HDR and large format?

[John Brady]

I have searched some old threads about hdr on the forum and haven't seen any too recent or from people employing it for large format.

I shoot 8x10 primarily and I imagine it wouldn't be practical there because trying to work with three or four 800 meg 16bit rgb images would grind my dual quad core to a halt plus the cost of 8x10 trannie's wouldn't be much fun either.

I still have my 4x5 and I photograph in the swamps of Florida under very difficult lighting conditions. So I was thinking it may be worth trying.

I scan with a Creo IQ 2 which offers lot's of range but I am still looking for more.

I have seen some very nasty looking images done with hdr and thats not what I am going for. I am looking to use it for more a subtle effect.

So are any of you employing this method or do you know of any well done examples out there? Please share some images if you have any.

Any thoughts on this would be appreciated.

John
www.gladesgallery.com

[D. Bryant]

I have searched some old threads about hdr on the forum and haven't seen any too recent or from people employing it for large format.

I shoot 8x10 primarily and I imagine it wouldn't be practical there because trying to work with three or four 800 meg 16bit rgb images would grind my dual quad core to a halt plus the cost of 8x10 trannie's wouldn't be much fun either.

I still have my 4x5 and I photograph in the swamps of Florida under very difficult lighting conditions. So I was thinking it may be worth trying.

I scan with a Creo IQ 2 which offers lot's of range but I am still looking for more.

I have seen some very nasty looking images done with hdr and thats not what I am going for. I am looking to use it for more a subtle effect.

So are any of you employing this method or do you know of any well done examples out there? Please share some images if you have any.

Any thoughts on this would be appreciated.

John

Here is an article you may wish to read.

http://www.thelightsright.com/CoachingSession4

Photomatix may choke on large file sizes.

You may wish to explore the HDR merge features of PS CS3 & CS4 Extended, particularly CS4 extended.

Don Bryant

[Bruce Watson]

HDR makes some level of sense when your capture medium has limited dynamic range. So if you insist on tranny film, and you want to photograph in SBRs larger than the tranny film can handle, then perhaps it would work for you.

Or... you could switch to negative films. I've never had a need for HDR using negative films. This would save you some serious bucks when shooting 10x8, and some serious hassle in Photoshop that isn't really needed.

But as always, YMMV.

[Tyler Boley]

I find HDR difficult to deal with. Adobe's requires conversion to rgb and back if the original is grayscale. Obviously as you suggest the file sizes get quite large from scanned sheet film, but how big a problem that is depends on your system. Adobe's interface is very non-intuitive, and it takes a few tries to get anything useful. Photomatix always chokes when I throw these big scans at it so I have no results to show from that. These tools are not really meant for this task, but can be made to help, as you suggest, in difficult lighting situations, which I tend to be drawn to. The problem is not that the film can't handle the range, or our scanners. The challenge for me has been to get to my original impression of the scene into a print I find pleasing, a straight approach to highly contracted film often is not what I had in mind, even though in the end the print may have a "straight" feel.
Complex adjustment layer masking becomes the process, and can sometimes get frustrating. So HDR has occasionally helped. I've gone two ways- two different scans, one favoring highlight description with compressed shadows, and other with enhanced shadow detail at the expense of the highlights, and then HDRing these two. I think I recall it wanting exposure info, I just fake something in there. The 2nd way is simply creating two files like those above, but from one straight scan that had uniform linearity hight to low and no clipping, but obviously low local contrast and a flat feel. Both methods require Hi bit scans.
Still, after HDR processing, I find it's a first step, and further editing definitely necessary, even possibly locally layering in parts of the original scans. The two attached images were done this way. It's been hit and miss each time, and I don't have a solid workflow to recommend.
I do not enjoy going to such lengths frankly, and it's rare that i do. I don't enjoy maniputed looking prints, and prefer a direct adherence to the feel of the scene and the light. Sometimes, one curve, and some edge touch up and I'm done. But to paraphrase one of my favorite printers, Caponigro, I will pull out any and all tools I know of to get the print I want.
So the bottom line of my rambling is- Yes, it can't be helpful if a creative approach to it's use is employed. I would also recommend downloading Perceptool and giving the demo a try on some of those difficult scans, it uses similar methods but from a single file, I'm still trying to determine it's usefulness. Again, a first step.
Tyler
http://www.custom-digital.com/

[Tyler Boley]

in reading Bruce's post then rereading yours, I see you are shooting trannies, the above was a waste of time!!!! So I guess bracketing, multiple scans, and some major HDR moves are what you have to play with. I tried this little guy as a demo on some little DSLR captures, looks promising and economical -
http://www.pangeasoft.net/pano/bracketeer/index.html
Tyler

[Eric Leppanen]

The impression I get is that the arguably best HDR program around (Photomatix) is oriented toward DSLR's and MFDB's, and no effort has been made to make it work reliably with large film scans. The other available HDR software tools are problematic to various degrees.

This entire subject gives me a headache, and I just avoid the issue entirely and use either chrome or color neg film depending on subject contrast.

An alternative to multi-scan HDR is combining color filtered scanned B&W negs into a single color image (something like Technicolor). This method is prone to registration issues due to subject movement, but I presume you could get even more dynamic range out of it versus color neg film by pulling the B&W negs. See Sandy King's posts in this thread:

http://www.largeformatphotography.info/forum/showthread.php?t=48583&page=4

[Ken Lee]

"So are any of you employing this method or do you know of any well done examples out there?"

Have you looked into compensating developers, or stand/semi-stand development ? Using such methods, people have been able to accomodate SBR ranges that would blow your mind, you might say.

There has been a lot of discussion here and elsewhwere on these techniques.

[John Brady]

"So are any of you employing this method or do you know of any well done examples out there?"

Have you looked into compensating developers, or stand/semi-stand development ? Using such methods, people have been able to accomodate SBR ranges that would blow your mind, you might say.

There has been a lot of discussion here and elsewhwere on these techniques.

Thank you all for the input so far! I probably didn't make it clear but I am trying to work with color tranparancies. I am using Povia which has some latitude but not as much as color negative film. I am not a fan of negative film because it much grainier then my trannies.

I am still intrigued by this process if it is feasible.

[dwhistance]

I have on occasion exposed two transparencies and then combined them in Photoshop using a combination of luminosity masking and adjustments to the opacity of the top layer to achieve the look I wanted. I have tried various HDR programs but have never been impressed enough to purchase one even for my DSLR images. I have also tried the built in HDR processing in CS3 but was again unimpressed. Given the time it takes any HDR program to process even 10mp images I would hesitate to use one with scanned LF images.

David Whistance

[Ken Lee]

I probably didn't make it clear but I am trying to work with color tranparancies.

In that case, you may want to consider a different media - or use what cinematographers use, when shooting outdoors: big reflectors and lights. ;)

[Wallace_Billingham]

I am not a fan of negative film because it much grainier then my trannies.


If you are worried about grain in 8x10 negative film you will never be happy with the results of HDR at least using current software and hardware. The problem is that no matter what you do the process will introduce grain, noise, and artifacts in several steps. First off you will have the grain from multiple pieces of film that will show up in the scans. So if you have 3 sheets of film you will get 3X the grain. Also since some of the scans will be over exposed and some under that will introduce more grain than a properly exposed trannie.

Then when you go to make the scans you will get 3X the digital noise from the scans, and the noise will be much higher in the over/under exposed trannies.

Then you will get sharpness and artifact issues with the exposures themselves. HDR works best when shot with a digital camera because you can fire off many frames in a second with little to no camera shake electronically adjusting the shutter each time often automatically. With a LF camera you have to take the shot, put in the darkslide, remove the holder, adjust the shutter, put in a new holder, remove the darkslide, take the shot, put in the darkslide, remove the holder, adjust the shutter, put in the new holder, remove the darkslide and take the 3rd shot. All the while you better make sure the camera does not move at all, the wind does not blow against your bellows, the subject does not move, the lighting does not change etc. All of these things would result in sharpness and artifact issues when combined in HDR. And in the swamps of Florida that would be pretty hard.

The other issue is that the better HDR programs work best by reading the exif data embedded in the digital files so they can know the variables in exposure by reading the f/stop and shutter speeds. Your scans will not have that data.

I think you would be much better off just shooting 400 speed negative film and get crazy wide latitude with the trade off of grain

[Kirk Gittings]

Then when you go to make the scans you will get 3X the digital noise from the scans, and the noise will be much higher in the over/under exposed trannies.

Interesting, as running HDR on digital files results in virtually noiseless results. I am not saying that I am thrilled with HDR results in general but noiseless images are an obvious benefit. For example noise gets enhanced when you try and pull detail out of deep shadows, but in HDR you are using a exposure for the shadows that has very open shadows, resulting in virtually no noise in the shadows. The difference in digital imaging is dramatic in that regard.

[Brian Ellis]

I agree with Wallace. I have Photomatix and I don't even like it much with my digital camera - too much nose, artifacts, whatever for my tastes. And for large format there are so many additional problems, outlined by Wallace and others, that I don't think it would be very practical. Rather than using Photomatix or HDR with large format, I think you'd be better off just making two exposures - one for the shadows and one for the highlights - and merging them in Photoshop. Or even making just one exposure, then making two scans and merging them.

[David Luttmann]

Interesting, as running HDR on digital files results in virtually noiseless results. I am not saying that I am thrilled with HDR results in general but noiseless images are an obvious benefit. For example noise gets enhanced when you try and pull detail out of deep shadows, but in HDR you are using a exposure for the shadows that has very open shadows, resulting in virtually no noise in the shadows. The difference in digital imaging is dramatic in that regard.

I agree Kirk. Adding 3 negs does not produce 3x the grain. In fact, it has quite the opposite effect....grain is reduced. I used to use this method in the darkroom, stacking 2 shots of astronomical photographs shot on hypersensitized Kodak PPF400. Combining images smooths out grain.

[Marko]

<OT>

You don't need HDR to accomplish grain/noise reduction, you can do that by layer averaging. You essentially shoot several identical exposures and stack them up in Photoshop then adjust their individual opacity according to a simple formula. The alternative (for digital capture) is dark frame averaging, where you shoot one "dark" frame (with the lens cap on) using the same exposure as with the other frame(s).

</OT>

[Wallace_Billingham]

Interesting, as running HDR on digital files results in virtually noiseless results. I am not saying that I am thrilled with HDR results in general but noiseless images are an obvious benefit.

the reason for this is that digital files have exif data that tells the program what your ISO was set for and then the program uses that data to reduce the noise. Your film scans will not have such exif data and the NR software will have a much harder time dealing with both digtal noise and film grain

[Kirk Gittings]

I don't think that is true. Both the straight file and the file used for the HDR shadows have the same ISO exif data. The only difference being the exposure. In terms of shadow noise it is simply a matter of exposure with the better exposed lower noise shadows being used for the HDR shadows. This is clearly visible by just looking at the deep shadows in the original files.

[Emmanuel BIGLER]

So if you have 3 sheets of film..

For those who are ready to use 3 sheets of film, the tri-color separation process as advertised by several groups (including a very active French group) uses the very long characteritic curves of modern B&W films like Tri-X or HP5 to record colour images with a high dynamic range.
Actually a single HP5 film can record a very high dynamic range per se, but you need a damn' good scanner to extract the highest densities on film.

My understanding is that the limits of the actual dynamic range that can be recorded on an HP5 film are due to the internal flare of the lens+camera+film system.. and the performance of the scanner if you have to process the images digitally.

The tri-colour group on flickr : http://www.flickr.com/groups/92087504@N00/pool/

You can see some examples on Henri Gaud's web site
Systematic tests with various ISO sensitivities and N+/N- processing of HP5+ in HC-110.
http://trichromie.free.fr/trichromie/index.php?post/2008/07/08/813-la-matrice-rlz-une-matrice-12x12-classement-par-iso
http://trichromie.free.fr/trichromie/index.php?post/2008/07/12/830-la-matrice-rlz-une-matrice-12x12-les-dtails

tri-color HP5 pushed to 6400 ISO just for fun : http://trichromie.free.fr/trichromie/index.php?post/2009/05/17/Peut-on-pousser-un-film
http://trichromie.free.fr/trichromie/index.php?post/2009/05/19/Peut-on-pousser-un-film-suite-II

A recent example of the tri-color process, a portrait by Laurent Askienazy : probably not eligible as "HDR", but yes, you can do portraits with this strange process...

http://trichromie.free.fr/trichromie/index.php?post/2009/06/29/Trichromie-by-Laurent-Askienazy

[Ken Lee]

If we wanted to get even more dynamic range, we could take multiple exposures with each color.

For example, a 9-color process: Red Green and Blue get 3 exposures each: one for the shadows, another for the mid-tones, and a third for the high values.

High-res scans of nine 8x10 negatives could possible strain one's computing resources - so it might be best to merge each color first, and then merge the final 3 ;)

[Wallace_Billingham]

.....Both the straight file and the file used for the HDR shadows have the same ISO exif data. The only difference being the exposure.....

Correct and the higher the ISO the more NR that gets applied behind the scenes. So if you have a 1600 ISO file it will get more than a 100 ISO file. This NR is set up to deal with digital noise which looks very different than film grain. One of the reasons that the Photoshop Actions/Plugins that add noise to an image to simutale grain look so bad.

Digital Noise combined with grain is very hard for software to remove and results in a loss of sharpness in the final image. Will you get a lot of grain and noise in the final image? Not really, but if the OP is bothered by film grain using 8x10 negative film than any added noise of grain would be too much.

[jp]

While HDR is certainly a cool creative technology, and I love digital photography and computers, I don't bother with it. For me, there's no glory in technical achievement (especially if I have to pay for it), as that's a moving target that get trumped regularly. That's why I am happy to use a 60 year old camera as well as 1 year old camera. I just want photos of things or places that meet my needs and quality/artistic objectives.

I shoot mostly local scenes, and if I get a good composition but difficult lighting, I come back later. In my films days, my color photography was mostly slides, and my first dslr had a fairly limited dynamic range, much like slides. I would advocate a simple solution whenever possible. For me, this might mean revisiting the location under a different lighting condition. For example snowy woods looked best on cloudy days usually with the digital camera, or late/early sunny days rather than mid day. However with B&W film, there were more conditions I could photography the snowy woods and get the right texture and shadows. At the beach, we have large tides, and often I time my adventuring to correspond with both tide and weather.

For people photos, I sometimes needed to use a reflector when shooting to put enough light into facial shadows so detail wouldn't be lost to the recording medium. I don't see why something like this couldn't be employed any any close quarters shooting.

[Kirk Gittings]

Correct and the higher the ISO the more NR that gets applied behind the scenes. So if you have a 1600 ISO file it will get more than a 100 ISO file. This NR is set up to deal with digital noise which looks very different than film grain. One of the reasons that the Photoshop Actions/Plugins that add noise to an image to simutale grain look so bad.

Digital Noise combined with grain is very hard for software to remove and results in a loss of sharpness in the final image. Will you get a lot of grain and noise in the final image? Not really, but if the OP is bothered by film grain using 8x10 negative film than any added noise of grain would be too much.

No, you are missing the point, all my files are shot at ISO 200. It has nothing to do with high ISO. I don't bracket with ISO ever. The low noise of exposure blended files is because of the healthy exposure for the shadows. The bracketed exposure for the shadows has virtually no noise in the shadows because the shadows are placed high like on Zone V, and that is the file that the HDR program uses for the shadows. Whatever noise you have in the boosted shadow exposure is what you will get in the file of the blended file.

Try it. It is obvious.
__________________

[George Stewart]

I have shot down in the swamps of Florida, several times. My typical equipment is an 8x10 (B&W) and a DSLR. My 8x10s are scanned on an IQSmart2, as well.

I have found that my results are better with the DSLR, bracketed and stitched, than with a single 8x10 B&W image. I haven't tried HDR with LF due to the cost, and logistics when traveling (I do not want to burn film on fewer images). You should probably try one or two images and see for yourself. Also, you may wish to try some HDR-stitched images and compare.

[Alan Davenport]

I've done LF HDR once, when I wanted a shot of a church interior with a 9 stop range and I had a bag full of Ektachrome. It works but it's awfully fussy.


http://farm1.static.flickr.com/120/253463006_bc7516df96.jpg

[John Brady]

Hi Alan, that looks like a pretty effective job to me!
George, I am referring to shooting color transparencies in the swamp, I find it to be way more difficult (at least for me) than shooting black and white, which I do also.
I will probably skip this project with LF and give color negative pro 160s a try again.

On the other hand, I just received a new cannon 5d mark II and the new Cannon 17mm tilt shift lens. That should be fun to experiment with HDR on. I think a 17mm with 12mm of shift/rise and fall should be good fun.

jb
www.gladesgallery.com

[George Stewart]

John, if you are not already familiar with Really Right Stuff products, their pano-mount might be the ticket.

http://reallyrightstuff.com/pano/07.html

Also, this, or a similar product, might be useful when doing two-shot panoramas with your new TS lens. Start with the lens shifted all the way left, then shift right and adjust the body so that the nodal point is where it was for the first image.

http://reallyrightstuff.com/macro/02.html

[Kirk Gittings]

Also, this, or a similar product, might be useful when doing two-shot panoramas with your new TS lens. Start with the lens shifted all the way left, then shift right and adjust the body so that the nodal point is where it was for the first image.

Unless something has changed that I don't know about on the Canon 17 TS, finding the nodal point is not necessary when doing a two shot shift panorama with all previous TS lenses as the nodal point doesn't shift hence the body doesn't need to move. I own Canon 24, 45, 90 TS and a Olympus 35 PC. Just do the shifts. Making sure to lock down your white balance. I do, on average 6 such panoramas on every commercial shoot (18 or such stitches a week), and they align perfectly and stitch effortlessly with just PS.

[Emmanuel BIGLER]

the nodal point is not necessary when doing a two shot shift panorama

Of course, dear Moderator, not necessary, you are right, for the simple reason : it is the entrance pupil that matters, the nodal points are totally irrelevant to panoramic stitching ;-);-)

[GPS]

I've done LF HDR once, when I wanted a shot of a church interior with a 9 stop range and I had a bag full of Ektachrome. It works but it's awfully fussy.


http://farm1.static.flickr.com/120/253463006_bc7516df96.jpg

Sorry Alan, nothing against a personal taste but this picture looks to me like a failure. The amount of the light in it is surreal. Every churchgoer knows that church ceilings do not have this light on them. It's like you wanted to take a photograph of the vaults surface. But in the same time it flattens the church interior terribly - shadows that make vaults so intriguing in the architecture were wanted by architects - they create volume filled with inner visual content. To me, your picture seems artificial and devoid of the architectural intention. The graphical and spiritual center of the picture (the altar) is empty. It almost seems as if the main purpose of the picture were making the lighting uniform. Sorry, just sincere.
What is more, the lamps do not give off any light - quite the opposite, they themselves seem to be illuminated by some light source that itself is omni directional and illogical. Sorry again.

[Kirk Gittings]

the nodal point is not necessary when doing a two shot shift panorama

Of course, dear Moderator, not necessary, you are right, for the simple reason : it is the entrance pupil that matters, the nodal points are totally irrelevant to panoramic stitching ;-);-)

Of course, dear Moderator? Cute.

Understood. It is popularly but incorrectly referred to as the nodal point. Regardless, shift stitching requires no adjustment of the camera position for near perfect alignment.

[Tyler Boley]

I think here and in the Perceptool thread people are just trying to show how a process helped (helped, not solved) with a difficult technical problem, generously sharing something they learned.
So whether or not everyone connects with examples artistically is irrelevant. It's questionable whether or not examples have been shown are even implied to be successful finals, only that particular issues were addressed.
Critiques irrelevant to the thread just discourages members from interacting, which is the real point of these lists. I for one appreciate every suggestion and example offered here.
Tyler
http://www.custom-digital.com/

[John Brady]

John, if you are not already familiar with Really Right Stuff products, their pano-mount might be the ticket.

http://reallyrightstuff.com/pano/07.html

Also, this, or a similar product, might be useful when doing two-shot panoramas with your new TS lens. Start with the lens shifted all the way left, then shift right and adjust the body so that the nodal point is where it was for the first image.

http://reallyrightstuff.com/macro/02.html

I agree they have some great stuff. I use their qr clamps and plates. I got one of their L brackets for the 5d.

My plan was to do as you have described Kirk. So far I have played with setting the camera up vertically (portrait) and firing three shots, left shift, center and right shift. The field of view with this 17mm lens and full frame is incredible. I tried just 2 images left and right but there was some missing area in the middle.

Now the next trick will be to do the above but also make multiple exposures and try some HDR.

jb

[Wallace_Billingham]

No, you are missing the point, all my files are shot at ISO 200. It has nothing to do with high ISO. I don't bracket with ISO ever. The low noise of exposure blended files is because of the healthy exposure for the shadows. The bracketed exposure for the shadows has virtually no noise in the shadows because the shadows are placed high like on Zone V, and that is the file that the HDR program uses for the shadows. Whatever noise you have in the boosted shadow exposure is what you will get in the file of the blended file.

Try it. It is obvious.
__________________

but that is not the way HDR software works. HDR was designed for use in computer generated animation for both videos you watch on a screen and video games. The idea was to have a very high bit depth file that could contain a lot of information at the pixel level about how that pixel could be rendered in a variety of simulated lighting effects. This data was then tone mapped on the fly so that if the animation called for say a robot in bright sunlight it would map the tones much brighter than the same robot would be in the dark. You would not have to have dozens of different models of the robot in various lighting conditions you would just have one model that would be rendered differently.

When used in still photography each exposure gets put into the data at the pixel level. Nothing gets tossed out every bit of data goes into the file which is why you will get better results if you have say 5 exposures than 3. The HDR software looks at the images and sees how the scene would look in variety or lighting conditions from very bright light (over exposed) to very dim light (under exposed). All of that data gets loaded into the program noise and all. That is why the software will do a simple noise reduction before hand by reading from the exif data what the ISO was. It also works better when it can read from the exif data what the shutter speeds were so it can better know what file is what.

It does not toss out the under and over exposed data with higher noise, it all goes into the file so that when you render the image it is able to have as much data as possible. That is why it is very easy to get very fake looking cartoonish images with HDR software because all of that data is in there, and the vastly over and underexposed images create color shifts

If all it was doing was using the properly exposed pixels you would not get the color shifts just like you do not get a color shift if you take two exposures and blend them together using a mask in photoshop.

You are getting very low noise files because you are starting with very low noise files and you have increased bit depth to render shadows without artifacts. The program is able to render the shawdows with a lot more data. If you are doing a 3 shots a stop apart in HDR the shadows that would normally fall in zone 2 also get data from those shadows being rendered in zone 3 and 4. All of that data then slides back down into zone 2 if that is how you choose to tone map the image.

When you are dealing with film scans however you have the same exposures in the digital file created with the imagers in the scanner. You will end up properly exposed digital files of the negatives/positives placed in front of the scanners imagers. The scanner and the HDR software will have no way of knowing what was over exposed and what was not. Is has no need to as all of the data gets loaded into file and then gets rendered. If shot one had a pixel that recorded at zone 1 and shot two had the same pixel that got recorded at zone 2 and shot three had the same pixel recorded at zone 3 you as the person rendering the file would have to tell the program (or let it guess if you use one of the automated renderings) what zone to put that pixel on in the final image. Of course the program would also have no way of knowing if that was a pixel of pure data or a pixel of noise. How would it?

[George Stewart]

kirk and Emmanuel, I concur and I do not concur. The "entrance pupil" is the correct term for the point at which a lens' axis must be rotated, or remain stationary, in order to avoid parallax . However, with respect to the TS lenses (Nikon 24, 45, & 85 PCs) I have used, the entrance pupil does move when the lens is shifted, hence requiring a corresponding but opposite shift in the camera body. While the effect may be negligible depending on subject distance, it is clearly visible through the viewfinder on close subjects.

John, if just shifting the lens works for you, great, otherwise consider also shifting the camera body. Finally, how is shooting in southern Florida during the summer (mosquitos)? Does Corkscrew have water? I'll be down there in about two weeks.

[Kirk Gittings]

I'm confused. It looks to me like you are saying the same thing basically I am....sort of.

So without the high bracket for the shadow detail (which has lower noise in the shadow areas of the normal exposure because of the increased exposure right?) what noise would you get in the shadows of the HDR? Or to put it another way-rather than using the high bracket (with the increased exposure in the shadow areas) and instead using the middle file and simply boosting its exposure in ACR to artificially create that bracket (which will increase shadow noise). Which method would give you less noise in the shadows of the HDR? The one with the proper high exposure bracket right? So how can you say that the high bracket with the less shadow noise does not account for the less shadow noise in a properly bracketed HDR. Help me out here.

[John Brady]

John, if just shifting the lens works for you, great, otherwise consider also shifting the camera body. Finally, how is shooting in southern Florida during the summer (mosquitos)? Does Corkscrew have water? I'll be down there in about two weeks.
George, Summer is my favorite time to photograph here. This is the time we get the most dramatic skies, best sunsets, best light, etc.

But the mosquitoes can be a pain. We have these little gems called no-see-ums that are a real treat when out on the islands.

Corkscrew is about 7 miles from my house, I haven't been there this year but based on the conditions of most of the surrounding swamps it should have water. It was bone dry for a long time. I don't go there very often because they don't let you get off the board walk. If you're feeling more adventurous than that give me a shout and I will give you some of my hotspots. I have a small gallery here you can check out if you get bored too.
www.gladesgallery.com

[Wallace_Billingham]

I'm confused. It looks to me like you are saying the same thing basically I am....sort of.

So without the high bracket for the shadow detail (which has lower noise in the shadow areas of the normal exposure because of the increased exposure right?) what noise would you get in the shadows of the HDR? Or to put it another way-rather than using the high bracket (with the increased exposure in the shadow areas) and instead using the middle file and simply boosting its exposure in ACR to artificially create that bracket (which will increase shadow noise). Which method would give you less noise in the shadows of the HDR? The one with the proper high exposure bracket right? So how can you say that the high bracket with the less shadow noise does not account for the less shadow noise in a properly bracketed HDR. Help me out here.

Kirk,

You and I are in the same book and chapter but not on the same page. You are refering to a digital file from start to finish and I an refering to the original poster where he is going to use film scans.

When you use a digital file from a DSLR or any other digital camera there is exif data the HDR program uses that exif data to build a very high bit depth model of what the photograph looks like under various lighting conditions. The program can read the exif data and makes a guess as to which ones were over exposed and which were under exposed. However all of the pixels from each file gets entered into the model. So yes noise from under/over exposed files gets entered into the programs model as well. The difference however unlike when you adjust the exposure from a single RAW file is that the noise in the shadows stays low because it gets burried in darker tones and colors and it does not get amplified by trying to slide it to the right of the histogram, because all of the data gets entered into the model the program will apply noise reduction based on the ISO of the exif file before those files get entered into the model.

Now when you render the output file or image from the HDR model the program creates all new pixels based on what output paramaters you have selected. It does not recycle or use any of the pixels from the original files but creates all new ones. This is why it is so easy to very funky and strange colors and other odd looking images because your computer is making an entirely new image right down to the pixel levels.

The problem with using film scans is that you have no exif data, and you do not have over exposed and under exposed files. What you have is a 2nd generation image that is exposed properly of a negative or tranny that was not exposed properly. So if you have blown out highlights the data at the pixel level in the scan will just render that as white. There will be no details just white just like on a darkroom print there would just be the white of the paper. With shadows you will have a very thin tranny or negative one that the scanner will try and pull data off of and thus introduce noise at the scanner itself. The scanner operator could slide the black point over to render all of that as black but that will make it harder for the HDR program to render the tonemap of the image and may also induce noise. It will not be a lot of noise but it is still there.

[cjbroadbent]

....So are any of you employing this method or do you know of any well done examples out there? Please share some images if you have any...
Sorry if you've seen this before. I tried HDR tone-mapping on seperate 4x5 negatives and on a two-scan single 8x10 negative. The two-stop bracketed 4x5s work better than anything I can do in the darkroom. The single 8x10 has nothing much to show for the effort. The tests are on this page:
http://picasaweb.google.com/cjbroadbent/Formats?feat=directlink
Disregard the digital camera tone-maps which are there for comparison (and which work much better).