Full Frame v Crop Factor issue?

Gilly B

Gilly B

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Gillian
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Maths was never one of my strong points, and the modern technology associated with photography gets the better of me - most of the time. The advice I am looking for from you pros will hopefully help me understand which lens I should have used yesterday.

I photographed a group of people (36) as a family portrait and overall was quite happy with the results. I used both cameras set up as follows:-

5D fitted with 24-105mm L and ISO 100, and my 20D fitted with 50mm 1.4 ISO 100 and 580EX on both camera with the wide angle screen down.

I took the first 5 shots not too far away from them and varied the distances in each shot between 32mm up to 65mm.

I then swapped cameras and had to walk right back to fit everyone in (as I expected due to the crop factor) and preceded to take the other 6 shots.

When I loaded them into my PC and going through the process of reviewing them, I simulated a 20"x16" crop and printed out 1 image from each camera to compare the resolution. The results have left me puzzled - as the faces on the image taken with the 20D are much larger and very clear as opposed to the image from the 5D at 65mm cropped to 20"x16" which is smaller and not that clear on the faces.

Could someone point me in the right direction as to which camera should have had the 50mm and which should have had the 24-105? :shrug: I have a wedding on Saturday, and whilst my confidence is growing by each event, I am keen to get it right in camera and not rely on PS just because I shoot in RAW.

I hope I have made sense above. I understand what I mean, I hope you peeps do too. Gillian

I will post an example in a mo...
 
1). 20D 50mm 1.4

IMG_7811-TP.jpg


2). 5D 24-105mm L

IMG_0104-TP.jpg
 
Can't say I completely understand the question :)

I can see they are cropped from the cameras 3:2 to a 5:4 ratio. Is the 5D shot full width as shot and just cropped top and bottom? And as there is no exif - what focal length?
 
Doh! I knew I wouldn't be able to explain this properly Robert - sorry!.

1). is at 50mm and cropped on screen to the finished size customer asked for - which won't work, as I have chopped the end few people off. So I won't be using that image!.

2). is at 67mm and cropped the same size etc as above. The only thing that is missing is a tiny bit of scenery from either side of the end people and top and bottom as you thought.

For some reason, I expected the 5D FF to be a better quality than the 20D and it is not. That's my dilemma. It is a little unfair for you as you are unable to see them close up or printed out like I have here.

Any help to understand, would be gratefully appreciated.
 
....Orrrr, as brain ticks over, is it the quality of the lens irrespective of half or FF sensor - I dunno:shrug:
 
Gilly B said:
as the faces on the image taken with the 20D are much larger and very clear as opposed to the image from the 5D at 65mm cropped to 20"x16" which is smaller and not that clear on the faces.
Click to expand...

If I crop the 5D shot to as many people wide as the 20D one and resize it back to 800 pixels then the size of the people (and faces) is the same.

5d_crop_and_resize.jpg


Gilly B said:
When I loaded them into my PC and going through the process of reviewing them, I simulated a 20"x16" crop and printed out 1 image from each camera to compare the resolution.
Click to expand...

Do you mean you cropped the original picture in a 5:4 ratio and printed it or are you doing something else? Just wondering if you are messing about with dpi settings or something.
 
Perhaps I am just thick, Robert. (Janice usually interjects at this point when I use the word 'thick')

What I did was to take the two images and just crop them both to 20"x16" (within the crop tool markers). Once cropped, I usm'd them both the same and printed out both images, as if they were going to printed out at 20"x16" by telling my (A4 Canon i965) printer not to fit to paper. Therefore, it only printed a section of the 20"x16" on a sheet of A4 paper. It was when I compared them side by side, the clarity and overall look was far superior from the 20D and 50mm combination.

Are you saying Robert, that had I started with exactly the same 'distance' images, then the result of performance, once cropped would be the same?

If so, then that answers my query entirely. I am female, and sometimes been accused of looking for something that is not there to start with. I just need to understand :shrug::popcorn:
 
Gilly B said:
I am female, and sometimes been accused of looking for something that is not there to start with.
Click to expand...

Us females are aways prone to that!!! :naughty: :D :lol:
 
I dont get your question either, sorry :shrug:

As far as quality is concerned, you've put the sharpest lens on the wrong camera. There will be a marked difference in IQ beween a zoom and a very good prime (excluding maybe the 70-200). Also, your 5D will pick up all the soft edge issues on the 24-105. Its a great lens, but not suited to people.

Zoomig with your feet is the way to go. With the 5D and the 50mm you can get a fair mount of empty space around your target and then crop to the customers wants.

Did that go anywhere near answering the question i didn't understand?

;)
 
you're at a higher level of magnification after the crop factor has been counted witht e 20D/50mm combination than 5D/67mm; its about 80mm effectively. That could account for the result you see, in fact (and oddly enough you might think) the first thing I noticed was the difference in how the backgrounds appear, that the 5D is essentially 15mm 'wider' than the 20D I'd have thought the 20D's image would have greater subject fill...
 
Jonnyreb said:
I dont get your question either, sorry :shrug:

As far as quality is concerned, you've put the sharpest lens on the wrong camera. There will be a marked difference in IQ beween a zoom and a very good prime (excluding maybe the 70-200). Also, your 5D will pick up all the soft edge issues on the 24-105. Its a great lens, but not suited to people.

Zoomig with your feet is the way to go. With the 5D and the 50mm you can get a fair mount of empty space around your target and then crop to the customers wants.

Did that go anywhere near answering the question i didn't understand?

;)
Click to expand...

What d'yer mean, you didn't understand the question grrrrrr! You're a man, you are meant to know what we ladies mean or just agree anyway.:bang: :lol: :lol:

Jonny R - You have just answered my question. My hubby is in his workshop :bang: :bang: :bang: against the wall, 'cause he can't help me either.

That's what I wanted to hear. So on saturday for the wedding, put the 50mm on the 5D and use the 24-105mm on the big group shots. Phew! I got there, Janice. Why don't men understand us:shrug:

Thanks everyone :thumbs:
 
nothing to do with the question, because I wouldnt have the slightest clue.

But to me it looks like the crop is closer on the first one so the face woudl be bigger, and also it appears that you have croppped one person of the each side on the first one.

If you look on the first to the left the lady with the dark blue and white dress and the dark hair is cut half way through and the blonde lady behind her is gone altogether (assuming she didnt just move of course)

perhaps it would have been a better test to crop them both to the same points and ratio and then compare the results?
 
Bolerus - I know, I know you are right. The above images are different lengths. ...and yes, they are about 4 people altogether cropped off - purposely. You see, I used the crop tool of 20x16 which was pointed out above that it was impossible to fit everyone in. I just did it to see h ow clear the faces would be cropped that large.

I stand by my very first post - "Maths was never one of my strong points, and the modern technology associated with photography gets the better of me - most of the time". :lol:
 
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