Ring Bokeh

[olythirds]

I've been dabbling with Bokeh abstracts, and I'm struggling with the broken that I'm getting with the 12-100 and the 40-150.
Below is an example made with the 12-100. I'm not sure how to avoid this. Any tips would be hugely appreciated! The attached example is a screenshot of the unprocessed image as rendered in LR.

Is PP the only way to address this?

Many thanks in advance!

[Wreckdiver]

Lens flare, you are ponting the lens into a bright light source. Turn the camera out of the direct light path.

Steve

[olythirds]

Lens flare, you are ponting the lens into a bright light source. Turn the camera out of the direct light path.

Steve

hmm. But this is what I want to photograph. I am trying to photograph the bokeh patterns. The Image that I shared above is the one I wanted to make, provided the ridges in the bokeh weren't present.

[Walti]

hmm. But this is what I want to photograph. I am trying to photograph the bokeh patterns. The Image that I shared above is the one I wanted to make, provided the ridges in the bokeh weren't present.

Do you mean that you want the bokeh circles not to be seven sided but more round? The only way to change that is to use a lens with a different aperture construction, e.g 9 or more aperture blades... I'm not sure this is what you mean though?

[Walti]

Oh and.... is the image you've shown with the aperture wide open on the lens? Playing with the aperture may make a difference...

If I understand correctly, the only point where the aperture is truly fully open is at max focal length and minimum f number on a fixed f stop zoom, as the aperture reduces as you zoom back to maintain the f stop relationship between aperture diameter and focal length. so at 12mm the aperture at f4 would need to be 12/4 mm or 3 mm diameter and at 100mm f4 it would need to be 100/4mm or 25mm diameter, so even at f4 the aperture is closing as you zoom to 12mm focal length. (I may have the maths wrong for which I apologise, but I think the principle is correct!)

[moggi1964]

Try one of these on an adapter: Tair 11A 135mm F/2.8

20 aperture blades is going to give you very nice and round bokeh.

You could also try the Helios 44-2 which is a 58mm that throws up some interesting bokeh swirls.

[olythirds]

Thank you, I will look around if I can find one to try.

[olythirds]

Do you mean that you want the bokeh circles not to be seven sided but more round? The only way to change that is to use a lens with a different aperture construction, e.g 9 or more aperture blades... I'm not sure this is what you mean though?

Hi.. I'm referring to the ridges that are visible inside the circles. I don't mind the shape of the circle. Its the ridges within which look weird to me. And one of them (the one at the bottom right) has a spot.
The aperture was widest (f4) as this is the 12-100

[Walti]

What focal length?

[olythirds]

There are no examples on this page, but I think what I'm seeing above is what this page refers to as "Ring shaped bokeh" https://asia.olympus-imaging.com/pro.../mlens/f12pro/

[Walti]

There are no examples on this page, but I think what I'm seeing above is what this page refers to as "Ring shaped bokeh" https://asia.olympus-imaging.com/pro.../mlens/f12pro/

Ah... Got you, I think the example you have posted would be classed as solid Bokeh on that scale, as it is a single density across it, a ring would be more like a mirror lens gives, e.g. doughnut shaped.

The ridges could be several things....

Are the points that are in the photo a single point of light?
How magnified is that image, .i.e. is that the whole image or a very small portion?
Is the image RAW or JPEG, and has ANY sort of correction been applied? (Lightroom does apply a couple of corrections before you start, you can remove these)

The graining could be sensor noise, dependant on size, JPEG compression artefacts or the shape of the light source coming through dependant on all the above (in part or combination)

[Walti]

Oh and the dot could be dead pixel(s) dirt on the lens or sensor - as it's round I'd be looking for a spec of dirt or water somewhere!

[Mark_R2]

The ridges, often referred to as onion ring bokeh, are caused by aspheric elements in the lens. Aspheric lenses are made by a diamond turning process (or the moulds from which the lenses are replicated are turned). The turning marks are extremely fine but act like a diffraction grating and this gives the ridge structure in the out of focus highlights. The way to avoid this is to use a lens without any aspheric elements, or maybe a higher quality lens in which the aspherics are made to higher precision (or maybe that have a post-turning polish to remove the ridges). Most modern lenses have aspherics in them now, so you should look at some classic old lenses. Triplets are well known to give soap bubble bokeh. The Trioplan is well known but they are pretty expensive to buy now.

[Mark_R2]

Looking at the original image closely, the ridges don’t form continuous rings so the lenses probably have been additionally finished to reduce the effect. The lenses are ‘Pro’ grade so that would make sense. So, an older lens is probably the best way forward.

[wornish]

Think I may have lost the plot. I am struggling to understand what is being asked in the original post?

What is it that you are trying to achieve?

No offence meant. But, sorry if I am being thick!

This thread is going around in circles IMHO.

[Jax]

You are not alone Dave ! Maybe it's going round in bokeh circles ?

[olythirds]

Circles

I've added some examples below https://www.e-group.uk.net/forum/for...978#post825978
and after some digging around, found the reason https://www.e-group.uk.net/forum/for...988#post825988

[moggi1964]

I've been dabbling with Bokeh abstracts, and I'm struggling with the broken that I'm getting with the 12-100 and the 40-150.
Below is an example made with the 12-100. I'm not sure how to avoid this. Any tips would be hugely appreciated! The attached example is a screenshot of the unprocessed image as rendered in LR.

Is PP the only way to address this?

Many thanks in advance!

I meant to say that the 'ridges' or rings inside each bokeh circle remind me of diffraction rings from my astronomy days.

Might not be relevant but thought I would mention it.

Bokeh images is a neat idea by the way.

[olythirds]

Many thanks to everyone who responded
My response was delayed as I was executing further tests will all my lenses. As none of my lenses are 1.2 primes, the bokeh contours are more or less the same on all, including the pro zooms and the non-pro primes.

So the only way out was to handle this in PP.

I guess the confusion arose because I'm trying abstracts based on patterns of bokeh, and usually Bokeh is not the subject of photographs. These are the full images, these are part of my abstract art exhibit. I am not pixel peeping

Here are some examples before / after using PP to smoothen out the contours. The left section of each image has the "before" and the right has the "after". These images were made at the widest aperture, by manually defocusing.

[Ian]

Are the circles not completely circular at full aperture?

Ian

[olythirds]

I meant to say that the 'ridges' or rings inside each bokeh circle remind me of diffraction rings from my astronomy days.

Might not be relevant but thought I would mention it.

Bokeh images is a neat idea by the way.

Thank you! Trying to push myself to use all aspects of the gear to make art.

As you pointed out, this is probably due to diffraction. Many examples on this page also have the same contours. https://photo.stackexchange.com/ques...m-bokeh-effect

According to this page, https://web.archive.org/web/20140722...ics/bokeh.html what I've reported is sometimes called Onion-ring bokeh and it results either from aspherical elements, or diffraction.

[olythirds]

Are the circles not completely circular at full aperture?

Ian

They are not circular at full aperture - but that's not the aspect I'm trying to address. I was trying to figure out what was causing the contours / ridges within the circles, and this link seems to give that answer. https://web.archive.org/web/20140722...ics/bokeh.html

So for what I'm trying to achieve with the lenses I have, I will need to resort to post processing.