Crop Factor, Low Light and Aperture with m4/3 lenses?

Started Jun 15, 2014 | Discussions
Anders W Forum Pro • Posts: 21,468
Re: A picture is worth...
3

bobn2 wrote:

Anders W wrote:

Noise can't be "blurred". It's not affected by the optical resolution.

Think about where the noise comes from, then have another go.

I already did. The noise can't be blurred.

 Anders W's gear list:Anders W's gear list
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bobn2
bobn2 Forum Pro • Posts: 62,707
Re: A picture is worth...
2

Anders W wrote:

bobn2 wrote:

Anders W wrote:

Noise can't be "blurred". It's not affected by the optical resolution.

Think about where the noise comes from, then have another go.

I already did. The noise can't be blurred.

Try again

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Bob

Anders W Forum Pro • Posts: 21,468
Re: A picture is worth...
4

bobn2 wrote:

Anders W wrote:

bobn2 wrote:

Anders W wrote:

Noise can't be "blurred". It's not affected by the optical resolution.

Think about where the noise comes from, then have another go.

I already did. The noise can't be blurred.

Try again

No reason. As one would hope you'd know, noise is defined by being perfectly random. You can't make something perfectly random more random than it already is.

 Anders W's gear list:Anders W's gear list
Panasonic Lumix DMC-G1 Olympus OM-D E-M5 Olympus E-M1 Panasonic Lumix G Vario 14-45mm F3.5-5.6 ASPH OIS Panasonic Lumix G Vario 7-14mm F4 ASPH +28 more
Glen Barrington
Glen Barrington Forum Pro • Posts: 20,023
Re: I found this video helpful
1

Levan wrote:

Glen Barrington wrote:

https://www.youtube.com/watch?v=DtDotqLx6nA

This video, while being correct, is very missleading for a begginer. It tells the truth, but not all of it. The reason, at least for me, is uknown. Beware, if you don't have enough information already.

Saying it is incomplete without saying HOW it is incomplete seems unfair to the OP and to us all.  How is it incomplete?

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Just another Canon shooter
Just another Canon shooter Veteran Member • Posts: 4,691
Re: A picture is worth...
1

Anders W wrote:

Nice spin. Now, show me how the m43 cameras compare.

Neither necessary nor possible. I don't how comparable test shots suitable for the purpose. A DR difference is a DR difference. And my example shows what such differences imply. Simple as that.

"Your examples" show what 4x the difference can imply. Simple as that.

Noise can't be "blurred". It's not affected by the optical resolution. The E-M1 shows less noise.

Of course it can, it is called NR, which can be done after the demosaicing, or incorporated in the demoasicing algorithm. Shot noise is of Poisson type, even on a Bayer sensor. If we make it B&W for simplicity, it has a well defined structure and spectrum. Missing high frequencies with the low frequencies present is an evidence of blurring, or NR, or call it whatever you want.

Go to ISO 100. The deep blue square has more blurred borders compared to the others. Look at the 6D crop - no such thing.

The borders are a matter of resolution. Note what I already said about the E-M1 shot not being appropriate for judging resolution.

Resolution magically changes from one color to another? It is not impossible and it might be lens related, in principle, but combined with the predominantly low frequency noise in the deep blues is a very strong evidence of selective NR for that color. Lens aberrations cannot change the structure of the noise of a uniform target.

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bobn2
bobn2 Forum Pro • Posts: 62,707
Re: A picture is worth...
3

Anders W wrote:

bobn2 wrote:

Anders W wrote:

bobn2 wrote:

Anders W wrote:

Noise can't be "blurred". It's not affected by the optical resolution.

Think about where the noise comes from, then have another go.

I already did. The noise can't be blurred.

Try again

No reason. As one would hope you'd know, noise is defined by being perfectly random.

Wrong way round, Anders. Noise is modelled as a Poisson process. The actual noise depends on the random arrival of photons and that in turn depends on the distribution of the photons.

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Bob

Anders W Forum Pro • Posts: 21,468
Re: A picture is worth...
2

Just another Canon shooter wrote:

Anders W wrote:

Nice spin. Now, show me how the m43 cameras compare.

Neither necessary nor possible. I don't how comparable test shots suitable for the purpose. A DR difference is a DR difference. And my example shows what such differences imply. Simple as that.

"Your examples" show what 4x the difference can imply. Simple as that.

Exactly. So feel free to detract three quarters of the difference.

We had a poll here recently where two anonymous images were pitted against each other. One had a one stop advantage for SNR at 18 percent and the other had a one stop advantage for DR, but the poll participants didn't know anything about that in advance. The question asked was:

Which picture has higher image quality as far as noise is concerned?

What do you think the verdict of the poll participants was?

Noise can't be "blurred". It's not affected by the optical resolution. The E-M1 shows less noise.

Of course it can, it is called NR,

NR blurs the detail. It reduces the noise.

which can be done after the demosaicing, or incorporated in the demoasicing algorithm. Shot noise is of Poisson type, even on a Bayer sensor. If we make it B&W for simplicity, it has a well defined structure and spectrum. Missing high frequencies with the low frequencies present is an evidence of blurring, or NR, or call it whatever you want.

So are you saying that ACR secretly applies more NR to the E-M1 than to the other cameras although the NR sliders are set to zero in all cases?

Go to ISO 100. The deep blue square has more blurred borders compared to the others. Look at the 6D crop - no such thing.

The borders are a matter of resolution. Note what I already said about the E-M1 shot not being appropriate for judging resolution.

Resolution magically changes from one color to another?

It does not need to do that in order to blur the border.

It is not impossible and it might be lens related, in principle, but combined with the predominantly low frequency noise in the deep blues is a very strong evidence of selective NR for that color.

See my question above?

Lens aberrations cannot change the structure of the noise of a uniform target.

Right. That's one thing I had in mind when I said noise can't be blurred.

 Anders W's gear list:Anders W's gear list
Panasonic Lumix DMC-G1 Olympus OM-D E-M5 Olympus E-M1 Panasonic Lumix G Vario 14-45mm F3.5-5.6 ASPH OIS Panasonic Lumix G Vario 7-14mm F4 ASPH +28 more
Levan Regular Member • Posts: 265
Re: I found this video helpful
1

Glen Barrington wrote:

Levan wrote:

Glen Barrington wrote:

https://www.youtube.com/watch?v=DtDotqLx6nA

This video, while being correct, is very missleading for a begginer. It tells the truth, but not all of it. The reason, at least for me, is uknown. Beware, if you don't have enough information already.

Saying it is incomplete without saying HOW it is incomplete seems unfair to the OP and to us all. How is it incomplete?

Sorry folks for late response.

As for the answer, put everything aside, it comes to statistics, while not only this.

Ok. Let me put it this way And this is one of the examples.

after watching this video 12 amatuer photographers contacted me and asked about it. They suggested, that 2.8 apperture on m4/3 equals to 5.6 on FF not only in terms of DOF, but in terms of exposure also.

In this video Tony explains the total light gathering ability of the sensor, but never mentions, that smaller sensors need less light to get the sensor exposed. He did not explain it the way, the begginer would understand. Only people who I saw understood his video the right way, are those who knew all this details even before watching the video. All the rest of the users were confused and felt really cheated.

non of the manufacturers claimed, that their 12-35 2.8 lens is the same as 24-70 2.8 FF. Only thing they claim is 12-35 (FF eq. FOV 24-70).

this lenses are not 24-70 2.8, nor 24-70 5.6. They are 12-35 2.8 with FF eq. FOV of 24-70.

All in all, none of the begginer photographers around me (and there are plenty of them) understood the video the right way. For them, this video was more confusing, than the marketing claims of the manufacturers mentioned by Tony as "cheaters".

P.S. This is only one example.

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A photographer, who observes the world only TTL, can be a good craftsman, but not an artist.

Anders W Forum Pro • Posts: 21,468
Re: A picture is worth...
2

bobn2 wrote:

Anders W wrote:

bobn2 wrote:

Anders W wrote:

bobn2 wrote:

Anders W wrote:

Noise can't be "blurred". It's not affected by the optical resolution.

Think about where the noise comes from, then have another go.

I already did. The noise can't be blurred.

Try again

No reason. As one would hope you'd know, noise is defined by being perfectly random.

Wrong way round, Anders. Noise is modelled as a Poisson process. The actual noise depends on the random arrival of photons and that in turn depends on the distribution of the photons.

Sure. I said defined (i.e. modeled) didn't I. So what?

 Anders W's gear list:Anders W's gear list
Panasonic Lumix DMC-G1 Olympus OM-D E-M5 Olympus E-M1 Panasonic Lumix G Vario 14-45mm F3.5-5.6 ASPH OIS Panasonic Lumix G Vario 7-14mm F4 ASPH +28 more
Just another Canon shooter
Just another Canon shooter Veteran Member • Posts: 4,691
Re: A picture is worth...
1

Anders W wrote:

Noise can't be "blurred". It's not affected by the optical resolution. The E-M1 shows less noise.

Of course it can, it is called NR,

NR blurs the detail. It reduces the noise.

It reduces the noise by blurring it. The noise in the deep blue has very non-Poisson structure, as simple as that.

which can be done after the demosaicing, or incorporated in the demoasicing algorithm. Shot noise is of Poisson type, even on a Bayer sensor. If we make it B&W for simplicity, it has a well defined structure and spectrum. Missing high frequencies with the low frequencies present is an evidence of blurring, or NR, or call it whatever you want.

So are you saying that ACR secretly applies more NR to the E-M1 than to the other cameras although the NR sliders are set 0 in all cases?

You cannot separate demosaicing from NR. The old ACR process, for example, has "hidden NR" in it, by your logic.

Go to ISO 100. The deep blue square has more blurred borders compared to the others. Look at the 6D crop - no such thing.

The borders are a matter of resolution. Note what I already said about the E-M1 shot not being appropriate for judging resolution.

Resolution magically changes from one color to another?

It does not need to do that in order to blur the border.

It blurs one border but not another, while the camera next to it does not do that.

Lens aberrations cannot change the structure of the noise of a uniform target.

Right. That's one thing I had in mind when I said noise can't be blurred.

But processing can.

 Just another Canon shooter's gear list:Just another Canon shooter's gear list
Canon EOS 5D Mark II Canon EF 15mm f/2.8 Fisheye Canon EF 35mm F1.4L USM Canon EF 50mm f/1.2L USM Canon EF 135mm F2L USM +4 more
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