If you're bored, with a bit of time on your hands.......

[Groupcaptainbonzo]

O.K. heres one for you.

If I attach a 300mm (or any other) lens to an EOS 5D MkII, (full frame, Image size 5616 X 3744), and then take a picture of a scene.

I then attach the same lens to an EOS 7D (APS C , image size 5184 X 3456) and I then take the same picture, of the same scene.

we all know that if I print both images un re-touched at A4, the resultant image will cover a larger angle of view with the EOS 5D MkII than that of the EOS 7D, the object of the image (Let's say a farm house in the dead centre) will appear larger in the image from the EOS 7D than the one from the EOS 5D MkII ( the apparent 1.6X crop factor or whatever way you refer to it) .

But, if I then crop the image from the EOS 5D MkII so that the borders of that image include exactly the same items in both images (so that at first sight to a casual observer they appear to be two prints of the same image), in which image will the "Farm House" have the best deffinition?

(Hi pigeons, here is a cat I prepared earlier ...).

 

[bazooka]

I don't know about the 7D, but I've been meaning to try this experiment on my 40D and 5dmk2. Does my 40D make a better x1.6 teleconvertor than the crop tool in photoshop on a mk2 image?

 

[Robin Usagani]

Good question.. If you only crop the 5DII file by 1.6, I would say the 5D will have better photo. If you try to crop it a lot more then probably the 7D is better. But I pull this out of my ass. I could probably be way wrong.

 

[EIngerson]

I say equal with proper exposure. I wish I had the gear on hand to do a test.

Cool idea.

 

[KenC]

No one who isn't a pixel peeper could see any difference.

 

[KmH]

It doesn't much matter what the focal length of the lens is.

FX = the 5D MKII....DX = the 7D

1.5x crop is close enough to 1.6 crop for illustration purposes.

 

[Destin]

Whichever one has a higher resolution left after the crop, assuming both were taken at the same exact camera settings and low iso's.

I'm too lazy to figure out which it would be though, because it really doesn't matter to me. But if you took the 5dII images and cropped them by 1.6, is it going to have more pixels left then the SOOC 7d image? Can shooters who know the specs, you tell me! I don't even know how many megapixels each body is to begin with.

 

[Robin Usagani]

You completely missed his question.. but ok.

It doesn't much matter what the focal length of the lens is.

FX = the 5D MKII....DX = the 7D

1.5x crop is close enough to 1.6 crop for illustration purposes.

 

[DiskoJoe]

MORE PIXELS = BETTER CROPPING

 

[usayit]

I don't think there will be any real world difference. You may see a difference in large prints simply because the 7D's resulting image will have more data to work.

Two cameras of mine with essentially the same exact sensor specifications (same pixels per inch) with one being a 1.3x versus a FF. Both use the same set of lenses. I don't see any obvious indication that one resolves more detail then the other. Of course, its not like I ran tests to prove or disprove.

 

[MLeeK]

Neither. you'd be cropping the 5d2 image to 5184 X 3456

 

[Groupcaptainbonzo]

Neither. you'd be cropping the 5d2 image to 5184 X 3456

Good point. As obvious as it is (After you pointed it out) I missed that one...

 

[Judobreaker]

Actually I think the EOS 7D will have a higher resolution.

Facts:

EOS 5D MkII:
Sensor size: 36 x 24 mm
Sensor pixel size: 5616 x 3744
Pixels per mm: 156 (5616 / 36 || 3744 / 24)

EOS 7d:
Sensor size: 22,3 x 14,9 mm
Sensor pixel size: 5184 x 3456
Pixels per mm: 232 (5284 / 22.3 || 3456 / 14.9)

Now if we want exactly the same object in the photos that would mean we have to crop the 5D photo to the same size as the 7D.
Basically this means cropping 36 x 24 mm to 22.3 x 14.9 mm.You can then simply calculate it's resulting pixel size by multiplying the mm with the pixels per mm.
That would be (22.3 x 156) x (14.9 x 156) = 3478 x 2324.


Resulting images:
EOS 5D MkII: 3478 x 2324
EOS 7D: 5184 x 3456


Unless I made some calculation mistake I think this means the 7D results with higher resolution.

 

[Garbz]

To make the calc easier, the pixels in the cropped area of a sensor is given by the following formula: Cropped_Pixels = Original_Pixels / (Crop_Factor)^2

So the 7D is a 21mpxl camera.
The 5DmkII is a 21mpxl camera.
The 5DmkII cropped to the same size as a 7d: 21 * 1.6^-2 = 8mpxl

Assuming the resolving power of the lens is up to this hard task the 7D would have the better quality. This is one of the reasons camera with a smaller crop factor are great for wildlife photography, and I'm secretly jealous of my girfriend's Olympus

 

[usayit]

I'm secretly jealous of my girfriend's Olympus

There are a bunch of new old stock olympus cameras on sale..... epl1 for $199 localled for example... slow AF and clunky UI but hey... dont be jealous just get even. lol