Blur versus Out-of-Focus: Discuss!

[GooniesNeverSayDie11]

Goonies, you're wrong... my example proves it. Sorry, but the whole bird is in focus, I'm not skilled nor fast enough to get just the body in focus... if the wings were still they would not be blurred. Motion blur and focus are two different things, you can have both - it's not a one or the other situation.

Actually, I am not wrong, unless birds suddenly fly only with their wings on the same exact plane as their body. Judging by the background and the style of shooting, I would guess you were shooting with a long tele. You are going to have quite a small slice of focus and I will GIVE you my camera if the wings , a large portion of which are inches in front and in back of the body ( your focus ) are actually in focus. Apparently we have differing views on focus and how it works. I ge the point you are trying to make, but in this case, even if the wings were not movings, the majority of them would be OOF.:greenpbl:

 

[PASM]

BLUR

film over: become glassy; lose clear vision; "Her eyes glazed over from lack of sleep"
to make less distinct or clear;[ "The haze blurs the hills"
confuse: make unclear, indistinct, or blurred; "Her remarks confused the debate"; "Their words obnubilate their intentions"
smear: make a smudge on; soil by smudging
make dim or indistinct; "The fog blurs my vision"
become vague or indistinct; "The distinction between the two theories blurred"
a hazy or indistinct representation; "it happened so fast it was just a blur"; "he tried to clear his head of the whisky fuzz"
wordnetweb.princeton.edu/perl/webwn


FOCUS

the concentration of attention or energy on something; "the focus of activity shifted to molecular biology"; "he had no direction in his life"
maximum clarity or distinctness of an image rendered by an optical system; "in focus"; "out of focus"
concentrate: direct one's attention on something; "Please focus on your studies and not on your hobbies"
cause to converge on or toward a central point; "Focus the light on this image"
a central point or locus of an infection in an organism; "the focus of infection"
concenter: bring into focus or alignment; to converge or cause to converge; of ideas or emotions
stress: special emphasis attached to something; "the stress was more on accuracy than on speed"
become focussed or come into focus; "The light focused"
a point of convergence of light (or other radiation) or a point from which it diverges
put (an image) into focus; "Please focus the image; we cannot enjoy the movie"
a fixed reference point on the concave side of a conic section
wordnetweb.princeton.edu/perl/webwn

 

[Light Artisan]

OK Goonies, explain this one then...

Front bird is in focus, head to tail, rear bird is in focus, head to tail - yet there is motion blur. Is there some super phenomenon I magically pulled off? How else could the head be in focus on the front bird and the tail in focus on the rear bird, the middle in focus, but only the wing tips blurred? Wait, they must be out of focus somehow, right?

Nope.


Light Artisan - 00009 11-23-2010 by Light Artisan Photography, on Flickr

 

[GooniesNeverSayDie11]

OK Goonies, explain this one then...

Front bird is in focus, head to tail, rear bird is in focus, head to tail - yet there is motion blur. Is there some super phenomenon I magically pulled off? How else could the head be in focus on the front bird and the tail in focus on the rear bird, the middle in focus, but only the wing tips blurred? Wait, they must be out of focus somehow, right?

Nope.


Light Artisan - 00009 11-23-2010 by Light Artisan Photography, on Flickr

Relax. I get what you are saying, but I still disagree that a motion blurred object is still in focus.I thought the tongue out face would have shown I was just busting your chops.I stand by my opinion though( and it is MY opinion, you can have yours too ) that its not in focus. ( which by definition above would be maximum clarity and you can't have maximum clarity if something is blurred ). I get that if the wings were not moving, they would be in focus, but they ARE moving. If you have no motion blur, then yes they are in focus. You do NOT have both at the same time. You have the POTENTIONAL at all times for both if you remove a variable from the equation but it is either one state or the other. Unless you use a super fast shutter speed to freeze the motion ( which takes motion out of the equation )

 

[RONDAL]

heres one for you that might help.

Audi Allroad Rig | Flickr - Photo Sharing!


Here you have motion blur, a sharp subject, and stuff that is out of focus.

The focus here was the brakes on the all-road up front. They are sharp and in focus.
Because of the settings I was testing with I was shooting at like f4 or something, because of the wide angle, as you work your way to the back of the car due to the depth of field you end up with the back of the car out of focus
You then have blur in the background done on purpose to give the effect of speed.

You can have all 3 and still have a good photo. it just depends what you want from the photo. Sometimes having these elements is a good thing.

 

[Overread36]

Goonies I think you're going to find everyone is against your train of thought here. Simply put in focus or out of focus are the descriptive words we use to describe the distribution of the plane of focus in a shot. The plane of focus is like a sheet of paper or a book (if its deep enough) and everything that lands within that plane of focus is in focus. It is the property of the focus setting of the lens (and distances etc...).

The blur of the photo is however a totally different property - you can easily set a shot to be in focus and then just set the shutter speed too slow to freeze that motion - or pan and get partial blur on moving parts not moving with the camera (both of which have been shown). The blurred parts Are still within the same plane of focus as the sharp parts - they are in focus - but the shutter speed is such that the blur of the motion they are experiencing is too fast for the camera to expose the details as crisp.

Take a look at blurry waterfalls - the shot is most certainly in focus again, but the water is blurred. Not because its out of focus, but because its motion is too fast for the camera shutter to capture.

 

[AgentDrex]

My line of thinking exactly Overread. The reason I find it to be more than mere semantics is amateur TPF users, looking for C&C, can be taught properly what to do when a photo seems OOF. But is it really OOF or a blur? Telling them their photo is OOF when indeed it was in focus and the problem stems from too low of a shutter speed or camera movement, makes it difficult to correct their mistake when we send them down the wrong road. They may start to believe that a fault lies with their lens instead of not having a tripod (for example). I know it seems like semantics, it probably is and I'm just anal (well I stink like one). But I find each should have a distinct meaning to people so that we can correctly point users looking for C&C to the right technique.

Again, I tend to confuse people when I write, so if this is hard to follow, well, then I deserve nothing more than a good ear-beating.

 

[PJL]

We have to set up some sort of Venn diagram here.

*Not to any sort of scale.

 

[AgentDrex]

Ouch...

 

[PJL]

"Ouch" what?

 

[AgentDrex]

Ouch in response to using a diagram to shut me down...out-of-focus being just a form of blur...I still hold a distinction between motion blur and OOF...considering OOF is a lens issue and motion blur is movement-based...perhaps you can include that further distinction in your diagram...or not...

 

[PJL]

Well, we describe a picture as "blurry," "blurry" meaning "blurred; indistinct." I think being out of focus is a form of blur, but it's not correct to say that all things that are blurry is out of focus. Like that picture in your original thread -- it's has blur whether it was from handshake because of a slow exposure time or because of focus, but it wouldn't be accurate to call it "out of focus" if, in fact, your focus was accurate, even though it's blurry. It's kind of the whole "every square is a rectangle, but not every rectangle is a square" thing. Motion blur in a picture is still "blur" as the object in motion is indistinct, it's just that types of blur are considered artistic, while others are considered technical errors. Personally, I liked the slightly blurry nature of the picture, whether intentional or not.

 

[KmH]

......but the whole bird is in focus... if the wings were still they would not be blurred. Motion blur and focus are two different things, you can have both - it's not a one or the other situation.

The wings aren't still, and are blurred because of the motion, so the entire bird isn't in focus because the shutter speed was to slow to stop the wings.

 

[bazooka]

Goonies, maybe you can understand from a scientific angle...

Motion Blur is a function of time and speed only.
Focus is a function of distance only and is not at all related to time or speed.
I think you understand the concept but you're terminology is not accurate. You can call a dog a cat if you want to, but when communicating with others, you will not be effective.

And Motion Blur, OOF, and camera shake can all cause "blur" according to the diagram posted above by PJL. You could also throw in Optic distortion and Chromatic abberation. They are all specific types of blur and may or may not look similar. For example, camera shake and OOF can look very similar.

 

[Derrel]

There are several different words that are helpful in describing image faults and flaws. One common image flaw is subject motion blur (like the wing tips of the geese in the example in this thread). Camera shake, due to too slow of a shutter speed being used hand-held. Out of focus: front focus and back focus, terms that are fairly self-descriptive I would hope. Panning blur: a subject deliberately allowed to blur via the use of panning. Dragging the shutter blur, caused by using a slow exposure time AND a pop of flash. So to me, "blur" and "out of focus" are in no way synonymous.