Not seeing crop factor (EF vs EF-S)

[dhensley]

Hi,

I am having a problem understanding why I am not seeing a difference between EF and EF-S lenses - I am at a loss.

I have a Canon T1I with two EF lenses (28-135 IS USM and a 50mm EF prime lens) and was waiting a long time to compare my lenses to some other wide angle and EF-S lenses. I finally had a chance to do this when I visited my brother this week and was very confused at the results.

I took pictures with the following lenses all set to 50mm (by zooming to that number on the camera lens when needed).

Canon EF 50mm prime
Canon EF 28-135 IS USM
Canon EF-S 18-55
Canon EF 28-50 USM

After taking a photo with each on of these and comparing there is NO noticeable difference in the zoom for each shots. My understanding is that photo from the EF-S lens should look zoomed out and appear that it was shot at a wider angle.

I have repeated this step at 28mm &35mm with all but the prime lens and I keep seeing the same results (all images have the same field of view.

What gives? I was trying to do this to show my brother the difference between EF and EFS lenses. Can anyone help explain why I dont see different results? FYI - I loaded the images on my computer and verified that they shots are all at the right focal (within 1mm) each time.

Thanks,

David

[RichardTaylor]

50mm is 50mm. That's it. The lenses do not make a difference.

However the camera body does.
A full frame camera will have a lot more field of view than a crop camera with the same focal length.

This will give you an idea.
JimDoty.com - Digital Field of View Crop

[dcclark]

It's the camera, not the lens, which determines the crop factor.

The "crop" lenses are designed to work ONLY on crop bodies, meaning, if you put them on a full-frame body, you'd see black edges where the lens doesn't project a large enough image. This makes them cheaper to manufacture.

To see the difference, you'd need to shoot the same lens on 2 different bodies.

[m.c.adams]

As said, 50mm is 50mm, on the same camera. If you put the 50mm on a full frame camera, you'll see quite a difference. On a full frame camera, you get the full 50mm, on a crop sensor camera, 1.6, you'll get the same as a 80mm. Also, the EF-S lens are built a bit different than a EF lens. Trying to use a EF-S lens on a full frame camera, at least on Canon, the rear part of the lens projects out a bit more than the EF type and will hit the mirror when the shot is taken. I hope this helps.
Mark

[Vagebond]

A previous thread has an example of this crop, easier to visualize

Best Lens For portraits