More about the upcoming high-megapixel EOS R system camera [CR2]

dcm

Good or bad - it's not the gear.
Apr 18, 2013
840
197
If you have a subject moving across the field of view, (a star, to take your example) it will describe an arc across the sensor. For any given shutter speed, that arc will be the same whether you are using a 20MP sensor or a 50MP sensor. So if you use a faster shutter speed on the low MP sensor, won't that also reduce the star trail in the same way?
The arc across the sensors would be the same when measured in millimeters, but not in pixels. In the example I'm comparing star trails of 11 pixels which can be scaled down to 1 pixel. If I want an image with no star trails (a 1 pixel star remains a 1 pixel star), the high MP sensor requires a faster shutter speed to not produce a trail. In my case I need a 2X faster shutter speed on the M6II compared to the 1DXII if I want no star trail using the same lens.
 

Mikehit

EOS R6
Jul 28, 2015
3,308
502
So you are saying that at the same shutter speed, the 1Dx does not produces a star trail but the M62 does ?
Is this the case if you have cropped the 1Dx2 for the same field of view? I ask this because if you have not cropped the 1Dx2 image you are looking at different magnifications (being, APS-C the M6ii will effectively be a crop of the 1Dx2).
Similarly, if you are looking at both images at 100%, you are looking at the M6ii image at a greater magnification than the 1Dx2.
 

Valvebounce

EOS R5
CR Pro
Apr 3, 2013
4,455
348
53
Isle of Wight
Hi Mike.
My understanding is that both cameras will have a star trail however at the same shutter speed the 1DxII will have (about) half as many pixels so viewed at 1:1 the star trail will appear shorter (Due to the lower pixel count?). Not sure what happens at full screen with one being a crop!

Cheers, Graham.

So you are saying that at the same shutter speed, the 1Dx does not produces a star trail but the M62 does ?
Is this the case if you have cropped the 1Dx2 for the same field of view? I ask this because if you have not cropped the 1Dx2 image you are looking at different magnifications (being, APS-C the M6ii will effectively be a crop of the 1Dx2).
Similarly, if you are looking at both images at 100%, you are looking at the M6ii image at a greater magnification than the 1Dx2.
 

Mikehit

EOS R6
Jul 28, 2015
3,308
502
That's my point - viewed at 1:1 there will be a difference because the M611 has more pixels so it is a larger presentation.
Full screen will be the same. It is like cropping out a section of the 1Dxii image then magnifying it to fill the screen.
 

Mikehit

EOS R6
Jul 28, 2015
3,308
502
The arc across the sensors would be the same when measured in millimeters, but not in pixels. In the example I'm comparing star trails of 11 pixels which can be scaled down to 1 pixel. If I want an image with no star trails (a 1 pixel star remains a 1 pixel star), the high MP sensor requires a faster shutter speed to not produce a trail. In my case I need a 2X faster shutter speed on the M6II compared to the 1DXII if I want no star trail using the same lens.
So you what you really mean is that you are taking advantage of the greater pixel density of the M6ii to create a more highly resolved image and give greater cropping ability, and if you want to use that advantage you need a faster shutter speed - that I agree with.
 
  • Like
Reactions: SecureGSM