Everything sharp with f2.5?

[lelavadee]

Hello everyone!

I've got a question. Lately I've been looking for the settings of some of my favorite pictures. Now something really confuses me. For example this picture:
wild roses.. | Flickr - Photo Sharing!

It's take with f2.5, and everything is sharp. Whenever I take pictures with f2.5 I get a really blurry background and some bokeh, but I would never have everything in the picture this sharp.
Can someone explain to me how this works?

Thank you!

 

[Village Idiot]

What lens were you using? That photo was taken with a 50mm lens @ f/2.5. The shorter the focal length, the more in focus everything will be regardless of what aperture was used. Also, in that photo, you can still see portions that are out of focus that are leaving the plane of focus. subject to lens to background distance also matters too.

A 300mm lens at f/9 may have a blurry background compared to a 50mm lens at f/9.

A subject that is 10' from a lens at f/2.8 and 10' for the background (Say 100mm lens for arguments sake) will have a blurry background. Move the subject back 10' so they are standing right on the background and the background should no longer be blurry, or at least entirely so.

 

[lelavadee]

I have been using multiple lenses, but not the 50mm (but I have one!). The other ones have been zoomlenses. So what you are saying is that say I am using my 50mm lens (English is not my native language, so I want to make sure I understand) is that the person should be standing closer to the background than to the lens and that is how I won't get the blurry background? Thank you!!

 

[Village Idiot]

I have been using multiple lenses, but not the 50mm (but I have one!). The other ones have been zoomlenses. So what you are saying is that say I am using my 50mm lens (English is not my native language, so I want to make sure I understand) is that the person should be standing closer to the background than to the lens and that is how I won't get the blurry background? Thank you!!

Won't be as blurry. Try this:
Online Depth of Field Calculator

It's a DOF calculator that will tell you what your DOF is depending on your sensor size, lens used, subject distance, and aperture used. All are factors in determining DOF.

 

[Braineack]

Would never have everything in the picture this sharp. Can someone explain to me how this works?

Maybe we are looking at different photos. Everything WITHIN the DOF is sharp. There are plenty of OOF roses in that picture.

I'm also not entirely convinced this shot is a single shot and not a composite--there is plently evidence of it to suggest it is (repeated flowers for one).

And depending how he exported the image, it could be showing the EXIF from just one of the frames.

Example: The WRX | Flickr - Photo Sharing!

I didn't shoot that at f/22 for 4 secs. only the flare on the headlights, which just happened to be the top most layer in PS.

 

[KmH]

Depth of field (DoF) is affected by multiple factors. Lens aperture is just one of them:
Lens focal length
Point of focus (PoF) distance
Lens aperture
Image sensor size

 

[Braineack]

I'm also not entirely convinced this shot is a single shot and not a composite--there is plently evidence of it to suggest it is (repeated flowers for one).

I zoomed into a small section of the photo and see three glaringly obvious signs of a composite shot.

It's easy to make everything in focus if you add in a sharpened background to the OOF areas of the image. there's still plenty of OOF flowers in front and behind the subject.

This picture has been highly manipluated in PS and you shouldn't use it to judge DOF vs. aperture on a 50mm lens.

 

[Derrel]

If you want to shoot at wide apertures like f/2.5 and have "acceptable" depth of field for portrait subjects like one- or two-person shots against natural-world background scenes, where the people are sharp, and a bit of the immediate background is acceptably sharp, it's easiest to just shoot from distances in the 5 to 10 meter distance range with a high-quality telephoto lens. For a shot of something like a woman standing in front of a large rose bush, in a real-world, not composite Photoshop world, you could use a 135mm lens at 6 meters, and get almost exactly the field of view show in the composite photo you linked us to.

 

[Overread]

A few additional thoughts:

1) zoomless lens = prime lens

2) Another way to get more of the frame in-focus that you'd otherwise see is to use a tilt-shift lens. What this kind of lens does is allow you to alter the plane of focus.

If you imagine the plane of focus (segment of the photo in-focus and sharp) to be like a book - the thickness of the pages is the depth of field. Now on a regular lens the plane of focus is parallel to the front of the lens; however with a tilt shift lens you can adjust the plane of focus, you can tilt it so that it covers a different angle. This can allow you to get some really creative effects with depth of field (if you google tilt shift you'll see lots of those classic landscape shots that look like miniature models taken with a macro lens).

For a shot like the one above it probably wouldn't work because everything is still on the same plane - the rose bush is covering the shot top to bottom.

2) Focus stacking. This is a method where by you take a series of photos at fixed settings, but where between each one you change the focus point by a tiny amount each time. This is so that each shot overlaps its depth of field with the shot before, but at the same time is including a new segment of the scene in the plane of focus. You then use software to automatically blend the shots together which gives you an increased apparent depth of field.
The bonus here is you can use a wide aperture and get a blurry background and yet still keep a deep depth of field; or you can use it so that you can use the sharpest aperture without sacrificing depth of field in the shot.
Zerine Stacker - Helicon Focus and Combine ZP (this last one is free to use) are all software packages you can use to stack - Photoshop CS5 also has its own stacking option.

It's typically used by macro photographers but can be used any static scene and subject (if it moves around the blending will likely fail).



Both those methods are not necessarily going to work on this kind of shot, however they are alternative ways in which you can manipulate the depth of field.


Like its said above I suspect that this shot is the result of a collage. Combining multiple photos into a single composite photo.

 

[greybeard]

Everything that is the same distance from your camera as the principle point of focus (the woman) is and should be in focus. The f/stop you use will determine how far in front of and how far behind of the point of principle objects will appear acceptably in focus. Large apertures (small numbers like f/2.5) will have a shallow DoF and small apertures (big numbers like f/16) will have a much deeper DoF.