Sensors and Pixels...

[sdkid]

I am looking to replace my trusty 7D MKii...

OK... in the world of surveillance cameras, cramming more pixels onto the SAME SIZE SENSOR is a terrible idea, as it divides the light available and each pixel gets less light. That wonderful 8mp surveillance cam ends up really being worthless at night where a 2mp sensor of the same physical size and same lighting conditions will give awesome quality.

So that leads me to this:
The full-frame sensors in cameras are roughly 36x24 mm. Within that same approximate physical size, a Canon R5 has ~45mp, and a Sony A7R IVa has about 62mp. What are the implications of that? Do the lessons seen in surveillance camera sensors also apply to the sensors in these cameras?

 

[Mark S Abeln]

That isn’t true.

In poor lighting you just need to downsample the 8 MP down to 2 MP, and the result will be less noisy than the 2MP sensor due to the lack of color aliasing by the color filter array; smaller pixels may also be less noisier in general but I can’t explain the mechanism. And in good light you get more detail, so it’s a win for the 8 MP sensor.

 

[jiberlin]

I am looking to replace my trusty 7D MKii...

OK... in the world of surveillance cameras, cramming more pixels onto the SAME SIZE SENSOR is a terrible idea, as it divides the light available and each pixel gets less light. That wonderful 8mp surveillance cam ends up really being worthless at night where a 2mp sensor of the same physical size and same lighting conditions will give awesome quality.

So that leads me to this:
The full-frame sensors in cameras are roughly 36x24 mm. Within that same approximate physical size, a Canon R5 has ~45mp, and a Sony A7R IVa has about 62mp. What are the implications of that? Do the lessons seen in surveillance camera sensors also apply to the sensors in these cameras?

The difference in pixel size between 45mp and 62mp (3:4) is not comparable to the difference between 2mp and 8mp (1:4).

I think the 7D is FSI, and the more modern cameras are BSI. BSI gives a better use of the sensor area (percent of sensor area is active pixel area).

And there are more factors that influence the noise/DR then the pur number of pixel over sensor area.

 

[John Sheehy]

I am looking to replace my trusty 7D MKii...

OK... in the world of surveillance cameras, cramming more pixels onto the SAME SIZE SENSOR is a terrible idea, as it divides the light available and each pixel gets less light. That wonderful 8mp surveillance cam ends up really being worthless at night where a 2mp sensor of the same physical size and same lighting conditions will give awesome quality.

There is no disadvantage to have more pixels, each getting less light, as long as the total light is the same for the entire image or subject.

You may be thinking of 100% pixel views, or what you get if you use nearest neighbor to downsample 8MP to fit a 2K monitor, or you may be thinking of gratuitous NR that the manufacturer does so that the 100% pixel viewer does not gag looking at the magnified noise.

So that leads me to this:
The full-frame sensors in cameras are roughly 36x24 mm. Within that same approximate physical size, a Canon R5 has ~45mp, and a Sony A7R IVa has about 62mp. What are the implications of that? Do the lessons seen in surveillance camera sensors also apply to the sensors in these cameras?

The issues with those two cameras is not pixel size, because smaller sensors with the same pixel size or even smaller have less noise per unit of sensor area. What you are really looking at with those two sensors is compromises in design presented by the challenge of reading out that many pixels at a decent speed without added electronic noise downstream that has nothing to do with pixel size, but pixel rate, and the higher power requirements of a larger sensor. That said, both of those cameras have less noise than 12 and 16MP FF cameras from yesteryear.

 

[John Sheehy]

That isn’t true.

In poor lighting you just need to downsample the 8 MP down to 2 MP, and the result will be less noisy than the 2MP sensor due to the lack of color aliasing by the color filter array; smaller pixels may also be less noisier in general but I can’t explain the mechanism. And in good light you get more detail, so it’s a win for the 8 MP sensor.

Even better to apply a median filter to the 8MP before reducing its pixel count.

Anyone working with raw data in a converter that is going to downsample the image much after conversion would be wise to turn off all converter features that enhance sharpness or detail, and get liberal with NR, and then only sharpen the image at all after the downsampling.

 

[PhotosFlight]

I will let others argue the specifics of your question.

I have the 7D Mark II, the R7, and the R6. The R7 is a little better in regards to noise relative to the 7D MII and that's with a sensor that's significantly higher resolution. But, the R6 is absolutely stunning when it comes to noise. Of course that's at "only" 20 megapixels.

For night sports I use the R6 almost exclusively. You can draw your own conclusions.

 

[John Sheehy]

I will let others argue the specifics of your question.

I have the 7D Mark II, the R7, and the R6. The R7 is a little better in regards to noise relative to the 7D MII and that's with a sensor that's significantly higher resolution. But, the R6 is absolutely stunning when it comes to noise. Of course that's at "only" 20 megapixels.

For night sports I use the R6 almost exclusively. You can draw your own conclusions.

I think if you reviewed all the details of the images, you would find that the only time the R6 had less noise than the R7 is when you were able to use a larger pupil or get closer to the subject. IOW, the angular size of the entrance pupil, as seen by the subject, was larger.

The R6 and R7 add almost exactly the same amount of electronic noise to a given amount of light, and the R7 is at least slightly cleaner than any other Canon FF than the R6, with a given amount of light.

 

[PhotosFlight]

I will let others argue the specifics of your question.

I have the 7D Mark II, the R7, and the R6. The R7 is a little better in regards to noise relative to the 7D MII and that's with a sensor that's significantly higher resolution. But, the R6 is absolutely stunning when it comes to noise. Of course that's at "only" 20 megapixels.

For night sports I use the R6 almost exclusively. You can draw your own conclusions.

I think if you reviewed all the details of the images, you would find that the only time the R6 had less noise than the R7 is when you were able to use a larger pupil or get closer to the subject. IOW, the angular size of the entrance pupil, as seen by the subject, was larger.

The R6 and R7 add almost exactly the same amount of electronic noise to a given amount of light, and the R7 is at least slightly cleaner than any other Canon FF than the R6, with a given amount of light.

 

[Bill Ferris]

As others have pointed out, pixel pitch doesn't determine noise in a photo. Exposure and the surface area of the sensor do.

When choosing an interchangeable lens camera (ILC), I recommend starting by setting a budget and evaluating camera/lens systems based on their compatibility with the specific kind of photography you want to do.

How did you settle on the Canon R5 and Sony A7RIV as you're preferred options? How would they be used?

 

[sdkid]

I am wanting to go to a full frame camera from my aps-c sensor in the 7Dmkii. I want to improve at taking night sky photos. Landscapes, along with Milky way and aurora pics have my attention. Those two higher end (for me) cameras both have very good reviews, though they seem to be catering to the video crowd as much as still photography.

I am now looking much more closely at the Sony A7-iv (minus the "R" and about $1,000 less than the A7Riv). Part of my irritation with Canon is that there is not much for lens choices on the Canon R mount format. Sony was smart to share the specs of their E mount system / electronics with other lens makers.

The point of my post here was to get some technical clarification regarding the Sensor size vs pixel count issue as it relates to making a purchase decision, or even IF it should factor into a purchase decision. I am ultimately not opposed to "upselling" myself to a more costly camera-- but it needs to make sense to me.

 

[sdkid]

It looks like a good portion of the answer to my question is found in this ~8 year old article, which is a very interesting and nerdy-cool level read...

https://www.dpreview.com/articles/5365920428/the-effect-of-pixel-and-sensor-sizes-on-noise/2

 

[JPAlbert]

OP:

What Canon lenses do you have?

EF and EF-s lenses work as naturally on the Canon R cameras as they do on the DSLR's. Some report that they work better with mirrorless.

Coming from the 7Dmk2, you ought to be looking at either the R6mk2 or the R8...

 

[Bill Ferris]

If you move to full-frame for your night sky photography and use lenses allowing you to fill the frame, you'll benefit from a full-stop more total light and less noise.

If you like the Sony lens lineup better than Canon's, that's a solid reason to migrate brands. Based on your comments about third party lens options for night sky work, it seems you prefer what's available in Sony-mount glass, as well.

I'd suggest visiting the Canon and Sony brand forums to ask members who use those products their thoughts on the R5 and A7IV for night sky. Which lenses do they use? What do they like best and least about those systems.

There's also a astrophotography forum, here. You may be able to get very specific feedback about the cameras and lenses you're considering by posting in that forum.

Good luck.

 

[PhotosFlight]

I am wanting to go to a full frame camera from my aps-c sensor in the 7Dmkii. I want to improve at taking night sky photos. Landscapes, along with Milky way and aurora pics have my attention. Those two higher end (for me) cameras both have very good reviews, though they seem to be catering to the video crowd as much as still photography.

I am now looking much more closely at the Sony A7-iv (minus the "R" and about $1,000 less than the A7Riv). Part of my irritation with Canon is that there is not much for lens choices on the Canon R mount format. Sony was smart to share the specs of their E mount system / electronics with other lens makers.

The point of my post here was to get some technical clarification regarding the Sensor size vs pixel count issue as it relates to making a purchase decision, or even IF it should factor into a purchase decision. I am ultimately not opposed to "upselling" myself to a more costly camera-- but it needs to make sense to me.

I took a class this summer in LaPalma on astrophotography. It was held by National Geographic's astrophotographer. He lauded the R6 and one of the Sonys as the two best for Astro. EF lenses were fine as one is always using manual focus.

 

[John Sheehy]

I am wanting to go to a full frame camera from my aps-c sensor in the 7Dmkii. I want to improve at taking night sky photos. Landscapes, along with Milky way and aurora pics have my attention. Those two higher end (for me) cameras both have very good reviews, though they seem to be catering to the video crowd as much as still photography.

I am now looking much more closely at the Sony A7-iv (minus the "R" and about $1,000 less than the A7Riv). Part of my irritation with Canon is that there is not much for lens choices on the Canon R mount format. Sony was smart to share the specs of their E mount system / electronics with other lens makers.

The point of my post here was to get some technical clarification regarding the Sensor size vs pixel count issue as it relates to making a purchase decision, or even IF it should factor into a purchase decision. I am ultimately not opposed to "upselling" myself to a more costly camera-- but it needs to make sense to me.

Sounds like you are thinking about long-but-still-weak exposures. You can not gauge the relative noise of cameras for that purpose by any normal-exposure-time noise comparisons, at all; blackframe noise at 1 minute is very independent of blackframe noise at 1/100. Thermal noise is usually worse with larger sensors.

The 7D2 really isn't all that bad a camera for long exposures compared to FF cameras. It is far better than the 6D. For short exposures, the 6D cropped 1.6x has a little bit less blackframe noise at "normal" exposure times, but at about 9 seconds at room temperature, the 6D is noisier and gets worse the longer the exposure, and even if you normalize the blackframe noise of the entire 6D sensor to the 7D2 sensor, the 6D is noisier after about 40 seconds.

Canon's 32.5MP APS-C sensor is one of the best you can use for long exposures with low dark current noise, AFAIK.

In any event, get advice from people shooting long exposures, if that is your main concern. Most photographers are talking about short exposures when they are talking about sensor noise.

 

[John Sheehy]

I will let others argue the specifics of your question.

I have the 7D Mark II, the R7, and the R6. The R7 is a little better in regards to noise relative to the 7D MII and that's with a sensor that's significantly higher resolution. But, the R6 is absolutely stunning when it comes to noise. Of course that's at "only" 20 megapixels.

For night sports I use the R6 almost exclusively. You can draw your own conclusions.

I think if you reviewed all the details of the images, you would find that the only time the R6 had less noise than the R7 is when you were able to use a larger pupil or get closer to the subject. IOW, the angular size of the entrance pupil, as seen by the subject, was larger.

The R6 and R7 add almost exactly the same amount of electronic noise to a given amount of light, and the R7 is at least slightly cleaner than any other Canon FF than the R6, with a given amount of light.

If you are suggesting that if I crop in on an R6 image to the same dimensions as an R7 image I will not argue the point. I'll take your word for it. But my experience in the field is that I don't have to think about high ISO on R6 images the way I do on R7 images.

Yes, but a shooting environment does not have an ISO. The ISO you wind up with depends on the lens (which is different to take the same photo with different sensor sizes) and the shutter speed, in addition to the ambient light.

There is no practical point in comparing different sensor sizes at the same ISO, because ISO will depend on lens choice, and you won't choose the same optics to take the same photo.

 

[Bill Ferris]

I will let others argue the specifics of your question.

I have the 7D Mark II, the R7, and the R6. The R7 is a little better in regards to noise relative to the 7D MII and that's with a sensor that's significantly higher resolution. But, the R6 is absolutely stunning when it comes to noise. Of course that's at "only" 20 megapixels.

For night sports I use the R6 almost exclusively. You can draw your own conclusions.

I think if you reviewed all the details of the images, you would find that the only time the R6 had less noise than the R7 is when you were able to use a larger pupil or get closer to the subject. IOW, the angular size of the entrance pupil, as seen by the subject, was larger.

The R6 and R7 add almost exactly the same amount of electronic noise to a given amount of light, and the R7 is at least slightly cleaner than any other Canon FF than the R6, with a given amount of light.

If you are suggesting that if I crop in on an R6 image to the same dimensions as an R7 image I will not argue the point. I'll take your word for it. But my experience in the field is that I don't have to think about high ISO on R6 images the way I do on R7 images.

Based on your comments, I'm guessing that, whichever lens you use with the R6, you're either filling the frame or cropping so minimally that you're making good use of the full-frame sensor. That wouldn't be surprising for an experienced photographer who knows the sport and has courtside/sideline access and reasonable freedom to move around and select where you want to be.

 

[jxh]

I will let others argue the specifics of your question.

I have the 7D Mark II, the R7, and the R6. The R7 is a little better in regards to noise relative to the 7D MII and that's with a sensor that's significantly higher resolution. But, the R6 is absolutely stunning when it comes to noise. Of course that's at "only" 20 megapixels.

For night sports I use the R6 almost exclusively. You can draw your own conclusions.

What's missing from many of the comparisons is 'all things being equal'.

There is a theoretical advantage to larger pixels, but there is so many other factors (image processing, construction of the sensor--stacking for example) that affect the outcome that a blanket statement really does not apply.

 

[PhotosFlight]

I will let others argue the specifics of your question.

I have the 7D Mark II, the R7, and the R6. The R7 is a little better in regards to noise relative to the 7D MII and that's with a sensor that's significantly higher resolution. But, the R6 is absolutely stunning when it comes to noise. Of course that's at "only" 20 megapixels.

For night sports I use the R6 almost exclusively. You can draw your own conclusions.

What's missing from many of the comparisons is 'all things being equal'.
There is a theoretical advantage to larger pixels, but there is so many other factors (image processing, construction of the sensor--stacking for example) that affect the outcome that a blanket statement really does not apply.

• This is why I've gone back after a night event where I've used both lenses on both bodies and done a blind evaluation of noise so that I'm not biased. For me the R6 produces better results. In fact I'm often surprised how good they are. The R7 is certainly better than the 7Dii. Ultimately we must be confident in the field with our gear and I'm sure some are comfortable with the R7's performance.

 

[dmanthree]

I am looking to replace my trusty 7D MKii...

OK... in the world of surveillance cameras, cramming more pixels onto the SAME SIZE SENSOR is a terrible idea, as it divides the light available and each pixel gets less light. That wonderful 8mp surveillance cam ends up really being worthless at night where a 2mp sensor of the same physical size and same lighting conditions will give awesome quality.

So that leads me to this:
The full-frame sensors in cameras are roughly 36x24 mm. Within that same approximate physical size, a Canon R5 has ~45mp, and a Sony A7R IVa has about 62mp. What are the implications of that? Do the lessons seen in surveillance camera sensors also apply to the sensors in these cameras?

Forget all that. It's just a distraction. Choose a camera based on the usual traits: image quality, features, handling, etc. If you get bogged down in over-analysing things you'll never actually get a cam.