*** 5Dc vs 60D resolution test ***

Started Mar 17, 2013 | Discussions thread
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schmegg MOD
Veteran MemberPosts: 5,768
Re: *** 5Dc vs 60D resolution test ***
In reply to Steen Bay, Mar 19, 2013

Steen Bay wrote:

schmegg wrote:

qianp2k wrote:

Might do later. however since my Sigma 150/2.8 OS is a prime so I have to adjust distance between 5D3/5D to 60D to frame into the same AOV as in real world I'd do on a flower for example.

The test involves rendering a very finely detailed subject at 1:1 magnification - that is what macro is.

To do this, you will need to set the lens at the minimum focus distance and then photograph the subject with both cameras to record it at 1:1 magnification.

This way the detail you present for each sensor to record will be identical - and from this it should be easy to see which sensor is able to resolve more of the same available detail, and hence, which camera resolves more detail.

The framing of the two images will be different, so the detail presented for each sensor won't be identical if using the same lens (but it would be, pretty much, if using the 60/2.8 on 60D and the 100/2.8L on FF).

Yeah - perhaps it's my way of trying to describe things that is confusing things here.

Imagine you have a very small creature (not a flower or something large) and you wish to get the most detailed image you can of it.

The way to do this is to select your macro lens (lets assume you only have one - I think that's probably realistic enough for many).

You mount the lens, set it to it's minimum focus distance and then move to the subject until it is in focus. Then take the shot.

Now, if you do this with, say a 5D, and then again with a 60D, you will effectively be recording exactly the same amount of subject detail with each camera (providing you got the subject in the centre and at MFD).

In this case, each camera has recorded the exactly same projected image from the same lens and at the same exposure (if you are doing this as a test). And it should be relative straight forward to compare the images and see which camera sensor resolved more of the detail projected onto it.

Not really needed to make such a comparison. Nobody disputes that a crop camera has more 'reach' (or higher 'magnification') if shooting with the same lens from the same distance (if the crop camera has a higher pixel density).

Peter does - he continues to claim that a 5D out-resolves an 18MP crop.

When he is confronted with the test above - which actually properly compares the resolving capabilities of the two, he avoids it.

He has now done other, and as you hint, possibly more practical (for certain shooting situations - though not all) tests. These are closer but still don't show any advantage in resolving capabilities for the 5D - but the amount of detail the cameras have been provided to record is different, so care should be taken in drawing conclusions regarding his 'out-resolving' claim.

In any case - it would seem to me that the above macro test (or, in fact, any fixed lens/exposure/subject distance test) is the best to settle the truth of the claim that a 5D out-resolves an 18MP crop.

Old Canon 100/2.8 macro (just sold more than I bought, same for 50/1.4 and 17-40L as all those lenses I bought in Dec 2007 - 1st half year of 2008) test shots on 10mp 1D3. I remember you used to try to compare from your old 50D.

Someone else? I've never owned a 50D.

My ones are obviously sharper I believe you cannot separate sharpness from resolution as you cannot separate details from noise. They are related.

I've tried to explain this to you many times now, but, as I've failed on every occasion, I'll have another go ...

Yes - they are related. Sharpness depends on resolution and acutance.

It's possible to have low resolution and high acutance and end up with an image that is perceived to be sharp even though it actually resolves less detail. That's what you have with a 5D compared to a 60D, where the resolution is higher but the acutance is lower.

The big difference between resolution and acutance is that resolution is set at capture time and can only ever be decreased. Increasing resolution after capture involves "inventing" detail ... that is, having a guess at what might have been there.

Acutance, on the other hand, can be altered after capture time by re-sampling to a lower resolution (for instance, 18MP to 12MP) and by post processing sharpening algorithms.

Many feel that it's better to capture with more resolution and lower acutance as the lower acutance can be recovered effectively to a great degree during post processing.

Of course, even better is to capture with high resolution and high acutance. And that's exactly what Canon's 20-odd MP full frame sensors are very good at.

That makes good sense. Worth to remember though that sharpening also increases the noise.

And also worth remembering that noise often increases perceived sharpness.

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