Any way to make cats eye bokeh circular?

Don't recall having this issue last year but I had different lenses back then(Canon 50mm 1.8 STM and Jupiter 8)

now with my Sony FE 50mm 1.8 and Canon FL 55mm 1.2 I'm getting bokeh that looks like a cats eye?

Is there a way to solve this? like is it a distance front the lights issue kind of thing? Glad I decided to do tests before my real shoots are planed to happen.

Sample is A7 + Canon 1.2(I need a lens hood also for that flare) I also got the same results with the Sony 50mm, which I found surprising since the lens group is identical to the STM I was using last year.

Thanks in advance!

I have yet to wake up so I am not going to be much help.

What shape are the lights in this photo? The reason I ask is that they seem to be closer to oval than round (at least it appears that way to me). One can tell that they are on "a string" because all of the shapes are not the same (horizontal then vertical).

Does this appear to lights of a different type such as table lamp or an outdoor light?

Good luck with diagnosis.

Gart

If I recall, anything with an aperture so large and an image circle that is not fully projected due to the larger aperture will get cut like this and result in cat eye.

Shoot it at F1.4 and F1.8 with something that remains circular (blades) and you'll get circle bokeh. I might be wrong here.

I just tried it with my F1.4 and F1.8 50's I have sitting around on a full frame and get perfectly circular bokeh at those apertures.

Distance to subject relative to whether you're focused near infinity or MFD also plays into this. I get perfect circle bokeh when focused opposite of my object. I also get cateye bokeh when the light source is very close to my subject and more towards the mid-range focal distance rather than the two extremes.

Very best,

The 2 top-right blue ones are almost circular. I suspect that they're pointed at the camera &all the bulbs are longer than they're wide?

MalVeauX wrote in post #18197291
If I recall, anything with an aperture so large and an image circle that is not fully projected due to the larger aperture will get cut like this and result in cat eye.

Shoot it at F1.4 and F1.8 with something that remains circular (blades) and you'll get circle bokeh. I might be wrong here.

I just tried it with my F1.4 and F1.8 50's I have sitting around on a full frame and get perfectly circular bokeh at those apertures.

Distance to subject relative to whether you're focused near infinity or MFD also plays into this. I get perfect circle bokeh when focused opposite of my object. I also get cateye bokeh when the light source is very close to my subject and more towards the mid-range focal distance rather than the two extremes.

Very best,

As mentioned in the first post i also shot it with my 1.8 and got the same results.

Gart wrote in post #18197290
I have yet to wake up so I am not going to be much help.

What shape are the lights in this photo? The reason I ask is that they seem to be closer to oval than round (at least it appears that way to me). One can tell that they are on "a string" because all of the shapes are not the same (horizontal then vertical).

Does this appear to lights of a different type such as table lamp or an outdoor light?

Good luck with diagnosis.

Gart

They're regular Christmas tree lights. I'll have to experiment and post up again, thank you so much!

PhotosGuy wrote in post #18197453
The 2 top-right blue ones are almost circular. I suspect that they're pointed at the camera &all the bulbs are longer than they're wide?

yes, they're this type https://www.riteaid.co​m …95/0/0/00729083​105227.jpg

This is mechanical vignetting. I think the only way to get rid of the cats eye look(and stay at large aperture for smooth bokeh and shallow DOF) is to try centering the light source in the frame.

I have to correct my statement above regarding mechanical vignetting. I am not shure if the cats eye produced by mechanical vignetting. The mechanical vignetting usually shows up as cut cats eye with one straight egde.

This doesn't have anything to do with the size/shape of light source causing the bokeh, it is simply a matter of the characteristics of the lens ... distance to subject and background, etc. Any specular light source that is off center can start looking this way, but I've never seen it happen so fast from center to edge, assuming the photo is not cropped.

I'm not going to guarantee that 100 percent, but I would put money on it.

I've also seen it called football bokeh.

I'll have to test my other 50s over the weekend when I get some time. Had a funeral today so unfortunately haven't had time to test out lenses. Should be able to tomorrow.

Left Handed Brisket wrote in post #18200880
This doesn't have anything to do with the size/shape of light source causing the bokeh, it is simply a matter of the characteristics of the lens ... distance to subject and background, etc. Any specular light source that is off center can start looking this way, but I've never seen it happen so fast from center to edge, assuming the photo is not cropped.

I'm not going to guarantee that 100 percent, but I would put money on it.

I've also seen it called football bokeh.

^

Just shot this test...frosted white nightlight bulb is 0.75"h x 1.25"v is a 0.6:1 aspect ratio in this photo. In the full frame the bulb fills 10% of the frame height. In spite of its oblong shape, it appears to be 0.9:1, both when photographed at the center of frame (left), and when laterally positioned at the wide dimension of the frame (right).

Wilt wrote in post #18202349
^

Just shot this test...frosted white nightlight bulb is 0.75"h x 1.25"v is a 0.6:1 aspect ratio in this photo. In the full frame the bulb fills 10% of the frame height. In spite of its oblong shape, it appears to be 0.9:1, both when photographed at the center of frame (left), and when laterally positioned at the wide dimension of the frame (right).

As is typically the case when I respond to a specific post on this forum (and said response does not resemble scarcastic hyperbole), I was responding to the specific question. It seems to me that the OP's question is in regards to the cause of the different shapes of bokeh in different parts of the frame. These bokeh effects, in the op, are caused by very small points of light that lie pretty darn far out of the plane of focus.

Your test shows a relatively large light source in presumably one part of the frame, and seemingly not too far out of focus. Sure the light bulb you photographed still resembles its original shape, but your test, so far as I can tell, is not representative of the issue in the OP.

Edit: I say this not really knowing your point, hell, for all I know you are agreeing with me. lol

Left Handed Brisket wrote in post #18202398
As is typically the case when I respond to a specific post on this forum (and said response does not resemble scarcastic hyperbole), I was responding to the specific question. It seems to me that the OP's question is in regards to the cause of the different shapes of bokeh in different parts of the frame. These bokeh effects, in the op, are caused by very small points of light that lie pretty darn far out of the plane of focus.

Your test shows a relatively large light source in presumably one part of the frame, and seemingly not too far out of focus. Sure the light bulb you photographed still resembles its original shape, but your test, so far as I can tell, is not representative of the issue in the OP.

Edit: I say this not really knowing your point, hell, for all I know you are agreeing with me. lol

Wait, in the test my lens was focused at its closest (MFD), and the light source was 20' away.
Second, the light source was oblong (you know, what a 4W night light bulb looks like) and the photo shows it within 10% of round!
Lastly, the "^" indicates agreement with the statements!!!

Wilt wrote in post #18202611
Wait, in the test my lens was focused at its closest (MFD), and the light source was 20' away.
Second, the light source was oblong (you know, what a 4W night light bulb looks like) and the photo shows it within 10% of round!
Lastly, the "^" indicates agreement with the statements!!!

word. (Also indicates agreement)

So what lens were you using? Was it wide open?

I took this last night with a 50mm Sears Auto that maverick75 sold me a year or so ago. Pretty sure it was focused at infinity and know it was wide open at f/2. Would have posted them last night, but my camera battery ran out and not long after that, I ran out of battery.

Full frame.