Shallow depth of Field... From a tiny lens?

It is a nice effect to open up the aperture of a camera, focus on the subject, and allow the background to go blurry. 

But many of today's still and video cameras have a tiny aperture.

How can I get shallow depth of field from such a camera?

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By using a proper camera and manual focus....

+1 for the proper camera, but manual focus has nothing to do with depth of field.


Agreed that manual focus has nothing to do with getting a great depth of field. Well, sort of, there is a weird little technique where you can make a close-up and manually focus so that the object goes to the edge of the focal length. I've read about it, but never tried it.

On a separate note, I find that manual focus produces better table top images that autofocus. What I do is:

1. Put the camera on a tripod

2. Switch to live view

3. Set to manual focus

4. If your live view has a zoom feature, zoom in on the object you want the subject to be and then manually focus. Note, I'm not saying to zoom with the lens. Just zooming in on a portion of what will be photographed. Most DSLR's have this feature.

5. Use the self timer feature if you have a very slow shutter speed so that you can take the shot without jostling the camera.

Hmm.. I should write this up. :)

All my table top shots follow this method and you can see the results at https://www.flickr.com/photos/savvyduck/

Re: your first comment--

With some knowledge of the characteristics of your lens, you can cheat the focus in (closer to the camera), because the acceptable sharpness within the "depth of field" will be greater behind the subject plane than in front of it ("front" being closer to the lens).

A very basic (and probably technically incorrect) rule of thumb we used in college was 1/3:2/3 -- I.E., two thirds of the "acceptable sharpness" will be "behind" the subject plane. That lets you cheat inward. But if I remember correctly, the closer the focus distance, the closer to equal the front/back distances.

The overall depth of course is dictated by the focal length of the lens, focus distance, and the current aperture.

FYI--most (older) SLR lenses had this calculation right on the lens. It's the F/stop numbers on each side of the focus indicator... on this lens (photo below), it's displayed as 22 16 8 I 8 16 22. This shows the extent of the depth of field at each of those apertures, forward and behind the focus distance.

DSC_7304.jpg

Yeah, I have a fairly old Nikon (film!) with a 50mm 1.8 and it has the focal length guide too.

It dawned on me that an easier way to get the camera to open up the aperture is to set the ISO to a fairly low number, like 100 or 200. Many cameras have ISO settings so giving it a fairly low number will require the camera to compensate. The camera has to achieve a certain frame rate so it will open up the aperture.

Right on...I'm so "vintage" I remember when ISO was called ASA. ;-)

Some digital SLR cameras have a couple "low" ISO settings that lower the "film speed" below the natural ability of the sensor (L 0.3, L 0.7, L 1.0, etc). I've used it on occasion.

You can also raise the shutter speed, to like 1/8000 or less (less being a smaller number) on some cameras. That'll get the aperture to open wider. 'Course that doesn't work with studio strobes, as the shutter speed doesn't have any real effect on the exposure with flash (and going shorter than 1/250 with a focal plane shutter won't work).

I guess the OP can always try a selective blur with software, if the camera / lens isn't getting the effect needed...

I have no big problems getting these pics with my SLR, just a matter of changing a few settings and using the right focal lenghts.

But even with good programs on my phone I can only get lame effect doing close ups.

Problem simply is that you can't get a mid range focus with the rest blurry from a tiny lens system.
On my cheap digital cam with 10X optical zoom I can do similar effects with no big problem although the further an object is away the harder it is to only have sharp focus on a single object.

There is a nice explanation on Digital Camera World:

http://www.digitalcameraworld.com/2014/05/09/a-lay...

gmoon2 years ago

Manual exposure to start. The largest aperture probably won't be the most likely "auto exposure" choice. Most auto settings bump both the shutter speed and aperture together. Or "aperture priority" if your camera has that option.

If you camera doesn't have any exposure control, you can "force" it to use larger apertures / longer shutter speeds with a neutral density filter (but don't expect it to work well on moving subjects).