Bokeh onion rings

[Eldar]

I fear that we may need to find Eldar a good marriage counselor or psychiatrist, or both, if we encourage him to keep going down this path

I'm kidding of course and I'm glad to know that I'm not the only one who obsesses over things like this from time-to-time!

He he, Luckily I have two days alone in my cabin (my wife´s at work), so I can be a lunatic all by myself :

First picture is one of the chandelier light bulbs, (bulb hight is 7cm. Light source is very much a point source) (look at the gorgeous bokeh from the 85 1.2L II ).

The other one is the dimmable DC bulb (light source app. 3-4mm in diameter). This is a more concentrated source than the christmas light shown in an earlier post.

We have some optical wizards out there in CR. It´s time for you to come and enlighten us!!!

 

[danski0224]

It´s time for you to come and enlighten us!!!

I see what you did there...



Do you have any DC powered LED lights you could photograph? Most of what I have for DC LED sources (flashlight, bike light, head lamp and undercabinet lighting) has some sort of frequency to it- video taken with my phone has a flickering effect.

 

[sagittariansrock]

As danski said, it might have to do with the varying intensity due to the AC current cycles.
What was the shutter speed?
AC current is usually 60 Hz (might be different in Norway)- so it swings from one extreme to the other in 1/60 of a second, passing zero. So it only needs 1/120 of a second to go from one extreme to zero.
So, if slower than 1/120 (or Norway equivalent), can you try higher shutter speeds?

Norway is 240V/50Hz.

For a lot of other things that has to do with light, the AC frequency of 60/50Hz comes into play. The Christmas candle picture is shot at 1/25s, with very clear onion rings. If the 50Hz theory was correct, it should have been clean. This one is shot at 1/40s (handheld)

Ah, I see. I must have misunderstood- I thought you got onion rings with AC and not with candle light or DC.

 

[Eldar]

Case solved and closed! Jrista posted a couple of very clarifying posts over at the Otus thread:

http://www.canonrumors.com/forum/index.php?topic=18169.msg387409#msg387409