How to use DOF preview?


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OzOn3

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#1
Hmm, i don't know how to use the DOF preview. I mean, i know what to press ar, but when the shutter blades come together, how do i tell what's what? at F27, almost everywhere darkens except the center... at 4.0, no change.. hmm..
 

meng

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#2
if you understand what's the meaning the DOF, DOF preview allows you to check the DOF from the viewfinder. Try it in a bright area, like outdoor during daytime, and notice the sharpness/blurness change as you press DOF preview for various aperture settings.
 

AReality

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#3
But I find it quite useless indoors..
It darkens by a lot even at large aperatures...
Hmmm... maybe my eyes dying liao... :confused:
 

OzOn3

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#4
meng said:
if you understand what's the meaning the DOF, DOF preview allows you to check the DOF from the viewfinder. Try it in a bright area, like outdoor during daytime, and notice the sharpness/blurness change as you press DOF preview for various aperture settings.
DOF = Depth Of field = Area of image that is sharp :D

Really meh?! Maybe i never see properly.. Ok, tomorrow i see properly. hahaha thanks.. =x
 

meng

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#5
try in outdoors and you should be able to see the difference.
The lens aperture only changes its size when you press the shutter or press DOF preview. When you changes the aperture setting on the EOS body, the actual aperture remains constant (at widest) before you press the shutter. SO logically, when you press DOF preview, the viewfinder will be darker.
OzOn3 said:
DOF = Depth Of field = Area of image that is sharp :D

Really meh?! Maybe i never see properly.. Ok, tomorrow i see properly. hahaha thanks.. =x
 

OzOn3

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#6
Meng help.. I still dun understand.. It seems no difference to me leh... Everything seems sharp, i think.. :(
 

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andylee

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#7
OzOn3 said:
Meng help.. I still dun understand.. It seems no difference to me leh... Everything seems sharp, i think.. :(
Set your camera on a tripod, set your lens to 35mm focal length, focus on a foreground object which is off center.after that, do not change the focusing or the focal length or the set-up.change the aperture setting after you press the DOF button to check every f number, note the foreground and background you see.

If you focus at infinity with a wide focal length, how to see depth?? depth is too great already. think fore and aft....
 

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andylee

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#8
OzOn3 said:
Meng help.. I still dun understand.. It seems no difference to me leh... Everything seems sharp, i think.. :(
If you still don't understand, go to Minolta Imaging Gallery.....
 

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andylee

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#9
AReality said:
But I find it quite useless indoors..
It darkens by a lot even at large aperatures...
Hmmm... maybe my eyes dying liao... :confused:
Do you understand DEPTH 1ST??
 

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andylee

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#13
West_ray said:
frankly speaking ... i didnt use it at all for most of my shot ... well ... maybe i can't really see the uses of it ..
:bsmilie: that depends on your composition of your shots,eg; composing with a strong foreground that leads you into the picture, shooting people, macro shots. these few types of photography relies on a lot of knowledge regarding D.O.F

A picture without DEPTH is very FLAT. if it's a wide angle scenery, then the DEPTH should be great...
 

Wai

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#14
I think DOF preview will be more useful on film cameras becos they cannot afford to have trail and error and there are no instant playback of the photo

also the viewfinder of film cameras are so much bigger than DSLR (except 1DS), so i can hardly see if the subjects i want is totally focused or not....in the end i just do a "bracketing" around different aperture :p
 

ace2001

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#15
OzOn3 said:
Hmm, i don't know how to use the DOF preview. I mean, i know what to press ar, but when the shutter blades come together, how do i tell what's what? at F27, almost everywhere darkens except the center... at 4.0, no change.. hmm..
when you view through the viewfinder, the camera uses the largest apperture offer by the lens(lowest f) so tat you can see your subject 'brighter'. it onli uses the app[erture you set when you ready takes the picture.
But when you press the DOF button, the camera stops down to your current apperture. tat is why, the smaller your apperture set, the darker you will see your subject through the viewfind, cause now less light goes through your cam.

wat happens now is you will be able to get the DOF offer by that apperture setting. Go to somewhere bright.
set your camera to focus on a subject say 4-5m from you say ard 50mm focal length, your viewfinder should show tat the other subjects at distant is out of focus, now, increase of your F say to F16, press the DOF button, the subject say at a distant ard should be clearer.(vaires w your focal length also)

nevertheless, in my personal exp, maybe my eyes spoil or wat, the DOV is still not exactly the same as the print out, sometimes jus use agaration, or if it ready impt, like someone mention, bracket your shots.

cheers =p
 

Sep 20, 2003
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#16
andylee said:
:bsmilie: that depends on your composition of your shots,eg; composing with a strong foreground that leads you into the picture, shooting people, macro shots. these few types of photography relies on a lot of knowledge regarding D.O.F

A picture without DEPTH is very FLAT. if it's a wide angle scenery, then the DEPTH should be great...

spot-on explanation
 

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andylee

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#17
ha ha, "the stop down" you see depends on the brightness & grain (Minolta make screens for hassy for your info)of your screen. It's all base on your experience. tat's why DIGICAM is easy, you just bracket the shots and get the one shot that suits you...
 

sulhan

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#18
Hi There,

Knowing the depth of field of the image or should i say being able to control it as you like....can help in giving that extra touch to your image.

Many people talked abput "I want my subject pin sharp and the background blurr"...

Yes...this is a normal want by most ....bust some people forget about the compositional quality of a image by using a very shallow depth of field for example...

IN some cases.. too much background blurring may kill all the other story line a photo can give ...for example...(my favorite example).....

A baseball-match. Lnowing that DOF is shallow at long zooms like 300 mm for example - coupled with large aperture....this will pop out the baseball player out of the photo by blurring the backgreound totally.....hence you cant tell where is the match held....is it behind you back yard?......is it at padang???or was it at one of those baseball stadiums in US??...

So being able to choose or control the aperture to the required DOF......is in deed crucial here. You can stop down to a comfortable aperture to at least give a blurred background of the spectators on the grand stand for example - as part of the compositional factor to gove the photo some story line.
SO how do you know whether the aperture chosen is suitable.....

This is where the DOF preview button is essential. It allows you to have afeel of the DOF of the actual photo prior to it being taken.

Some cameras...allow you to adjust aperture while pressing the dof button.....
while some only allows you to press DOF ->release->change aperture->PRESS DOF->release->change aperture...

Whichever way....you still have the function.....

When you say that you image is sharp all the way......it look like you may have been using a wide angle range of lens which will give you deep DOF hence difficult to really see the effect....OR your lens maximum aperture is not that large.....maybe like a zoom lens with f5.6 or f4.....

To try the effect of the DOF.....take one simle lens like an 80mm....then focus on a close subject...like a shoe......then put another shoe in front of it ........

Then with different apertures......repeat the DOF checks with different aperture and you will see slowly the shoe in front would show up sharper though the image may be alittle darker.

So in aperture priority mode.....make sure to look at the shutter speed chosen and ensure that to that aperture chosen (if you want to complete the shot).....make sure the speend is not too slow.... as a rule of thumb.....1/focal length....else a higher ISO or a flash needs to be used.....

Hope this long blabbering make sense to you....


regards,
sulhan
 

OzOn3

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#19
Oh!! I finally know how to use the DOF already!! I need to "move" my eye balls a bit and see the "surroundings"! haah thanks all!! :)
 

mervlam

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#20
just a casual remark... if everything appears pin-sharp w/o pressing the DOF button, dont bother pressing the DOF button. go figure why. answers are already given above.
 

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