7D vs cropped 5d III = same image???

I heard something in another post that made me wonder if it is true. The poster said that you don't really need a 7D for reach because you can just use a 5D III and crop the image to get the same result as the 7D without crop.

Is that true? Anyone with experience with this? I have a 7D, and want a 5D III to go along with it, however, I would really like to know it this statement is true.

I was the one who said it, I figured it out by accident when I started in photography, check out this thread:
https://photography-on-the.net …/showthread.php​?t=1217121


Haven't you ever wondered why they're called crop cameras?

No
Maths was done in a current thread
"which full frame lense..

5D111 cropped to 1.6 is about 9MP

I apply old known example.
5 D classic FF 12.8MP
cropped to 1.3 (more accurate 1.25) 1DMKII = 8.2 MP
cropped to 1.6 = 5MP (1.6 at the time was 8.2MP)

Crop FF to 1.6 and result is fair bit less than half MP.

maverick75 wrote in post #15871295
I was the one who said it, I figured it out by accident when I started in photography, check out this thread:
https://photography-on-the.net …/showthread.php​?t=1217121


Haven't you ever wondered why they're called crop cameras?

Ears burning ?

EDIT:
Actually, your ears are probably normal temp.
It was Tom in this thread commenting on the 9MP result of cropping 5D3
https://photography-on-the.net …/showthread.php​?t=1294464

The math:
7D = 5184 by 3456 and a sensor 22.3 by 14.9 which yields about 232 pixels per linear mm of sensor.
5DIII = 5760 by 3840 and a sensor 36 by 24 which yeilds 160 pixels per linear mm of sensor.

So, multiplying the 7D sensor size by the 5DIII pixel density you get a image of 3568 by 2378 or 8.49 megapickles.

With that said, the only time it's going to make a difference is if you are cropping a 7D image such as bird photographers do all the time. Then the 7D put a whole lot more pixels on the target or if you are printing large images. Pictures shrunk to web size have nearly all the data tossed away anyways.

All you would have had to do is look up "pixel pitch" for each camera...if the pixel pitch is not the same (which it isn't), then the resulting "cropped" image won't be the same either.

It depends what you mean.

The image from the 7d will have much more pixel density.

However, the image will be the same as the crop. It depends what you limiting factor is and what you are doing with the image. If you are going to crop it even further the 7d may have an advantage depending on the resolution of the lens.

Thanks for the input on this subject guys.

From what I am hearing the 7D will be better for birding etc.

Still want a 5D III for other photography.

5D III as primary, and 7D for backup. What a fantastic pair.

Yup.

They are a great setup together.

gjl711 wrote in post #15871419
With that said, the only time it's going to make a difference is if you are cropping a 7D image such as bird photographers do all the time.

You don't even need to crop a 7D image to get the benefit - if the bird is filling the sensor plane, that's a lot of cropping in a full-frame image (which will be, as noted earlier here, about half as detailed, in terms of total pixels, though the full-frame image should have considerably better than half the horizontal and vertical detail).

This happens to me pretty frequently, actually.

the fact that the 5DIII will soon be able to auto-focus at f8, kinda negates any benefit a 7D may have...you could just throw a 1.4X TC on most lenses to get more pixels on target with the 5D

'cept I've already got a 2X TC on my lens

DreDaze wrote in post #15871842
the fact that the 5DIII will soon be able to auto-focus at f8, kinda negates any benefit a 7D may have...you could just throw a 1.4X TC on most lenses to get more pixels on target with the 5D

Although you could indeed AF at f/8 with a 1.4x extender on the 5DIII, that would limit you to centre-point focusing only, whereas the 7D at f/5.6 would still have 19 cross-type AF points for use, so not quite the same in practice.

Madweasel wrote in post #15872025
Although you could indeed AF at f/8 with a 1.4x extender on the 5DIII, that would limit you to centre-point focusing only, whereas the 7D at f/5.6 would still have 19 cross-type AF points for use, so not quite the same in practice.

why would it be center point only? i thought it would work with all the cross type AF points...