Which lens was used?

[480sparky39 38]

It's a totally useful comparison - of what an OOF background that's far away is going to look like at f/2.8 versus f/1.8. You do have to ignore the subject and look at what's actually being offered for comparison, though.

Only if all other variables are the same. Changing the camera-to-subject distance skews things.

 

[amolitor]

The BACKGROUND, dude. The BACKGROUND.

"You have to ignore the subject and look at what's actually being offered for comparison"

 

[o hey tyler]

The BACKGROUND, dude. The BACKGROUND.

"You have to ignore the subject and look at what's actually being offered for comparison"

It still doesn't make sense. What about that don't you understand? If the camera is focused closer at f/2.8 vs 1.8, it's still going to have a shallower DoF, this skewing the comparison. That's what sparky is saying, and it's true.

 

[frommrstomommy]

the whopping 2 feet closer I was in the 2nd image isn't going to make a night/day difference on DoF.

 

[480sparky39 38]

the whopping 2 feet closer I was in the 2nd image isn't going to make a night/day difference on DoF.

Get out your DOF app and punch the numbers in.

 

[amolitor]

A DoF calculator won't tell you a damn thing about the background. It tells you where the circle of confusion is small, not how big it is when it's big.

You buggers are gonna make me do math. I hate doing math.

A point "at infinity" renders as some sort of little fuzzy spot in the image. We can consider backgrounds that are pretty far away as "at infinity". The size of that fuzzy spot varies according to where you're focused. The size of that fuzzy spot is a measure of how blurry your background looks, if your background is "pretty far away". When you're focused at normal working distances, pretty large multiples of the focal length (so, let's say more than 3 feet for 35mm or 50mm lens) then the size of that little fuzzy spot depends pretty much on the inverse of:

(distance to the in-focus subject) * (f-number)

So, if you halve the distance to the in-focus subject, you double the fuzziness. If you were focused at 6 feet and now you're focused at 4 feet, you've change the distance by a factor of 2/3, you get 3/2 fuzzier -- the little fuzzy circles are 1.5 times as big.

If you change from f/2.8 to f/1.8 the fuzziness increases by almost 1.6.

I dunno where frommrstomommy was focused. Looks like she might have gone from whatever distance to about 2/3 of that distance. So about half the "added fuzziness" is due to being closer to the in-focus subject, and the other half is from the change in aperture. Which is more than I thought, to be sure.

It ain't a lens test, it wasn't intended as a lens test. It looks to me like a fine example of "here are two pictures at two apertures. They look different. Check it out."

 

[Buckster]

With the difference in distance to subject, they'd have looked different even at the same aperture.

Do the experiment. Stationary camera on tripod pointed at and focused on a stationary subject several feet away, with a stationary background 100 feet behind the subject. Take two shots; one at f1.8 and one at f/2.8. Post them.

That's a comparison.

 

[Buckster]

the whopping 2 feet closer I was in the 2nd image isn't going to make a night/day difference on DoF.

It looks like that two feet is about half the distance to the subject, so yeah, it makes a difference.

 

[480sparky39 38]

..........You buggers are gonna make me do math. I hate doing math.........

Then don't do the math. Just put your camera on a tripod, toss on a fifty, and turn the focus ring until the background is out of focus when using your DOF Preview button. While looking through the viewfinder, or on the monitor with LiveView, change the focus distance and watch in awe as the background bokeh changes.

 

[amolitor]

..........You buggers are gonna make me do math. I hate doing math.........

Then don't do the math. Just put your camera on a tripod, toss on a fifty, and turn the focus ring until the background is out of focus when using your DOF Preview button. While looking through the viewfinder, or on the monitor with LiveView, change the focus distance and watch in awe as the background bokeh changes.

I don't actually have any cameras.

 

[Derrel]

Here's some somewhat comparable images shot with a Canon 7D and 50mm f/1.4 EF lens. Look very closely for the subtle green fringing on OOF background objects, and note the size of the bokeh dots on out of focus point light sources in the background. See how FAST the depth of field drops off with a 50mm lens on a 1.6x Canon body; these look pretty similar to the fashion blog shots, in that they are urban, and mostly full-body or half body-type shots. This one fellow has a LOT of 50/1.4 shots to look at with fashiony-type poses. I found this link through pixelpeepers.com's CANON lenses section samples.

CANON 50/1.4 on EOS 7D


All sizes | Kitty IMG_1813 | Flickr - Photo Sharing!


All sizes | Kitty IMG_1893 | Flickr - Photo Sharing!


All sizes | Kitty IMG_1873 | Flickr - Photo Sharing!


All sizes | Kitty IMG_1693 | Flickr - Photo Sharing!

 

[Robin_Usagani]

I know the answer. It is a Louboutin.

Christian Louboutin

 

[o hey tyler]

I don't actually have any cameras.

Doesn't surprise me.

 

[ktan7]

I would guess 50mm @ 2.8