Canon eos 90d vs canon rebel eos sl3

[Hero]

Hello everyone,

I have an astrophotography related question.  I currently have a canon 6d and use a williams optics redcat 51 (250mm), but i am severely undersampled with this setup in regards to pixel scale.  

Formula pixel scale: (pixel size/focal length)x 206.265 

i have a t4i which has smaller pixels, but i am trying to look for a newer model that offers a better sensor and processor.   I am very interested in the eos 90d and sl3.  They both are crop sensors which i think would help with my reach in regards to equivalent focal length.  The pixel scale of the sl3 is about 3.07 arc sec/ pixel and the eos 90d is about 2.68 arc sec/ pixel.  I am just wondering given average seeing conditions which one of these cameras would be best?  I have found a new 90d body for 1200 bucs and the sl3 body for about 650 bucs.   I would mainly be doing single shot imaging.  Is the 90 d worth the extra cost or would i be able to get by with the much cheaper sl3. 
i have had great success with canon dslrs for years and i hope one of these 2 cameras will continue that.

i look forward to any opinions or responses i can get   If you need more info i can offer that too since this is somewhat of a complex subject.

thanks. 
chris 

[Mark35mmF2]

Hi,

Based on what you are describing, specifically that the smaller pixel pitch is what will give better results with your accessories/filters, then the EOS 90D would likely provide better results, but I might also contact the manufacturer of the filter in case they have specific testing samples for each model. Based on the numbers given I would guess that the results will be similar but when it comes to the most detail on the pixel level the EOS 90D would probably have an advantage.

Another possible option if you wanted to stay within a full frame image sensor would be the EOS 5DS which you might be able to find for a similar price used, although this camera is not known for stellar performance at higher ISO ratings, or the mirrorless EOS R5 which performs very well at high ISO ratings and would likely have a similar pixel size to the EOS Rebel SL3 (45mp on a full frame sensor = approx. 22.5mp at APS-C size, EOS Rebel SL3 = 24mp at APS-C) but this camera is still fairly new and a more premium product so the price will be much higher and you would still see larger pixel photosites than the EOS 90D.

[Crews69]

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@Hero wrote: WestPennPower

Hello everyone,

I have an astrophotography related question.  I currently have a canon 6d and use a williams optics redcat 51 (250mm), but i am severely undersampled with this setup in regards to pixel scale.  

Formula pixel scale: (pixel size/focal length)x 206.265 

i have a t4i which has smaller pixels, but i am trying to look for a newer model that offers a better sensor and processor.   I am very interested in the eos 90d and sl3.  They both are crop sensors which i think would help with my reach in regards to equivalent focal length.  The pixel scale of the sl3 is about 3.07 arc sec/ pixel and the eos 90d is about 2.68 arc sec/ pixel.  I am just wondering given average seeing conditions which one of these cameras would be best?  I have found a new 90d body for 1200 bucs and the sl3 body for about 650 bucs.   I would mainly be doing single shot imaging.  Is the 90 d worth the extra cost or would i be able to get by with the much cheaper sl3. 
i have had great success with canon dslrs for years and i hope one of these 2 cameras will continue that.

i look forward to any opinions or responses i can get   If you need more info i can offer that too since this is somewhat of a complex subject.

thanks. 
chris 

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This will be an interesting match up as even though these two cameras doesn't have the exact same body type, they are both ranked amongst Top 10 cameras in their classes

[ebiggs1]

I would have no hesitation and get the 90D. It is the best crop sensor camera Canon ever made. The sensor is just one part of the camera. However, in this case both cameras are pretty equal. Both cameras have an APS-C sensor, but their sensors differ slightly in size. The sensor area in the SL3 is 2 percent smaller. If I remember correctly, I believe DXO Mark did IQ tests on both.

The 90D is weather sealed. The SL3 is not. The 90D is a little newer than the SL3. The 90D is a bit bigger and to me that is a plus. The SL3 is just too small, IMHO.