@scottbb LMAO at deleting comment on your joke but not the joke itself.

@scottbb cameras are not colorimeters. D65 is matched to black body 6500K in CIE std observer sense but cameras are not std observers, not even matrix-convertible to them.

@EuriPinhollow which joke?

@EuriPinhollow re: D65/6500K: yeah, I follow now what you were saying. I deleted my comment from your answer, especially after you edited the answer.

@scottbb your joke about red shift.

I am probably going to revisit all you possible answers about WB and brag about that one should take the speed of grey card into account when setting WB by measuring patch.

@scottbb aaaaaaaaand done.

@EuriPinhollow *slow clap*. Well played sir. =)

I want to be honest, my sides hurt.

@EuriPinhollow I don't know if it makes it funnier, or ruins the entire thing, but I wasn't joking about redshift. I was talking about images of stars. I just wasn't imagining taking pictures of any other black body radiator (i.e., light source), and trying to get color information from it.

@EuriPinhollow still, your response comments are hilarious, and will probably confuse the utter hell out of somebody without the full context... =)

@scottbb I see. The question author does not seem to be involved in astronomy in any way though, it is as strange to suggest so as with any other question about WB.

I should probably check color-temperature tag too......

Oh ok there is none.

I may finally go to bed then.

@EuriPinhollow but getting actual temperature from color temperature seems kinda meaningless unless the subject is an actual black body radiator. Other than stars, what black body objects are actually imaged?

I take it back, there are many things besides stars that are imaged for temperature.

You may always learn the actual temperature scale for a given material.

After you study the combination camera+material of course.

After all the existing accuracy (after measuring reference black body or the SPD) might be enough for certain applications.

But making a spectrophotometer from a camera would obviously be a superior way of doing same task.

I am rushing to sleep, k thx bye.

(after measuring reference black body or the camera spectral response, not SPD)

I've been contemplating this question for a while: Is it mechanically possible to create an aperture that is oval instead of circular? It's a very theoretical question. Maybe you can think of some place where people would be able to answer it.

It is possible to create an aperture with any shape one desires. In fact, it has been done.

google.com/…

@Expotr I'm sure it's possible. I'm assuming you mean an adjustable aperture. In that case, there might be some big gotchas. For instance, as a circular / rounded polygon iris aperture closes, the polygon shape rotates. So keeping a shape (polygon, or in your case, ellipse) in a certain orientation would add additional complexity, which would increase the cost of such a lens, for very little typical benefit.

@Expotr you'd probably need to use some sort of flexible material that you can alter its shape (curvature), rather than the simple rounded-blade segments in typical iris apertures.

If you create an oval opening and put it all the way in the front of the lens, maybe you still get that same oval bokeh effect (at every aperture stop)

@Expotr Well, putting custom bokeh apertures on the front of the lens is cheap. It works fine for a range of the in-lens aperture settings (but as with any bokeh, the wider the aperture, the better). Even at small in-lens apertures, you'll see some of the shape of the front-of-lens bokeh aperture.

@scottbb Just to make sure I understood, you're saying that the bokeh shape of the cutout you place in front of the lens becomes less pronounced as you stop down the aperture?

@Expotr Basically, yes. If the ln-lens aperture is the main light-limiter, then its character becomes dominant. But really, if you want distinctive bokeh shapes, and shallow depth of field, you'll be using the front-of-lens bokeh aperture as your primary aperture. You'd be better off leaving your in-lens aperture wide open, and swapping out different-sized front-of-lens apertures. Example: diyphotography.net/…

In effect, you're using Waterhouse Stops. Which are a great way to get precisely controlled aperture shape and size, but with the inconvenience of having to swap them out, rather than flick a dial.

@scottbb That's very cool. Thank you. I'm waiting for a richardgaleoptics Flare Factory 58 with an oval aperture, but that aperture is fixed

@Expotr ah. I assumed you were going for the anamorphic look.

@scottbb It also has an anamorphic look

That's what I'm going for. I asked him to keep the flare and contrast moderate

@Expotr that's what I meant. You confirmed my assumption. =)

Haha. My bad :)