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07-12-2008, 10:34 AM   #136
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QuoteOriginally posted by kenyee Quote
IIRC, the reason it works so well is Samsung shrunk the distance *between* photosites instead of the photosites themselves which are close to the K10D's photosite size. Anyone remember the actual numbers?
Oh yes, forgot about that. Well the nice thing about "parrot" research is I can always blame someone else.
anyways all I found was it's either the same size or "slightly smaller" pixel size.
If I remeber correctly, slightly smaller is correct but will check.

07-12-2008, 03:35 PM   #137
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Diffraction

Okay okay, most of this stuff is way over my head. Iím just an artist who happens to have a camera, but I am trying to get the general idea of whatís going on, even if I donít (and donít have a lot of interest in) understand the details.

What Iím trying to understand is the role that diffraction has in all of this.

After reading some comparisons between the Canon 5D and 40D
Canon 40D Hands-On Report
Iím starting to think that FF isnít all itís hyped up to be. Iíve read several other comparisons but most of them seem to have serious flaws in the testing technics. I followed some other threads on Nikon forums on the D300 verses the D3 and many are coming to the same conclusion. The differences in real world use at lower ISOs is so small as to be insignificant. With prints up to 12x18 even less so. Hereís another real world view of the Canon 450D
Canon EOS Xsi (450D) Field Report

Now to the question, if I can figure out how to frame it.

After playing with the calculators on this site
Digital Camera Sensor Sizes: How it Influences Your Photography
Using the diffraction calculator it appears as if diffraction is a zero sum game. If I hit the diffraction limit on a 12MP 1.5x camera at f9.1, and I hit the limit on a 12MP FF at f13.6 thatís about a 1 ⅓ f stop difference. The difference in the depth of field for a given FOV is, you guessed it, 1 ⅓ f stop. To make that a bit clearer, to get the same depth of field at a given FOV you need to close down FF 1 ⅓ f stop over a 1.5x camera. You also hit the diffraction limit 1 ⅓ later with a FF. It all seems to be a zero sum game. Now you can stuff more pixels into FF but youíll just hit the diffraction limit sooner. Thatís likely an advantage for shallow depth of field shooters but for the rest of us there seems to be no advantage. The question is how much effect does diffraction have on IQ? Iíll make a guess and say that after a point more MP just cancel each other out. Any increase you get in resolution is lost to Diffraction. That last statement is pure speculation. I can say without a doubt that Iím not an authority.
07-12-2008, 10:34 PM   #138
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To say honestly, FF lenses at APS-C and at FF are not the same emotions.
07-13-2008, 01:41 AM   #139
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QuoteOriginally posted by Alan 2 Quote
Iím starting to think that FF isnít all itís hyped up to be. Iíve read several other comparisons but most of them seem to have serious flaws in the testing technics. I followed some other threads on Nikon forums on the D300 verses the D3 and many are coming to the same conclusion. The differences in real world use at lower ISOs is so small as to be insignificant. With prints up to 12x18 even less so. Hereís another real world view of the Canon 450D
Canon EOS Xsi (450D) Field Report

Now to the question, if I can figure out how to frame it.

After playing with the calculators on this site
Digital Camera Sensor Sizes: How it Influences Your Photography
Using the diffraction calculator it appears as if diffraction is a zero sum game. If I hit the diffraction limit on a 12MP 1.5x camera at f9.1, and I hit the limit on a 12MP FF at f13.6 thatís about a 1 ⅓ f stop difference. The difference in the depth of field for a given FOV is, you guessed it, 1 ⅓ f stop. To make that a bit clearer, to get the same depth of field at a given FOV you need to close down FF 1 ⅓ f stop over a 1.5x camera. You also hit the diffraction limit 1 ⅓ later with a FF. It all seems to be a zero sum game. Now you can stuff more pixels into FF but youíll just hit the diffraction limit sooner. Thatís likely an advantage for shallow depth of field shooters but for the rest of us there seems to be no advantage. The question is how much effect does diffraction have on IQ? Iíll make a guess and say that after a point more MP just cancel each other out. Any increase you get in resolution is lost to Diffraction. That last statement is pure speculation. I can say without a doubt that Iím not an authority.
I agree but in the end ...
Ok, let's say there's no "quality" difference (it's just for the reasoning), the only difference left are lenses.

1/ So the question is: what with the lenses made for APS-C we/you/they/someone bought a couple years ago to now ?? Useless are not

2/ Another interesting question is: those clever guys who thought they wouldn't eve buy an APS-C lens because they would useless later, do their 'older' 'FF' lenses be at least good on an FF camera?

Note sure for both of those questions. Someone who owns essentially APS-C lenses has no reason (except if the budget is really large) to go FF soon this its lenses would be in the better case, cropped on a FF body. Which means you pay hayve cash and heavy weight for an FF body and you can't even benefit from it.

The only hope (but really it could only come back into a 'pro' body) is the aperture simulator. In this case, yes there're a shedload of very good primes which would probably perform OK to very good (depending on design and tendency to show CA or not).

I know my K 30/2.8 is a heck of very good lens and is almost never used because of exposure problems with my K10D

07-13-2008, 02:31 PM   #140
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QuoteOriginally posted by Alan 2 Quote
Using the diffraction calculator it appears as if diffraction is a zero sum game. If I hit the diffraction limit on a 12MP 1.5x camera at f9.1, and I hit the limit on a 12MP FF at f13.6 that’s about a 1 ⅓ f stop difference. The difference in the depth of field for a given FOV is, you guessed it, 1 ⅓ f stop. To make that a bit clearer, to get the same depth of field at a given FOV you need to close down FF 1 ⅓ f stop over a 1.5x camera. You also hit the diffraction limit 1 ⅓ later with a FF. It all seems to be a zero sum game. Now you can stuff more pixels into FF but you’ll just hit the diffraction limit sooner.
Hi Alan,

I talked about the diffraction limit above (post #127) and about DoF (post other thread, #47) earlier. Consult for details.

Basically,
Depth of Field depends on Field of View (to be considered a constant here) and aperture in mm, only!
So, to keep the Depth of Field constant, you keep the aperture in mm constant.
Constant aperture (in mm) means to keep d = f / F constant, where F=f/d is the F-stop number).

So, in your example above, if you increase f by 1.5x when going from APS-C to FF, like 200mm to 300mm), you increase the F-stop number by 1.5 as well to compensate (like F9.1 to F13.6).

This is what you write. Now without a calculator


On the other hand...

The diffraction limit
x = 1.22 lamda F
is increased as well, meaning you obtain the same number of pixels below the diffraction limit.

This is what you write.


Additionally, if you stop down, you gather the same amount of light (smaller F-stop but larger sensor), leading to the exact same noise.
This means the following:
You may stop down a larger sensor (by the corresponding crop factor compared to a smaller sensor) and obtain the following:
  • Same Depth of Field.
  • Same noise.
  • Same diffraction-limited number of pixels.
  • => the same image...
Thank you for having pointed this out.

However, the advantages of a larger sensor are as follows:
  • You have the choice to not stop down, giving you more artistic choices and options for better noise or better resolution (at the expense of a more shallow DoF).
  • It may be easier to build, say, a diffraction-limited F2.0 50mm FA lens than a diffraction-limited F1.3 33mm DA lens.
I hope that this clarifies what benefits a larger sensor may have and which it won't.

Last edited by falconeye; 07-13-2008 at 02:38 PM.
07-13-2008, 03:08 PM   #141
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Hi, guys

There is a Japanese photography magazine called "Digital Photo,", and in its July issue(I believe), the photos taken by the "18 megapixel FF in progress" were being compared to pics taken by K20D. This magazine was granted an exclusive preview of the camera, but the company was very firm in that the camera did not represent the final product at all although the pictures were very impressive.

Last edited by Nubi; 07-13-2008 at 03:10 PM. Reason: typo
07-13-2008, 03:12 PM   #142
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QuoteOriginally posted by Nubi Quote
Hi, guys

There is a Japanese photography magazine called "Digital Photo,", and in its July issue(I believe), the photos taken by the "18 megapixel FF in progress" were being compared to pics taken by K20D. This magazine was granted an exclusive preview of the camera, but the company was very firm in that the camera did not represent the final product at all although the pictures were very impressive.

Was this 18mp camera supposed to be a Pentax?
07-13-2008, 03:46 PM   #143
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QuoteOriginally posted by PŚl Jensen Quote
Was this 18mp camera supposed to be a Pentax?

My guess is that this is the Canon D5MkII....


07-13-2008, 04:56 PM   #144
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QuoteOriginally posted by Alan 2 Quote
After reading some comparisons between the Canon 5D and 40D
Canon 40D Hands-On Report
Iím starting to think that FF isnít all itís hyped up to be. Iíve read several other comparisons but most of them seem to have serious flaws in the testing technics. I followed some other threads on Nikon forums on the D300 verses the D3 and many are coming to the same conclusion. The differences in real world use at lower ISOs is so small as to be insignificant. .

That is because these FF cameras have very few megapixel for their sensor size. They only make lots of sense at higher ISO.
A 28mp FF Pentax will be whole different animal....
07-13-2008, 06:00 PM   #145
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QuoteOriginally posted by ogl Quote
A lot of Pentaxist have a lot of FF lenses. Also 645 and 67 lenses.
No need any competition with Canon and Nikon. It could be camera for all us.

It will definitely be a camera for "all". If this camera have the pixel density close or at the 14,6mp sensor level, then it means we will have several cameras in one.
1. a high resolution camera rivaling medium format (large format?)
2. in cropped APS mode you'll have image quality that is state of the art for an APS sensor.
3. High ISO camera; a bigger sensor have less noise at a certain output size and you can apply much more noise reduction to a high resolution file and still have enough details left to make a pleasing image.

Basically, you get the best of APS and FF in one and the same body.

Lets say the DA* 60-250/4 is an FF lens, and that they will release a FF DA* 20-40/4 ED IF (or something similar). Then add the coming 1,4x dedicated converter. You then have a two lens system that covers basically everything (for most). In cropped mode you get the max reach of a 35mm (FF) 525/5.6(!); in addition you have with you the equivalent (at least!) to an medium format camera! Thats right folks; everything from 20mm to 525mm with hardly any holes and capable of very high image quality. It will be affordable (all things considered!) and possible to lift!

This will be fantastic camera for nature photographers that often have conflicting needs.
Below are examples of what I'm shooting and why having essentially a medium format resolving camera and a APS format camera in one and the same body is such a good idea. I really hope Pentax makes an 28mp DSLR

[Images below shot with Pentax 645NII + FA645 33-55/4.5 and Pentax MZ-S + FA* 600/4]
Attached Images
   

Last edited by PŚl Jensen; 07-13-2008 at 06:15 PM.
07-13-2008, 07:25 PM   #146
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QuoteOriginally posted by falconeye Quote
Jeff, interesting read ... but!

The claim that the photon collecting efficiency per area is the same for 2 um P&S sensor cells and 8 um DSLR cells is too important to be made w/o a source.

I understand that this may be the case. Or that it may not.

All those threads give no source. They are circle referencing themselves. Can you provide a scientific source to back up this claim?
Thought I'd post a link to
"The JOY of Pixel density". Keep your eyes posted...........
The Joy of Pixel Density: Open Talk Forum: Digital Photography Review
07-13-2008, 08:52 PM   #147
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QuoteOriginally posted by PŚl Jensen Quote
My guess is that this is the Canon D5MkII....
Except the fact the 5d is not 18 MP.
07-13-2008, 08:57 PM   #148
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QuoteOriginally posted by PŚl Jensen Quote
Was this 18mp camera supposed to be a Pentax?

Yes, of course.
07-13-2008, 11:28 PM   #149
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QuoteOriginally posted by Nubi Quote
Yes, of course.
So there is a prototype already in the demo stage, very interesting. Perhaps the K20 was more of a smoke screen than a revelation.
07-14-2008, 12:31 AM   #150
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QuoteOriginally posted by Nubi Quote
Hi, guys

There is a Japanese photography magazine called "Digital Photo,", and in its July issue(I believe), the photos taken by the "18 megapixel FF in progress" were being compared to pics taken by K20D. This magazine was granted an exclusive preview of the camera, but the company was very firm in that the camera did not represent the final product at all although the pictures were very impressive.
Hi
Is it possible to scan the article ? Or take a photo of it and post it here ?

Only for the pictures off course Because I don't understand Japanese
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