Good exemples of the DoF difference between FF and crop.

Here a test made on Nikon that show the DoF difference between equivalent situations (50mm on crop, 85mm on FF, 85 on crop, 135 on ff)

http://tonycorrea.com …portrait-lens-comparison/

Have fun!

I knew there was a difference, but that's more than I was expecting.

kinda double...

However if you prefer wide DoF and more reach, crop is all good.

I wanted to get a 135L for my t3i but now I am quite hesitating. Not sure it is worth it if I cannot mimic the narrow DoF I see everywhere on this forum. Might be better to keep that money for a 5D mark II down the line...

I took my 135L out on my T3i right before I sold it. It was ok, but nothing compared to that lens on a 5D or 5DII.

Wow... that is a big difference. Apparently I need to upgrade...

The comparison is not exactly apples to apples, but it's close enough given that there is usually no prime lens that, when used on a crop camera, would provide the exact same field of view as another prime lens on a FF camera (and using zoom lenses introduces other variables when they are focused at different distances).

The difference is easily visible and is probably even bigger for Canon, as the Nikon is a 1.5x crop (slightly closer to the size of FF than the Canon 1.6x crop). If you need that "look," FF is the way to go.

Looks about right.

Interesting example! Thanks for sharing!

i would've liked to have seen 50mm on a crop, and then 50mm on a FF moved forward to obtain the same framing

DreDaze wrote in post #14935156
i would've liked to have seen 50mm on a crop, and then 50mm on a FF moved forward to obtain the same framing

It will give you basically the same result.

archer1960 wrote in post #14935192
It will give you basically the same result.

Not quite...you'd have to get a bit closer with the FF camera yielding less DOF

Unless you meant the same result as the link...

DreDaze wrote in post #14935625
Not quite...you'd have to get a bit closer with the FF camera yielding less DOF

Unless you meant the same result as the link...

Yes, that's what I meant.

I think it would be a bit similar as the 85mm now used produce more bokeh than the 50mm. Thus the 50mm closer would be quite similar to the 85mm farther. Still I would like to see that too.

Earwax69 wrote in post #14934721
Here a test made on Nikon that show the DoF difference between equivalent situations (50mm on crop, 85mm on FF, 85 on crop, 135 on ff)

http://tonycorrea.com …portrait-lens-comparison/

Have fun!

Like most of these analyses, it demonstrates the effect of differences in focal length on DoF, not the effect of differences in format.

(Yes, I'm doing it again.)

To do a proper comparison, you need to mount the SUITABLE FL for the format size on each camera to frame the same amount of subject space on both format cameras, at the identical camera position for both!

For example, at subject distance of 10' using f/2 on the lens

• the 50mm lens on APS-C body has 2.9' x 4.4' within frame, and DOF zone of 0.75'
  
• the 80mm lens on FF body has 2.95' x 4.4' within frame, and DOF zone of 0.46'
  

• so f/1.23 on 50mm lens on APS-C give same DOF as f/2 on 80mm on FF
  
• so f/2.48 on 50mm lens on APS-C give same DOF as f/4 on 80mm on FF