So what is HDR then?

karmagarda

karmagarda

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I left a comment on a photo recently that I presumed was a HDR. What I said was along the lines of "Great photo, Not too over cooked either for a HDR". Now, mentioned in his description was use of multiple exposures and blending them. And it was a sunset. But he replied "It's not HDR". Fair enough, maybe it wasn't for dynamic range he was blending the exposures, but quite frankly I'm not so sure. It's shot into the sun so I'd made the presumption the multiple exposures were used to bring the foreground detail back. He also mentioned in his description that it was taken at the time he was "all for HDR".

Anyway, I wasn't going to argue. It was on flickr. So I just apologised, mentioned why I made the presumption, and said it was good shot either way anyway. Some other guy jumps in with this: "You must get fed up with people thinking that blending different exposures is HDR!". Ok, correct me if I'm wrong, but isn't that exactly what HDR is? Granted, we could get picky and say different "exposures" doesn't necessarily mean one overexposed, one underexposed, etc... but unless there's something I've missed along the way 99% of the time isn't that exactly what it means?

:thinking:
 
In my opinion:
If the shot is a blend of differing exposures its HDR

If its one exposure processed extensively to bring out shadow and highlight detail its HDR

Basically any processing that involves creating more visible dynamic range, for me counts as HDR

Though when I hear HDR i always imagine the horrible over-processed images with disgusting tone-mapped clouds *shudder* so I can imagine why some people would prefer to call it exposure blending!
 
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Exactly my thoughts. I must now go find out off him why his "exposure blending" wasn't a HDR then...
 
I think the term HDR can drum up thoughts of over the top HDR/tone mapping shots ;) where as exposure blending sounds a bit posher.
 
Photomatix has two options of processing multiple exposures.

HDR (Tonemapped) or exposure blending.

I'm not to sure what the difference is in the mathamatical processing, and I'm assuming there must be a difference or there wouldn't be two options, but I find the exposure blending a lot more pleasing to the eye (ie more realistic).

HDR can often be over cooked.
 
Thmaga said:
In my opinion:
If the shot is a blend of differing exposures its HDR

If its one exposure processed extensively to bring out shadow and highlight detail its HDR

Basically any processing that involves creating more visible dynamic range, for me counts as HDR

Though when I hear HDR i always imagine the horrible over-processed images with disgusting tone-mapped clouds *shudder* so I can imagine why some people would prefer to call it exposure blending!
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You could argue, for the sake of being pedantic, that using a filter to control the exposure is also HDR as it brings a higher dynamic range to the image. I know a few people, myself included, who use exposure blending to mimic the effect that a graduated filter has on a scene, and to me, this is just a digital way of using an age old photographic technique...Which you do by taking an exposure for the sky & then for the foreground, and then using photoshop, you layer them and then erase out the parts of the exposure you don't want.

@ OP - it wasn't this image was it http://www.flickr.com/photos/ch9sab/4712269803/ ?
 
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I've been reading up a bit on this and I think I get it now. When you say HDR it's probably now viewed as a technique as opposed to "the result". So if you use 2 or 3 exposures and just blend them together (somewhere in the middle for example) they don't see that as a HDR technique. Although, from my point of view you're still trying to achieve a HDR image as in an image with a somewhat High Dynamic Range.

Suppose you could argue that exposure blending is also just another technique to produce a HDR image without using a HDR technique... or something :thinking: :lol:
 
karmagarda said:
Ok, correct me if I'm wrong, but isn't that exactly what HDR is? Granted, we could get picky and say different "exposures" doesn't necessarily mean one overexposed, one underexposed, etc... but unless there's something I've missed along the way 99% of the time isn't that exactly what it means?
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I've seen confusion even on TP before - people these days do associate/confuse HDR with the tone compression and algorithms to do that. Unfortunately this is only one aspect of it and not even the necessary one. To me HDR encompasses anything that allows to capture scene with DR higher than is possible by normal means (hardware limitations etc). This may or may not involve multiple exposure, blending and tone compression.

Multiple exposures are typically done to allow capture high DR scenes where the limitation if in the capture equipment (camera, sensor). There are ways of doing it in one exposure (like the high DR scanning sensors) even though their use may be limited.

Blending also adheres to the above so if you capture the high DR scene in one exposure you won't need to do that.

To refer to that specific Flickr post you commented on, I'd say that those guys are incorrect - even though they blended 4 exposures manually in PS, it is still HDR because it is still about capturing High Dynamic Range scene which was not possible by standard means.

Tone compression is what gets me the most - people use it as a synonym to HDR most of the time yet it is only relevant for some of the HDR processes. The main use of this is to compress extended tonal range into more narrow one which in case of HDR applies to the compressing tones for extended 32bit scenes into standard 8/16bit ones. This is only applicable if

a) you ever need to compress back to 8/16 bit (some workflows may not ever need this)

b) the exposure fusion methods (manual in PS with layers or automatic) can do without tone compression altogether as it merges exposures into single one without going to the full 32 bit mode and stays within standard limited DR space.

Regarding that Flickr page though I would say that the guy was wrong, what he did is still HDR because even though he blended 4 exposures manually because it was still about capturing High Dynamic Range scene impossible to obtain by standard means.
 
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Sectionate said:
You could argue, for the sake of being pedantic, that using a filter to control the exposure is also HDR as it brings a higher dynamic range to the image.
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Filter does not bring higher DR to the image - it lowers the DR so it can be captured. Truly ND filter will also be better than any HDR algorithms (except where you blend exposures manually with layers) because blending and TC will cause hue shifts thus compromising colours. But i guess that is one of the things some people love HDR and TC so much.
 
ecoleman said:
Photomatix has two options of processing multiple exposures.

HDR (Tonemapped) or exposure blending.

I'm not to sure what the difference is in the mathamatical processing, and I'm assuming there must be a difference or there wouldn't be two options, but I find the exposure blending a lot more pleasing to the eye (ie more realistic).
Click to expand...

Exposure blending tries to simulate what you would do if you are to do it manually - i.e. layer exposures and mask them. As such it avoids tone compression altogether (which is one of the reasons it results in more natural look). It still can suffer from halos but not as much.
 
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I only really see something as HDR if you are using more than one shot taken from the camera at different exposures.

Even though you can take a RAW shot and create two different exposures from this and then blend, the original shot will still be restricted by the camera's physical dynamic range so I don't believe you can get a true HDR image from this (without loss of detail at the least compared to using multiple exposures from the camera).

This is my understanding of it (the dynamic range of the camera is a bit low but it's just for an example's sake. I think the D3 is about 9-stops of dynamic range?

HDR.jpg
 
Any multiple exposures shot purposely to record higher dynamic range in the highlight and shadows detail, then overlayed, overlapped, blended or however else you want to dress it up is a HDR image.

It's a technique that's been used for a long time but unfortunately the technique has been raped and exploited to create these overcooked cartoon looking CGI abominations people try putting out as good photography.

They forget the photo that gets whacked in the oven should really have the ingredients to be a good image on it's own, before it is retired to the AGA for tone mapping.
 
That's pretty much what I was thinking. Obvious mix up between what is a technique and what is a result you're trying to achieve.
 
gman said:
Interesting stuff! I still believe that you'll not get as high a quality result from one image than if you used three - could be a nice excuse to get the camera out tonight! :) Of course if the scene contains movement then you are pretty much stuck to using one exposure.
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i think there is another part that explains the procedure with 3 exposures.

with a static scene, me thinks 5 exposures would be best
 
Of course if the scene contains movement then you are pretty much stuck to using one exposure.
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unless you're good at layer masking. It can be done with people - they might take 2 steps for every 3 shots you take but for sky and other vast amounts of movement in the frame it's not worth it
 
dalex_257 said:
Filter does not bring higher DR to the image - it lowers the DR so it can be captured. Truly ND filter will also be better than any HDR algorithms (except where you blend exposures manually with layers) because blending and TC will cause hue shifts thus compromising colours. But i guess that is one of the things some people love HDR and TC so much.
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