Is there a market for an 8mp crop body with excellent iso performance?

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May 31, 2011
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I know the argument with full frame v. crop is that you have a larger sensor so the individual sensor "pixels" aren't as close together and that allows for larger pixels and better low light performance.

So if that is true... do you think that with all the in camera processing we have today that anyone would consider a crop sensor that has full frame low light capabilities at 6400 iso? 8mp is still a decent amount of data and would allow for some cropping, though not as much as a 20+ mp sensor in good light.

I think there are too many people who wouldn't be willing to pay $500 for a camera with ONLY 8 mp.
 
neuroanatomist said:
It's not the pixel size, it's the total sensor area that gives FF the better ISO performance. The 5DII and 20D have the same pixel pitch.

Depends on what you're looking at:

  • If you're looking at the entire picture scaled down, then yes, the total sensor area plays a role because you're binning multiple pixels together in a way that increases the effective pixel size.
  • If you're looking at a crop to the same number of megapixels, the total sensor area is irrelevant. To the extent that the 5DMk2 has better low-light performance than the 20D under those circumstances, the difference is caused by better amplifiers, improvements in the sensitivity of individual subpixels, and other factors.
 
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Downsampling ≠ binning. Binning is summing pixel outputs, which has differential effects on signal vs. noise. Downsampling is averaging pixels, not summing them.

Pixel size does matter...but sensor size matters a lot more.
 
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neuroanatomist said:
Downsampling ≠ binning. Binning is summing pixel outputs, which has differential effects on signal vs. noise. Downsampling is averaging pixels, not summing them.

True, it's not hardware binning, which means you don't get that extra read noise win. That said, I've frequently seen the term binning used both for summing and averaging, both in hardware and software, but if you'd prefer to limit the term to hardware binning, that's fine by me.

The point I was trying to make is that if you take a 5DMk2 image and scale it down to the same size as a 20D image, each pixel on the 5DMk2 image came from a much larger area of silicon than each pixel in the 20D image, hence the SNR improvement from a larger sensor, if everything else is equal, comes from not doing an apples-to-apples comparison. The fact that (AFAIK) folks can see real differences even when pixel peeping tells us that all else isn't equal.

With that said, I agree with you that no, there probably is little to no market for an 8MP camera with good ISO performance. Read noise is getting better every day, and IIRC, the shot noise benefits of lower MP sensors can be achieved just as easily through simple downscaling.
 
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The other argument for a crop sensor is extra reach, and it is often assumed to be x1.6 for APS-C. But, the 1.6 is for field of view. What is important for reach in this case is pixel size, smaller pixels giving better spatial resolution. An 8 MP crop has a 6.4 micron pixel, slightly larger than the 6.25 for the 5DIII. So the 8 MP crop has no advantage for wild life photographers as well as having lower IQ than FF.
 
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jdramirez said:
I know the argument with full frame v. crop is that you have a larger sensor so the individual sensor "pixels" aren't as close together and that allows for larger pixels and better low light performance.

So if that is true... do you think that with all the in camera processing we have today that anyone would consider a crop sensor that has full frame low light capabilities at 6400 iso? 8mp is still a decent amount of data and would allow for some cropping, though not as much as a 20+ mp sensor in good light.

I think there are too many people who wouldn't be willing to pay $500 for a camera with ONLY 8 mp.

An 8MP crop camera with today's tech would perform far worse than a current 5D3. It has about the same density (and even if it was say 4MP in this entire range of densities you don't gain THAT much, like you made an 8MP FF camera it would only do a little bit better at high iso than a 22MP one) anyway so all you'd do is lose 2.56x total light collecting surface area and even compared to a high density 18MP 7D it would only do a tiny bit better than if the same tech were used to make a new 18MP 7D2.
 
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neuroanatomist said:
It's not the pixel size, it's the total sensor area that gives FF the better ISO performance. The 5DII and 20D have the same pixel pitch.

So, to answer your question...no.
Hi,
I had to disagree... the iso performance of the sensor is base on the pixel size and the sensor technology, not the sensor size... 5DII have better ISO performance than 20D is due to the sensor technology and image processing advancement.

For example, if I crop a 5D3 image to the same size as a crop sensor or I create a crop sensor mask and install in a 5D3 camera, will the iso performance suddenly become bad??

Have a nice day.
 
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weixing said:
neuroanatomist said:
It's not the pixel size, it's the total sensor area that gives FF the better ISO performance. The 5DII and 20D have the same pixel pitch.

So, to answer your question...no.
Hi,
I had to disagree... the iso performance of the sensor is base on the pixel size and the sensor technology, not the sensor size... 5DII have better ISO performance than 20D is due to the sensor technology and image processing advancement.

For example, if I crop a 5D3 image to the same size as a crop sensor or I create a crop sensor mask and install in a 5D3 camera, will the iso performance suddenly become bad??

Have a nice day.

What she said.
 
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weixing said:
neuroanatomist said:
It's not the pixel size, it's the total sensor area that gives FF the better ISO performance. The 5DII and 20D have the same pixel pitch.

So, to answer your question...no.
Hi,
I had to disagree... the iso performance of the sensor is base on the pixel size and the sensor technology, not the sensor size... 5DII have better ISO performance than 20D is due to the sensor technology and image processing advancement.

For example, if I crop a 5D3 image to the same size as a crop sensor or I create a crop sensor mask and install in a 5D3 camera, will the iso performance suddenly become bad??

Have a nice day.

Your last sentence (before Have a nice day) is correct. But Neuro is writing about something very different. If you have the exactly the same image on the FF and crop (eg by standing 1.6x further away from the scene or by using a 1.6x shorter lens with the crop), then, all technologies being equal, you would get better signal to noise on the FF because its area is 2.56x greater and it gathers 2.56x more photons.
 
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I think of the 40D as one of the best APS-C cameras in terms of IQ and usability of the camera itself. On the other hand I like the IQ the of 600D in good light (or with tripod "enabled") - not so much the buttons etc. of that camera ...

At the moment I would prefer a 32 Mpix APS-C camera which has a "clean RAW mode" with 8 Mpix consisting of quaduplets of 2 green, 1 red and 1 blue pixels:
[1] 32 Mpix raw for standard scenery with lots of light or a tripod (if feasible).
[2] 8 Mpix raw for low light and critical color conditions (monochrome light sources etc.)

In terms of FF I would prefer a 48 Mpix sensor with a 12 Mpix "clean RAW mode".

So in the end I don't think there is a market for an 8 MPix APS-C camera except ... it has a monochrome sensor with excellent iso performance (missing color filters) and the chance to do classical B/W photography with filters without the limitations of electronic filters in PP.
 
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You have two sensors, one a FF 20M sensor and the other an 8M crop sensor. Both are made with the same technology.... Each and every pixel on the crop sensor has a corresponding identical pixel on the FF sensor.

The physical size of the pixels is identical. They will have the same light gathering characteristics. They will have the same noise. They will have the same depth if field. You will not be able to tell the difference between a picture taken with the crop sensor or the middle 8Mpixels of a picture taken with the FF sensor.

The difference between the two pictures will be that the FF sensor has additional pixels to the sides and gives a wider view, but the central part will be identical.

A lot of people do not understand what "crop" really is. They think of it as a 1.6X teleconverter, a device which changes optical properties such as magnification and depth of field... A crop sensor does no such thing. There is no change to the optical properties of a lens when it is moved from a FF camera to a crop camera. The depth of field stays the same. The focal length stays the same. The F-stop stays the same. There is no magical shape-shifting, a lens is an inert collection of solid materials. What a crop camera does is to sample the central 40 percent of the image at a much higher resolution and to ignore the outer 60 percent.
 
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A plot of Canon vs Nikon DR suddenly appears as the first posting from a new member! Is this a noobie with no knowledge of the DR history or is it the return of the Mikael R?
 
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I saw the pictures that a photographer did with 5D classic, processed with Lightroom, and I was happy with my humble APS-C 18 megapixel. ::) The noise in the shadows of the 5D classic is horrible and looked worse than any Canon Rebel that I have ever used. :( Yes, technology has evolved in the last decade, and with current technology, I believe it is possible to make an 8 megapixel APS-C with ISO 6400 that has performance as good as 5D mark ii. If this hypothetical camera was being sold now I would buy three or four of them. ;) However, I understand that I am a minority, and that this is not a strategy of profitable market for Canon. :-\
 
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ajfotofilmagem said:
I saw the pictures that a photographer did with 5D classic, processed with Lightroom, and I was happy with my humble APS-C 18 megapixel. ::) The noise in the shadows of the 5D classic is horrible and looked worse than any Canon Rebel that I have ever used. :( Yes, technology has evolved in the last decade, and with current technology, I believe it is possible to make an 8 megapixel APS-C with ISO 6400 that has performance as good as 5D mark ii. If this hypothetical camera was being sold now I would buy three or four of them. ;) However, I understand that I am a minority, and that this is not a strategy of profitable market for Canon. :-\

You are mixing several thing here. Shadow noise is mainly read noise. With older cameras, at very high ISO, read noise is worse than say, ISO 1600, which increases the lead of 5D3 vs. 5D2 there, for example. If that is what is important to you, buy three of the D7100. It has slightly better DR at ISO 6400 than the 5D2 (and much better at base ISO). The shot noise however depends on the QE, and there is no crop camera yet that can beat the 5D2, for example.

Comparing formats is a bit tricky because same ISO with different formats does not mean much. For the same DOF, larger sensors do not have better noise performance but have more resolution which helps offset the noise. On the other, if you are shooting wide open on FF, say at 50/1.4, you cannot shoot with the same DOF on crop because there is not such lens. But if you need the DOF, is different, etc.
 
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neuroanatomist said:
It's not the pixel size, it's the total sensor area that gives FF the better ISO performance. The 5DII and 20D have the same pixel pitch.

So, to answer your question...no.

If the sensor size plays such an important role in good ISO performance, then why does most medium format cameras have a really bad ISO performance?
 
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