?: EOS R5 vs. EOS R3 low light, high ISO image quality

[greyhoundrick]

Hello!

Longtime professional photographer here and going on 5 years shooting with Canon! 

I shoot mostly weddings, events, graduations and headshots professionally and also love to shoot birds in flight for fun.

I currently have an R5 Mark ii and an R5. When shooting in low light I see a little more noise on the R5M2 vs. the R5 which Im sure is a result of the stacked, BSI sensor. However, the R5M2, for me, has been an absolute joy to use!

I am considering trading in my R5 for a used R3 and am interested in your opinion as to whether or not I will notice a fairly big improvement with low light and high ISO image quality. In the low light shoots I have I will shoot as high as 25600 ISO but most of the time 6400 to 12800.

Thank you very much for your input and I appreciate you time and expertise!

best to you,

Rick 

[shadowsports]

Greetings,

The short and sweet of it.  The R3 can outperform the R5 in low light after about 1,000-1600 ISO.  It just improves from there.  The R3 has much less pixel density and larger photo sites.  YouTube has numerous videos on this topic.  Reviews claim 2/3rds to 1 stop additional low light performance between the two body's.  If you are ok with 24MP and have an R5 mkII, the R3 sounds like a welcome upgrade for your R5.

[NatalyaP]

Greetings greyhoundrick,

I would agree with shadowsports. Both camera bodies have a full frame sensor but the EOS R3 has a lower pixel count compared to the EOS R5 Mark II camera. This allows for larger pixels on the EOS R3 which are able to capture more light which results in less noise compared to the EOS R5 Mark II camera at the same ISO setting.

[greyhoundrick]

Thank you very much for your input! 

Quick question..... Why would a larger photo cell capture more light than 2 smaller photo cells if the Toal size of the 2 cells were equal to the 1 cell? I would think that the 2 sensors would capture the same amount. 

[shadowsports]

Greetings,

This has to do with pixel density and the size of the photo sites.  The surface area of the single larger site captures photons of lights more efficiently.  This is how visible light is measured.

[wq9nsc]

The single larger photosite is more efficient in terms of light collection and lower added noise from the sensor.  Binning is a process used to combine adjacent photosites to improve low light performance, particularly in space photography.

When you compare two sensors using the same generation and type of technology, the one with fewer and larger photosites is going to provide better low noise performance.  But since you do wedding photography, you will need to consider whether the R-3 will offer sufficient pixel density for very large prints which the R5 series does very well when there is sufficient light.  For high school homecoming games, I will bring one of my 5DS bodies to shoot the homecoming court but it wouldn't work for the action shots.

I shoot primarily sports and I love my 1DX III bodies with their 20 MP sensors which do a wonderful job in low light.