Need some help predicting Bokeh results

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Originally Posted by ScoutR

Boy did that get copied and pasted to my Cambridge Tips documents quickly.
Yup, that helps (understatement) it is EXACTLY what I wanted to know and the nutshell format works wonders for me.
Now I can quit studying EXIF on my old shots, and go and watch a movie. :D

Thank you so much
Wendy

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No worries :)

By the way, I've just realised that I've worded part of the above badly ... a wider angle lens doesn't capture more detail per sec - what I was meaning is the wider field of view shows us more of the background, which has an effect on percieved sharpness. Still not explaining it well, but hopefully you get the idea!

Yup, got it - with regards to throwing background out of focus:

Combined with other factors

Telephoto Good
Wider angle Not as good

Wendy

PS: If it helps Wendy, have a look at the Bokeh of my shots in this thread here. Basically all long focal lengths / wide apertures / and good background seperation.

(which is what I was shooting for).

Oh Oh, I think I might have to revise my definition of bokeh again. I see what you mean by the background in all of these shots, but according to the definition I decided on earlier I don't see bokeh in any of these except maybe 4,5, and 6 and the last one, but even in those the light colours just look out of focus, they do not look like disks round or cornered.

How do you define bokeh?

Wendy

Hi Wendy,

If you search for ‘DOF calculators’ you can download calculators or charts that will give you DOF distances for each focal length and aperture setting. It will also give you the hyperfocal distance, just like the tutorial. If you have an i-phone you can also download an App for DOF calculations.

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Originally Posted by ScoutR

How do you define bokeh?

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Well rightly or wrongly, I think of it as a characteristic of how background elements are out of focus - but don't forget, that's going to depend on the shape of the item. This shot is probably a good example ...

http://www.pbase.com/cjsouthern/imag...2834/large.jpg

Personally I consider all the OOF background stuff to have good bokeh in this shot. Many would probably consider the bokeh to be only the specular highlights above Ellie's head, but I think (for example) the way the plants just below the shoulder line where it transitions from brown to green is also part of it. From a "strictly speaking" point of view I haven't a clue which is correct; typically bokeh examples have a nice circular OOF area around something, but I'm guessing that that's only because it shows it best.

Put it this way ... what I described in my earlier post was all about maximizing the degree to which the background appeared to be out of focus; HOW that degree of out of focus appears is pretty much solely a function of the lens design (which - short of changing lenses - one can't do anything about).

Others might like to add to this.

:)

I have always considered Bokeh to be the smooth quality of the blur where you do not see the shape of aperture blades in the blur. It also depends on the subject matter but generally the blur should be smooth.

The first shot below was taken with my Nikor 70 – 300m lens at 300m with the aperture wide open. With the specula highlights within the blur are visible but round and smooth.

http://i56.tinypic.com/2dvqyxt.jpg

The next shot was also taken with the Nikor 70 – 300 m at 80mm. I wanted to highlight the thistle and also show the thistle in its environment.

http://i52.tinypic.com/rwv3wl.jpg

The next was using my Tamron 180 Macro, which I love. I was the same distance from the thistle as in the second example but the background has been rendered as a tonal value. It is important to place the tonal elements in the shot in appropriate places to take advantage of the blurred tonal patches.

http://i53.tinypic.com/2ros315.jpg

This shot of grasses was taken with the Tamron 180 m macro and I carefully placed the dead and green grass behind the subject to form the background.

http://i55.tinypic.com/2eby5gl.jpg

As Colin says the focal length of the lens combined with the camera to subject distance and subject to background distance makes all the difference as to how the background is rendered.

They do say that two identical lenses can have different Bokeh qualities. It is not something you can buy, you can just be lucky with your lens.

I hope other add to this discussion.

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Originally Posted by Colin Southern

Well rightly or wrongly, I think of it as a characteristic of how background elements are out of focus - but don't forget, that's going to depend on the shape of the item. This shot is probably a good example ...

http://www.pbase.com/cjsouthern/imag...2834/large.jpg

Personally I consider all the OOF background stuff to have good bokeh in this shot. Many would probably consider the bokeh to be only the specular highlights above Ellie's head,

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Excellent example. I would be one of the ones who thought the bokeh was just the round specular highlights.

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but I think (for example) the way the plants just below the shoulder line where it transitions from brown to green is also part of it. From a "strictly speaking" point of view I haven't a clue which is correct; typically bokeh examples have a nice circular OOF area around something, but I'm guessing that that's only because it shows it best.

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I will start to pay attention to the transitions too. Now I am wondering if poor Bokeh might be one possible cause of some types of banding that I see on out of focus transitions. For example if the photo is properly exposed the transitions should be smooth, but if bokeh is not good, the transitions could be abrupt and rough looking?

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Put it this way ... what I described in my earlier post was all about maximizing the degree to which the background appeared to be out of focus; HOW that degree of out of focus appears is pretty much solely a function of the lens design (which - short of changing lenses - one can't do anything about).

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Yup, I'm with you on everything in your earlier post. Right now this is just about definitions, which won't really help me take a better shot - just curious because I thought I knew what the word meant, but am finding there seem to be different ideas on the subject.

Thanks again for the help, I'm going to go and have a look at Peter's shots. I think he defines bokeh as a nice smooth out of focus background too. Based on a quick look, I don't see many specular disks.

Wendy

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Originally Posted by Peter Ryan

I have always considered Bokeh to be the smooth quality of the blur where you do not see the shape of aperture blades in the blur. It also depends on the subject matter but generally the blur should be smooth.

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OK, I understand what you are saying but if the background is completely out of focus due to shallow DOF and the other variables, will the shape of the aperture blades really make any difference?

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The first shot below was taken with my Nikor 70 – 300m lens at 300m with the aperture wide open. With the specular highlights within the blur are visible but round and smooth.

http://i56.tinypic.com/2dvqyxt.jpg

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I love the background in this. It is also the only one of the series that meets my present definition of Bokeh. It's also one of the few shots I've seen where I like the oof specular highlights. Now how much of that has to do with the lens and how much has to do with other characteristics of the background and the way the shot was taken I don't know. I am assuming that bad bokeh on this shot would distinct lines at the major tonal transitions and may also show up as hexagonal disks instead of round.

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The next shot was also taken with the Nikor 70 – 300 m at 80mm. I wanted to highlight the thistle and also show the thistle in its environment.

http://i52.tinypic.com/rwv3wl.jpg

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Ok, without the calculator - was the f stop around 5.6 - 8. I don't see aperture in the EXIF of any of these shots

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The next was using my Tamron 180 Macro, which I love. I was the same distance from the thistle as in the second example but the background has been rendered as a tonal value. It is important to place the tonal elements in the shot in appropriate places to take advantage of the blurred tonal patches.

http://i53.tinypic.com/2ros315.jpg

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Now this is what I am trying for. I love this. Again I cannot see the aperture but it must be 2.8 or less???? This is an example of what I mentioned above about the background being totally out of focus. Does the shape of the blades really affect or even create bokeh in this type of background?

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This shot of grasses was taken with the Tamron 180 m macro and I carefully placed the dead and green grass behind the subject to form the background.

http://i55.tinypic.com/2eby5gl.jpg

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Another winner, and again exactly what I have been trying for lately. Getting two or more tones to blend in with the subject all while dealing with the wind and trying to maintain focus is difficult.
My question on the "bokeh" in this on involves the transitions from gold to green. Can the shape of the aperture blades cause uneven colour transitions in a background that is this much out of focus?

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As Colin says the focal length of the lens combined with the camera to subject distance and subject to background distance makes all the difference as to how the background is rendered.

They do say that two identical lenses can have different Bokeh qualities. It is not something you can buy, you can just be lucky with your lens.

I hope other add to this discussion.

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Thanks very much for taking the time to post these examples and for the suggestions. Now that I have a better idea of the other 2 variables required to produce shallow DOF, I think I will get better results. Bokeh will end up being whatever it is - but I need to be able to get better control of DOF. I think I can do that now. Time will tell. :)

Wendy

Hi Wendy,

Below are the aperture setting for each image.
1/160 @f5.6
F8
F6.3
F4

The following is an extract from Wikipedia and might help. You need to draw a distinction in your mind about DOF and Bokeh. Bokeh is just the Japanese word for Blur and this occurs outside of the DOF (see below). The first shot of mine would be classed as coarse bokeh and the others smooth bokeh.

Depending upon the construct of the lens and its characteristics the aperture blades can be reflected in the blur and can be distracting. When we talk about good quality blur (or Bokeh) we are trying to see smooth transition between tones without seeing the aperture blades mirrored in the blur.

"In photography, bokeh (pronounced /boʊ'kɛ/) is the blur,[1][2] or the aesthetic quality of the blur,[3][4][5] in out-of-focus areas of an image, or "the way the lens renders out-of-focus points of light."[6] Differences in lens aberrations and aperture shape cause some lens designs to blur the image in a way that is pleasing to the eye, while others produce blurring that is unpleasant or distracting—"good" and "bad" bokeh, respectively.[1] Bokeh occurs for parts of the scene that lie outside the depth of field. Photographers sometimes deliberately use a shallow focus technique to create images with prominent out-of-focus regions.

Bokeh is often most visible around small background highlights, such as specular reflections and light sources, which is why it is often associated with such areas.[1] However, bokeh is not limited to highlights, as blur occurs in all out-of-focus regions of the image."

There are three things that determine the DOF being, aperture setting, focal length of the lens and camera to subject distance (and as Colin points out subject to background distance as well).

Thanks Peter: When I saw the reference to Wikipedia I thought now why didn't I do a search and check other sites so I did and I got my answer. Because there are too many differing opinions.
I think what you have written pretty well sums it up, and it makes sense to me. :)

Thanks again
Wendy

No probelms Wendy. I like this type of discussion.

To take it a fraction further there is a concept called 'Nicen Bokeh' where an object in the blur divides. You will notice the branch in the background divides. I understand this is a design concept that is very pleasing to the Japanese.

http://i53.tinypic.com/f9i99k.jpg

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Originally Posted by Peter Ryan

Hi Wendy,

If you search for ‘DOF calculators’ you can download calculators or charts that will give you DOF distances for each focal length and aperture setting. It will also give you the hyperfocal distance, just like the tutorial. If you have an i-phone you can also download an App for DOF calculations.

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Apps also available for Android phones. Take a look HERE
Edit: And it works brilliantly

Hi, Wendy, and all!

I've been so glad to see this thread!!! I've been working on bokeh, background and DOF, too (along with everything else :rolleyes:). I was going to suggest the Wikipedia article. That is where I found my answer when everyone seemed to be using the word "bokeh" a couple of months ago. I'm going to put the link here, even though it sounds like you guys have read it already. It seems to bring together everything that everyone's touched on so far (well,..... mostly.:)) Also, as you've seen, it gives some great broken down examples, too.

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

Also, I've had some people helping me a little with this issue (not that I've totally been practicing it :o) and I've been given some DOF calculators. I'm embarrassed to ask it but do you guys REALLY use them??? I was thinking that it was more like for a general frame of reference and understanding..... :o

Anyway, I was working on it and I got these two photos. Please, please, pretty please, may I share mine, too? :) Are these what we're talking about?

http://backup.cambridgeincolour.com/...b29f3b3a_z.jpg

In this one, the insect isn't as illuminated as it should be, but, I love this shot! (It just makes me laugh, Wendy, when I hear you talking about trying to focus on the subject with a high enough shutter speed....or whatever it is that you actually said...) - I was losing my mind because of the breeze!!!

http://backup.cambridgeincolour.com/...02c4db84_z.jpg

So, I don't see the blades in these. Are they there? AND, this is why I want the Canon 60mm f 2.8 macro prime lens. Among other things, it's reported to produce a lovely bokeh. However, I think that it's really good for me to just be using the 18-55mm kit lens, though. I'm learning a lot, every day! (if you know what I mean.)

Anyhoo, thanks, again, for this thread. It's really helpful and I'm learning! :) Is there something else that you hear or see that I'm not getting? (I'm sure there is......) In other words, more illumination on the subject?????? AND, these are gorgeous - very pleasing - photos, everyone (Wendy, Peter, Colin......)!!! I really should say this more often but, believe it or not, am still shy."

Hi Katy: Thanks for posting, I wish more people would. Really there is no reason to be shy here, and the more input the better.

I laughed when I read what you said about the calculators. I get a headache just thinking about it. :eek: Maybe someday, but right now after reading about hperfocal distance the only circle of confusion I can relate to is the one in my head. Not that I discount what is being said. I just don't get it at this point in my photography adventure. All in good time. :)

With regards to bokeh, I would say it is excellent in both your shots. I hope others will chime in. In the first one the highlights in the spider are blown, but this is about backgrounds, and the background looks perfect to me. What is in the background of the first shot?
The background in the second looks quite good too. I might clone the light blue spot on the left, but that's just me. The bokeh looks ok but that one spot is a bit distracting.
I like the second shot as is, but I'm sure there are things that could be done to make the subject pop a bit more. Again though if we are talking about background and using DOF to advantage, then I do believe you've got it. :)

I hope you get more comments on these shots, my head is still spinning from circles of confusion and hyperfocal distances and calcuators and how to use them, and besides I'm more of a student myself, so my critiques are very basic and for the most part just personal opinion.

Thanks again for posting. I really would like to see what everyone has to say and lots and lots of sample shots.

Wendy

I've been browsing my catalogue and found these two examples, both take with the same lens, my 24-85 f2.8-f4 Nikkor

Shot 1 is taken at 85mm f4 and I think demonstrates the smooth bokeh obtained with the combination of maximum focal length and aperture. Shot 2 on the other hand, same lens, at 60mm f3.8 does not display the same creamy out of focus effect.

Shot 1
http://backup.cambridgeincolour.com/...k/DSC_4085.jpg

Shot 2
http://backup.cambridgeincolour.com/...k/DSC_4086.jpg

Thanks Mike - 2 great examples of what can be done with the same lens at different settings. The background in the first one is certainly something to aim for.
Of course if I'm understanding all this correctly (and please correct me if I am not) - the focal distance and distance between subject and background could also have factored into the differences and then there is the tone colours and lighting on the subject and background that also have to be considered.
All in all a lot of factors to consider, but I do think one could gage a pretty good idea of what to expect with lots of practise and consideration (no calculators though)
On my old film camera I used to have a DOF preview button that I used all the time. I think some digital cameras have this too. Handy thing to have. I know my Nikon does not have it, not sure about the Lumix. I'm still learning icon speak for that one, and am nowhere near having a grasp on all the settings.

Thanks again for posting. Hope to see more. I love the first shot.

Wendy

Hi Katy,

You couldn't resist adding the pictures and I couldn't resist trying to make it pop a bit more - you can blame Wendy ;)

http://i56.tinypic.com/dd2dcy.jpg

Sorry,

Here is another example similar to Mikes that I think shows the difference with just a different focal length. Even though technically DOF does not change (that's how I understood the tutorial anyway) You can see there is quite a difference in the blur of the background with all settings and distances the same but the first shot is at 62mm and the second at 170mm. The distance to subject for both shots is 500mm and they were shot within a minute of each other
Note: the first 2 are both shot with the Nikon D3000 18-200mm. These have not been processed other than LR presets.

#1 1/60s: f8: ISO 400: 62mm: Subject Distance 500mm
https://www.cambridgeincolour.com/fo...achmentid=7376

#2 1/40s: f8: ISO 400: 170mm: Subject Distance 500mm
https://www.cambridgeincolour.com/fo...achmentid=7377

#3 This is just a general idea of the type of leaves that are in the background
https://www.cambridgeincolour.com/fo...achmentid=7378

Wendy

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Originally Posted by ScoutR

Here is another example similar to Mikes that I think shows the difference with just a different focal length. Even though technically DOF does not change (that's how I understood the tutorial anyway) You can see there is quite a difference in the blur of the background with all settings and distances the same but the first shot is at 62mm and the second at 170mm. The distance to subject for both shots is 500mm and they were shot within a minute of each other
Note: the first 2 are both shot with the Nikon D3000 18-200mm. Wendy

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Hi Wendy,

The first thing you need to get under control is DOF. You say from your understanding that DOF does not change but the level of blur does.

DOF does change and the blur occurs sooner and quicker – read below.

Changing Aperture.
With a subject sharply focused 15ft (4.5m) from the camera with a 50 mm lens.

Working at f2 DOF extends from 14ft (4.2m) to 16.5ft (5m) a distance of 2.5 ft (0.7m).

A t f8 DOF is 11 – 33ft (3.3 – 10m), a total of 22 ft (6.7m).

At f16 DOF is from 8ft (2.4m) to infinity.

Changing Distance.

If we change the subject distance using the same 50 mm lens set at f8.

With a subject at 5ft (1.5m) DOF is 4.5 – 6ft (1.3 – 1.8m) giving 1.5ft (0.4m) in sharp focus.

At 10ft (3m) DOF becomes 7.5 – 14ft (2.2 – 4.2m), total sharpness of 6.5ft (2m).

And at 15ft (4.5m) DOF is 11 – 33ft (3.3 – 10m) giving 22ft (6.7m)

Changing Lens.

Using different focal length lenses with the aperture is set to f8 and subject distance constant at 15ft (4.5m).

A 135mm telephoto lens is in sharp focus from 14.5 – 16ft (4.3 – 4.8m), only 1.5ft (0.4m).

A 50mm lens gives11 – 33ft (3.3 – 10m), a sharp field of 22ft (6.7m).

And with a 28mm lens the DOF is from 6ft (1.8m) to infinity.

So there are three elements that effect DOF and you can control all three to get different results in your image.

I do not use calculators just knowledge from time practising these techniques and knowing what my lenses will do. The hardest thing in the field sometimes is to work out how far the subject is away from you so you can input details to a calculator. When working in a controlled environment you might want to be more specific, particularly macro work where DOF usually extends 50% in front and 50% behind, rather than one-third/two-thirds.