I am bringing the 90D for my Guiding work last week, but due to the special task and low light condition. Plus the High megapixel of the camera , I would say it is not suitable for me use handheld … lack of IBIS high shutter is require so ISO has to push to higher which rarely lower than my acceptable level (<3200)

with the Tripod I managed to test 2 subjects that many of us concern

1. ISO performance of such high megapixel Camera

2. AF especially Liveview tracking ? (do I need ? and we know it is typical way of us Optical Viewfinder of DSLR) but I still test it after saw the performance of A9 + Sony 600mm F4

but here I am sharing ISO performance only

as usual all picture

1. EOS 90d

2. Canon EF 300mm F2.8

3. Canon 14x TC III

4. AV mode

5. remote shooting with phone

6. AF use Liveview tracking all (all sample below)

7. open with Adobe Photoshop CC 2019 (no NR mean no NOise reduction full size with 240 ppi)

8. NR mean use auto setting of Define2

9. I also resize to 2400 at long site to at ~A4 size of print

10. Click the link for Larger size (un crop) picture

11. I add in a SONY A7r4 RAW file No NR and CANON EOS 90D RAW no NR (on software

[both on body high ISO Noise Reduction -Standard]

both 100% crop

ANYONE can tell which is which ?

as below

100% crop above picture

A. ISO100 , No NR

ISO100 , NR

I forgot ISO200 … hmmm so continue with ISO400

B. ISO400 , No NR

ISO400, NR

C. ISO800, No NR

ISO800 , NR

ISO1000-2000 is my common use ISO range so I add on 1250

D. ISO1250, No NR

ISO1250, NR

E. ISO1600 , No NR

ISO1600, NR

F. ISO2000, No NR

ISO2000, NR

G. ISO3200, No NR

ISO3200, NR

H. ISO4000, No NR

ISO4000, NR

I. ISO6400, No NR

ISO6400, NR

J. ISO8000, No NR

ISO8000, NR

I am not really interest on anything more as the details start losing when ISO5000-6400 and at 8000 . the grain is too much for this high megapixel camera

I am overall ok with ISO2000-3200 for small print and as usual web use ..

ISO2000 ~A4 size