Double Exposure?

[ketsueki]

Would it be possible to somehow put double exposure in for photography? Before I get jumped on too harshly, I do know this can be done in photoshop, but I would like to have the ability to spontaniously use it in the field play with settings and focus and overlay on to the same file. I hope this makes sense I am not trying to troll and would love to have this feature to go with the other photographic features ML gave me

[kazeone]

I would like to see this feature for the 650D / T4i

[ilguercio]

And HOW would you do it?

[kazeone]

And HOW would you do it?

well a few of the more higherend canons and nikons already do this and Im assuming its doing it digitally and since Magic Lantern has brought higher end camera features to budget friendly cameras, maybe the same can happen here by figuring out how the more expensive cameras do it and seeing if it can be compiled and reproduced for the budget cameras.

[ilguercio]

So, again, why can't you do it in photoshop?

[ItsMeLenny]

BULB + black piece of cardboard.

Make shutter open with cardboard in front of lens, take away cardboard, put it back, take away cardboard, put it back, end bulb.

[brapodam]

There is another purpose for this: long exposures with little noise. Or extend a long exposure to an ultra long one (can use just a 10 stop ND to achieve a ~4 or 5 min exposure in bright daylight rather than stacking NDs)

Basically shoot multiple long (or long enough) exposures (each image will be the correct exposure, unlike in astrophotography) and combine them into a single long exposure image. Combining the images/averaging them takes away the noise and also adds the motion from each long exposure.

In post, you would open all the images up as layers, then each layer would be (100/x)% opacity, so bottom layer will be 100%, second from bottom would be 50%, third from bottom would be 33% and so on. Tedious in post without some form of automation. With Photoshop I think there are image stacking tools, but in GIMP, you probably have to write your own script which I don't know how to.

Either way, the advantage of having this in-camera is that you can preview the final result, rather than waiting for you to get home to combine in post. If the results are not satisfactory, you can at least shoot another set of pictures, but if you do it in post, it's guesswork as to what the final image would look like.

[a1ex]

You can preview it in the camera (SET+MainDial: Exposure Fusion).

[brapodam]

You can preview it in the camera (SET+MainDial: Exposure Fusion).

Exposure fusion preview uses enfuse right? Does enfuse combine long exposures well? I personally haven't tried it and I haven't seen many people recommending enfuse for stacking (for long exposure purposes - I have only seen people use it for focus stacking). The tutorials I've seen suggested using GIMP/Photoshop to stack through layers or using Photoshop's image stacking features, or using ImageMagick as described here: http://blog.patdavid.net/2013/09/faking-nd-filter-for-long-exposure.html

If enfuse does it, then the preview would be useful; otherwise it will produce a preview that is different, which is not very useful.

[a1ex]

Nope, it's a simple exposure-weighted average. If you combine two identically-exposed pictures, you get a plain old average.