Computer Graphics with Photoshop - multi-exposure and digital

Author

multi-exposure and digital

jeecee

2005-05-25, 11:14 pm

Hi all

I've be a photographer for more than 30 years and now I'm into digital
(D70) for the first time; I'm trying to duplicate an effect that I did
with a standard camera. I exposed the same frame with up to 64
exposures and now I'm starting to see what the digital world has in
store for me.

I made 8 exposures and then opened them in PhotoShop; I copied them in
the same file and did an alignement (vertical center-horizontal center)
and put all the layers in "multiply" state.

I'm playing now with fill and transparency but I don't know exactly if
there is a method to find end exposure so when flattening the layers I
would get a properly esposed picture.

I was accustomed to calculations with slide film but I'm a bit lost in
digital situation.

Thanks for helping me

--

johnboy

2005-05-25, 11:14 pm

"jeecee" <jeecee@home.ca> wrote in message
news:250520051908293625%jeecee@home.ca...
> Hi all
>
> I've be a photographer for more than 30 years and now I'm into digital
> (D70) for the first time; I'm trying to duplicate an effect that I did
> with a standard camera. I exposed the same frame with up to 64
> exposures and now I'm starting to see what the digital world has in
> store for me.

Curious - what are you trying to do with all those exposures on one frame?

Bill Hilton

2005-05-25, 11:14 pm

>Curious - what are you trying to do with all those exposures on one frame?

If you do it just right you can get some interesting impressionistic
effects ... here are some examples from Freeman Patterson, using film
.... if interested in learning more he has an excellent book out titled
"Photo Impressionism and the Subjective Image" ...

http://www.freemanpatterson.com/pri...ressionism1.htm
http://www.freemanpatterson.com/ima...sionism1/20.jpg

Bill

Bart van der Wolf

2005-05-26, 7:14 pm

"jeecee" <jeecee@home.ca> wrote in message
news:250520051908293625%jeecee@home.ca...
> Hi all
>
> I've be a photographer for more than 30 years and now I'm into
> digital (D70) for the first time; I'm trying to duplicate an effect
> that I did with a standard camera. I exposed the same frame
> with up to 64 exposures and now I'm starting to see what the
> digital world has in store for me.
>
> I made 8 exposures and then opened them in PhotoShop; I
> copied them in the same file and did an alignement (vertical
> center-horizontal center) and put all the layers in "multiply"
> state.

There are, broadly speaking, traditionally two methods that are used
in photography.
Either one shoots correctly exposed subjects against a black
background, and by multiple non-overlapping exposures of the same
frame, creates a composition or one records a motion sequence in a
single frame. Or one shoots multiple overlapping exposures on the same
frame but, because exposures add up, each individual exposure is
reduced in exposure value to avoid overexposing the composite frame.

If that is what you want to mimic, you need to either use a "Lighten"
layer blending mode if you have black backgrounds (also works great on
fireworks) and non-overlapping images, or you need to "Add" the
exposures (Image|Apply image..., and Add the RGB channels, with an
opacity to compensate for the weight per image and avoid
over"exposure").
You can also combine only the R, G or B channel of different shots of
the same subject, and thus mimic the effect of combining e.g. three R,
G and B filtered exposures.

Bart

jeecee

2005-05-26, 7:14 pm

In article <4295b1db$0$143$e4fe514c@news.xs4all.nl>, Bart van der Wolf
<bvdwolf@no.spam> wrote:

> "jeecee" <jeecee@home.ca> wrote in message
> news:250520051908293625%jeecee@home.ca...
>
> There are, broadly speaking, traditionally two methods that are used
> in photography.
> Either one shoots correctly exposed subjects against a black
> background, and by multiple non-overlapping exposures of the same
> frame, creates a composition or one records a motion sequence in a
> single frame. Or one shoots multiple overlapping exposures on the same
> frame but, because exposures add up, each individual exposure is
> reduced in exposure value to avoid overexposing the composite frame.
>
> If that is what you want to mimic, you need to either use a "Lighten"
> layer blending mode if you have black backgrounds (also works great on
> fireworks) and non-overlapping images, or you need to "Add" the
> exposures (Image|Apply image..., and Add the RGB channels, with an
> opacity to compensate for the weight per image and avoid
> over"exposure").
> You can also combine only the R, G or B channel of different shots of
> the same subject, and thus mimic the effect of combining e.g. three R,
> G and B filtered exposures.
>
> Bart

Answering to Jonhboy, the impressionistic effects described by M.Bill
Hilton is perfectly right. Moreover, I try to keep at least one object
perfectly clear (ie rock, tree trunk, fence...) in the frame so the eye
can get a bit of relief from all this movement. Although I knew
M.Patterson work, I thank you for the link. (I worked with M.Patterson
in some of the slide presentations he was doing on composition and
lightning)

Thanks Bart, I'll try the "add" method and will try to figure out the
opacity needed for each added pictures. I'm working on 8 frames but the
minute I get the knack of "adding" I'll move up to my 64+ exposures.

Thanks again all

>

Bill Hilton

2005-05-26, 7:14 pm

>jeecee writes ...
>
>the impressionistic effects described by M.Bill
>Hilton (Freeman Patterson link) is perfectly right ...I worked with
>M.Patterson in some of the slide presentations he was doing on
>composition and lightning ...

What Freeman typically does is shoot either 9 multiples at -3 ev
exposure or 16 at -4 ev on the same piece of film with slight (or
sometimes exaggerated) movement between frames (I took a week-long
class with him in New Brunswick once) ... I tried duplicating this with
digital by shooting 9 separate frames at -3, processing them normally
with the RAW converter and stacking them, with the blend mode of the
top 8 layers set to 'screen' at 100% opacity. This works well for the
exposure BUT because of the way digital data is captured there is very
little info at -3 stops and I got serious banding with this method ...
I can post an example if you want to see it.

I've also tried shooting at a normal exposure and stacking the files
with reduced opacity (say 10% for 10 shots), which sort of works but
not really, at least on the one or two test cases I tried. I also
discussed this problem with a lady who's writing a Photoshop book due
out this summer and she said she got good results *sometimes* using the
'overlay' blending mode at 50%, though I didn't get all the details
from her. So there's probably a way to do this right but it's not as
easy as with film so far as I can tell. If you find a good
bullet-proof solution please post it.

There are a couple of digital cameras that allow multiple exposures
in-camera, I think by Nikon or one of the Nikon-mount companies like
maybe Fuji ...

Bill

jeecee

2005-05-26, 7:14 pm

In article <1117119242.070617.27160@g14g2000cwa.googlegroups.com>, Bill
Hilton <bhilton665@aol.com> wrote:

> What Freeman typically does is shoot either 9 multiples at -3 ev
> exposure or 16 at -4 ev on the same piece of film with slight (or
> sometimes exaggerated) movement between frames (I took a week-long
> class with him in New Brunswick once) ... I tried duplicating this with
> digital by shooting 9 separate frames at -3, processing them normally
> with the RAW converter and stacking them, with the blend mode of the
> top 8 layers set to 'screen' at 100% opacity. This works well for the
> exposure BUT because of the way digital data is captured there is very
> little info at -3 stops and I got serious banding with this method ...
> I can post an example if you want to see it.
>
> I've also tried shooting at a normal exposure and stacking the files
> with reduced opacity (say 10% for 10 shots), which sort of works but
> not really, at least on the one or two test cases I tried. I also
> discussed this problem with a lady who's writing a Photoshop book due
> out this summer and she said she got good results *sometimes* using the
> 'overlay' blending mode at 50%, though I didn't get all the details
> from her. So there's probably a way to do this right but it's not as
> easy as with film so far as I can tell. If you find a good
> bullet-proof solution please post it.
>
> There are a couple of digital cameras that allow multiple exposures
> in-camera, I think by Nikon or one of the Nikon-mount companies like
> maybe Fuji ...
>
> Bill
>
You're right about the -3EV information data; you can always push a bit
in exposure in your RAW plug-In and then reduce a bit the transparency
in PhotoShop. Who knows? Maybe the banding will get reduced?

I'm still working with the different blending (even "softlight" could
do) of layers and the way opacity and fill work together. Believe me,
if I find a way to duplicate the results that I had previously with
conventonial photographhy, I'll sure post the method.

I'm not into a race to see who can find the best ways, but I'll run
experiences from time to time.

Tim Smith

2005-05-26, 7:14 pm

"Bill Hilton" <bhilton665@aol.com> wrote:

>There are a couple of digital cameras that allow multiple exposures
>in-camera, I think by Nikon or one of the Nikon-mount companies like
>maybe Fuji ...

The Nikon D2X can do this.

Bill Hilton

2005-05-26, 11:15 pm

> Bill wrote ...
>
>I also discussed this problem with a lady who's writing a Photoshop
>book due out this summer and she said she got good results *sometimes*
>using the 'overlay' blending mode at 50%, though I didn't get all the
>details from her.

OK jeecee, I emailed this lady and she sent me a receipe that seems to
work better than anything else I have tried, at least on my one quickie
test case I just ran. Here's what she wrote ... "It's in the book, but
the idea is basically this. The first layer is 100% opacity, the second
50%, the third 33%, the fourth is 25%, the fifth is 20%, etc. Divide
100 by the number of the layer and you get the percent opacity to use
for that layer. Sometimes I change the blending mode of the final
layer to overlay."

This is with all images shot at normal exposure so you bypass the
banding problems I mentioned earlier with underexposed images.

This is courtesy of Dr. Ellen Anon, who is co-authoring a book with Tim
Grey titled "PhotoShop for Nature Photographers: A Workshop in a Book"
due out in July. Thanks Ellen!

Bill

jeecee

2005-05-26, 11:15 pm

In article <1117149980.557878.243130@o13g2000cwo.googlegroups.com>,
Bill Hilton <bhilton665@aol.com> wrote:

>
> OK jeecee, I emailed this lady and she sent me a receipe that seems to
> work better than anything else I have tried, at least on my one quickie
> test case I just ran. Here's what she wrote ... "It's in the book, but
> the idea is basically this. The first layer is 100% opacity, the second
> 50%, the third 33%, the fourth is 25%, the fifth is 20%, etc. Divide
> 100 by the number of the layer and you get the percent opacity to use
> for that layer. Sometimes I change the blending mode of the final
> layer to overlay."
>
> This is with all images shot at normal exposure so you bypass the
> banding problems I mentioned earlier with underexposed images.
>
> This is courtesy of Dr. Ellen Anon, who is co-authoring a book with Tim
> Grey titled "PhotoShop for Nature Photographers: A Workshop in a Book"
> due out in July. Thanks Ellen!
>
> Bill
>
Hi Bill

Many thanks to you and Dr.Ellen Anon; I sure will buy the book. Someone
trying hard to get the photographer back into PhotoShop (instead of the
usual click-action stuff and push-that-button-and-wow; don't get me
wrong, I use actions and filters but it's rewarding to duplicate
closely an effect from scratch). The recipe is very good and it opens
new vistas as how to interpolate transparency and blending mode in
multiple layers.
Tons of fun ahead

Many thanks again

jeecee

2005-05-29, 7:16 pm

Mike

2005-05-29, 11:15 pm

In article <260520052043592065%jeecee@home.ca>,
jeecee@home.ca says...
> In article <1117149980.557878.243130@o13g2000cwo.googlegroups.com>,
> Bill Hilton <bhilton665@aol.com> wrote:
>
> Hi Bill
>
> Many thanks to you and Dr.Ellen Anon; I sure will buy the book. Someone
> trying hard to get the photographer back into PhotoShop (instead of the
> usual click-action stuff and push-that-button-and-wow; don't get me
> wrong, I use actions and filters but it's rewarding to duplicate
> closely an effect from scratch). The recipe is very good and it opens
> new vistas as how to interpolate transparency and blending mode in
> multiple layers.
> Tons of fun ahead
>
I 'discovered' this technique when I was trying to merge
multiple exposures of sea-sapes (crashing waves etc). For
around 4 exposures it works quite nicely, but for 64
exposures it gets messy and also the transparency for the
uper layers cant be chosen properly.

I used the following adaptation (which requires you to only
remember 50%, 33%, and 25%).

Takke your first pictures (1,2,3,4) put 1 as background and
layer 2,3, and 4 (in normal mode) at transparencies 50%,
33%, and 25%. Now flatten (or whatever) and save as 'a' (or
whatever). Repeat with photos 5,6,7,8 - saving as 'b'.
You will end up with 16 composites of 4 shots each, and now
you can begin combining them together in groups of 4. I.E. a
at 100% with b,c,d, at 50% 33% and 25% respectively (save
this as w). Repeat the process again with e,f,g,h etc (saved
as x). Finally you have 4 pictures, each consisting of
composites of composites and you can now combine them in the
same way. W(100%)+x(50%)+y(33%)+z(25%) and voila - a nice 64
shot composite.

Obviously you can combine groups of 3,4,5 etc photos in the
same way to deal with totals of 12 (=3*4) or 20 (=4*5) or
300 = (3*4*5*5 if you are very patient), and the underlying
layers will always contribute exactly the right 'exposure
share'.

You might want to adjust the levels occasionally (and
equally for all layers) to avoid blowing out highlights.

jeecee

2005-05-30, 11:14 pm

In article <MPG.1d0537179fe7cee99896b5@news.fx.net.nz>, Mike
<m.fee@irl.cri.nz> wrote:

> I 'discovered' this technique when I was trying to merge
> multiple exposures of sea-sapes (crashing waves etc). For
> around 4 exposures it works quite nicely, but for 64
> exposures it gets messy and also the transparency for the
> uper layers cant be chosen properly.
>
> I used the following adaptation (which requires you to only
> remember 50%, 33%, and 25%).
>
> Takke your first pictures (1,2,3,4) put 1 as background and
> layer 2,3, and 4 (in normal mode) at transparencies 50%,
> 33%, and 25%. Now flatten (or whatever) and save as 'a' (or
> whatever). Repeat with photos 5,6,7,8 - saving as 'b'.
> You will end up with 16 composites of 4 shots each, and now
> you can begin combining them together in groups of 4. I.E. a
> at 100% with b,c,d, at 50% 33% and 25% respectively (save
> this as w). Repeat the process again with e,f,g,h etc (saved
> as x). Finally you have 4 pictures, each consisting of
> composites of composites and you can now combine them in the
> same way. W(100%)+x(50%)+y(33%)+z(25%) and voila - a nice 64
> shot composite.
>
> Obviously you can combine groups of 3,4,5 etc photos in the
> same way to deal with totals of 12 (=3*4) or 20 (=4*5) or
> 300 = (3*4*5*5 if you are very patient), and the underlying
> layers will always contribute exactly the right 'exposure
> share'.
>
> You might want to adjust the levels occasionally (and
> equally for all layers) to avoid blowing out highlights.

Thanks Mike, that's a nice way to get around my 64 exposures "mess". As
you already discovered, patience and fine tuning is the key.
I made some test comparing between the 100-50-33-etc version, the
"copy-paste" using transparency and the add method via the "apply
image" and using either "multiply" or "overlay" blend with different
percentages of transparency.

All good exercises to practice my patience and to see what please me
the most (or I should say what's closer to what I want).

Still trying stuff

Thanks again for the tip