Which is sharper?

[excal]

Hypothetical thinking just entered my brain...

a) 20D + 300/2.8 IS L + 1.4x
b) 5D + 300/2.8 IS L + 2.0x

Hmmm....

Excal

 

[Parn190423]

My guess would be a) because 2x TC really hampers the image quality whereas 1.4x only slightly decreases it. However if you downsize the 5D image(12MP) to 20D size(8MP), then the result might be different.

--
Kind regards from a DP beginner(350D + S60).
http://www.pbase.com/knight_parn

 

[excal]

My guess would be a) because 2x TC really hampers the image quality
whereas 1.4x only slightly decreases it. However if you downsize
the 5D image(12MP) to 20D size(8MP), then the result might be
different.

But, you project the image 1.6x larger on the film-plane.
Plus, 8.2um vs 6.4um

--
Kind regards from a DP beginner(350D + S60).
http://www.pbase.com/knight_parn

--
Excal

 

[thx1138]

But, you project the image 1.6x larger on the film-plane.
Plus, 8.2um vs 6.4um

????. The image on the 20D sensor is just a reduced FOV version of the that on the 5D sensor.

I think the 5D + 300 f/2.8L IS +2x TC will be sharper, because for an equivalent image size the 5D shot will have more pixels. Lets say a bird fills about a 25% of the frame on the 5D combo, which is a 600 f/5.6L IS. The 20D combo is 672 f/4L IS effective, so the bird fills about (672/600)^2 x 25% = 31.4% of the frame. Now this means in this case the 5D shot has about 4.2MP devoted to the bird, and the 20D has about 2.57MP devoted to the bird. There should be more detail in the 5D shot. Now of course the 2x TC will soften the image compared to the 1.4x TC, so the actual difference might not be huge, but the 5D wins IMO. If you had used the 2x TC on the 20D it would be a lot different, as the bird would have filled 64% of the frame and thus had 5.48MP devoted to it.

So you can see how pixel density affects the equation.

 

[ruzzy196922]

Off Course..... If you used TC 1.4x and 2.0 x, The Sharper is TC 1.4x , No matter your Camera....

 

[Graham_02]

b) will be sharper because a 2x converter is slightly better than upressing from 1.4x

Because the size of the pixels on either camera are smaller than the size of the lens defects with those configurations, they are irrelevant when making the comparison.

If a 300/2.8 + converters was so good that it could focus within a pixel the size of a 5D's, then b) would win again because you get more pixels in your image.

agree? If not, explain why you see it differently.

Hypothetical thinking just entered my brain...

a) 20D + 300/2.8 IS L + 1.4x
b) 5D + 300/2.8 IS L + 2.0x

Hmmm....

Excal

 

[BadtzMaru]

Its not 1.6 times larger.

 

[thx1138]

Because the size of the pixels on either camera are smaller than
the size of the lens defects with those configurations, they are
irrelevant when making the comparison.

If a 300/2.8 + converters was so good that it could focus within a
pixel the size of a 5D's, then b) would win again because you get
more pixels in your image.

agree? If not, explain why you see it differently.

Hypothetical thinking just entered my brain...

a) 20D + 300/2.8 IS L + 1.4x
b) 5D + 300/2.8 IS L + 2.0x

Hmmm....

Excal

As I said B wins, but a 20D with 12.8MP would have been equal to the 5D shot in MP alone and probably sharper due to it using a 1.4x TC not a 2x TC. In this case the uprezzing would not be for size as the 20D image is larger, but for resolution.