture and focal length) and this annoys people. Also because the viewfinder and noise is better, and more importantly ( and most intruigingly for me) the local contrast with FF is much better. And people who really look for detail like to be able to stop their lenses down more to avoid diffraction softening. That and having a bigger, more expensive piece of gear is always fun. I think I may sell off my Pentax gear. Its neither Canon nor Nikon, and pros want me to have their system to assist them. Pentax can shoot DNG so RAW compatability isn't an issue, only the lens compatibility. </p>
<p>&nbsp;</p>
<p>Pros don't want anyone from my experiences, so I want my equipment to be reliable and to deliver top quality photos. So far I can't see how investing an extra grand over the K-5 will be worth it. I guess in internally trying to justify staying with Pentax. Looking back i should have bought a Nikon instead. </p>
<p>&nbsp;</p>
<p>But again, thanks for all the help so far, just please help rather than patronising me. I hate Physics. Though i did re ieve a scholarship to study on that degree so go figures. Why the personal criticisms <img src="https://www.pentaxforums.com/forums/images/smilies/frown.gif" border="0" alt="" title="Frown" smilieid="11" class="inlineimg" /></p>
12-03-2011, 12:55 PM   #1578
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QuoteOriginally posted by Mareket Quote
<p></p>
<p>&nbsp;</p>
<p>:[ in asking questions and saying these things because I want to know more. And is shooting at 200 f/5.6 on FF goimg to give the same results as 135 f/4 on APS-C? If not then they aren't equivalent surely? </p>
<p>&nbsp;</p>
<p>And don't patronise me. I've studied in a masters degree in Physics, so you're free to tell me all I need to know about photons. Electronics and software however, I have no idea about, so save telling me what I already know about light and tell me something useful. Thank you for contributing to me learning though. I'll read the DXO article when I get home.</p>
<p>&nbsp;</p>
<p>I left my physics course to become a photographer, and never leaent about diffraction limits and all that because its never made my shits any better knowing stuff like this. But I'm interested anyway, so rather than dismissing me help me learn. WOULD a normal person sew the difference in FF if they were looking at it on a 20inch widescreen HD monitor?, or a 6x4 300dpi print? I want to know that, and then in happy. I now understand that people want full frame because lenses are made to full frame specifications (aperture and focal length) and this annoys people. Also because the viewfinder and noise is better, and more importantly ( and most intruigingly for me) the local contrast with FF is much better. And people who really look for detail like to be able to stop their lenses down more to avoid diffraction softening. That and having a bigger, more expensive piece of gear is always fun. I think I may sell off my Pentax gear. Its neither Canon nor Nikon, and pros want me to have their system to assist them. Pentax can shoot DNG so RAW compatability isn't an issue, only the lens compatibility. </p>
<p>&nbsp;</p>
<p>Pros don't want anyone from my experiences, so I want my equipment to be reliable and to deliver top quality photos. So far I can't see how investing an extra grand over the K-5 will be worth it. I guess in internally trying to justify staying with Pentax. Looking back i should have bought a Nikon instead. </p>
<p>&nbsp;</p>
<p>But again, thanks for all the help so far, just please help rather than patronising me. I hate Physics. Though i did re ieve a scholarship to study on that degree so go figures. Why the personal criticisms <img src="https://www.pentaxforums.com/forums/images/smilies/frown.gif" border="0" alt="" title="Frown" smilieid="11" class="inlineimg" /></p>
What kind of pro is looking for help from someone who can't make good pictures (or can you?)?

Well on small prints and a cheap HD screen you can't see the difference. I have Fujitsu P27T-6 screen, 27 inch and 2560x1440 pixels and you will see the difference.
12-03-2011, 02:23 PM   #1579
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QuoteOriginally posted by RonHendriks1966 Quote
What kind of pro is looking for help from someone who can't make good pictures (or can you?)?

Well on small prints and a cheap HD screen you can't see the difference. I have Fujitsu P27T-6 screen, 27 inch and 2560x1440 pixels and you will see the difference.
Ron your tv has roughly 1/3th of the resolution an normal print does

12-03-2011, 03:24 PM   #1580
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QuoteOriginally posted by Mareket Quote
WOULD a normal person sew the difference in FF if they were looking at it on a 20inch widescreen HD monitor?, or a 6x4 300dpi print? I want to know that, and then in happy.
Nah. In fact the only thing you would notice from a K-5 over a point and shoot under your conditions is probably that there is less depth of field on the k-5.

Now, when you shoot a picture of those bears in Yellowstone with your point and shoot, you'll be getting 5 usable pixels worth of bear. Even with the Q, it's pretty apparent that it is diffraction limited at around F5.6, and there's not much point in stopping down beyond that, as you will lose resolution.

The same can be said for APS-C, especially as the resolution goes up. If they cram a 22mp sensor in the next model, shooting above F8 will start to diffraction limit. Will it be visible? Probably not in the conditions you describe, unless you crop, but then again, you really won't need more than a 6mp sensor to fulfill your conditions, so you could say that the K-5 level of camera is not at all for you.
12-03-2011, 03:46 PM   #1581
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QuoteOriginally posted by Anvh Quote
Ron your tv has roughly 1/3th of the resolution an normal print does
And Hi-iso K-7 pictures look very crappy on it.
12-03-2011, 05:48 PM   #1582
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QuoteOriginally posted by Mareket Quote
But again, thanks for all the help so far, just please help rather than patronising me. I hate Physics. Though i did re ieve a scholarship to study on that degree so go figures. Why the personal criticisms
Hi Mareket,

I didn't want to patronize you. It even made me feel sorry because I normally try at least to avoid being like that (I fail often enough though). But I really wanted you to try harder to understand why ISO must scale if you change the sensor size, when comparing for equivalent results. Key is to understand that two equivalent images will have collected an identical total number of photons per image. Now knowing your background in physics, I am sure you'll sort it out w/o further "help" from my side. It wasn't meant as a personal criticism.

Having said this, I agree with you that APS-C at the level of the K-5 is good enough for at least 90% of applications a photographer meets today.
12-04-2011, 01:21 AM   #1583
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QuoteOriginally posted by falconeye Quote
Hi Mareket,

I didn't want to patronize you. It even made me feel sorry because I normally try at least to avoid being like that (I fail often enough though). But I really wanted you to try harder to understand why ISO must scale if you change the sensor size, when comparing for equivalent results. Key is to understand that two equivalent images will have collected an identical total number of photons per image. Now knowing your background in physics, I am sure you'll sort it out w/o further "help" from my side. It wasn't meant as a personal criticism.

Having said this, I agree with you that APS-C at the level of the K-5 is good enough for at least 90% of applications a photographer meets today.

I would say 99%

12-04-2011, 01:56 AM   #1584
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I would agree if with that if Pentax had good a aspherical 10mm lens and some lenses around the f1.0 mark to try and narrow that DoF.. I think a FF/APS-H sensor would simply be easier and cheaper than new lens designs to try and cover would a bigger sensor would bring to it's imaging.
12-04-2011, 02:50 AM   #1585
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QuoteOriginally posted by Chex Quote
I would agree if with that if Pentax had good a aspherical 10mm lens and some lenses around the f1.0 mark to try and narrow that DoF.. I think a FF/APS-H sensor would simply be easier and cheaper than new lens designs to try and cover would a bigger sensor would bring to it's imaging.
Well this is an intersting quest. If you use FA*85mm/f1.4 on aps-c, but you really would like an expensive 85mm/f1.2 (no idea why) then you could use that FA*85mm/f1.4 on an aps-H sensor that messures 27,3mm width giving you that same DOF as a 85mm/f1.2 on aps-C. Small steps it is.
12-04-2011, 03:25 AM   #1586
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QuoteOriginally posted by RonHendriks1966 Quote
Well this is an intersting quest. If you use FA*85mm/f1.4 on aps-c, but you really would like an expensive 85mm/f1.2 (no idea why) then you could use that FA*85mm/f1.4 on an aps-H sensor that messures 27,3mm width giving you that same DOF as a 85mm/f1.2 on aps-C. Small steps it is.
One thing to keep in mind is that the fastest lenses often don't work as expected on digital sensors - the depth of the sensor wells prohibits them from gathering all the light. So a 1.4 lens may not give you the full advantage of f/1.4.
12-04-2011, 03:40 AM   #1587
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QuoteOriginally posted by gazonk Quote
the fastest lenses often don't work as expected on digital sensors
Indeed:

QuoteQuote:
For years, lens makers have fought hard to market lenses of wider and wider aperture... (e.g., f /1.4 instead of f /2) but a series of measurement published on dxomark.com cast some doubts on the real benefits, for digitally equipped photographers, of these progresses.

Loss of light at wider aperture

“We have been very surprised,” explained Frédéric Guichard, chief scientist at DxO Labs, “to find out that some of the gain from wider lens openings seems to be offset by the present state of sensor technology. Our measurements all point in the same direction: as you go further than f/ 4 – to f /2 and wider, the accrued quantity of light falls marginally onto the sensor. A stronger and stronger part of this additional light is blocked or lost. I am therefore inclined to question the real benefit of faster lenses.”

This loss seems to increase when the pixel size decreases
DxOMark - F-stop blues
12-04-2011, 04:39 AM   #1588
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QuoteOriginally posted by gazonk Quote
One thing to keep in mind is that the fastest lenses often don't work as expected on digital sensors - the depth of the sensor wells prohibits them from gathering all the light. So a 1.4 lens may not give you the full advantage of f/1.4.
I think most people would pay extra for a 85 f1.2 or 50mm f1.2 for shallow DOF anyways even if Dxo is right, though they have a lot of BS on their site to generate page views.
12-04-2011, 05:11 AM   #1589
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QuoteOriginally posted by borno Quote
I think most people would pay extra for a 85 f1.2 or 50mm f1.2 for shallow DOF anyways
No doubt. But not only will those fast lenses be darker than you'd expect, as DxO says, but most 1.2's also perform their worst, resolution wise, wide open.

So you will usually pay a high price - literally and optically - for dat bokeh.
12-04-2011, 06:50 AM   #1590
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QuoteOriginally posted by rawr Quote
No doubt. But not only will those fast lenses be darker than you'd expect, as DxO says, but most 1.2's also perform their worst, resolution wise, wide open.

So you will usually pay a high price - literally and optically - for dat bokeh.
I think there is a lot more to IQ than resolution or test bench numbers.JMO
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