50mm difference on 30d and 5d?

catchpole_11

catchpole_11

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Chris Catchpole
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I'm currently using a Canon 30d. I've had it for a year and its been very reliable. I'm thinking about getting either a fixed legth 50mm, 85mm or 100mm for general street/portrait photography.

I've always been confused as to how the focal length/crop changes from a small sensor to a full frame sensor.
My question is... if i get one of these lenses how will the focal length change if i was to upgrade from the 30d to a full frame 5d (or its upgrade :) ) in the future?

Thanks, Chris
 
Being all techy geeky here but the focal length does not change at all, it's the field of view that changes because the chip in the 30D is smaller. (oh how I wish I could draw a diagram right now!)

Take a lens, draw it on a piece of paper and it still focuses at the same point, it's just the recording device (chip) that changes size. 35mm and the 5D are the same size so 50mm has the same field of view on either. On a 30D with the chip being smaller it records what is an equivalent to 80mm, not focal length, but field of view.

Have I just complicated things?
 
You would get more pixels for the same field of view on the 30D than the 5D basically....so gives the impression that you are closer to the subject than you are.....I think thats the basics of it!
 
It just so happens I am getting a 5D delivered tomorrow. I'll do a test shot with my 50mm on my 30D and the new 5D to show you the difference. I'm so excited about it turning up, it feels like Christmas.
 
thanks guys. I'll be honest that has confused it slightly for me. So I would appreciate seeing the difference in real images (thanks ranarama)

From what i understood it sounds as if the focal length will be the same, but there will be more/less image to see in the same photo? AliB says that..... "a 30D with the chip being smaller it records what is an equivalent to 80mm, not focal length, but field of view." are you saying it still has a 50mm focal length but the field of view is equivalent to that of an 80mm lens?

if this is the case then that wouldn't be too much of a problem when switching between cameras. But like i said it would be good to see it in real images.

Now i have to decide what focal length I will suit my needs!
 
Spot on that man!

I've got a 20D and a 5D and it took me a while to get my head round it. I think that is why people always talk in equivalency terms. 50mm=80mm etc.
 
Found this on another forum, this should give you an idea the difference between what each sensor will capture

ffcrop.jpg


sensor.jpg


Hope this helps
 
More info HERE

Mike.
 
I did an experiment a while ago to answer this same question :)


50mm on a 5D

Playground-5D.jpg



50mm on a 30D

Playground-30D.jpg



Both these shots were taken standing in exactly the same place, using the same lens (24-105L) at 50mm, swapped between my 30D and 5D.

A few other focal length comparisons in this thread ;)

HTH :)
 
wow, i didnt realise the difference was that dramatic!!
helped me understand more too!
thanks guys
 
Looks like I've been beaten to it!

The 5D arrived this morning :D but I had to go to work shortly afterwards :razz:. It's just superb from what I've seen of it. That viewfinder is huge and my 24-70 just seems so much more right for it than it was on my 30D. I think the 70-200 will be staying on the 30D from now.
 
Enjoy! I love my 5D, the image quality is just fabulous. I hope you have many years of taking fab pics with it.
 
big difference in the DOF control - on full frame it will be much shorter when the shot composed equally and from the same point, because the actual focal length is much longer and the DOF is inversly proportional to the focal length.
 
I must admit that I'm confused as the landscape example shows the focal length as the same and the field of view different. however, the playground example makes it appear that the 1.6 camera did zoom in further. which one is correct?
 
hi shadow, it hasn't zoomed in. It is the fact that the bit around the edge is simply missing, and the photos has been sized the same overall - i.e. the second shot is blown-up. This is why the circle of confusion is smaller for crop factors too, since the resultant images are blown-up more in order to get to the same size as a FF print would have been.
 
That makes sense so as the images are the same size so perceived size is larger. Cheers.
 
This was the thing that put me off going digital for a long time. I was in Grays of Westminster a few years ago, whilst a customer was buying a D1 or some other early Nikon model. The assisant casually mentioned that all his lenses would effectively increase focal length by 1.5x, and I remember thinking that was a major drawback.

I'm a happy 5D user now, so 50mm stays 50mm :)

A.
 
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