Canon viewfinder overlay photo

[r_j_k_p]

Hi,

This may take a bit of explaining but bear with it:

Basically i do alot of close up dental photography where i take a photo of some teeth and then try and get the exact same photo a few months after.
Then from this i make a before and after comparison.

What i would like to do is be able to print out the 'before picture' and overlay the canon viewfinder on it (https://encrypted-tbn3.gstatic.com/i...gZnGNc_fwO4MuA)

This way when i'm taking my 'after' pic, i can make sure i've got pretty much everything at the same angle etc and not too zoomed in or out. So i can align the previous left, right, up and down focus points on where they were before..

Can anyone give me any tips/info on how i can do that?

[kalniel]

1) upscale a picture of the viewfinder focus points to the same size as your photo (or downsize your photo to the same size as the viewfinder picture (remember to chop off the LCD bar at the bottom if using that one)
2) open the photo in GIMP
3) File->open as layer and select your viewfinder picture
4) Select the viewfinder picture in the layers toolbar and right click 'add layer mask', initialize to Greyscale copy of layer
5) Right click the layer again and check that 'edit layer mask' is selected, then go colors->invert (because we want the white background to be transparent, not the black focus points).

This will superimpose the viewfinder onto the photo, making the background transparent so you only get the focus points.

When you export as jpeg the layers will be merged. Or you can merge them in GIMP before exporting.

[r_j_k_p]

Thanks Kalniel! You are a genius!
Very much appreciated. :-)

[r_j_k_p]

Whilst i have your expertise kalniel, anyway to batch process many photos like this??

[kalniel]

Whilst i have your expertise kalniel, anyway to batch process many photos like this??

If you're happy with scripting then yes.

http://www.gimpdome.com/gimp-general...scripting-101/

If you're looking for a macro that records what you do.. no unfortunately.

Note if you have photoshop you can do the same kind of thing with layers and probably can record a macro to batch apply. I don't have photoshop

[r_j_k_p]

Just had a look on photoshop.
Was very easy to do, Using 'Actions', just make a new 'action', press record, paste the view finder in, stretch it so it covers whole screen, go to blending mode, blend options to linear burn, and done.

[Bobster]

blend mode 'multiply'

[r_j_k_p]

blend mode 'multiply'

Whats the difference? To me linear burn makes the AF points look thicker, and with multiply, they appear as they are on the original layer