Same lens on 20D & 1Ds Mark II, diff pic

[crp0499]

I'm working with a 1dS Mark II and a 20 D using a 24-105 F/4L IS USM. I zoomed back as far as I could and took the same picture with each camera in both RAW and jpeg. I wanted to compare the pics and see if I could detect any difference.

As far as picture quality, I could tell no difference. They both looked good to me.

BUT

I captured a larger area with the Mark II. For example, I caught only half the TV on the left and half the door on the right and no ceiling and no floor using the 20D and the 24-105.

With the Mark II, same lens, same zoom (all the way out) I got ALL of the TV, past the TV, half the wall behind it, ALL of the door on the right and the ceiling and the floor.

Can someone explain that for me?

Thanks.

Cliff

[Sonsey]

Basicly, your 20D is a 1.6 crop factor camera, and your 1ds mkII isn't...

...have a read http://www.cambridgeincolour.com/tutorials/digital-camera-sensor-size.htm

[crp0499]

So that's the focal conversion factor referenced in the Mark II specs isn't it? The Mark II specs states that there is no focal conversion factor.

[mrclark321]

http://photography-on-the.net/forum/showthread.php?t=42034

http://photography-on-the.net/forum/showthread.php?t=45388

http://www.photoworkshop.com/canon/EOS_Digital.pdf

There is a wealth of information here please check it out. :)

[Sonsey]

I would say so as I believe the 1Ds is a full frame camera, which means that you 24-105mm lens is just that, a 24-105mm lens. When used on your x1.6 crop factor 20D, that lens effectivly becomes a 38-168mm lens.

:confused: Hope I've explained it correctly :D

[crp0499]

OK, got it. Thanks for the information.

[Jon]

No. Here we go again.

Your 24-105 mm lens is a 24-105 mm lens. Period. Full stop. That's a property of the optics, and can't be changed.

Your 1Ds II has a sensor 24x36 mm. Your 20D has a sensor 15x22.5 mm. If you enlarge the picture from a 1Ds II to make an 8x12 print and you enlarge the picture from a 20D to make a 5x7.5 print (same exact magnification; do the math) and superimpose the 20D print on the 1Ds II print, they'd match perfectly. The only difference between the two is the angle of view/field of view. Perspective is the same. DoF is the same.

Many people take this angle of view and decide that therefore the lens somehow "gets longer" on a "crop" sensor. Really, if you enlarge the 1Ds II picture to the same amount, you'd have the same effective magnification. The only rel difference you'll see between the two is that the 20D has a higher pixel density, so if you enlarge something as far as it'll go, you'll see more detail in the 20D picture. But if you enlarged the picture from a D30 (3 MP, but same sensor dimensions as the 20D), it wouldn't have as much detail as either. But that doesn't make the lens any shorter.

[Eagle]

http://www.cambridgeincolour.com/tutorials/digital-camera-sensor-size.htm

Read and look here.

[spaced]

lol, can of worms

[Sonsey]

No. Here we go again.

Your 24-105 mm lens is a 24-105 mm lens. Period. Full stop. That's a property of the optics, and can't be changed.

Erm, I knew it didn't come out right :confused:

I didn't mean to imply that the lens magicly changes size when on a crop camera :p , just that the view throught it changes due to the smaller sensor on the crop camera... I bet this hasn't come out right either lol, either way I agree with your post :D

[crp0499]

Thanks again for all of the help.

[basroil]

i'de say you really messed up the pre-buying phase of camera/lens purchase. never jump into something until you know what you're getting yourself into. that's usually the first lesson you learn in managment isn't it :rolleyes: as was said in the other treads, don't rush it, get a professional to do the wedding and try to learn the 1ds II by throughly reading the manual first.

[goatee]

Erm, if you read crp0499's posts in that first thread (and others) you'd have read that he bought a couple of 20Ds, for the wedding, and bought a 1DS2 to get to know it, for future work.

crp is experienced in video - could be analogous to a friend of mine who was a grade 8 pianist, and then went out and bought a £1,500 guitar even though he couldn't play - he knew nothing of the technology of guitars, but in a couple of months was very accomplished as he already had the music theory and musical ability - here, we have someone who is experienced in video, so has experience with lighting, and composition, etc, just needs to get up to speed with the technology in photography, but knew he needed pro level equipment.