HDR

<p>Finally - the weekend is here and I get to work on some of the really good shots I got from a recent trip out west. I did some bracketing with my new Nikon D90 – I think I’ll go ahead and download Photomatix and try my hand at some HDR’s. Okay, all set - I’ll just throw a few raw files directly into Photomatix to see what happens. Wow! Very cool, I think I may like this. Maybe I will quit my day job after all and turn pro. Okay, what if I tweak the raw files in camera raw a little then save them all as TIFF’s, then run them thru Photomatix. What if I tweak the raw files, then let Photoshop merge them to HDR, then run the HDR file through Photomatix. What if I converted the raw files with Capture NX2, then save them as TIFF’s, then run them through Photomatix. After all, Nikon was good enough to give me a 60 day free trial. Oh wait, I have been processing everything under the details enhancer tab, now I have to go back and do everything again under the tone compressor tab. I almost forgot I could also just blend exposures. I’d better go back and do everything again that way, you know, just in case. Wouldn’t it be interesting to take a detail enhanced image and a tone compressed image and run them back through Photomatix. Naturally I would have to do this using the details enhancer, tone compressor, and exposure blending methods. Okay, what if …. wait a minute it’s Monday morning, I need to get to work. When was the last time I slept. Why isn’t the lawn mowed. Why don’t I have any prints of my vacation. Where’s my wife. How did I use up 50GB of disk space so fast. “Jane! Stop this craze thing!” </p>

<p>The really scary part, Tom, is that it's actually the <em>second</em> weekend, and you've missed the entire week in between, too. HDR = "High Dubious Recreation" time. Now go mow the lawn.</p>

<p>Tom -<br>

I had some of the same thoughts when I first downloaded Photomatix about a month ago. I was also wondering about the merits of running Photomatix within Aperture, or running it in Photoshop, or running it as a stand-alone. I haven't developed any workflow yet, but I'd like to hear from anyone who has.<br>

Also, there was a good tutorial posted to this forum some time in the past few days that's worth a look, if you haven't seen it. A good example of producing realistic results.</p>

<p >HDR=High Dynamic Range photography</p>

<p >to do hdr- </p>

<p >if you put camera into full auto matrix metering, take first shot note fstop and shutter speed. put camera into full manual, see if camera still has the matrix fstop and shutter speed. if yes, then using shutter speed go up 2-4 shutter speeds 1 fstop worth of shutter speed at a time. then back to matrix shutter speed and go down same number of shutter speeds.</p>

<p >christian bloch in his hdri handbook did a test of 1 fstop bracketing vs 2fstop bracketing. there was an obvious image quality falloff using the 2fstop bracketing. if the image quality decline in 2stop bracketing is acceptable to you then use the 2 stop. 1 stop is recommended for max image quality, though of course it needed more shots. personally, if you can see the difference in 1 stop brackets then you might well have to use that. But if you cannot then 2stop brackets work fine.</p>

<p >this is on a tripod with cable release. </p>

<p >no, you should not use 1 raw shot and convert 1 stop up and down, because their is not enough dynamic range in the 1 raw shot. dynamic range is why we are doing this, hdr is trying to get all it can. If you use a single raw shot and triple convert it, you still end up with no more DR than the single raw shot.</p>

<p >the group of shots can be raw or jpeg. if jpeg they can be used as is. if raw remember that you HAVE to batch process all 3-9(?) shots. this is because the pp has to be all the same on every pic. you cannot, for example make any attempt to get the shadow details of the group of raw pics, because that would require different amounts of pp, and you cannot do that with hdr. the pp for all shots has to be identical.</p>

<p >for me i just shoot them in jpeg and use them from the camera, that way they are all identical because the camera jpeg settings are the same for every shot. i also put my hand streched in front of the lens and take a check shot and when done take a ending shot with hand. this tells me where the hdr group is on my memory card when i transfer to the pc.</p>

<p >the only important item is to bracket using shutter speeds only. if fstops are used it changes dof between shots. and shoot enough shots, 3-9(?) is the optimum. the only other thought is to shoot a scene that deserves the the hdr technique, too many people are shooting hdr because it is new or different or whatever. many people are using hdr software on scenes that do not have enough dynamic range; they end up with images that have been enhanced by hdr software, they are not hdr images. the dynamic range was not in the scene to begin with. the scene for hdr should have a very wide dynamic range. this can be checked with a spotmeter on different areas. NOTE: use of auto bracketing on a camera may not work unless you know the bracketing is using the shutter speeds to bracket. in any event, you really need 3-9(?) shots for hdr; this is more than the auto bracket fcn on almost all cameras. and the bracketing has to be both sides of the middle shot. make you use enough brackets to cover the previously checked dynamic range. it does little good to bracket for a 10stop dynamic range when the scene has 14stops.</p>

<p >and the scene should have no movement, if so the item will blur in the hdr image.</p>

<p >do not adjust the focus. set the focus on infinity or use a hyperfocal setup for focus.</p>

<p >do not adjust the white balance for individual shots. go with awb or 1 setting and do not change it.</p>

<p >remember, hdr was created and meant for scene that have a dynamic range that exceeds the dynamic range of the camera sensor, about 5-6stops for jpeg or 7-9 for raw. hdr with the required software allows the user to capture a scene that has very high dynamic range. </p>

<p >I currently use Dynamic-Photo HDR and recommend it. Less than ½ the price of photomatrix and it has 6 different looks, (the photomatrix look is included), and each of the 6 looks can be fine tuned. Get Dynamic-Photo hdr here-http://www.mediachance.com/hdri/index.html; also included is a program that is part of DP hdr that can make a fake hdr look image from a jpeg.</p>

<p >pp. after the hdri is made and is in a folder, i open in pe6. there i use noise ninja(to reduce noise), auto levels(to give a normal overall brightness amount), and focus magic(to sharpen and give a better focus. also if focus magic is used do not sharpen at all, that is double sharpening and is guaranteed to make artifacts.). save as tiff. DO NOT USE AUTO CONTRAST OR ANY OTHER CONTRAST ADJUSTMENT. that is what you just did in the hdr software. also do not adjust any shadows or bright areas. the point of hdr is to let the shooting of multiple shots and the hdr software combining of those shots take care of the dark areas and bright areas. if any areas are dark or highlight blown, then the brackets were not extended out far enough from center.</p>

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<p>Tom, loved your rant. Reminded me of when I started with HDR.</p>

<p>First, check out some of the tutorials on hdrsoft.com as well as other sites. Indeed, there are probably a gazillion YouTube tutorials out there now.</p>

<p>As for workflow, here's what I do.....</p>

<p>* Convert RAW files to TIFF in NX2. Indeed, they tell you not to use Photomatix as a RAW converter. Besides, this takes advantage of the full RAW conversion.</p>

<p>* TIFF files are tone mapped with specific settings, then saved as a HDR TIFF</p>

<p>* The HDR TIFF goes back into NX2 for final conversion.</p>

<p>The first two steps are done by batch process. In other words, do it while you are sleeping or whatever. The last step takes only seconds. All I do is adjust levels, maybe some contrast, then sharpen it. Sometimes I might also make light adjustments to shadows or highlights but rare. That's it.</p>

<p>For a good quickie tutorial, check out Matt Kloswkowski's tips from D-Town TV. Scroll down to the bonus for Episode 2 at the bottom...<br /><a href="http://www.dtowntv.com/category/episodes/page/2/">http://www.dtowntv.com/category/episodes/page/2/</a></p>

<p>Oh, one more thing. Make sure auto ISO is turned off. I learned this one the hard way.</p>

 

<p>When you do 2-stop versus 1-stop bracketing, you are trading off a certain amount of image degradation for the opportunity to supersample. The more pictures you take, the more opportunity for camera shake, camera shift, and subject movement to creep in. The data is very, very clean from a 2-stop bracket. I'm skeptical of Bloch's claims. [Are his examples published online anywhere?] Keep in mind that unless your camera shifts only around the lens nodal point, the slightest change in position of the camera (1 px) is going to produce images that have to be warped to get correct registration, and the degree of error will increase with the number of exposures. </p>

<p>The best single advice I can give to an HDR shooter using a Nikon DSLR is to capture RAW to 16-bit TIF using the "neutral" setting on NX and no other adjustments whatsoever except for CA mitigation. If you use CaptureOne, use the "linear" setting. Your results depend upon having nice, clean, LINEAR data. You might prefer to do white balance after tonemapping, since you will preserve the most information in the source files, and do white balance on the most information-rich data you can have.</p>