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06-23-2013, 03:20 AM   #2071
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QuoteOriginally posted by VoiceOfReason Quote
Basically, would shooting with a 16mp sensor at f/9 vs a 24mp at f/9 where one is below and one is above the diffraction limit. In a nutshell, would it have a noticeable effect on my image with all things equal in the real world doing it at full resolution, ...
That's what I thought your question was and the answer is still:

"The number of MP does not matter when it comes to comparing the sharpness of images taken on two sensors with a different MP count".

One image will have been recorded below the sensor's "diffraction limit" and the other above the sensor's "diffraction limit", but they have the same overall image sharpness.

Note that stopping down less will help both images -- unless you want to maximise DOF -- because decent lenses peak in terms of sharpness before f/9. As Falk wrote, if you are after the best image sharpness, you need to balance many aspects.

But in any event, you can ignore the number of MP when it comes to comparing images. In other words, your image sharpness will not suffer, just because you upgrade to a higher MP sensor. On the contrary.

06-23-2013, 03:34 AM   #2072
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QuoteOriginally posted by Class A Quote
Why are you concerned with pixel sharpness?

What matters is the image sharpness. For a given sensor size, a particular f-stop will always produce the same image-level diffraction, independently of the MP.

Worrying about the effect of diffraction at the pixel level is like worrying about noise at the pixel level.

Yes, higher MP sensors have higher per-pixel noise (everything else being the same). But the image-level noise is the same.

As a matter of fact, the higher MP sensors have a finer grain pattern (once images are scaled to the same size). Likewise, increasing resolution with more MPs is possible even when the diffraction limit has been passed. An image chain does not work according the "weakest link defines the maximum"-principle. All individual link performances multiply so every improvement helps (to a degree that is naturally also determined by other links).
I must admit that I am somewhat of a pixel peeper myself but have come to realize a few 'truths' from using a D800E over the past year. The problem with being a PP on a D800E is that the detail when zoomed in is always phenomenal but when looking at the entire image that detail can go missing due to the resolving power(lessness) of the human eye. If there are no larger scale features showing some contrast/detail/acutance then the image can appear 'soft'. For instance, I have pictures of my cats that look very 'soft' when taking in the entire image but are super sharp and full of detail when PP'ing at 100%. IMO, if you're Pixel Peeping then you're not thinking about the image or the Art, you are thinking about whether you bought the right hardware or not!
06-23-2013, 04:02 AM   #2073
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QuoteOriginally posted by VoiceOfReason Quote
That's all I wanted it from, is a sharpness standpoint. Basically, would shooting with a 16mp sensor at f/9 vs a 24mp at f/9 where one is below and one is above the diffraction limit. In a nutshell, would it have a noticeable effect on my image with all things equal in the real world doing it at full resolution, or would other factors nullify the differences in the question I posted.
No. Not noticeable unless you print enormous or crop massively.
06-23-2013, 05:31 AM   #2074
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QuoteOriginally posted by jatrax Quote
By this you mean this resolution would achieve the maximum quality for that particular size sensor?
Not exactly. I mean that going beyond the particular MP numbers may always be more economically done by going to a larger sensor.

It is a soft argument though because the respective resolution numbers may only apply to image centers and perfect AF. So, upgrading to larger sensors may make sense well below these limits. Moreover, the numbers are projections into the future and are entirely based on my gut feeling, not a scientific argument.

QuoteOriginally posted by Cannikin Quote
intuitive sense to a lot of people. Perhaps an analogy will help
I tried to make things intuitive though.

You have several blur spot sizes and I believe it is a very intuitive concept to grasp that it doesn't make sense to look at / minimize one of the sizes without taking care of the others too.

Like with your car analogy, if you upgrade to 2000hp cars you have to consider speed limits.

QuoteOriginally posted by VoiceOfReason Quote
Basically, would shooting with a 16mp sensor at f/9 vs a 24mp at f/9 where one is below and one is above the diffraction limit.
I hoped you could answer such questions yourself now. So, I failed.
BTW, F/9 isn't above the diffraction limit for 24MP. The Raleigh limit for 24MP APSC is F/11. But diffraction is always visible, below and above the Raleigh limit. Maybe, read my long post again.

QuoteOriginally posted by Cynog Ap Brychan Quote
For reasons that escape me, I had always thought that diffraction was a factor of the actual diameter of the aperture hole, not its f number per-se.
You are correct and wrong at the same time. It depends on the factors you consider to be constants.

Case 1: Field of View is a constant, sensor size is a variable. Then diffraction effects (e.g., as expressed by LW/PH Raleigh resolution) are a function of the actual diameter of the aperture hole in mm. This is part of the equivalent camera theoreme which covers other effects like noise and depth of field too. I guess, this is where your idea is coming from.

Case 2: Field of View is a variable, sensor size is a constant. This is a more typical case corresponding to a change of lens with a given body. Then diffraction effects are a function of the F-Stop, i.e., the actual diameter of the aperture hole divided by focal length.

Case 1 and case 2 are not in conflict of course. Just rewriting the same formulas.

06-23-2013, 07:34 AM   #2075
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So, can someone sum up what the implications of all this discussion of diffraction, resolution etc may mean for the average punter buying a new camera like a 24MP APS-C K-3, compared to the current K-5 family?

Further, if Pentax rolled out a 24MP APS-C K-3 AND a 24MP full-frame, which of the two - assuming equal megapixels - would likely produce the best resolution, sharpness, IQ etc?
06-23-2013, 07:42 AM   #2076
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QuoteOriginally posted by rawr Quote
So, can someone sum up what the implications of all this discussion of diffraction, resolution etc may mean for the average punter buying a new camera like a 24MP APS-C K-3, compared to the current K-5 family?
Nothing at all.
06-23-2013, 08:00 AM   #2077
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QuoteOriginally posted by rawr Quote
So, can someone sum up what the implications of all this discussion of diffraction, resolution etc may mean for the average punter buying a new camera like a 24MP APS-C K-3, compared to the current K-5 family?

Further, if Pentax rolled out a 24MP APS-C K-3 AND a 24MP full-frame, which of the two - assuming equal megapixels - would likely produce the best resolution, sharpness, IQ etc?
The full-frame would be about 50% sharper.
06-23-2013, 08:48 AM   #2078
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QuoteOriginally posted by rawr Quote
So, can someone sum up what the implications of all this discussion of diffraction, resolution etc may mean for the average punter buying a new camera like a 24MP APS-C K-3, compared to the current K-5 family?

Further, if Pentax rolled out a 24MP APS-C K-3 AND a 24MP full-frame, which of the two - assuming equal megapixels - would likely produce the best resolution, sharpness, IQ etc?
It would depend on your final output. For web galleries, absolutely nothing. For 13" x 19" prints the FF sensor is enlarged 180 times. The same image from an APS-C would have to be enlarged 457 times. If MPs and S/N is the same for both sensors the larger sensor will still produce a cleaner image simply because the noise/defects are not magnified nearly as much.

Hassy has a traveling gallery that they send to trade shows. Anyone who doesn't think sensor size matters for medium size prints should go see the gallery.

For output from a typical consumer grade photo printer there would be no difference.

90% of the population is viewing images on an sub-HD 8 bit monitor with a DR of around 7EV. These same people then troll the web claiming they have done their own tests and downloaded imaged from Image Resource and they can't see any difference between a D800 and a K-5 and insist that nobody needs a FF camera that that APS-C is just as good. Or they have made comparison 8" x 10" prints from their Epson all-in-one and proclaim there is no difference.

The average enthusiast is not using a monitor or printer capable of displaying a much a of difference.

06-23-2013, 09:27 AM   #2079
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QuoteOriginally posted by ElJamoquio Quote
The full-frame would be about 50% sharper.
But only noticeable if you super-crop or blow it up by a metre+ across or more.

If you print at 11x17 and use a loupe you might see a difference, if you know what you are looking for and had the exact same subject and all other parameters controlled for.

The more pronounced advantage is ISO and the resulting noise control etc., and a bit more control over DOF at the shallow end of the pool. DR is better on FF, but agains, it is very difficult to measure so good have the current APS-C sensors been.
06-23-2013, 11:23 AM   #2080
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06-23-2013, 11:43 AM   #2081
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QuoteOriginally posted by Winder Quote
It would depend on your final output. For web galleries, absolutely nothing. For 13" x 19" prints the FF sensor is enlarged 180 times. The same image from an APS-C would have to be enlarged 457 times. If MPs and S/N is the same for both sensors the larger sensor will still produce a cleaner image simply because the noise/defects are not magnified nearly as much.

Hassy has a traveling gallery that they send to trade shows. Anyone who doesn't think sensor size matters for medium size prints should go see the gallery.

For output from a typical consumer grade photo printer there would be no difference.

90% of the population is viewing images on an sub-HD 8 bit monitor with a DR of around 7EV. These same people then troll the web claiming they have done their own tests and downloaded imaged from Image Resource and they can't see any difference between a D800 and a K-5 and insist that nobody needs a FF camera that that APS-C is just as good. Or they have made comparison 8" x 10" prints from their Epson all-in-one and proclaim there is no difference.

The average enthusiast is not using a monitor or printer capable of displaying a much a of difference.
I agree, but you have to consider that 99% of the population is well satisfied with the results from their cell phone. Few lurk in camera forums or strive for the perfection seen by the few that do. Not saying it is not important, or worth pursuit, but in the "real world" there are far too few that will recognize your efforts at perfection. You may have a masterpiece of perfection, but old Granny might prefer the one shot with a cell phone.....it happens!
Regards!
06-23-2013, 11:43 AM   #2082
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QuoteOriginally posted by beholder3 Quote
No.

As much as you can predict the weather to get better after rain as much you can assume the resolving power should increase. That is about the level of serious scientific predictions you can actually make.

Reality is far more complex than all the amateur DIY "calculations" brought forth here.
As for the percentage you can also play roulette and guess the numbers. Same chances of correctness.

Anyone simply has to wait for the real products (lens and camera) and then measure it - if the result is of any interest at all based on viewing habits (currently completely excluding everyone who preferable consumes photos on electronic 1-3 MPx screens).
This made no sense at all.

The values stated are ideal theoretical numbers.
06-23-2013, 12:01 PM   #2083
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QuoteOriginally posted by Rupert Quote
I agree, but you have to consider that 99% of the population is well satisfied with the results from their cell phone. Few lurk in camera forums or strive for the perfection seen by the few that do. Not saying it is not important, or worth pursuit, but in the "real world" there are far too few that will recognize your efforts at perfection. You may have a masterpiece of perfection, but old Granny might prefer the one shot with a cell phone.....it happens!
Regards!
It happens because people take photos for vastly different reasons. Some (mainly people here) are after an outstandingly rendered and sometimes creative image. Many others are trying to capture a memory of being at a place with other people. Mobile phones do that very well and, perhaps, do it better than any DSLR if you consider that it's much more likely that anyone would have their mobile phone in their pocket instead of some big honking camera.
06-23-2013, 12:51 PM   #2084
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06-23-2013, 01:03 PM - 1 Like   #2085
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QuoteOriginally posted by Rupert Quote
I agree, but you have to consider that 99% of the population is well satisfied with the results from their cell phone. Few lurk in camera forums or strive for the perfection seen by the few that do. Not saying it is not important, or worth pursuit, but in the "real world" there are far too few that will recognize your efforts at perfection. You may have a masterpiece of perfection, but old Granny might prefer the one shot with a cell phone.....it happens!
Regards!
Many people are satisfied with low quality results because they don't know any different. We were pretty poor growing up and I didn't know I needed glasses. I had never been to an eye doctor until I was in junior high. I thought everyone saw things just as I saw them. I just didn't know any different. Then one day I got an eye exam and was blown away by how clear everything became when my vision was corrected. In hindsight I was damn near blind, but I never knew any different.

Most people never get to see really amazing prints. They spend their entire life looking at photographs on low quality laptops or small cheap prints. When I moved to a Eizo 2560 x 1440 monitor it was a little like getting glasses again. I realized there was a lot more being captured than what my old 1600 x 900 was capable of displaying. It changed how I was working in post and changed my prints.... for the better.

This is why cell phone cameras and even those Canon 7D wanna-be's don't bother me. Sending over images on a CD when you have no idea if the viewer has a color calibrated high quality monitor is like having someone else process your images without you ever seeing them. You have no control over what they will actually look like to the potential client. The same applies with a website. You could send a link to a potential client and for all you know they open it on their 3 year old company computer with an 8 year old monitor. I would say that 90% of the 7D Wana-bes don't even own any type of color calibration equipment. Hell they don't even know what a grey card is.

I always present 13" x 19" prints as a portfolio so that I have total control over what my viewer sees. It's 10x easier to justify why I am 10x more expensive that they guy with the Canon 7D and the super slow, super soft, super zoom who sends over a link to their Flickr account.

Many people are satisfied with low quality results because they don't know any different.
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