# Getting Portrait Bokeh..



## RSisco (May 25, 2011)

I am obviously new to this forum and to photography. I have a new D5100 and two lenses, both in my sig. One is the kit lens (18-55) and one is a 55-300. They seem to work well for some things, but if I want to take a portrait with a backdrop the backdrop is in focus as well as the subject. I want the backdrop to blur so it's nice and smooth and doesn't distract from the subject. I tried a few setting and came to a conclusion that I need another lens!?. Right?

I did a bit of reading and I think what I want is either the..

AF-S NIKKOR 50mm f/1.8G

or the

AF-S NIKKOR 35mm f/1.8G

Suggestions? comments?


----------



## Kbarredo (May 25, 2011)

If you want more bokeh the longer focal length has more. the longer the focal length the shorter the dof. A 300mm 1.8 will be much shallower than a 25mm 1.8


----------



## willis_927 (May 25, 2011)

Not necessarily...  There is a few other ways that you can obtain a nice blurred background (although, yes getting a lens with a larger aperature can also do this).

A few other things to consider are:

1) Increase focal length- with your 55-300 you have a good amount of focal length. Shooting at 300mm, (given a set aperature and shutter speed) vs shooting at 55mm (given the same aperature and shutter speed), will result in the background being much more out of focus (at 300mm).
2) Focusing Distance - focusing on the subject when you are closer to it will make the background much more blurred than if you focus on the subject from a long distance away.


----------



## willis_927 (May 25, 2011)

Kbarredo beat me to some of that.


----------



## mrpink (May 25, 2011)

More distance between your subject and background will help as well.

Bokeh is not DoF.






p!nK


----------



## SwiftTone (May 25, 2011)

You should note that the 35mm 1.8G is a DX lens and the 50mm 1.8G is a full frame lens, which really acts like a 75mm. Out of these 2, the 50mm should be better, however, its not even released yet so no one can speak of the optical quality, though it should be good.


----------



## seekinglight (May 25, 2011)

The bigger the aperture, the more bokeh. This is not the same as the f-stop. A 100mm f2 lens has twice the aperture size as a 50mm F2 lens. So between your two choices, the 35mm will not have as much bokeh as the 50mm.

The 85mm lens is popular for portraits because of the compromise of having a big aperture and still being able to take portraits in a normal sized room. With the 50mm, see if you can be closer to the subject than the subject is to the background.


----------



## RSisco (May 25, 2011)

seekinglight said:


> The 85mm lens is popular for portraits because of the compromise of having a big aperture and still being able to take portraits in a normal sized room.


 
I think that is the issue I am having. I am shooting in a livingroom at the moment, so I am limited on space. I have the backdrop against the wall, the subject 4 or 5 feet from that. So I have about 10 feet of room left to work in.


----------



## MWG (May 25, 2011)

mrpink said:


> More distance between your subject and background will help as well.
> 
> Bokeh is not DoF.
> 
> ...


 
This. 

The infinity point gets farther from the camera as the focal length increases, meaning the shallow depth of field becomes more proclaimed on longer lenses.


----------



## RSisco (May 25, 2011)

Thank you all for the input. I will mess around with the camera some tomorrow. Everyone is in bed and I don't want lights to wake the babies. 

Rick


----------



## MissCream (May 25, 2011)

Didn't read any of the above posts. Put your subject a lot further away from the background and put your f# as low as it will go. If you're still not getting bokeh with the lenses you have then move the subject even further away from the background!


----------



## Dao (May 26, 2011)

If you shoot indoor inside a small room with a backdrop, I think it is kind of tough to create a nice blur background.  You maybe able to make the background out of focus, but may not be able to create creamy blur background.   But why do you want to do that?  You have a very ugly looking backdrop?


----------



## The_Traveler (May 26, 2011)

MissCream said:


> Didn't read any of the above posts.


 
Ditto


----------



## KmH (May 26, 2011)

Kbarredo said:


> If you want more bokeh the longer focal length has more. the longer the focal length the shorter the dof. A 300mm 1.8 will be much shallower than a 25mm 1.8


Not if the subject scale in the frame is the same. With a longer focal length lens, you have to be further back from the focal point to maintain the same subject scale in the frame.

If the subject scale is the same the DOF range of distance will be the same for both focal lengths. What the longer focal length does is compresses the background making it appear closer to the subject, which makes the blurred elements appear larger in size, not more blurred. Obviously, in a studio or home setting there may not be enough space to use longer focal lengths.

Everyone seems to concentrate on lens aperture, and ignore the fact that the focal point distance from the camera has a lot to do with DOF. In other words you can also change the DOF by moving away from, or getting closer to your subject with the same focal length.

Four things effect DOF, so you need to consider all 4 when setting up a shot:

Focal point to background distance.
Focal point to camera distance.
Lens focal length.
Lens aperture.
As mentioned elsewhare bokeh and a blurred background are not the same thing.

Bokeh is a subjective visual quality of the blur that a particular lens produces. That subjective visual quality is a function of the "circle of confusion' a lens produces. The circle of confusion a lens produces is affected by the number and shape of the lens aperture blades, and by how the lens maker controlled the spherical aberration the lens produces. http://en.wikipedia.org/wiki/Circle_of_confusion

From http://en.wikipedia.org/wiki/Bokeh


> Although difficult to quantify, some lenses enhance overall image quality by producing more subjectively pleasing out-of-focus areas. Good bokeh is especially important for large-aperture lenses, macro lenses, and long telephoto lenses because they are typically used with a shallow depth of field. Bokeh is also important for medium telephoto "portrait lenses" (typically 85&#8211;150 mm on 35 mm format) because in portraiture photography, the photographer typically seeks to obtain a shallow depth of field to achieve an out-of-focus background and make the subject stand out.


----------



## Derrel (May 26, 2011)

The 35mm 1.8 AF-S G-Nikkor is known as a lens with atrociously poor bokeh. Bokeh is the quality if the out-of-focus regions in an image. Not "how out of focus the background or foreground" is, but how pleasingly the OOF areas are rendered by the lens.

You are looking to create "selective focus". Unfortunately, with a limited shooting area, with the subject quite close to the background, it is going to be exceedingly difficult to well and truly separate the focus on the foreground from the background's degree of focus. THIS IS A PROBLEM with small-sensor cameras!!! They have greater depth of field at each angle of view and at each subject size in the picture, compared against cameras that use BIGGER sensors or bigger film to capture their images.

Do what you can.


----------



## AgentDrex (May 26, 2011)

hhahahahahaha...more bokeh....hahahaha...sorry...I think milk just came out my nose...and I'm not drinking milk...


----------



## AgentDrex (May 26, 2011)

But seriously...if you want to have nice, pleasing bokeh (IMHO)...I find water drops make for some nice creamy OOF "circles" or anything small and reflective in the background....you could also try to shape the "circles" with a cutout placed over the lens

I have the same problem with the background too in focus...in my efficiency...I cannot get far enough way to get a small enough sliver of focus to soften the background and keep the entire subject in proper focus...so I try to go for a very dark background...small aperture...fast shutter speed (according to amount of light...) and hopefully none of the light hits the background....but I'm a weirdo, so take what I say with a grain of salt/cheese/sand blah blah blah


----------



## gsgary (May 26, 2011)

No,you will not get what you want shooting with  and a backdrop any lens will do for that because you will be shooting at F8 in the studio you do not get as you put it 
Portrait bokeh


----------



## GeneralBenson (May 26, 2011)

SwiftTone said:


> You should note that the 35mm 1.8G is a DX lens and the 50mm 1.8G is a full frame lens, which really acts like a 75mm. Out of these 2, the 50mm should be better, however, its not even released yet so no one can speak of the optical quality, though it should be good.


 
Just to calrify, the DX 35/1.8 and FX 50/1.8 are both equally affected by the crop factor of the D5100. So the 50 would act more like a 75, and the 35 would act more like a 52 or so. The focal length of DX lenses is still represented in FX standards.


----------



## OrionsByte (May 26, 2011)

GeneralBenson said:


> SwiftTone said:
> 
> 
> > You should note that the 35mm 1.8G is a DX lens and the 50mm 1.8G is a full frame lens, which really acts like a 75mm. Out of these 2, the 50mm should be better, however, its not even released yet so no one can speak of the optical quality, though it should be good.
> ...


 
Doesn't the crop factor make the 50mm lens "act like" a 75mm lens in terms of field-of-view only, and not in terms of depth-of-field?  The lens is projecting the same image no matter what camera it's attached to, but if that camera has a crop sensor it's just trimming off the edges, which wouldn't affect the DOF.  The sensor can have other effects on the DOF, but theoretically speaking, if you had a 50mm FX lens and a 75mm DX lens and took a shot with each using the same camera without changing any other variables, the 75mm lens would have a shallower DOF but the FOV would be identical.

Right?


----------



## KmH (May 26, 2011)

OrionsByte said:


> GeneralBenson said:
> 
> 
> > SwiftTone said:
> ...


Nope!, not if you don't change any other variables.

If you go to www.dofmaster.com to use the DOF calculator, you have to select what camera you are using, because the calculator has to take the crop factor into account.


----------



## 2WheelPhoto (May 26, 2011)

GeneralBenson said:


> SwiftTone said:
> 
> 
> > You should note that the 35mm 1.8G is a DX lens and the 50mm 1.8G is a full frame lens, which really acts like a 75mm. Out of these 2, the 50mm should be better, however, its not even released yet so no one can speak of the optical quality, though it should be good.
> ...


 
^^^^  this. because a 35mm lens will still be "35mm" no matter what body it goes on. After the crop factor of the D5100 body its 52 all day.


----------



## OrionsByte (May 26, 2011)

KmH said:


> OrionsByte said:
> 
> 
> > GeneralBenson said:
> ...


 
Okay I don't know why I'm not wrapping my head around this today.  I seem to be having an off week for my photo brain.

Why would simply cropping an image decrease the DOF?  Crop sensors are crop sensors because the image projected by the lens is larger than the sensor, right?  So the image projected by a 50mm lens is the same regardless of what body it's on, and the sensor is recording different portions of that image.  So if it's the same image, why would the DOF change from camera to camera?

I knew that different camera bodies had an effect on DOF but I honestly thought that had more to do with the sensor design and capabilities than simply the crop factor.

I need to do some reading and figure out what part of the puzzle I'm missing.  :scratch:


----------



## Ryan L (May 26, 2011)

gsgary said:


> No,you will not get what you want shooting with  and a backdrop any lens will do for that because you will be shooting at F8 in the studio you do not get as you put it
> Portrait bokeh


 
Yeah I aimed for this, this past weekend....You have to get a LONG ways back to get that oof on the background...Problem is if you want the subjectstanding full length on a background you can only have so much distance.


----------



## Dao (May 27, 2011)

OrionsByte said:


> KmH said:
> 
> 
> > OrionsByte said:
> ...






This is what I understand.  Hope that make sense.



You are correct and on the right track.  Before we discuss Depth of Field (DoF).  Let's talks about Circle of Confusion (CoC).

In photography world, we need to define what is in focus, what is out of focus.  As you can see, it is affected by many factors.  So someone defined the CoC for us  better understand in focus or out of focus..
CoC is defined that when the largest blur spot appears to be a point by human eye in a certain condition. Take a look at the following image.


Image from "http://www.cambridgeincolour.com/tutorials/depth-of-field.htm"







From the above image, when you look closer, how many dots are in focus?  And when you stand farther away, how many dots are in focus?  As you can see, they changed    So if you develope a photo and view it in a very short distance, the "In focus / Out of focus" changes (=> so as DoF) (of course, if you enlarge the photo, and view it at the same distance, DoF also changed)

So for the CoC, they define the photo is developed on a regular photo size (8x10) and view it in a normal distance (about 10 inches).

If you take a photo with full frame sensor camera, without any modification, just print it on a 8x10 paper. (Paper A)
Then stand on the same spot and take a photo with a cropped body, without any modification, just print it on a 8x10 paper (Paper B)

You may notice the objects on Paper B is larger than in Paper A.  Because it is enlarged.  So the out of focus tree in the background may appear blurrier (CoC).  In other words, the DoF on Paper B is narrower.

Example:
Condition A: Camera = 5Dmk2, focal length = 50mm, f-stop = 5.6 subject distance = 10ft  ................... DoF = 4.25 ft
Condition B: Camera = 7D, focal length = 50mm, f-stop = 5.6, subject distance = 10ft  ................... DoF = 2.62 ft



But wait a minute, how come everybody said larger sensor body produce a narrower DoF?  It is because in order to have the *same framing*, the photographer with a full frame body need to walk closer to the subject and that affect the DoF.   So if you compare 2 portrait head shot type photos with the same framing (without any post processing), the one that shot with full frame body has a narrower DoF than the one shot with a cropped body.


----------



## Geaux (May 27, 2011)

Derrel said:


> *The 35mm 1.8 AF-S G-Nikkor is known as a lens with atrociously poor bokeh.* Bokeh is the quality if the out-of-focus regions in an image. Not "how out of focus the background or foreground" is, but how pleasingly the OOF areas are rendered by the lens.
> 
> You are looking to create "selective focus". Unfortunately, with a limited shooting area, with the subject quite close to the background, it is going to be exceedingly difficult to well and truly separate the focus on the foreground from the background's degree of focus. THIS IS A PROBLEM with small-sensor cameras!!! They have greater depth of field at each angle of view and at each subject size in the picture, compared against cameras that use BIGGER sensors or bigger film to capture their images.
> 
> Do what you can.



35mm 1.8 Bokeh Circles .... When I think of bokeh, this is all I really think or care about lol.











To say it's atrociously poor is going a little overboard imo.


----------

