High Dynamic Range

[Briancd]

Instead of using the Auto Exposure bracketing to create differently exposed images would it be possible to use one exposure only using RAW and create up to five different exposures by converting the same RAW image five times with different exposure adjustments. Will this then allow you to use the five differently exposed images to create a HDR image?

[trueimage]

Yes it would be possible, but you don't get as latitude in one RAW file as with 5 bracketed, properly exposed shots.

[Tsmith]

Yes it would be possible, but you don't get as latitude in one RAW file as with 5 bracketed, properly exposed shots.

Good answer as I've been experimenting with one RAW image and its just not always enough room for adjustments sometimes ... but it will work depending on the exposure.

[darkvibe]

I use your method with one RAW file when I want to try it with something that I can't get multiple shots of. Things like a moving car. It works OK.

[adas]

You'll have to expose for the highlights, so you have to shoot way underexposed.
Just imagine you want to shoot a bridge at night. You will expose for the lights, as to get the colors of them. Then the bridge itself will be way to dark, it'll became very grainy when you lighten it up.

[Picture North Carolina]

As was mentioned, you'll have to shoot way down. It is always preferrable to shoot multiple pics with different exposures for deep shadows and bright highlights (when possible). However, using the camera bracketing feature is not always necessary. I shoot most HDR images manually, each shot metered for each end of the spectrum.

If the shot you take is beyond the dynamic range of the camera, you can slide the exposure slider up and down all day and it will not help much. For example, if you have a bright sky that is a blown highlight (which means there is not detail in that area), moving the exposure slider down will not create detail that is not there.

I have been playing with HDR for some time now and have had some great successes with shots that would otherwise be impossible to capture. One thing to note, tho, is that manual metering does also have drawbacks. I have run across some pieces of software (panorama and HDR stuff) that looks at the exif info for the exposure comp. factor. It uses it, and when it does not find it (as in two manually metered shots), the applications get hopelessly lost and in some cases may not complete the task.

-Dan

[BryanP]

It's possible but you're just essentially using the same shot to make the final image (so you won't really gain anything in terms of capturing more range, you get essentially what you recorded in the dynamic range of that single shot).

The reason why you shoot multiple exposures is so you can maximize the data recorded in throughout the dynamic range (which is why this method is recommended) - pretty much tacking on more data than what can be recorded by the camera in a single exposure. Using the different ranges of the unique exposures at the each end of the spectrum and blending them gives you more data in one shot, and a better shot overall.

Of course, like noted above, theres just times when these types of shots won't work (when recording moving objects).

[FlashZebra]

Instead of using the Auto Exposure bracketing to create differently exposed images would it be possible to use one exposure only using RAW and create up to five different exposures by converting the same RAW image five times with different exposure adjustments. Will this then allow you to use the five differently exposed images to create a HDR image?
No.

[Briancd]

Thanks you all for the advice. I now understand a bit better. Although I though Longduck's response was a bit, how should I say long winded.:lol:

[FlashZebra]

That's "londuck" not "longduck".

Enjoy! Lon

[BryanP]

That's "londuck" not "longduck".

Enjoy! Lon

:lol::lol:

[sando]

I've researched 'simple' ways to get a good HDR 'effect' by skimping on images and I think I've found it... I'm trying it this weekend on a landscape:

Take 2 RAW's. One expose the sky. One expose the foreground.

Produce 2 JPEG's from the Sky RAW, going, say 1 stop under and then 2 stops under

Produce 5 JPEGs from the Forground RAW. Aim for a graduated exposure through the JPEGs starting with the very front forground to where the sky hits the land.

Save them all 'For Web'

Run HDR.

I'll let you now how I get on but I'm hoping that by just using 2 RAW's I can get a scene that changes a hell of a lot less than taking 7 different JPEGs!

[Picture North Carolina]

but I'm hoping that by just using 2 RAW's I can get a scene that changes a hell of a lot less than taking 7 different JPEGs!

By this and other posts, I assume most of you folks are using the HDR feature in CS2. I've never had much luck with that. Never really had good results. I prefer to do digital blending manually. Perhaps I should give the auto feature another chance.

[sando]

Yeah, it is good... but you have to make sure you play with the curves and stuff before you 'Ok' it.
And ensure that the images are identical, apart from the exposure. That's why i was looking into using 2 RAW's for landscapes when clouds move etc...

[chtgrubbs]

I think you would risk losing quality if you processed the raw file to that extreme variation in exposure. I would do a three stop bracket and then adjust the process on the over and under frames to give you the full five stops.

[AJSJones]

Here's a very comprehensive tutorial on HDR

http://www.naturescapes.net/072006/rh0706_1.htm

(Note I did say comprehensive - it's long but helpful :D )

[Picture North Carolina]

Here's a very comprehensive tutorial on HDR

http://www.naturescapes.net/072006/rh0706_1.htm

(Note I did say comprehensive - it's long but helpful :D )

Thanks for the link! It's actually a good tutorial. The longer, the better. (Nah, I won't go for the obvious joke).:)

[Lord_Malone]

Here's a very comprehensive tutorial on HDR

http://www.naturescapes.net/072006/rh0706_1.htm

(Note I did say comprehensive - it's long but helpful :D )

Exactly what I needed. Thanks!