digital multi-exposure?

[panocho]

As far as I know, dSLR's don't have multi-exposure, since that's supposed to be done "after-camera".

First, is that so?
Second, if that's so, is there any way to really shoot multi-exposure with a digital? I don't want to post-process, I just would like to do exactly the same I did with film: multi-expose one frame -and after, only after, if I want, edit it with software.

Perhaps this is a silly question; it may be very easy, and sounds like it (just like different layers that you put together), but is that so? The thing is I am what here is being discussed as "shooting raw as a matter of fact"...

 

[The_Traveler]

As far as I know, dSLR's don't have multi-exposure, since that's supposed to be done "after-camera".

First, is that so?

Well if you are shooting RAW, then I guess its theoretically possible - adding the bytes in the same position - but it would require more processing just to do the addition.

Second, if that's so, is there any way to really shoot multi-exposure with a digital? I don't want to post-process, I just would like to do exactly the same I did with film: multi-expose one frame -and after, only after, if I want, edit it with software.

I am only familiar with my own cameras and I don't see that its possible.

I am interested why you think that film multi-exposure is conceptually much different than importing two successive exposures into the same file and reducing the opacity to 50% on the top one?

 

[Alpha]

AFAIK, this is not possible on 35mm-sized digital SLR's. It is, however, possible, and quite common on MF digi backs. However, it only works for static subjects of course (think product photography).

 

[droyz2000]

The D200 has a feature that lets you take multiple exposures. I have tried it a few time and have been pretty pleased with the results.

 

[Alpha]

At the very least, it doesn't appear to work on 35mm sized SLR's the same way it does on digi backs. All of the pros I've spoken to have absolutely raved about the quality increase with multiple exposure on their dbacks. Conversely, this is the first time I've even heard anyone mention multiple exposure on a smaller dslr.

 

[Garbz]

Depends on the camera. Either way it's software based not hardware based, exactly identical to a very simple post processing method. Take two exposures and it's the same as putting 2 images on top of each other in photoshop with an opaque mask.

 

[PhotoPhoenix]

The D200 has a feature that lets you take multiple exposures. I have tried it a few time and have been pretty pleased with the results.

yeap, i was going to say the same thing. the D200 has an awesome multiple exposure feature. i love it. if i didn't get the 30D i definitely would have gotten the D200..

 

[panocho]

Great for the D200!

I don't have any problem in doing it at processing. Only don't want to turn the whole thing into an editing, since my aim is to multi-expose with the same conditions (limitations) as with in-camera multi-exposure on a frame of film.

As long as software won't affect the whole thing further than the simple putting the two images together, it's allright with me. But then the two images have to be sub-exposed (as one of the various shots on a multi-exposure film shot actually are) or render backgrounds overexposed, etc. That is, I just don't want software to do more than reproducing a multi-exposed frame. Otherwise, it's OK

 

[Garbz]

Image editing software only puts out as much as you put in

 

[Sw1tchFX]

High-end Nikon's do it.

 

[tr0gd0o0r]

Pentax's *istD can do up to 9 exposures on a single image (I don't know if this was carried through to later iterations though)

 

[shorty6049]

yeah, nikon adds a bunch of features to their dSLRs it seems, a lot of them kind of useless in my opinion (in camera color changes???) but multi exposures would be sorta neat to have i guess, but how often are you NOT going to go through some post processing on an image?

 

[glaston]

I don't know if this is what you're talking about or not, but there's a technique called HDRI(High Dynamic Range Imaging).
I have some experience with 3D renderings and this is what the technique is for, but the end result is amazing as far as quality goes for any image.

You take a series of snapshots at multiple stops of exposure.
You want them to be about 4 stops of exposure apart.
You then combine all the images using Photoshop CS2's built in module and you end up with a 32 bit float image.
These images contain ALOT of data, and being 32bit float they are able to display a much higher dynamic range of luminance values in the image.

RAW conversions are 16 bit images, which is still considered low dynamic range.
By using HDR imaging, you end up with image data that describes the real world levels of light present in the scene.
This technique was developed by Industrial Light and Magic for the specific purpose of combining computer generated objects and characters with live footage. Since the image contains real world light values, they input that data into a 3D rendering application so that the lighting of the computer effects exactly matches the lighting of the live film footage.
It's pure genius!

ILM's format is known as OpenEXR, and photoshop cs2 can open and manipulate them. There's also a format called Radiance which photoshop can understand. The general one is .hdr.
You can find them all over the web.
If you've never seen one you should take a look at them.
The contrast and resolution of these images is mind blowing.
They can actually represent the entire dynamic range that the human eye is capable of. The problem is finding a display that can accomodate that.
I've never actually taken one on my own. I've worked with them alot in 3D applications though.

There's a free application for windows only called HDRshop.

Here's the explanation::

How do I shoot an HDR image?
Most digital cameras are only able to capture a limited dynamic range (the exposure setting determines which part of the total dynamic range will be captured). This is why HDR images are commonly created from photos of the same scene taken under different exposure levels.
Here are some recommendations for taking different exposures for the HDR image:

1. Mount your camera on a tripod
2. Set your camera to manual exposure mode. Select an appropriate aperture for your scene (e.g. f/8 or less if you need more depth of field) and the lowest ISO setting.
3. Measure the light in the brightest part of your scene (spot metering or in Av mode to point only the highlights) and note the exposure time. Do the same for the darkest shadows of your scene.
4. Determine the number and value of exposures necessary. For this, take as a basis the exposure time measured for the highlights. Multiply this number by 4 to find the next exposure with a stop spacing of 2 EV. Multiply by 4 successively for the next exposures till you pass the exposure measured for the shadows. (Note: For most daylight outdoor scenes excluding the sun, 3 exposures spaced by two EVs are often sufficient to properly cover the dynamic range).
5. You can make use of Auto-Exposure Bracketing if your camera supports it and if it allows a sufficient exposure increment and number of auto-bracketed frames to cover the dynamic range determined in step 4. Otherwise, you will have to vary the exposure times manually.

 

[shorty6049]

no , thats not what they're talking about, they;re talking about superimposing one image on top of a completely different image for artistic effect

 

[panocho]

but how often are you NOT going to go through some post processing on an image?

me, VERY often (and feel free to call me whatever you feel like )

That was precisely the point in my asking. I just don't want that a 100% in-camera feature as multi-exposure turns up to be, at software, as rather a post-processing (BTW, I do know you could easily do that on the darkroom, but I'm just talking about doing it in-camera). Sometimes (many times) I just don't want to post-process. I have more fun and believe I learn more (am I wrong? so what, let me be wrong, please!) when I command myself to get the picture I want in-camera, not to have some data out of it that I later use on the computer.

If we were talking about film, I wouldn't say so at all, but in digital, processing has become such an easy and next-to-boundless work that I just don't want to fall systematically in it. I like trying to do things with the camera, not with the computer. I know for many of you I'm completely wrong, but that way i feel an image editor rather than a photographer. Sorry, that's the way I feel it.

For this reason I just wanted to now whether it was possible to just reproduce at "processing" an in-camera feature that my camera doesn't have. Anyway, it seems from your replies that it is possible.