GBP Notes 11/3/22 – Going Geeky

Geeking Out on Numbers

I sent back the new camera I ordered (a Canon R6) after taking a few shots with it.  Why?  Because I’m a dummy and forget to check out what kind of sensor it uses.  I knew it was a mirrorless camera but I didn’t put the fact that it’s a Full-Frame sensor into my thinking.  In a nutshell, a Full-Frame sensor captures all the image provided to it by the lens whereas a Crop-Sensor camera (like my old Canon 7D Mark ii) captures a portion of the image coming in, essentially magnifying it by 1.6.  To help me understand my choices I put together this little chart:

The camera I currently own is the first one listed.  It’s an 8 year old model so it’s pretty cheap now.  I purchased (then returned) the Canon EOS R6, the third on the list.  The first difference you notice is that it is a Full-Frame sensor.  Full-Frame sensors are typically larger than Crop-Sensor cameras and you can see that easily here (330mm vs 864mm). However, does that compensate for the amount of cropping I often do to get my bird pictures.  Below is a shot of my computer as I crop a picture down to bird size on my current camera (7D):

Now here’s how I would have to crop the same image on the R6.

If the first shot is small (about as small as I can go to get a decent image) the bottom one is pretty extreme.  Note in the chart that both the R6 and the R5 have the same sensor area, so I would have to do some extreme cropping with either of those cameras.

Notice that the sensor size of the 7D and the R7 are the same size – both are Crop-Sensors – so the cropping would be more like the top picture than the bottom one.  However look at the pixel size of both.  The 7D has a pixel size of 4.1µm and the R7 has 3.2 µm (the µ is a micro – a thousandth of a millimeter).  A smaller pixel means a couple of things.  First, more of them can fit on the sensor, increasing resolution.  Second, they don’t capture light as well, which negatively affects ISO and ultimately noise.

So if the R7 has smaller pixels than the 7D, negatively affecting the ISO then why is its ISO range higher (16,000 vs 32,000). The answer lies in the new processor, the DIGIC X.  The processor converts the light hitting the sensor into an image on the SD Card and the newer processors are doing a better job than the processor in the eight-year-old 7D camera.  Similarly look at the ISO range for just the two Full-frame cameras the R5 and R6.  Why is the R6 so much better (104,000 vs 52,000)?  Look at the pixel size – the R6 has the largest pixel (6.6 µm) of the entire group so it handles the light better.

Which brings us to file size, which isn’t really an issue but an indicator.  The R5 has a whopping 45 meg file size – every image takes that much room to store, whereas my old 7D only takes 20.2  Why does the R5 have such a bigger file size than the R6 (45 meg vs 20.1 meg)?  It has to do with the size of the pixels – the R6 has pixels that are 50% bigger than the R5: the smaller the pixel, the more that can be packed in the same space.  Similarly the 7D and the R7 have the same sensor area but the pixel size of the R7 is smaller so more pixels can fit in the same size and the resulting file size is bigger.

In conclusion (yea! say all who have read this far), I don’t want to buy a Full-frame camera.  If I did I would either have to do very small crops or buy a very expensive zoom lens.  I could stick with my current 7D Mark ii but what’s the fun in that?   I met two people on the trail recently that have them and they love them.  Ron Ziglar from GreatBirdPics said he agreed.    I decided to go with the Canon R7 Crop-Sensor camera, so I put my order in!  The only problem is it is on backorder due to a parts shortage.  All that decision-making only to find that they can’t make the thing right now and who knows when they’ll be able to.


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