Help please - Using multiple apertures during a single exposure.

[CodyW]

Hallo Everyone,

I remember reading something that briefly mentioned using multiple apertures during the one exposure for night and light art photography. Has anyone else heard of this technique? Could someone please explain a bit more on how this technique works, how it affects the overall image and what it allows you to do this. Any information would be greatly apriciated! :)

Cheers,
Cody

[ricktas]

Are you talking about image stacking? Where you take several shots, and then use software to 'stack' them to produce a better result than what one image can. If this is what you are after, something like deepsky stacker : http://deepskystacker.free.fr/english/index.html

[Xenedis]

I remember reading something that briefly mentioned using multiple apertures during the one exposure for night and light art photography. Has anyone else heard of this technique? Could someone please explain a bit more on how this technique works, how it affects the overall image and what it allows you to do this. Any information would be greatly apriciated! :)


I believe the technique is called focus stacking, and is used to gain more depth of field than would otherwise be possible without stopping the lens down to a point where diffraction becomes a problem.

This technique could be particularly beneficial with macro photography, where DOF (in my experience) is always a problem, even at narrow apertures.

I believe you need software which can blend the images together, much like the HDR technique requires software which mathematically blends multiple exposures.

I have not tried focus stacking myself, so I cannot offer you much there; but if you Google that term I'm sure a wealth of information will be returned.

[fillum]

Don't know if I'm on the right track here Cody...

There is a technique where you vary the focal length on a zoom lens during a long exposure. Basically you just set your zoom at one end, then zoom in/out during the exposure. Lights fan out and give a result like this...

82117


Varying aperture in a similar way might give some interesting results. The subject should remain sharp but as the depth-of-field changes areas in front of, and behind the focal point would be a mixture of in focus and out-of-focus which might be interesting. The problem doing this is that most modern cameras control the aperture from within camera so I don't believe it's possible to alter the aperture during the exposure. It might be possible with a manual lens?



Cheers.

[ameerat42]

Heard of it? Now that you've mentioned it, only 1/2 time before (or less), and searching it gave me these abstruse examples,
http://people.csail.mit.edu/green/multiaperture/
http://www.binarycrumbs.com/2009/05/multi-aperture-photography-and.html
http://www.youtube.com/watch?v=8ENfPYpkHp4

If it's not this, then the only way I could picture it, using the same words in the description, is to try to vary your aperture on a long exposure with a manual lens, to what end though, I couldn't hazard.

[arthurking83]

Yeah, without a manual lens, you can't vary aperture value during a single exposure.

[geoffsta]

Not talking about HDR? Using apature to adjust exposure over 3 or more images. Then using software to create a single image?

[Bennymiata]

Not talking about HDR? Using apature to adjust exposure over 3 or more images. Then using software to create a single image?

That IS HDR.
High Dynamic Range is the blending of multiple shots to get one shot with even exposure.

Some cameras can do it themselves, like some Pentax models, or you can do it by using Photoshoop and manually blending the images together (or parts of them) or you can buy some cheap software that will do it for you.

[kiwi]

...we may never know what Cody was wanting....

[ameerat42]

It certainly wasn't HDR, he went to some pains to clarify that.