What lenses "Swirl"

**goatsNdonkey** · 11-29-2016, 03:00 PM

Things in the background seeming to take on a life of their own is something one sees in swirly bokeh pictures. It isn't always pleasing. The effect can even be on the scary side of grating, but finally the question has to be whether the effect is fitting for the picture you're taking.

**W.j.christy** · 11-29-2016, 03:14 PM

Originally posted by goatsNdonkey

Things in the background seeming to take on a life of their own is something one sees in swirly bokeh pictures. It isn't always pleasing. The effect can even be on the scary side of grating, but finally the question has to be whether the effect is fitting for the picture you're taking.

I agree, I thought it would be a pretty neat picture, though, especially with the back ground I plan on using.

**Scorpio71GR** · 11-29-2016, 06:57 PM - **1 Like**

Sometimes under the right conditions my Rokinon 85 1.4 can produce similar results.

maltfalc · 11-29-2016, 07:04 PM - **1 Like**

the effect is caused by deeply recessed front elements or other design aspects that begin to block the light path as you move away from the center of the image. mounting a step-down ring or too long or narrow hood on your fa 50 will make it swirl.

**pres589** · 11-29-2016, 07:46 PM

maltfalc, will you get this sort of effect with an F or FA 50 Macro? Those have really deeply set front elements and I'm not sure if I've seen swirls in sample shots.

maltfalc · 11-29-2016, 08:32 PM

Originally posted by pres589

maltfalc, will you get this sort of effect with an F or FA 50 Macro? Those have really deeply set front elements and I'm not sure if I've seen swirls in sample shots.

the front opening seems wide enough that i wouldn't expect much swirl.

stevebrot · 11-29-2016, 08:44 PM - **1 Like**

Originally posted by maltfalc

the effect is caused by deeply recessed front elements or other design aspects that begin to block the light path as you move away from the center of the image. mounting a step-down ring or too long or narrow hood on your fa 50 will make it swirl.

This has not been my experience. My Helios 44M 58/2 will swirl with some subjects despite having a front element that is not particularly deep set and despite being used with a hood that is appropriate to the focal length. Other lenses in my bag with similar front element depth and focal length with the same hood do not swirl. My Sigma 50/2.8 has a very deep front element and never swirls.

Steve

maltfalc · 11-29-2016, 09:03 PM

Originally posted by stevebrot

This has not been my experience. My Helios 44M 58/2 will swirl with some subjects despite having a front element that is not particularly deep set and despite being used with a hood that is appropriate to the focal length. Other lenses in my bag with similar front element depth and focal length with the same hood do not swirl. My Sigma 50/2.8 has a very deep front element and never swirls.

Steve

never claimed all deep set front elements or only deep set front elements cause swirl. it has to be deep enough and with a narrow enough front edge to begin significantly obstructing the light path at an angle captured by the sensor, and other parts of a lens can cause the same obstruction.

stevebrot · 11-29-2016, 09:27 PM

Originally posted by maltfalc

never claimed all deep set front elements or only deep set front elements cause swirl. it has to be deep enough and with a narrow enough front edge to begin significantly obstructing the light path at an angle captured by the sensor, and other parts of a lens can cause the same obstruction.

Again, not my experience. Your claim is fairly novel and not something I have heard of before. I think it would be appreciated if you started a new thread with examples of how this works, preferably with/without a step-down/hood of the same subject and composition.

Steve

**clackers** · 11-29-2016, 09:41 PM

Originally posted by maltfalc

never claimed all deep set front elements or only deep set front elements cause swirl. it has to be deep enough and with a narrow enough front edge to begin significantly obstructing the light path at an angle captured by the sensor, and other parts of a lens can cause the same obstruction.

Do you have a reference for this, Maltfalc?

maltfalc · 11-29-2016, 10:06 PM

Originally posted by stevebrot

Again, not my experience. Your claim is fairly novel and not something I have heard of before. I think it would be appreciated if you started a new thread with examples of how this works, preferably with/without a step-down/hood of the same subject and composition.

Steve

not your experience in what way? my claim doesn't conflict with your experience. just look at the change in shape of the bokeh in a photo with swirl as it nears the edges vs one without swirl and it should become obvious what causes it. the main cause is the lightpath being constricted too much in front of or behind the iris, with things like edge softness, barrel distortion, etc. also contributing somewhat to the final look.

---------- Post added 11-29-16 at 11:10 PM ----------

Originally posted by clackers

Do you have a reference for this, Maltfalc?

nope. don't need one either. anyone on this forum can easily verify this for themselves in a few seconds with a camera, a fast lens and a hole.

**clackers** · 11-29-2016, 10:15 PM

Originally posted by maltfalc

nope. don't need one either. anyone on this forum can easily verify this for themselves in a few seconds with a camera, a fast lens and a hole.

Okay, your claim about the phenomenon *has* been challenged in this forum, and I've never read any reference to support your conclusion, and you don't seem to have either.

Is that a fair statement?

BrianR · 11-29-2016, 10:19 PM

Isn't the swirly bokeh (at least partially) caused by a hard optical vignetting that changes the shape of the aperture at off-axis angles? As in figure 2 here: Vignetting. There are other factors of course, so just having a deeply recessed front element isn't enough, but for a given lens if you added an inappropriately sized lens hood, or stacked a bunch of filters, the cats eye bokeh would be exaggerated? Should be easy enough to test with a roll of black cardboard and some Christmas lights.

I think there's other factors to the overall wiggy swirlies though, the soap bubble bokeh, a generally sharp thing in focus but soft elsewhere, or other funny things that tend to be "corrected" in more modern lens designs.

maltfalc · 11-29-2016, 10:25 PM

Originally posted by clackers

Okay, your claim about the phenomenon *has* been challenged in this forum, and I've never read any reference to support your conclusion, and you don't seem to have either.

Is that a fair statement?

i repeat, it takes literally a few seconds for you to see for yourself that i'm right.

**clackers** · 11-29-2016, 10:29 PM

Originally posted by maltfalc

i repeat, it takes literally a few seconds for you to see for yourself that i'm right.

I repeat, you have no reference.

What's your explanation with this:

New Petzval 58 Creates Bokeh Like No Other Camera Lens | Digital Trends

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11-29-2016, 03:00 PM	#16
goatsNdonkey Site Supporter Join Date: Jan 2016 Location: Fulton County, Illinois Posts: 3,736	Things in the background seeming to take on a life of their own is something one sees in swirly bokeh pictures. It isn't always pleasing. The effect can even be on the scary side of grating, but finally the question has to be whether the effect is fitting for the picture you're taking.

11-29-2016, 03:14 PM	#17
W.j.christy Site Supporter Join Date: Oct 2015 Location: Texas Photos: Albums Posts: 558 Original Poster	Originally posted by goatsNdonkey Things in the background seeming to take on a life of their own is something one sees in swirly bokeh pictures. It isn't always pleasing. The effect can even be on the scary side of grating, but finally the question has to be whether the effect is fitting for the picture you're taking. I agree, I thought it would be a pretty neat picture, though, especially with the back ground I plan on using.

11-29-2016, 06:57 PM - 1 Like	#18
Scorpio71GR Loyal Site Supporter Join Date: Nov 2014 Location: Michigan Photos: Gallery \| Albums Posts: 6,014	Sometimes under the right conditions my Rokinon 85 1.4 can produce similar results.

11-29-2016, 07:04 PM - 1 Like	#19
maltfalc Veteran Member Join Date: May 2010 Location: Winnipeg Photos: Albums Posts: 396	the effect is caused by deeply recessed front elements or other design aspects that begin to block the light path as you move away from the center of the image. mounting a step-down ring or too long or narrow hood on your fa 50 will make it swirl.

11-29-2016, 07:46 PM	#20
pres589 Site Supporter Join Date: Jan 2014 Location: Wichita, KS Photos: Albums Posts: 4,533	maltfalc, will you get this sort of effect with an F or FA 50 Macro? Those have really deeply set front elements and I'm not sure if I've seen swirls in sample shots.

11-29-2016, 08:32 PM	#21
maltfalc Veteran Member Join Date: May 2010 Location: Winnipeg Photos: Albums Posts: 396	Originally posted by pres589 maltfalc, will you get this sort of effect with an F or FA 50 Macro? Those have really deeply set front elements and I'm not sure if I've seen swirls in sample shots. the front opening seems wide enough that i wouldn't expect much swirl.

11-29-2016, 08:44 PM - 1 Like	#22
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	Originally posted by maltfalc the effect is caused by deeply recessed front elements or other design aspects that begin to block the light path as you move away from the center of the image. mounting a step-down ring or too long or narrow hood on your fa 50 will make it swirl. This has not been my experience. My Helios 44M 58/2 will swirl with some subjects despite having a front element that is not particularly deep set and despite being used with a hood that is appropriate to the focal length. Other lenses in my bag with similar front element depth and focal length with the same hood do not swirl. My Sigma 50/2.8 has a very deep front element and never swirls. Steve

11-29-2016, 09:03 PM	#23
maltfalc Veteran Member Join Date: May 2010 Location: Winnipeg Photos: Albums Posts: 396	Originally posted by stevebrot This has not been my experience. My Helios 44M 58/2 will swirl with some subjects despite having a front element that is not particularly deep set and despite being used with a hood that is appropriate to the focal length. Other lenses in my bag with similar front element depth and focal length with the same hood do not swirl. My Sigma 50/2.8 has a very deep front element and never swirls. Steve never claimed all deep set front elements or only deep set front elements cause swirl. it has to be deep enough and with a narrow enough front edge to begin significantly obstructing the light path at an angle captured by the sensor, and other parts of a lens can cause the same obstruction.

11-29-2016, 09:27 PM	#24
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	Originally posted by maltfalc never claimed all deep set front elements or only deep set front elements cause swirl. it has to be deep enough and with a narrow enough front edge to begin significantly obstructing the light path at an angle captured by the sensor, and other parts of a lens can cause the same obstruction. Again, not my experience. Your claim is fairly novel and not something I have heard of before. I think it would be appreciated if you started a new thread with examples of how this works, preferably with/without a step-down/hood of the same subject and composition. Steve

11-29-2016, 09:41 PM	#25
clackers Otis Memorial Pentaxian Join Date: Jul 2013 Location: Melbourne Photos: Albums Posts: 16,397	Originally posted by maltfalc never claimed all deep set front elements or only deep set front elements cause swirl. it has to be deep enough and with a narrow enough front edge to begin significantly obstructing the light path at an angle captured by the sensor, and other parts of a lens can cause the same obstruction. Do you have a reference for this, Maltfalc?

11-29-2016, 10:06 PM	#26
maltfalc Veteran Member Join Date: May 2010 Location: Winnipeg Photos: Albums Posts: 396	Originally posted by stevebrot Again, not my experience. Your claim is fairly novel and not something I have heard of before. I think it would be appreciated if you started a new thread with examples of how this works, preferably with/without a step-down/hood of the same subject and composition. Steve not your experience in what way? my claim doesn't conflict with your experience. just look at the change in shape of the bokeh in a photo with swirl as it nears the edges vs one without swirl and it should become obvious what causes it. the main cause is the lightpath being constricted too much in front of or behind the iris, with things like edge softness, barrel distortion, etc. also contributing somewhat to the final look. ---------- Post added 11-29-16 at 11:10 PM ---------- Originally posted by clackers Do you have a reference for this, Maltfalc? nope. don't need one either. anyone on this forum can easily verify this for themselves in a few seconds with a camera, a fast lens and a hole.

11-29-2016, 10:15 PM	#27
clackers Otis Memorial Pentaxian Join Date: Jul 2013 Location: Melbourne Photos: Albums Posts: 16,397	Originally posted by maltfalc nope. don't need one either. anyone on this forum can easily verify this for themselves in a few seconds with a camera, a fast lens and a hole. Okay, your claim about the phenomenon has been challenged in this forum, and I've never read any reference to support your conclusion, and you don't seem to have either. Is that a fair statement?

11-29-2016, 10:19 PM	#28
BrianR Veteran Member Join Date: Dec 2010 Location: Ontario Photos: Gallery Posts: 3,332	Isn't the swirly bokeh (at least partially) caused by a hard optical vignetting that changes the shape of the aperture at off-axis angles? As in figure 2 here: Vignetting. There are other factors of course, so just having a deeply recessed front element isn't enough, but for a given lens if you added an inappropriately sized lens hood, or stacked a bunch of filters, the cats eye bokeh would be exaggerated? Should be easy enough to test with a roll of black cardboard and some Christmas lights. I think there's other factors to the overall wiggy swirlies though, the soap bubble bokeh, a generally sharp thing in focus but soft elsewhere, or other funny things that tend to be "corrected" in more modern lens designs.

11-29-2016, 10:25 PM	#29
maltfalc Veteran Member Join Date: May 2010 Location: Winnipeg Photos: Albums Posts: 396	Originally posted by clackers Okay, your claim about the phenomenon has been challenged in this forum, and I've never read any reference to support your conclusion, and you don't seem to have either. Is that a fair statement? i repeat, it takes literally a few seconds for you to see for yourself that i'm right.

11-29-2016, 10:29 PM	#30
clackers Otis Memorial Pentaxian Join Date: Jul 2013 Location: Melbourne Photos: Albums Posts: 16,397	Originally posted by maltfalc i repeat, it takes literally a few seconds for you to see for yourself that i'm right. I repeat, you have no reference. What's your explanation with this: New Petzval 58 Creates Bokeh Like No Other Camera Lens \| Digital Trends