Thread photos dual iso

[ygor]

New tests, these are to compare quality.

Canon 7D
Canon 10-22 @10mm
f/8
30"
Highlights/shadows and some stuff processed in LR 5

The shots:
ISO 100


ISO 160


ISO 100/1600


ISO 160/1600


Vertical Banding
ISO 100


ISO 160


ISO 100/1600


ISO 160/1600


For the next comparisons I picked the best quality to compare
Sharpness
ISO 160


ISO 100/1600


Color Noise
ISO 160


ISO 100/1600


My thoughts about it:
1 - Without Dual ISO, ISO 160 has less vertical banding than ISO 100. But with Dual ISO I get no vertical banding at all, on both ISOs, that's good.
2 - Sharpness and color noise was way better without Dual ISO.

If you have some tip to improve my shots, I'd be glad if you share it : )

[a1ex]

Hm, the banding from ISO 100 looks familiar. Can you check whether it repeats every 8 pixels? If yes, I may have a fix.

For sharpness, it matters a lot whether the tested area was covered by both ISOs (where you get full resolution) or only one (where you get half resolution and possible aliasing and moire).

Can you upload the CR2 files?

[Doyle4]

sooooooo jealous of this function! 

<---- 5Dmkii owner 

[ygor]

Hm, the banding from ISO 100 looks familiar. Can you check whether it repeats every 8 pixels? If yes, I may have a fix.

For sharpness, it matters a lot whether the tested area was covered by both ISOs (where you get full resolution) or only one (where you get half resolution and possible aliasing and moire).

Can you upload the CR2 files?

Here are the CR2 files:
https://www.dropbox.com/sh/66pp28wpxtsrdv0/uQbrLi7cVE

You may check IMG_0021.CR2 for Vertical Banding.

And yes, the vertical banding repeats every 8 bits.

[Magic 7D]

Ok so I took some test pics, but not sure if I use it right.. judge and comment

@Danne, do you experience any trouble with the Auto ETTR when shooting non live view?
For me it's rather random, sometimes (only sometimes) it works fine, but most of the time it just lights up the LV and state Auto ETTR and then shut down right away without doing any changes... but when shooting in LV it works fine most of the time (sometimes I get rather random results though). I've been trying to search and read up on how to best use the Auto ETTR but haven't found much..

Anyhows here are my test pics all shoot at f/8 straight out from camera (obviously the DUALs have been converted) only added tiny sharpening in LR5. DUAL ISO set to 100/800

First ISO 100 1/100sek


Then a DUAL one exposed for ISO 100 1/83sek


DUAL with Auto ETTR gave me ISO 100 1/41sek (seem to get some blown out highlights but maybe that should be fixed in post?)


Then I tried to make the ISO 100 and the DUAL Auto ETTR to look as similar as possible by changing exposure, pulling down highlights and boosting shadows, tweaked blacks and whites a bit too, everything else untouched. Oh sorry I had to change the white balance too as the colors were way different the DUAL one was a lot warmer (as you can see comparing the first 2 pics), sampled it from the same spot on both.

First out is the ISO 100


Then DUAL Auto ETTR ISO 100/800


Don't know really but almost seems like ISO 100 is coming out on top for the shadows? The DUAL ISO one is more vibrant though, a bit like boosted saturation! BUT maybe I'm using it all wrong? And I did shoot hand held so I know the frame isn't exactly the same (which I find a bit annoying, should have brought my 3pod)

So let me know what you think, tell me if I'm using it completely wrong etc, just shout anything at them
CR2s are available if anyone should be interested.

On a side note, imagine if we could have the duals processed in camera

[Danne]

Hi Magic 7D. Nice work with the dual iso tests. I think the best benefits with dual iso is that you are able to photograph motion. In static situations one can do hdr. However I feel dual iso gives more natural results than working with more files that often removes shadows etc to much.
Looking at your posted examples you probably could have done the picture with native raw. It,s in the extreme situations dual iso will work best.
I seldom use ettr at the moment, instead I set the ev+3 or 4 and than I simply meter the low iso in camera and mostly I get a good exposure for shadows in the ev+3 or +4 iso range. You could try to set the base iso at 100 and then the ev+ and switch to Av mode. Should give consistent results.  Ettr works ok most of the time. Often when I get some random results with ettr I simply do some readings on a dark area with no highlights to "wake up" the function. Usually after that I get good readings.
Please feel free to post some more examples and good luck
/D

[ozcancelik]

100/3200, 5D Mark III with Tamron 24-70 F2.8 VR

[Walter Schulz]

Well, the technical side apart: As a photographer I like the first one more than the second one.
Second one it's the opposite. The blown areas are just to disturbing.
Background issue with the second example.

Spoken as a geek/nerd: Impressive demonstration of dynamic range enhancement enable by latest developments.

Location?

Ciao
Walter

[ozcancelik]

Processed photos are here:
http://www.flickr.com/photos/ozcancelik/9621433392/
http://www.flickr.com/photos/ozcancelik/9618215003/

They are not processed.  Just highlight and shadow recovery. And I agree second photo's background silly

Location Antalya, Turkey

Well, the technical side apart: As a photographer I like the first one more than the second one.
Second one it's the opposite. The blown areas are just to disturbing.
Background issue with the second example.

Spoken as a geek/nerd: Impressive demonstration of dynamic range enhancement enable by latest developments.

Location?

Ciao
Walter

[elijahalcantara]

Beautiful shots! I wanted to try it so bad to my 5dmkiii but I think I may want to play it safe and wait for it to be stable

[brapodam]

Here's mine. It's my first time doing a night shot, though I've done sunsets before.

F6.3, 8s, ISO 100/1600 on the 60D


Untitled by |Panzer|, on Flickr

[kirkt]

I've been experimenting with the dual ISO feature for my 5DII for a couple of weeks.  A huge thanks to A1ex and the gang for giving me the ability to do Zero Noise in my camera in a single exposure.  Unreal!

This exposure was rendered in Raw Photo Processor (RPP) - RPP has no noise reduction.  Tonal and contrast edits in Photoshop.  Remarkable image quality, especially considering the magic that is going on in the image acquisition and conversion to DNG. 

kirk

cr2hdr log:

Code Select Expand


Input file     : _MG_0001.CR2
Canon EOS 5D Mark II detected
Full size      : 5792 x 3804
Active area    : 5634 x 3753
White level    : 12500
Black borders  : 158 left, 51 top
Black level    : 974
ISO pattern    : BddB GBRG
Noise levels   : 12.75 9.05 9.22 12.13 (14-bit)
Estimating ISO difference...
ISO difference : 3.18 EV (904)
Black delta    : -9.59
Interpolation  : mean23-chroma5x5-alias
Dynamic range  : 10.31 (+) 9.82 => 13.00 EV (in theory)
Matching brightness...
Looking for hot/cold pixels...
Hot pixels     : 16
Cold pixels    : 1
Full-res reconstruction...
ISO overlap    : 4.1 EV (approx)
Half-res blending...
Chroma filtering...
Building alias map...
Filtering alias map...
Smoothing alias map...
Noise level    : 5.08 (16-bit), ideally 4.86
Dynamic range  : 13.15 EV (cooked)
Black adjust   : -7
Output file    : _MG_0001.DNG


[painya]

1600/3200 It effectively worked as a Graduated ND filter.

[Danne]

Some really nice examples lately

[a1ex]

@kirkt also has some cool examples and in-depth analysis here: http://photography-on-the.net/forum/showthread.php?t=1333150

[Magic 7D]

1600/3200 It effectively worked as a Graduated ND filter.

That pic is so nice, I've been tryin to get some star photos lately, but haven't got any good ones so far. Would you share the rest of your settings? f value, Time Value, camera, lens? Would be very thankful!

[Walter Schulz]

Would you share the rest of your settings?

He did. If you're using Firefox you may want to install Exif Viewer add-on.

Ciao
Walter

[Danne]

Those are good links from kirkt. I, m getting full use of dual iso in outdoor pictures photographing gardens and exteriors. Enfuseor hdr will create fuzziness in trees and other loose things. Saves my shutter aswell. Perfect with the dual prefix also

[Magic 7D]

He did.

Thanks Walter, that's a nifty add on.
Sorry for my ignorance though.. but I can't work out the focal length and the f value, it's probably staring me right in the face but I can't see it..

[Walter Schulz]

[...]focal length and the f value

That's not your fault, it's mine. Looks like a full manual lens without electric coupling therefore no lens data in Exif.

Ciao, Walter

[painya]

That pic is so nice, I've been tryin to get some star photos lately, but haven't got any good ones so far. Would you share the rest of your settings? f value, Time Value, camera, lens? Would be very thankful!

You're right it is a fully manual 14mm Rokinon fisheye lens. I had an F-stop of 2.8- wide open, and a 25 second exposure. It was shot with my 6d and in post I applied a light S curve and cropped to straighten. If you have any more questions feel free to PM me I would love to help.

[kirkt]

@kirkt also has some cool examples and in-depth analysis here: http://photography-on-the.net/forum/showthread.php?t=1333150

Hi A1ex, thanks for noticing.  Here is a comparison I did using the above image I posted earlier in this thread.  In the below post, I was comparing the dual ISO shot with a conventional raw taken at the same settings immediately after acquiring the dual ISO shot.  Not only is the visual annoyance of noise reduced, but the tonal and color fidelity in the deep shadows is maintained and permits more flexible post-production.

kirk

***

Here is another example, shooting a scene that would typically make me consider using an HDR approach.   This gives you an idea of the DR of the scene (about 13 stops) - the face is backlit and difficult to bring out without good data.  This rendering is hyper real, in that the interior light level was lower than is depicted here.  However, with good data, you can craft the image the way you want to!




Here is a composite of the raw and ML DNG in RPP.  Both files have been pushed 4 stops to expose the face in the shadow tones.  What a difference.



I posted a more detailed discussion about this comparison in the HDR section:

http://photography-on-the.net/forum/showthread.php?t=1333150

kirk

[elijahalcantara]

I gave it a test for portraits to see how it would affect midtones: (dng left side, I took 2 shots, one raw and another for dual-iso)

Not that noticeable when zoomed out. Please ignore the color, must be some color adjustment I missed in editing.

Zoomed in:

Moire is kind of bothersome for the hair, in some shots it went really bad for the skin detail.

Interesting to note the banding in the sky:


Dual-iso setting is 100/1600

I'm going to try a less powerful setting next, maybe a 100/400, I really don't like moire even in the midtones (maybe a lesser setting may prevent it? ). Kind of hard to fix it without affecting detail. I still like dual-iso, it has it's use for high contrast situations, but it would've been great for general use.

[Audionut]

I'm going to try a less powerful setting next, maybe a 100/400, I really don't like moire even in the midtones (maybe a lesser setting may prevent it? ). Kind of hard to fix it without affecting detail. I still like dual-iso, it has it's use for high contrast situations, but it would've been great for general use.

If you overexpose a regular image, you loose all detail to white.  With dual-ISO, you can overexpose highlight detail at the expense of less resolution in those highlights.  One of the primary goals when using dual-ISO is to consider where wanted detail, must retain full resolution.  So for skin tones, your base/recovery ISO must be set where the skin tones haven't been overexposed in either ISO. 

The same applies for the shadows.  Only in this case, we keep the full resolution but suffer the noise.

Interesting to note the banding in the sky:

I'm not sure what banding you are describing.  Note also you have described ISO 100/1600 but the LR panel it's ISO 400.

[Audionut]

Out practicing the Brenizer method and figured I'd see how dual-ISO could help.




Source frame.


And the darker shadows.