Luminous Landscape Forum

Equipment & Techniques => Digital Cameras & Shooting Techniques => Topic started by: ymc226 on September 28, 2012, 10:47:28 am

Title: HDR and exposure/bracketing options
Post by: ymc226 on September 28, 2012, 10:47:28 am
With the D800 I can choose up to 9 exposures with various steps between brackets.  If memory and speed was not an issue, should I use all 9 exposures and what steps of bracketing?  I would be taking mostly higher contrast beach type scenes?  I was limited to 7 bracketed shots on the Leica M9P and liked the results but was wondering if 9 would add any improvement.
Title: Re: HDR and exposure/bracketing options
Post by: walter.sk on September 28, 2012, 01:14:17 pm
In my experience I get the smoothest results when the shots are 1 or 1 1/3 stops apart, but I get quite good results up to 2 stops apart.  As far as how many shots you need in the bracket, you can do a test in one of two ways (at least).  Using spot metering measure the brightest part of the scene and the darkest part of the scene.  That will tell you the dynamic range of the scene, and you can then set the number of shots and the required distance between them.   A less elegant way is to shoot to get details in the shadows, another to get detail in the highlights, and count the stops between the two exposure; then, choose the number of shots you want and the distance between shots.

Another part of the technique would be to choose your best "normal" exposure, and if that requires exposure compensation, use that setting (with the compensation) as your middle exposure in the sequence.

Both the NIK HDR program and Photomatix are now quite adept at merging the images with as few artifacts as possible, so I can even get a sequence of 3 or 5 images to work well in most situations when I have to hand-hold a sequence.
Title: Re: HDR and exposure/bracketing options
Post by: Paul2660 on September 28, 2012, 01:22:43 pm
A couple of thoughts.

1.  Are you shooting raw or jpg.  If raw, you may hit the buffer on 9 brackets if you are shooting them in continuous mode.  I have not tried the D800 in continuous mode so I don't know where the wall is on the buffer.  

2.  You might be surprised at 3 frames or 5.  or 2  You can pull a lot of DR from one frame of a raw file of the D800.  Experiment with the Active D lighting, it does make a difference.   The HDR in camera only allow 2 brackets which at first surprised me but after working with the files from the D800 the DR is very amazing in just one file.  

3.  If I understand the D800 bracketing, the max exposure per bracket is 1 full stop, 9 set to 1 stop  should give you 4 down 1 center and 4 up.  That's a pretty big range.  

The D800 has opened up a totally different aspect for me since before I tended to always lead off with a exposure bracket series with Canon, knowing that I would not be able to pull up the shadows without considerable noise.  The D800 will allow at least 2 to 3 stops of movement in one raw file.  

Paul
Title: Re: HDR and exposure/bracketing options
Post by: lfeagan on September 28, 2012, 01:27:23 pm
I have two thoughts on this from my experience.

First, at base ISO the D800 images have a lot more data in the highlights and shadows than my D700 (and most other cameras for that matter). On the day I received the camera I created a 12-shot stitched pano of an evening sky and a garden and unfortunately the sun had gone down enough that the garden was heavily in shadow but was up enough to make the sky quite bright. When looking at the initial results it looked like I had blown the highlights for most of the sky and sunk into the shadows in parts of the garden. I ended up doing +100 shadows and -100 highlights in LR and amazingly enough there was still enough info to come out with a wonderful print. I was shocked that +/- 100 didn't create something awful looking. The sky went from white to having clouds and the areas of the garden from black to having orange pumpkins.

Second, given the DR available with a single shot and the firmware only allowing up to +/- 1.0 for each step in the bracketing, the 9-bracket shot may strangely prove to be useful. If Nikon would un-gimp their firmware to allow +/- 2.0 you could go with a 5-shot bracketing, which should yield similar results (visually the same). I did +/- 2.0 bracketed shots years ago when shooting Canon. I am surprised and annoyed that Nikon still hasn't implemented this super-simple feature. As a programmer, I would guess they did something goofy like allocating 3-bits to the storage of the exposure offset, which would allow 8 steps + 1 bit for if you are using 1/2 or 1/3 EV per step. I know, this sounds very messy and odd. Years ago I dealt with data formats like the signals that come in raw from GPS satellites. After that you start to have some funny ideas about what people were thinking when they design things. Some engineers are obsessed with saving a single bit and work themselves into a corner.
Title: Re: HDR and exposure/bracketing options
Post by: ymc226 on September 28, 2012, 01:44:42 pm
Thanks for all that replied.  I shot RAW and always convert to monochrome.  As I understand it, HDR from the D800 is JPEG and restricted to 2 shots.  The D800 buffer capacity should be able to handle more than 9 at a time; I believe up to 15 before slowing down. 

I'm going to Nantucket next week and have a few spots in mind and will try the 9 shot with +/-1 exposure steps.  If the dynamic range of the subject is not too wide (Paul, based on your suggestion, I probably will dig out my Pentax digital spotmeter), would decreasing to 2/3  or 1/2 stop increments (keeping the 9 total shots) improve tonality or any other aspect of the HDR result?
Title: Re: HDR and exposure/bracketing options
Post by: Tony Jay on September 28, 2012, 06:06:26 pm
A couple of further points:
The D800 has the highest recorded dynamic range of any camera commercially available - period.
You may find out that substantially less bracketed images are required to produce a stunning result.

Your fastest exposure should be an appropriate ETTR exposure.
Subsequently one exposes slower and slower to expose for the shadows.
I would experiment with the gaps between brackets - try a 1 stop gap and then 2 stops with another bracket.
The D800 has broken so many 'rules of thumb' - who knows what the rules really are for HDR imaging using this body.

Regards

Tony Jay
Title: Re: HDR and exposure/bracketing options
Post by: RFPhotography on September 28, 2012, 07:59:26 pm
Whether you use all 9 shots in a bracket will depend on the scene.  You may be able to use just 7 or 5 or 3.  As others have said, the brightness range of the D800 sensor will put a whole different spin on what's possible in terms of single shot and what's needed for multi-shot techniques.  The one thing to keep in mind; however, is that you can never have too many images in a bracketed sequence (no rule says you have to use all you capture), but you can have too few and that will lead to very sub-optimal results in an HDR merge.
Title: Re: HDR and exposure/bracketing options
Post by: Ellis Vener on September 28, 2012, 11:14:34 pm
As I understand it, HDR from the D800 is JPEG and restricted to 2 shots. 

maybe , if your camera is doing the tone mapping process internally. I'm not a fan of that.

If you use Lightroom a good place to start is the Enfuse plug-in for Lightroom. It is available here: http://www.photographers-toolbox.com/products/lrenfuse.php
Title: Re: HDR and exposure/bracketing options
Post by: wolfnowl on September 29, 2012, 12:58:38 am
If you use Lightroom a good place to start is the Enfuse plug-in for Lightroom. It is available here: http://www.photographers-toolbox.com/products/lrenfuse.php

I think Enfuse is great and use it a lot, but unless Timothy has upgraded it, you won't get 32-bit output.

Mike.
Title: Re: HDR and exposure/bracketing options
Post by: deejjjaaaa on September 29, 2012, 01:57:40 am
With the D800 I can choose up to 9 exposures with various steps between brackets.  If memory and speed was not an issue, should I use all 9 exposures and what steps of bracketing?  I would be taking mostly higher contrast beach type scenes?  I was limited to 7 bracketed shots on the Leica M9P and liked the results but was wondering if 9 would add any improvement.

Fuji was using sensors that were essentially taking 2 exposures (at once) to achieve high DR... so why do you need 9 exposures where Fuji was able to live w/ 2 exposures and you have a sensor that beats any set of Fuji's sensels (2 sets of sensels that were combined) by a good margin ?
Title: Re: HDR and exposure/bracketing options
Post by: allegretto on September 30, 2012, 06:16:11 am

The D800 has the highest recorded dynamic range of any camera commercially available - period.


Tony Jay

Compared to the D4 only at ASA 100, about equal @ 200 and after that the D4 is actually deeper per sensorgen.info
Title: Re: HDR and exposure/bracketing options
Post by: Tony Jay on September 30, 2012, 06:21:02 am
Compared to the D4 only at ASA 100, about equal @ 200 and after that the D4 is actually deeper per sensorgen.info

That's true but with HDR one shoots at base ISO.

Regards

Tony Jay
Title: Re: HDR and exposure/bracketing options
Post by: Bart_van_der_Wolf on September 30, 2012, 07:42:28 am
That's true but with HDR one shoots at base ISO.

Hi Tony,

Indeed, it's often overlooked by a lot of people. Shooting HDRs is about optimizing the Signal/Noise ratio (SNR), and the best way is to collect as many photons as possible for all relevant levels of subject brightness. Shooting at the native ISO level is a first step towards that goal, shooting the darker areas of the scene with longer exposures is the next.

Cheers,
Bart
Title: Re: HDR and exposure/bracketing options
Post by: Tony Jay on September 30, 2012, 08:16:18 am
Hi Tony,

Indeed, it's often overlooked by a lot of people. Shooting HDRs is about optimizing the Signal/Noise ratio (SNR), and the best way is to collect as many photons as possible for all relevant levels of subject brightness. Shooting at the native ISO level is a first step towards that goal, shooting the darker areas of the scene with longer exposures is the next.

Cheers,
Bart

Yes.
HDR shooting is actually not that difficult - provided one already has a grasp of the fundamentals.
Small things like shooting at base ISO, shooting the fastest image as an appropriate ETTR and then bracketing slower exposures from there to bring out the shadows.
One or two stop brackets - I have got excellent results with either.

IMHO using a tripod with cable release and live view is crucial for optimal results.

Regards

Tony Jay
Title: Re: HDR and exposure/bracketing options
Post by: Guillermo Luijk on September 30, 2012, 02:00:16 pm
Your D800's sensor is today's highest DR sensor in the market.

Regards
Title: Re: HDR and exposure/bracketing options
Post by: RFPhotography on September 30, 2012, 03:18:06 pm
Your D800's sensor is today's highest DR sensor in the market.
  • IMO you should first understand what HDR means, which is NOT a synonymous of doing several exposures.
  • Then I would try to find out which scenes really need more than one shot with your D800. If one shot is enough to capture the entire DR from the highlights to the shadows with an acceptable presence of noise, you are wasting your time, resources and money spent in that fantastic camera in doing several shots. You never shoot more than once when doing a portrait because you don't need it, the same applies here.
  • If you really find you need extra shots to cover the entire DR of the scene, I would never shoot less than 2EV apart, it's again a waste of time and resources, and a bad way to understand and optimise your digital camera's usage. Shooting 3 times with a D800 2EV apart should suffice 99% real world scenes (that adds 4 extra stops of DR to your camera's effective base DR: 12+4 = 16 stops, this is simply huge and in fact tricky to handle in postprocessing).

Regards


Except that the D800, like other higher end Nikon bodies is restricted to 1 stop gaps using in camera AEB.  Going to 2 stops requires (a) touching the camera, which is not recommended, or (b) using an accessory remote release like Promote Control (maybe there are others on the market, I'm not sure).

As far as what cameras have the best dynamic range and how much, the D600 appears to be very much the equal of the D800 and better in some cases, particularly if the 'Screen' or raw sensor data is looked at rather than the downsampled 'Print' data on the DxO site.  Like most 'non-professional' bodies the D600 AEB is even more hobbled in that it allows only up to 3 frames but can go to 2 stop increments; which, given the drange of the sensor, may be all that are needed in most cases.
Title: Re: HDR and exposure/bracketing options
Post by: Guillermo Luijk on September 30, 2012, 03:28:21 pm
Shame on Nikon. With such a high DR sensor I would even prefer Canon's rudimentary {3 shots, up to 3EV apart} bracketing.
12+6=18 stops!!!
Title: Re: HDR and exposure/bracketing options
Post by: allegretto on September 30, 2012, 06:31:54 pm
Thanks Tony, I didn't know that since I don't really do HDR. I was last deeply involved when it was emulsion, so some modern techniques are new to me coming back.

I was just commenting on the sensor, not the technique but that will help me if I think I need HDR.
Title: Re: HDR and exposure/bracketing options
Post by: Tony Jay on September 30, 2012, 07:08:44 pm
Shame on Nikon. With such a high DR sensor I would even prefer Canon's rudimentary {3 shots, up to 3EV apart} bracketing.
12+6=18 stops!!!

I take the camera's controls right out of the picture by using a remote control (Promote Control) and doing whatever I need to.
Currently this is much less of an issue with my current body (5D III) that is fairly accomodating with image bracketing.

BTW the Promote Control is also very useful in doing focus stacking.

Regards

Tony Jay
Title: Re: HDR and exposure/bracketing options
Post by: RFPhotography on September 30, 2012, 07:19:10 pm
I take the camera's controls right out of the picture by using a remote control (Promote Control) and doing whatever I need to.
Currently this is much less of an issue with my current body (5D III) that is fairly accomodating with image bracketing.

BTW the Promote Control is also very useful in doing focus stacking.

Regards

Tony Jay

It's also north of $300, a luxury not everyone can afford.  Focus stacking is, currently, only an option with Canon cameras (I expect they'll get there with Nikon at some point as they did with bulb ramping)
Title: Re: HDR and exposure/bracketing options
Post by: Tony Jay on October 01, 2012, 05:36:59 am
Thanks for the reminder Bob - I do use Canon equipment so I am not always completely up to date on how other brands relate to things like Promote Control remotes.
As for the price I guess it is a 'horses for courses' thing.
If you need it you will get it - if you don't then don't waste your hard-earned cash.

Regards

Tony Jay
Title: Re: HDR and exposure/bracketing options
Post by: Bart_van_der_Wolf on October 01, 2012, 06:08:18 am
Focus stacking is, currently, only an option with Canon cameras (I expect they'll get there with Nikon at some point as they did with bulb ramping)

Hi Bob,

Shooting a focus stack is also possible with a number of Nikons when using Android based Tablets with USB host controller and Helicon Remote (http://www.heliconsoft.com/heliconremote.html) (for Android version). It also does exposure bracketing and timelapse.

Cheers,
Bart
Title: Re: HDR and exposure/bracketing options
Post by: RFPhotography on October 01, 2012, 07:00:26 am
Yes, I was specifically referring to the Promote, Bart. 
Title: Re: HDR and exposure/bracketing options
Post by: BernardLanguillier on October 02, 2012, 08:25:05 am
Except that the D800, like other higher end Nikon bodies is restricted to 1 stop gaps using in camera AEB.  Going to 2 stops requires (a) touching the camera, which is not recommended, or (b) using an accessory remote release like Promote Control (maybe there are others on the market, I'm not sure).

I understand that the need to shoot HDR may still be more present for those shooting with bodies equipped with lesser sensors, but frankly, I am yet to find a scene that requires HDR with the D800.

In the rare cases where you would need to, can't you take a 5 shot bracketing sequence?

That takes you to the 4 extra stops recommended through +2, +1, 0, -1, -2.

Cheers,
Bernard
Title: Re: HDR and exposure/bracketing options
Post by: RFPhotography on October 02, 2012, 11:46:16 am
I understand that the need to shoot HDR may still be more present for those shooting with bodies equipped with lesser sensors, but frankly, I am yet to find a scene that requires HDR with the D800.

In the rare cases where you would need to, can't you take a 5 shot bracketing sequence?

That takes you to the 4 extra stops recommended through +2, +1, 0, -1, -2.

Cheers,
Bernard


I've certainly shot scenes with 15 and 16 stops of brightness so it would still be necessary in some cases with a D800.  But as I said earlier on, a camera like the D800 does change the game when it comes to HDR and the need for it. 

And yes, of course you could shoot 5 shots.  I was simply pointing out that the upper end Nikon bodies don't permit a 2 stop bracket. 
Title: Re: HDR and exposure/bracketing options
Post by: PhotoEcosse on November 13, 2012, 11:37:32 am
If I am faced with a scene with a very large dynamic range then, because the D800 exposure bracketing only allows for up to 1EV increments, I tend to shoot 9 exposures but then only use numbers 1,3,5,7 and 9 when I send the images from Lightroom into HDR Efex Pro2. (I might use a different five or even just 3 or 4 if I assess the shots to require less range.)
Title: Re: HDR and exposure/bracketing options
Post by: leuallen on November 13, 2012, 12:49:54 pm
I use an E-M5 and bracket 5 stops 1 EV apart. I shoot sunrise and sunset pictures frequently and have had problems with the sun in the image even when it is partially obscured by haze. The solution I came up with is to use a 3 stop neutral density filter (square Lee) on one of the lowest exposures, usually the lowest. That brings that exposure down a total of five stops. I bracket in single exposure mode and on the second exposure (the lowest) hold the Lee in front of the lens. The other exposures are normal. Of course, on a tripod.

I have not had any problems yet with flare or color change although in some cases this could be a problem. So far, the results have been good. I am able to get a much cleaner sun disk with better color saturation around the sun. (Tip: SNS HDR Pro gives the best rendering around the sun) This technique is usually used just when the sun is at or near the horizon so the sun is not full strength but is still too strong for a good exposure. I have not tried it with a full bore sun but doubt whether it would help much. It works well also when the sun is higher but partially obscured by clouds.

Here is an example I used that technique on.

Larry
Title: Re: HDR and exposure/bracketing options
Post by: gmargittai on December 27, 2012, 07:10:08 pm
It is a in the human nature to try to push things farther and farther as much as the technology allows. But sometimes it turns that it is not necessary and it does not do any good. My question to you is on what medium will you display this high dynamic range image that you plan to capture? Because no printers or electronic monitors will be able to reproduce that much dynamic range, even if you compress it.

My experience is that using lots of shots does not come for free. You loose sharpness and gain very little DR.
 
Title: Re: HDR and exposure/bracketing options
Post by: Tony Jay on December 27, 2012, 08:43:42 pm
... My question to you is on what medium will you display this high dynamic range image that you plan to capture? Because no printers or electronic monitors will be able to reproduce that much dynamic range, even if you compress it.

My experience is that using lots of shots does not come for free. You loose sharpness and gain very little DR.

Welcome to LuLa.

I am not sure how much experience you actually have with HDR in particular and printing in general.
You may be unaware of the fact that printing a 'normal' full tonal range image results in substantial tonal compression in itself.

HDR imaging has never been about projecting the full dynamic range of tones in the scene on any medium (It is on the wishlist for the future though).
It has always been about tone mapping for effect - for some people the effect desired is a garish one and for others the effect desired is a realistic one.
In fact one can represent the entire dynamic range (that's the whole point of the exercise) and it is done by tone-mapping (compression and perhaps rarefaction of tonal ranges).

It is true that progress is being made in designing transmissive media (monitors etc) that can can project much larger dynamic ranges. The situation with reflective media (papers, canvas etc) has not changed much in recent history.

As for your complaint about sharpness (or should that be resolution) there are a lot of technique preconditions that need to be met for ultimate image quality. Also, if elements in your scene are moving between shots - well no technique can solve that problem.

Overall your post is somewhat provocative, mainly because it represents an opinion (yours) but is not backed up by factually credible information.
This is your very first post on the LuLa forum and no one would want to chase you away from what could be a very fruitful association with the forum and the website in general.
Many, many members of this forum are acknowledged masters of their craft (I am not yet of that benchmark).
They will be very helpful and full of useful advice - many of them though look dimly on newcomers who make brash and unsubstantiated statements.

If you are interested in learning about HDR imaging and printing then ask questions.
There is a lot of expertise on HDR on this site (I have actually had excellent success with the technique) and printing and colour management are particular strong points on this forum with many contributors owning large galleries (including the owner of the site) and exhibiting regularly.

There is a lot to be learnt on this site - even the experts ask each other for help here.
Again welcome to LuLa and hopefully a long association with the site.

Tony Jay
Title: Re: HDR and exposure/bracketing options
Post by: Bart_van_der_Wolf on December 28, 2012, 09:39:35 am
It is a in the human nature to try to push things farther and farther as much as the technology allows. But sometimes it turns that it is not necessary and it does not do any good. My question to you is on what medium will you display this high dynamic range image that you plan to capture? Because no printers or electronic monitors will be able to reproduce that much dynamic range, even if you compress it.

Hi,

Judging from your remarks, there seem to be a few misconceptions about what HDR photography is (or should be) about.

First of all, the scene as captured will often have a range of luminosities that will be compressed for viewing on your display or on print, even if you do nothing special to it. The problem is that as the scene contrast gets higher, the rendering of all tones from dark to light in a limited dynamic range output modality such as a 200:1 display, or even worse a 100:1 (glossy) print, wil result in a very low contrast dull looking output. So some sort of tonemapping is usually required anyway.

Second, when tonemapping the image, some significant local tonal adjustments may (have to) be applied. This typically results in poor shadow quality, assuming the initial exposure was correctly exposed to only just avoid clipping of the highlights. The goal of exposure bracketing is first to achieve the best possible exposure for the highlights (maximum exposure while avoiding unwelcome clipping), and second to increase the quality of those shadows (improve signal to noise ratio).

Quote
My experience is that using lots of shots does not come for free. You loose sharpness and gain very little DR.

My experience is different, but it may have to do with your subjects (moving objects are not as suitable for HDR bracketing), or your technique.

Let me illustrate the situation with a few image fragments. The image has no particular artistic merit, it was a demonstration file shot for a client.

Here are 2 different bracketed exposures of the same subject. The first was a little less than 1/3rd of a stop below clipping of the Raw data. The bracket (not shown here) with 1/3rd of a stop more exposure had clipped green channels in the sky area, so might have survived highlight recovery, but I was aiming for a perfect ETTR exposure. The second exposure was 10.67x as long (= +3.42 EV), which is not a problem with stationary subjects, and obviously has significant (unrecoverable) clipping of highlight detail, but also much better shadow detail.

(http://bvdwolf.home.xs4all.nl/temp/LuLa/6301_CO701_sRGB.jpg) (http://bvdwolf.home.xs4all.nl/temp/LuLa/6299_CO701_sRGB.jpg)

Here are three crops of the relevant shadow area, at 100% zoom, no noise reduction, no sharpening. First one is the correct ETTR highlight exposure version, the second is that same exposure boosted in Raw conversion, and the third is from the longer exposure time version. Mind you, there was no tonemapping applied other than a gamma conversion from linear Raw to sRGB. Additional tonemapping would have exaggerated the shadow issues even more.

(http://bvdwolf.home.xs4all.nl/temp/LuLa/6301_CO701_sRGB_1.jpg)

(http://bvdwolf.home.xs4all.nl/temp/LuLa/6301_CO701_sRGB_2.jpg)

(http://bvdwolf.home.xs4all.nl/temp/LuLa/6299_CO701_sRGB_1.jpg)

When these two are combined in a single file (I would normally use a few more intermediate exposures), it becomes possible to significantly tonemap the local contrast of the images for a more realistic look (as we saw it in real life) without compromising the shadow and highlight detail quality. And this is just one of many possible tonemapping renderings.

(http://bvdwolf.home.xs4all.nl/temp/LuLa/6299+6301_CO701_sRGB-HDR(2).jpg)

And this scene was shot under an overcast sky, imagine what would have happened under direct sunlight ...

The goal of HDR and exposure bracketing is to provide a more robust set of data for further postprocessing. It obviously benefits larger format output more than reduced size web images.

Hope that this helped to explain the issues a bit.

Cheers,
Bart
Title: Re: HDR and exposure/bracketing options
Post by: gmargittai on December 28, 2012, 01:52:06 pm
Hi there,

Looks like I touched a nerve with my "provocative" post. Sorry if I offended anybody. I thougt that the idea of posting is to tell your personal opinion and experience on the subject and does not require any proof or substantiation. I am sure there are many more knowledgeable people here about this subject. I am not contesting that.

My point was that if one takes lots of photos to compose an HDR (my personal unsubstantiated experience) it impacts sharpnes, (or resolution). It is true that in an ideal situation this should not happen but in reality in a landscape, things move, waves on water, leaves, people, even the sturdy tripod can move.

Title: Re: HDR and exposure/bracketing options
Post by: RFPhotography on December 30, 2012, 08:53:29 am
You're right that you can get a lack of sharpness due to movement between shots using HDR.  This can be true of any image blending method.  That's why good technique is so important.  It's also true; however, that you can get movement in a single shot, causing a lack of sharpness, so it's not something unique to HDR. 

As far a not getting much increase in dynamic range, I'd have to contest that. Sometimes a big increase isn't needed to generate a much better end result.  But if a sensor has a range of, say, 10 stops and by bracketing you can capture 16 stops, that's a pretty dramatic increase.  The key then becomes effective tonemapping of the blended exposures to create an end product that is visually appealing.