What went wrong

[Pjerry]

My last shot was a complete failure. Almost nothing happened as I expected.

It was just an experiment, I didn't want to make the-once-in-a-lifetime-picture. I could always, afterwards think about a nice composition.

I wanted to picture the filling of a glass with coffee. This process takes about 40 seconds. So I positioned the light (a normal twilightlamp top left), the camera (on tripod) and made the settings that way that the exposure time was 30 seconds. After a couple of test shots with water (setting exposure time, aperture, WB and ISO), it looked fine.
So, I made myself a cup of coffee .

I expected the stream to go "into" the coffee (or something like that), the glass would become gradient brown (mixed with cream) from the bottom (most brown) to above. I was very curious about the result.

Only the stream is fading away from top-down, that's the only result. No coffee can be seen, totally different from what I expected.

Was there to much light? (I don't think, the picture has the correct exposure light). Did the light only reflect on the outside, so you couldn't see what was in it (I can test that of course)? Did the cream layer (Senseo) "disappear" the coffee (in and out side)?

A complete failure..... .

Do you have any ideas how this can happen?

[Colin Southern]

yep

The long exposure effectively averages the scene; when there's movement, it gives the effect of blurring it (which often presents as "mist").

Similar to what's going on here (which were really breaking waves) ...



I think what you were expecting was more along the lines of a "time lapse"

[Pjerry]

Dear Colin,

How fast you are .

"Time lapse"? That's a kind of a film.....

What I at least expected that was that the out side was gradient brown. But even that I don't see at all.

Regards

[Dave Humphries]

Hi Pierre,

Theoretical answer (I have never tried this)

How about a fairly weak* flash, on the second curtain, just as the shutter closes?
That might give something like the effect you wanted as it should provide an exposure of the top of the coffee just at the highest point.

But do experiment, perhaps the end isn't the best time, perhaps 2/3 in? (manually triggered while you're waiting - may not be possible unless you have a separate flash gun)

* I suggest "weak" as you don't want to over-power the time exposure, so at least a couple of stops minus FEC (Flash Exposure Compensation) will be needed.

Beware; this will take several attempts and you can't practice it with see-through water, so don't drink all the coffee or you may not sleep for a week

Good luck and do show us the next attempts,

[Pjerry]

Dear Dave,

Haha, I going to think about it, how I 'm going to manage the things. It's always nice to make ugly pictures .

Thanks.

[MiniChris]

Just as a side note, it seems as if the color of the light might be affecting the inside color you are seeking (coffee brown). By the color, I am referring to the Kelvin temperature and in this shot, you are way to the warm side which won't give you all the contrast you might want as you will be warm on warm on warm (glass, light, coffee).

The following image was obtained by cooling the overall value more toward the blue side while maintaining the brown of the coffee, but I discovered no matter how much PP I used (in photoshop), I couldn't get rid of the yellow cast given off by the lamp you used. hence, the loss of coffee color in the bottom of the cup....I suspect the angle of the light and lens also affected this color cast.

[Pjerry]

Dear Chris,

Thanks for your reaction and you even post-edited it. Great!

At first I had only ambient TL-light. The glass was as cooler then (sothing like you get right now).

After placing the twilight I lowered to 2500 K (as low as I can go), but didn't any fine adjustments, by which I could cool it down further. I didn't pay any attention to it at that time (that was maybe wrong). (I think the lamp is about 2200 K, such a mood light ).

Besides the flash, I will try a different lamp (or no extra lamp at all, only the TL-light).

Thanks again.

P.S. I will also start later, in that way I got the last 30 seconds in stead of the first 30 sec, maybe that could also give a better result.