Ad
Ad
Ad
Pages: « 1 [2]   Bottom of Page
Print
Author Topic: HDR and exposure/bracketing options  (Read 8612 times)
Tony Jay
Sr. Member
****
Offline Offline

Posts: 2029


« Reply #20 on: October 01, 2012, 04:36:59 AM »
ReplyReply

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
« Last Edit: October 01, 2012, 04:44:18 AM by Tony Jay » Logged
BartvanderWolf
Sr. Member
****
Offline Offline

Posts: 3019


« Reply #21 on: October 01, 2012, 05:08:18 AM »
ReplyReply

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 (for Android version). It also does exposure bracketing and timelapse.

Cheers,
Bart
Logged
RFPhotography
Guest
« Reply #22 on: October 01, 2012, 06:00:26 AM »
ReplyReply

Yes, I was specifically referring to the Promote, Bart. 
« Last Edit: October 01, 2012, 06:05:56 AM by BobFisher » Logged
BernardLanguillier
Sr. Member
****
Offline Offline

Posts: 7526



WWW
« Reply #23 on: October 02, 2012, 07:25:05 AM »
ReplyReply

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
Logged

A few images online here!
RFPhotography
Guest
« Reply #24 on: October 02, 2012, 10:46:16 AM »
ReplyReply

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. 
Logged
PhotoEcosse
Sr. Member
****
Offline Offline

Posts: 546



« Reply #25 on: November 13, 2012, 10:37:32 AM »
ReplyReply

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.)
Logged

************************************
"Reality is an illusion caused by lack of alcohol."
Alternatively, "Life begins at the far end of your comfort zone."
leuallen
Sr. Member
****
Offline Offline

Posts: 264


« Reply #26 on: November 13, 2012, 11:49:54 AM »
ReplyReply

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
Logged
gmargittai
Newbie
*
Offline Offline

Posts: 2


« Reply #27 on: December 27, 2012, 06:10:08 PM »
ReplyReply

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.
 
Logged
Tony Jay
Sr. Member
****
Offline Offline

Posts: 2029


« Reply #28 on: December 27, 2012, 07:43:42 PM »
ReplyReply

... 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
Logged
BartvanderWolf
Sr. Member
****
Offline Offline

Posts: 3019


« Reply #29 on: December 28, 2012, 08:39:35 AM »
ReplyReply

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.


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.






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.


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
« Last Edit: December 28, 2012, 09:33:10 AM by BartvanderWolf » Logged
gmargittai
Newbie
*
Offline Offline

Posts: 2


« Reply #30 on: December 28, 2012, 12:52:06 PM »
ReplyReply

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.

Logged
RFPhotography
Guest
« Reply #31 on: December 30, 2012, 07:53:29 AM »
ReplyReply

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.
Logged
Pages: « 1 [2]   Top of Page
Print
Jump to:  

Ad
Ad
Ad