BoKeH


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mazeppa26

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wads the biggest f stop (thats means up to which f) or smallest APErture necessary to haf bokeh effect?
 

mazeppa26

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actually
if u focus on the front object the backgrd will be blur
is tt bokeh too?
 

Snoweagle

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#4
Yes...bokeh is the blurred background. Usually a lens with more aperture diaphragm blades will create a nicer bokeh.
 

tsdh

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#5
mazeppa26 said:
wads the biggest f stop (thats means up to which f) or smallest APErture necessary to haf bokeh effect?
Bokeh is closely related to DOF (Depth of Field).
While DOF is depend on three factors: aperture, actual focal length, and distance to the object.
The larger the aperture (lower f-number), the less DOF would be.
The longer the focal length (actual focal length), the less DOF would be.
The shorter the distance to object, the less DOF would be.

Less DOF means --> higher chance of getting bokeh.

Full-frame 35mm camera has less DOF as compared to the compact digicam, why?
Because its actual lens' focal length is much longer for the same field of view.
A compact digicam with sensor size 1/1.8" using 28mm lens, will have the same field of view as a SLR 35mm film camera using 140mm lens. If both cameras were set at same aperture and both focusing at the same distance, the DOF for the SLR will be much shallow, meaning: more bokeh than the compact digicam.

So, if you want to produce background blur or bokeh, you have to use longer focal length (note: actual focal length, not the "35mm equivalent"), lower f-number (larger aperture), and shorter camera-to-object distance.
 

darrelchia

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#6
do note. Bokeh is NOT blurred background, or shallow depth of field and should not be used interchangeably. This is a common misconception that new photographers have.

I'll leave it to you guys to do your homework and figure out what's bokeh.
 

tsdh

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darrelchia said:
do note. Bokeh is NOT blurred background, or shallow depth of field and should not be used interchangeably. This is a common misconception that new photographers have.

I'll leave it to you guys to do your homework and figure out what's bokeh.
Correct. That's why I'm saying: "Less DOF means --> higher chance of getting bokeh."
You will never get any bokeh if your image doesn't have blur portion.
 

mazeppa26

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#8
let me start...
bokeh, a word of jap origin....:)
 

Snoweagle

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tsdh said:
Correct. That's why I'm saying: "Less DOF means --> higher chance of getting bokeh."
You will never get any bokeh if your image doesn't have blur portion.
That's what i'm trying to say, at any aperture u still can achieve bokeh but depending on how far away is your subject from u and how much you zoom.
 

tsdh

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#12
Snoweagle said:
That's what i'm trying to say, at any aperture u still can achieve bokeh but depending on how far away is your subject from u and how much you zoom.
If the whole frame all sharp (in focus), can you get bokeh?
 

Snoweagle

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#13
tsdh said:
If the whole frame all sharp (in focus), can you get bokeh?
If everything is sharp, let's say infinity focus, there won't be any bokeh at all. Usually this is achieved by taking distant objects.
 

tsdh

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#14
Snoweagle said:
If everything is sharp, let's say infinity focus, there won't be any bokeh at all. Usually this is achieved by taking distant objects.
That's right. Therefore if somebody want to get bokeh in his/her photo, he/she must create a photo with some blur portion. So he/she must know how to create a blur background, or in other word; must understand what DOF is.
The next step:
Blur background will not always produce bokeh (blur is not the same as bokeh). So how to create bokeh? by including a high contrast dot in that blur portion.
Bokeh is actually a high-contrast dot (or a small area) which is greatly out of focus, thus it become a circle (if you want to understand this phenomenon, please read any article about "Circle of Confusion").
Some lenses produce a nice bokeh, some others not. The shape of bokeh will be determined by 2 factors: aperture blade, and the amount of spherical-aberration correction in the lens. Over-corrected lens, tend to come with ring-shaped bokeh.
Below are the sample images:
This is the image taken using Nikon 35-70/2.8, the bokeh is irritably ring-shaped due to spherical-aberration over-correction in the lens, but nevertheless this lens is one of the sharpest zoom from Nikon.


This picture was taken using Nikon 80-200/2.8, the bokeh is nicely shaped. (both pictures were taken at 70mm f/4 and 80mm f/4 respectively).
 

Snoweagle

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#15
Correct, the nicer the bokeh, the better the background blur. Whenever i use my 50mm f/1.8 II to take a pic, especially with lights behind, i always notice that the bokeh of the lights is pentagon due to only 5 diaphragm blades of this lens. Even when i open it to f/1.8, it's still the same.

I think to produce good bokehs is still according to the greater number of blades to make it more round and as i've learnt earlier, or with lens that have a curved diaphragm blades.
 

tsdh

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#16
Diaphragm blades is just half of the story. It only determines the outer shape of bokeh (whether it is pentagonal or hexagonal or round).
But the most important factor, is the lens design.
A ring-shaped bokeh will still look bad even if its shape is fully round. And a lens with that kind of bokeh, can not produce a smooth background blur with blending colors, although it is usually able to produce very sharp image.
This is one of the properties which is emphasized on a "portrait lens". (bokeh will be mostly important on portraiture and macro photography).
 

Snoweagle

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#17
tsdh said:
Diaphragm blades is just half of the story. It only determines the outer shape of bokeh (whether it is pentagonal or hexagonal or round).
But the most important factor, is the lens design.
A ring-shaped bokeh will still look bad even if its shape is fully round. And a lens with that kind of bokeh, can not produce a smooth background blur with blending colors, although it is usually able to produce very sharp image.
This is one of the properties which is emphasized on a "portrait lens". (bokeh will be mostly important on portraiture and macro photography).
Yes, only these 2 fields are especially important when dealing with bokeh. For portrait lens i think the 85mm has the best bokeh, even the 50mm f/1.4 is very gd.
 

tsdh

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#18
Snoweagle said:
Yes, only these 2 fields are especially important when dealing with bokeh. For portrait lens i think the 85mm has the best bokeh, even the 50mm f/1.4 is very gd.
Based on my experience, Leica lenses have excellent bokeh. Generally, german lens designers are very particular with bokeh, thay pay attention in correcting the spherical aberration. For Nikon lenses (I'm a Nikon user, so I only know about this brand), only the three portrait lenses have praisable bokeh: 85mm, 105mm, 135mm.
Nikon also produced 105/2 DC, with spherical aberration control to alter the amount of blur (they call it "Defocus Control"). This lens is purposely designed for portraiture.
 

Snoweagle

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#19
tsdh said:
Based on my experience, Leica lenses have excellent bokeh. Generally, german lens designers are very particular with bokeh, thay pay attention in correcting the spherical aberration. For Nikon lenses (I'm a Nikon user, so I only know about this brand), only the three portrait lenses have praisable bokeh: 85mm, 105mm, 135mm.
Nikon also produced 105/2 DC, with spherical aberration control to alter the amount of blur (they call it "Defocus Control"). This lens is purposely designed for portraiture.
Well i'm not a nikon user so i only know about canon ones. Yes Leicas are very gd for their lens qualities but price is a major drawback.
 

lsisaxon

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#20
tsdh said:
Based on my experience, Leica lenses have excellent bokeh. Generally, german lens designers are very particular with bokeh, thay pay attention in correcting the spherical aberration. For Nikon lenses (I'm a Nikon user, so I only know about this brand), only the three portrait lenses have praisable bokeh: 85mm, 105mm, 135mm.
Nikon also produced 105/2 DC, with spherical aberration control to alter the amount of blur (they call it "Defocus Control"). This lens is purposely designed for portraiture.
Nikon has 2 AF-DC lenses. 135/2 and 105/2.
 

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