shallow depth of field

grandmaR

Most of the shallow depth of field photos that I've seen are close-ups with the background out of focus.

Is it possible to have a shallow depth of field where the in focus part is in the middle and objects in front of the item and those in back of the item are out of focus? If so, how is it done?

I ask because there is a photo Forum where the current topic to illustrate is shallow depth of field. One photo has a very sharp middle of the photo and the outsides are blurred. I think he just used some type of vingnetting to blurr everything except the center, but is that really SDoF? In this picture there are about five figures, and the two forward figures are blurred, and the two back figures are blurred and the center one is in focus. But his feet are blurred and the one figure closest behind him is not blurred on the edge toward him. So I can see a circle inside of which is not blurred and outside of which is. Is that an acceptable way to get to a shallow depth?

pathfinder

grandmaR wrote: »

Most of the shallow depth of field photos that I've seen are close-ups with the background out of focus.

Is it possible to have a shallow depth of field where the in focus part is in the middle and objects in front of the item and those in back of the item are out of focus? If so, how is it done?

Yes, it is possible to have a narrow depth of field, with foreground and background out of focus, with a slim area between in focus. The way to do this is to use a wide aperture lens - say f2.8 or larger - and have the subject fairly close to the film/sensor plane. Longer focal lengths will help also. A larger sensor favors shallower depth of field, relative to a smaller sensor also, if the aperture and focal length are similar.

I was thinning files in my Lightroom catalog, shortly after reading your question, and I came across this image from Grime's Point, Nevada, which demonstrates what you are asking about. The forground objects, and the background objects are clearly less focused than the rock in between. This was shot at 70mm focal length at f4. A wider aperture would have demonstrated this even more clearly.



There are a number of web pages, and smart phone apps that will help calculate depth of field, or one can just look through their DSLR and press the preview button to stop the lens down to the chosen aperture, and see the depth of field through the viewfinder.

DOF Master has a web page, and there are numerous apps easily found for smartphones. Many older lenses had marks on the lens barrel displaying the approximate area that would be in focus at a given aperture, and distance form the sensor plane.

grandmaR

That seems to be very subtle to me. This one was more like this (this is one of mine where I've tried to reproduce the effect)

pathfinder

I am not seeing your image in your post.....

Had I shot at f1.4, instead of f4, it would not have been as subtle, I assure you. But my 70mm lens did not open wider than f4.

I just grabbed that throw away image to demonstrate the dof.

In a studio, at f1.2 or f1.5 with an 85mm lens, or at f 2.8 with a 200mm lens, one can have portraits with only one eye in focus.


Maybe this is a better example, again shot at f4, to show the shallow dof at f4





You favor more like this, shot at f2?



When shooting at f1.4, one must be quite accurate with the focusing precisely where desired, or the image is just out of focus. There are a few wedding shooters who shoot at f1.2 for the majority of their images, for that narrow dof style of imagery. It takes great skill and precision to do that.

With image editing tools, one can now have blur almost wherever desired, but making the blur look "correct" or "normal" can be more difficult. The Lens blur filter done well works nicely, but a simple Gaussian blur does not always look "right" to the eye of an observant viewer.

grandmaR

The photo I posted was blurred using Picasa and that's what I think this person did in this contest. It doesn't look quite right which your photos do. I am sure in my oen mind that it ws a pp blurred photo instead of a real narrow depth of field. It works very well as a photo, but IMHO NOT well for the contest. So I won't vote for it because I don't think it follows the rules. Unfortunately, it is such a good photo that it has already quite a few votes.

Thank you very much for explaining the process that COULD have been used to me. Looking at your examples, I don't think that is what does done.

pathfinder

Here is an tourist shot of mine from Mt Rushmore. and below is it with a Gaussian blur of the margins of the image for a peripheral blur, like as a vignette - is this more in line with what your were describing?

grandmaR

Yes that is it. EXACTLY

These are two that I just did

puzzledpaul

Together with much more experienced w/life shooters than me, trying to blur (to some degree or other) areas other than the subject is a fairly common technique, although retaining interesting texture (with complementary colours) is another matter ...

Relative distances play a big part, imo - together with pov.
In my case, getting as close to water level as possible minimises the vertical height of the horizontal in focus strips of image going across the frame ... as well as offering other benefits (for what I'm looking for)

Choosing a location where the probable cam > subject distance is considerably shorter than the subject > background distance is something I definitely keep in mind. Since blurring the bg in pshop is too much like hard work, I prefer trying to get it right in cam.

Obviously it depends on what you're interested in shooting, too

If there'd been something of interest in the immediate foreground that I'd wanted to be in frame with this linked shot, chances are (depending on distance from cam) it too would've been oof like the bg.

(500mm lens @f4 btw)

http://www.dgrin.com/showthread.php?t=189538

pp

Blackwood

Here's a more obvious example of what pathfinder described. The squirrel (and bee) are fairly close to me, probably on the order of 5 feet. I'm shooting at 200mm/2.8. Some of the sharp sliver comes from the narrow dof, and some comes from the immediate foreground being closer than the minimum focus distance of the lens.

grandmaR

In the example of the 2 girls with the coach, the giveaway (to me) that shows I did not use SDoF but merely blurred the edges is that the bench behind the coach is in focus. In the cemetery one (which is in St. Barths) the cross on top is out of focus and it is the same plane as the inscription.

When I get home (I've been traveling all month), I may try some of those type of photos because it is interesting. Although most of the time I have no time or need to do such photos. I'm still playing with light painting which we've had several contests for. Not too good at it yet.

Blackwood

Based on those manipulations, You may be interested in a tilt shift lens Which will allow you to skew the focus plane off parallel from the imaging plane

grandmaR

I don't think I'm ready for that yet

I'm just an old lady who likes to take photos and travel.

rdalland

grandmaR wrote: »

Is it possible to have a shallow depth of field where the in focus part is in the middle and objects in front of the item and those in back of the item are out of focus? If so, how is it done?

Here is a good example from a classified ad by p27rpy posted in this thread. I hope it is OK that I posted it here, it is a perfect example. It also answers the question of how it is done (1.8 aperture).

grandmaR

Thank you all. I will try doing that and see what I can do with it.

The contest in which the photo that I thought was a fake shallow depth of field - it didn't win and the ones that won were really good. So I've learned a bit and the ones that won deserved it.

puzzledpaul

Took this a few days ago and also thought it demonstrated aspects under discussion - esp for a non 'close up /macro' shot, as the subject was a goodly No of metres away.

Line along the bottom of frame shows the dof (from this low viewpoint) in the ice, related to what's in focus on the flying bird - with examples of oof subjects in front and behind this line.

(500 f4 @ f4.5 on a 1.6 crop body)

pp

grandmaR

Thats a cool photo. Almost looks time dimensioned

puzzledpaul

grandmaR wrote: »

Thats a cool photo. Almost looks time dimensioned

Thanks - slightly intrigued by 'time dimensioned' though ... care to elaborate?

'Cool' is certainly appropriate / relevant tho'...

We've just come through a 2 wk period of ice / snow / low temps etc, and this particular lake (where the gulls were) was frozen over. It took me a while to realise that one other difference was the lack of orange buoys in said water, used by the youth sailing club based there - a right pita to have such items in the bg.

I went there almost every day whilst such conditions existed, trying to get pics like this, and with (falling) snow in frame.

'Entertaining' cycling conditions, too ...

pp

grandmaR

I think I made up the term time-dimensioned when looking at the photo because I thought it was almost like you photographed time travel with the sitting gull in the past and the flying gull in the present. We are normally picturing three dimensions but presenting them as two dimensions. I was making a fourth dimension of it.