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Dynamic Range - again
What do you do if your camera's DR can't handle a very contrasty scene?.

Do you have to accept a blown histogram in both ends? Or do you have to revert to bracketing and a tripod? Do DR vary a lot between brands?..

Comments (17)

Linslus wrote:.

What do you do if your camera's DR can't handle a very contrasty scene?.

1. Come back later when the light has changed.2. Recompose to avoid very bright/very dark areas.3. Use a graduated ND filter.4. Use fill flash (if feasible)..

Do you have to accept a blown histogram in both ends?.

Blown histogram and lack of detail at the black end is often acceptable to the eye. Lack of detail at the white is a lot less acceptable.5. Or do you have to revert to bracketing and a tripod?or shoot raw and process twice..

Do DR vary a lot between brands?.

DSLRs are better than P&S. Fujifilm cameras with the Super CCD sensor, particularly the S5 DSLR, have the best DR..

Chris R..

Comment #1

If you are stuck using JPEG and have control over it turn the contrast way down..

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Comment #2

Linslus wrote:.

What do you do if your camera's DR can't handle a very contrasty scene?Do you have to accept a blown histogram in both ends? Or do you haveto revert to bracketing and a tripod? Do DR vary a lot between brands?.

Slide film and digital have 1 thing in common, both have a limted dynamic range. I shoot slides for 32yrs and had not problem. I simply adjusted my shooting. for digital you have about 6stop of DR with jpegs and about 8stops with raw. for all cameras the jpeg DR is the same; it is how jpeg works. but raw changes slightly depending on the camera.

You just have to get ujsed to it..

In practice the normal procedure is to make sure that you do not blow the highlights. the way to do this is "to shoot to the right". this make sure the histogram has the histo line hitting the floor of the histogram before it hits the right wall, BUT as far to right as possible. the give the max DR for every shot no matter the recording format. this may mean that the right side histo is blown, that is hitting the wall before the floow. well, so be it.



There are some things that the user can do to help the situation..

First-try to equalize the DR. that reduce it to something the camera can handle. you can do this by using a fill flash or using reflectors to put more light into the darker areas. a reflector can be as simple as alminum foil stapled to cardboard, shiny side out. if shooting people and/or portraits move the location of the shoot to the shade so the light DR is smaller..

Second-use a technique that can handle higher DR. the 2 would be exposure blending and HDR. the next reply is a explanation of the differnce. both have the problem having heavy limits on having movement in the scene. since exposure blending is a simple 3 shot bracket, center and plus and minus 2EV, you can get away with slight movements; but it still takes time to do the 3 shots. hdr has the same limits only more, since to shoot hdr takes longer if the user is trying get all the DR the scene has got.

Many people use a 3 shot bracket for hdr. but they also make no attempt to find out if the 3 shots are covering the scene's DR. the way to do this is to use a spotmeter on the bright and darket areas of the scene and mentally calculate the dr. if you use shutter or aperture priority you can simply determine the DR from the differnce in selected settings. for proper alignment later normal technique calls for the use of a tripod and cable release with exposure blending or hdr.

But if without then there is the possibility of of have=ing a potential problem aligning the 3 shots later. it depends how much you want sharpness. I personally use the tripod for all my hrd and panorama work. my view is that it takes more effort to get the hdr or panorama and I always have the possible printed large output in mind so I need the shrpness for enlargements..

Me, I shoot jpeg all the time. and do not have a problem with DR. I am used to the limited DR anyway from my slide shooting. in viewing a picture be on the monitor on printed people tend to ignore the dark blown side. but blow the highlights and they turn white and everyone will see them. they are simply too obvious.

Some metering systems have builtin protection against some highlight blowouts, but it has limits. it just depends on the maker and how they setup the metering system...

Comment #3

There is a fundamental difference between hdr and exposure blending. it is not just a look, it is intent of the technique. assuming that you have 3 shots of a scene, and the scene is worthy of hdr at all(not all are), and the shots are plus and minus 2ev from the center metered shot and you have the center shot also. what exposure blending does is that the process selects the properly exposed portions of the scene from all 3 images and literally puts them together into a image in which all parts are properly exposed. but in the real scene that you saw with your eyes there is also a relationship between adjoining sections of the scene. if part a and part b adjoin each other and a is twice or four times as bright as b, then with your eyes that is what you see looking at the real scene with your eyes.

The 2 parts will appear exposed right but the 2 times or 4 times differnce in brightness will not be right or even present..

If the above 3 shots are processed in hdr software. the actual 32bit image, which cannot be seen in true form, only parts of it, maintains the relationship between any and all adjoining parts of the image that have any brightness differences. then through the process of tonemapping the 32bit image is changed to a 8 or 16bit jpeg or tiff. this image is maintaining the image differences and brightness differences between the adjoining sections and NOT just using the properly exposed sections..

The gradient between the sections is being maintained in hdr in an approximation of the true real scene. in exposure blending the only criteria is that the parts of the scene are all properly exposed. hdr is trying to show what the scene looked like in it's real form and view while exposure blending is just showing an image that has no wrongly exposed parts...

Comment #4

To do panoramas-.

For panoramas- -use tripod. you must keep it level with the horizon. if your tripod does not have a level builtin then buy one that slides into your flash hotshoe. again make a max effort to get the camera level..

-for exposure. set the exposure by pressing halfway and noteing the fstop and shutter speed. you are trying to find the brightest part of you panorama scene to be. once you have found the brightest check the fstop and shutter speed. put camera into manual metering mode and use those settings. do not change them for any part of the panorama..

-lens selection. I shoot mine with a 20mm. note: SHOOT THE LENS VERTICALLY. this is the only way to get some vertical scene, otherwise the panorama will be shaped like a hotdog. this is why I went to a 20mm. in vertical you are cutting your angle of view way down.

I later shot panoramas with 35mm 50mm 70mm; the hot dog effect was more pronounced. the panorama itself did work. With higher mm lens you would have to go to double rows..

-determine in advance the center point of the scene and try to go X number of shots on each side of it. for me with my setup a 120 degree scene is 7 shots; the center and 3 on each side. if I go with a 35mm lens then a 120degree scene will take 13 shots. no matter what lens you use realize that you are adding only 33% new scene with every shot, the rest is overlap for the right and left adjoining shots. the only exceptions are the end shots in the whole scene. it is possible to add another row above and/or below the first one.

For multiple rows are the same as 1 row, but you know have to overlap on the vertical as well as the horizontal. you must make sure that there are no gaps..

- I stick my hand in front of the lens and shoot, then shoot the panorama, the 7 shots, then put hand in front of lens and shoot. later I know that everything between hands is the panorama..

-i have used cs2 or the panorama factory software to make the panorama. for either couldn't be simpler simply select the shots and it does the work. this is where using a level pays off. the software is leveling the scene to make the long rectangle, but if the scene was not as level as possible in the first place the vertical becomes less and less(you end up with hotdog shape). so having the tripod and camera level is very important. also when mount and shooting vertically make sure the camera really is vertical, carefully check by looking threw the viewfinder.



-on focusing- what I do is to simply preset the 20mm lems at infinity, because of depth of field everything from 5.64ft to infinity is in focus at f11.0 distance 200ft. you can also use a hyperfocal focus setup. but thanks to the DOF table, just setting the lens at infinity is simpler. -i left WB alone, that is set at AWB; or you can use a preset setting like sunny or cloudy, but once set do not change it till panorama shots are done..

-online depth of field calculator available here- http://www.dofmaster.com/dofjs.html.

-parallax error. It is usually not so much a problem outdoor shooting. This is because the distances are greater than inside. In any event if you shoot panorams outside and at short distances OR any inside any building, you should be thinking of getting a panorama tripod head. This is to eliminate parallax error. I have the panosaurus pano head, cheap durable, and it works..

-for panoramas, the software I use is either panorama factory orPTGui or cs2. the one that works best for me is PTGui. I have since gotton PTGuiPRO, expensive but worth it. has many features and abilities that the other software does not have, including the ability to process 360 and 720degree spherical panoramas, plus many projection types..

-on post shooting work. If jpeg DO NOT PP. just use as is. After the pano is made then pp as desired. If raw, does your panorama software do raws? Not all do. If yes raw batch convert only.

All shots must be the same before the pano is made, then do any pp you wish but on the whole pano..

If any pp work is done to the pano before stitching then there will be a difference in the sections, and you could(probably?) get vertical bands where the sections join...

Comment #5

HDR=High Dynamic Range photographyto do hdr-.

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. the back to matrix shutter speed and go down same number of shutter speeds..

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.this is on a tripod with cable release..

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..

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..

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..

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.

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.

And the scene should have no movement, if so the item will blur in the hdr image..

Do not adjust the focus. set the focus on infinity or use a hyperfocal setup for focus..

Do not adjust the white balance for individual shots. go with awb or 1 setting and do not change it..

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..

I currently use Dynamic-Photo HDR and recommend it. Less than 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..

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 is focus magic is used do not sharpen at all, that is double sharpening and is guerenteed to make artifacts.). save as tiff. DO NOT USE AUTO CONTRAST OR ANY OTHER CONTRAST ADJUSTMENT.

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...

Comment #6

Note-using raw and triple converting to get what amount to 3 differnt exposure is 1 way of creating a hdr. BUT rpt BUT rpt BUT the triple converted raw shots does not have anymore DR than the original raw shot by itself. the ONLY way the get more DR is to shoot more shots that capture that increased DR. a triple converted raw will not get more DR since it wasn't in the original shot to begin with..

Many people use the triple and make a hdr from it. but the total DR is still the same as the original shot. Dynamic Photo HDR software program is a hdr program. it also includes a subprogram that has the ability to make a fake hdr from any jpeg you wish to use...

Comment #7

I try to capture without blowing the upper end of the histogram anduse the curve feature during photo editing. Make it curved up. Thehigher the curve, the larger DR. Adjust to the level that noise is stillacceptable in the dark area. So far I just use RAW and bump up thecurve..

I doubt the default DR setting will be changed with newer camerabecause it has to do with human perception of the scene.But having high DR as a camera setting is a trend in recently released ones...

Comment #8

I echo the comment: Turn the Contrast (Nikon calls it Tone) right down. That is the first and most obvious step. Many DSLRs have an auto-tone setting which seeks to guage the DR of the scene and adjust accordingly. Most of the time I leave my D80 on auto contrast but in exteeme situation I dial it down..

Chris Elliott.

*Nikon* D Eighty + Fifty - Other equipment in Profile.

Http://PlacidoD.Zenfolio.com/..

Comment #9

BA baracus wrote:.

If you are stuck using JPEG and have control over it turn the contrast way down..

I'm not so sure about this advice won't you have to introduce contrast in software? They would be fairly lackluster JPEGs. But I can see why you suggest this..

Especially when handholding, a considered reduced exposure that best suits the subject is a better plan overall but the lower the DSLR's ISO the better..

AN.

Http://slashedcanvas.co.uk/photography/photo4.htm.

Http://slashedcanvas.co.uk/photography/photo8.htm..

Comment #10

Very contrasty scenes often involve sunlight, hence a lot of bright reflected light from surfaces. A circular polariser helps here because it acts on the reflected light (highlights) but not the diffuse light in darker areas which is not polarised. It has the effect of reducing the *average* exposure by 1 - 2 stops, but the highlights will be brought down more than the darker areas, hence reducing the dynamic range of the scene..

Best wishesMike..

Comment #11

With a lot of good advice on various techniques already, multiple exposures blended through Enfuse is another suggested starting place..

See http://wiki.panotools.org/Enfuse.

...Bob, NYC.

Galleries: http://www.pbase.com/btullis.

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Comment #12

I'll second the recommendations made earlier - lots of good advice. If you can't or don't want to do HDR or have other options, the latest versions of Adobe Photoshop Elements and Photoshop CS3 make life a little simpler in post processing if you have one of them..

Both of the latest editions now allow you to do exposure adjustment up to +/- 2 stops and adjust white balance on JPEGS. Yes, you read that right, on JPEGS! Adobe did this only in the most recent editions - it was like being set free for those that can't or don't want to shoot RAW for whatever reason..

Now, to help in the DR department, in the past, all you had (in PS) before was contrast, levels, curves and such as the major tools. With the latest versions of Adobe Photoshop Elements and Photoshop CS3, you get some powerful new tools. In addition to Exposure, the two I am most impressed with are Fill Light and (Highlight) Recovery - these tools work like magic to recover a lot or highlight and shadow detail in an image..

Its expensive for most to upgrade constantly to the newer versions of these packages, so I am guessing that the reasons why more people arent yelling HALLELUJIA! from these forums is that not a lot of people have upgraded yet. But they will and you'll hear more about these new tools to deal with DR..

Here is an example of the tools in CS3; Photoshop Elements has similar controls:.

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Regards,Mike..

Comment #13

How do you open JPegs in ACR under PSE 6 so that you have access to Recovery and Fill Light?.

I cannot find these commands in PSE 6 menus...

Comment #14

ACR (Adobe Camera Raw) is for processing RAW files. Jpegs open directly into photoshop elements.Best wishesMike..

Comment #15

No you can use the ACR tools on Jpegs, at least in PSE 5 and 6..

I have now found a partiial answer to my question. Using Open As and selecting Camera Raw as file type does open ACR for a JPeg..

I would like the default opening for Jpegs to be ACR...

Comment #16

With a decent camera + shadow/highlight control in CS3..

Http://lordofthelens.co.nz/..

Comment #17

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This question was taken from a support group/message board and re-posted here so others can learn from it.

 

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