Assignment 2- DOF

[menacejean]

Nice try, and you got the idea, but I would do these again- one with the lens wide open and one with it closed down all the way.  There's not enough difference between the f-stops to make see the difference (and yes, the shutter speed will have to vary quite a bit too).  Focus on the near tombstone each time.

This is probably a dumb question, but when you mean the lens wide open, and closed down all the way are you talking about focal length?  (50mm etc?)  If so the only way I can change the focal length is by zooming in on my point and shoot camera. 

Thanks for the newb help

[Doc]

No question is too dumb!  Always ask if you have a question!

I'm not talking about the zoom amount- that should stay the same, I'm talking about the f-stop.  "Wide open" means using the largest f-stop your lens has (say f2.8 or f4), and the smallest lens opening (say f16).   

You might want to check out the tutorial I wrote on "F-stops and other confusing stuff":
http://photographyatnewenglandmoments.com/index.php?topic=31.0

Now that you know roughly what we're talking about, the question is, with your P&S, can you adjust any of the settings manually?  In other words, can you set it to Aperture Priority or Shutter Priority?  If so, just set it to Aperture Priority and change the aperture between pictures.

If, on the other hand, you DON'T have those kinds of settings, this gets quite a bit trickier.  You have to "force" the camera to use different settings.  For one shot you can use the Sports mode.  This will force the camera to use a more "wide open" f-stop and faster shutter speed.  For the other shot you can use the Lanscape mode.  This will use a more closed down f-stop and slower shutter speed.

Any more questions just ask, but let me know what kind of camera you're using, ok?

[menacejean]

Hi Doc.  The camera I am using is the Fuji FinePix F70 EXR. 

I had previously read every article in that section so I was pretty sure I knew what you meant by wide open, and I guess I was right.  I should learn to trust myself.

I do have the ability to change the f stop.  Unfortunately as my pictures show there is only two stops I can choose depending upon how far I am zoomed in/out.  I zoomed all the way in to take the two cemetery pictures because the lens would be a 50mm.  I then have a manual setting that allowed me to choose only two options, 5.6 and 11, as my stops.   That being said if these stops are not far enough apart to produce the desired effect, then I will fool around with the different modes of the camera (landscape, sports) and see what kind of stops it uses automatically.  I may be wrong, but I think my stops only go from 3.3 - 11 regardless of the mode they are in.

Thanks again for all the help.

[Doc]

Ok, set it for wide angle, find something about 2-3 feet away to focus on but the background way far away.  Open the lens to it's widest at f3.3, and take the shot.  Now focus on the same thing, same zoom, but at f6.4.  There's not a whole lot of difference between the two f stops, but you should be able to see the difference the f-stop makes between pictures.

Give it a shot!

[Amber582]

I don't really understand most the concepts of photography yet, but I'm learning! Didn't really understand DOF, but tried my best. Hope I did it right!

I took some of my siblings stuffed animals and lined them up, took forever to line them up the way I wanted! Yet, it still doesn't look how I picture. I have a Point and Shoot camera so I don't think It turned out well. I followed your tips though. These have not been edited at all by the way.

<a href="http://www.flickr.com/photos/52942046@N04/4885600696/>[/url]

<a href="http://www.flickr.com/photos/52942046@N04/4885601686/>[/url]

<a href="http://www.flickr.com/photos/52942046@N04/4885602886/>[/url]

[Doc]

First, nice try.

I had to do some digging on your site, but all three pictures were taken at the same with the same shutter speed and f/stop (1/200th, f3.3).  Humm.  That didn't work at all- they shouldn't be the same f-stop.  More digging....

Ah ha!  In order for this to work, you need to take these with 2 completely different f/stops (say f-3.2 and f-16).  However, you camera only has an f/stop range of f-3.2 to f-3.4 (virtually no range at all).  It adjusts the exposure by adjusting the shutter speed.  So you can't change the DOF with the aperture setting because there's no setting to change!  Sorry, I didn't know what kind of camera you had or I would've never asked you to try this assignment.  I'm going to give you a K for giving it a shot though!!!!  It's not your fault- it's the limitation of the camera!

The good news is you shouldn't have any trouble doing assignment 3 with your camera.  Good Luck!

[Amber582]

Thanks! Guess I need to go hunting for a new camera.

[TbogFL]

A simple and boring picture for this one, but I got the idea after seeing the results.

@ f 5.6


@ f 32


I noticed a definite difference in the blurriness of the background between the two settings.

[Doc]

And THAT's how it's done!  You're right, these aren't "wall hangers", but that's beside the point.  This "trick" is for future photos.  Great examples, and a nice job.  Have a K!

[wilky22]

f/10

DOF by wilky22, on Flickr

f/32

DOF by wilky22, on Flickr

Is this what you are looking for?

[pixhunter]

Hey all this is my modest indoor attempt; got this assignment at school too.

50mm; f1.4


50mm; f22


PH

[Doc]

Nuthin to it!  Great examples!  Have a K!

[oldCarlos]

We actually had a couple of hours without rain today, so tried this aft focussing on the conifer from about 4-5ft away.
You can see a difference, but maybe the `subject` was a bit large.

I set to 35mm (eq to 52mm) Wasn't sure whether you ment 50mm on full frame. 

F4.5




F29




Decided to get Gerry stood outside the front door & try again  from about 3ft away

Got a better result, although I missed the focus a bit on the 2nd shot.   :

F4.5




F29

[Doc]

Have a K.

The problem with the lack of DOF between the sets of pictures is the wide-angle lens you used.  For instance, the last set was at 35mm.  If you would've used a 50mm or 80mm setting, then you would've more of a difference.  You could re-take these again to see for yourself if you wanted, and I hope you do and post the results.  But you got the idea, and you can see a difference (though barely). 

[oldCarlos]

Done them again @ 50mm with my 16-85mm lens.  Defo more obvious, thanks Doc.

F4.5




F32

[oldCarlos]

Took a couple of pics today playing with my new lens & BOY is there a marked difference!

From about 2ft away.

50mm
F10




50mm
F1.8

[Royston]

Well here goes #2
Wide open 1/250, AV5.6, 55mm

Closed Down 1/6, AV36, 55mm


Keeping my fingers crossed

[Royston]

Oops    got the captions wrong way round, first pic is closed down and second wide open

[Royston]

Wow Carlos, that F1.8 sure makes a difference

[Doc]

Glad you mentioned about the captions, Royston, cause I was gonna say....
BTW, If you would've gotten a bit closer to the sign (shorter focus distance) you would've seen a more marked difference in your backgrounds.

Both you and Carlos did good!  Both of you get a K!  Good Job guys!

[Royston]

Thanks for the advice an 'K' Doc

[Dwayne]

OOPS .... no background
 
f2.8

 
f11

 
I went out and shot one with a back ground.
 
f2.8

 
f32

 
 

I also check out the http://en.wikipedia.org/wiki/Depth_of_field

[Doc]

Wow, you didn't need a background on that first set.  Very nice series!  Have a K!

[Dwayne]

Thanks Doc,  so if your subject is closer the dof is going to be smaller.
(Like Macro photography)

If subject is further out, will the dof be infinite?

Is that true? or its because I am at the same plane and DOF is larger.

I am going to play with the DOF calculator more.

[Doc]

Right, play with the calculator more.

For this assignment we just messed with changing the focal length to adust the DOF.  Actually, there are three things that determine DOF:
1- Focus point.  The closer you focus, the narrower the DOF.
2- Focal length.  The longer the focal length, the narrower the DOF.
3- F-stop.  The wider the lens opening, the narrower the DOF.
4- Combinations of the above give you the narrowest DOF.

The opposet of the above is true to get the deepest DOF.  That's how people get those shots with the rocks at their feet in focus and so is all of the beach clear back to the ship on the horizon (wide angle lens, small f-stop, focus pretty close).

[Dwayne]

Thank you Doc.