Three Images - Three Focal Points

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#1
Afternoon all,

I want to take 3 images of exactly the same scene, but all three with different focal points, and then merge all together so that I can get clarity throughout the image

Any ideas how I would do this please?

Was thinking that i'd have to take the first image, take a note of the settings, then switch to manual for the last two shots and program in the original settings?

Unless there is another way?

Thanks
 
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IanD
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#3
Isn't this focus stacking? I've never done it myself but I'm sure there's tons of info on it online.
Could well be Graham - I wasn't aware of it's technical name

I'll pop over to youtube :)

Cheers for the reply
 
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#4
Yes, it is focus stacking. You should use manual settings for all three shots, with camera on a tripod. Very simple job in photoshop then, the three files are loaded and the program automatically aligns them and selects the sharpest areas for the final resulting image
 
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#5
Thanks David. The bit i'm struggling with is when out in the field - how do I set up focus for the different points?
 
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#6
That becomes easy with the camera on a tripod, and iso, shutter speed and aperture all set.
Next focus on the near subject, take an image, then the middle subject, take an image, then the furthest subject and take last image.
Download all three into photoshop, open all three and merge them.
HTH
 
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#7
I would guess that you are manually focusing using the focus ring and simply adjusting the focus until each chosen object is sharp and take the photo. I suppose you'd start with the closest object first?


EDIT: I suppose auto focus would work also by changing the focus point within the camera for each shot, but you would need to make sure each focus point falls on a chosen object you want in focus. If your camera has focus peaking in the settings then this could help with manually focusing.
 
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#8
Afternoon all,

and then merge all together so that I can get clarity throughout the image
Assuming that things won't move between shots, if you want to get clarity throughout the image can you not just shrink the aperture, up the shutter to give greater depth of field? Or is something limiting you doing that?
 
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#9
You can also use hardware mounted on your tripod. I believe you leave the focus where it is (initially set manually) then rack the camera forward (or backwards) taking an exposure each time, precise movement can be created by using a high quality racking system.
 
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#10
That becomes easy with the camera on a tripod, and iso, shutter speed and aperture all set.
Next focus on the near subject, take an image, then the middle subject, take an image, then the furthest subject and take last image.
Download all three into photoshop, open all three and merge them.
HTH
Thanks very much - I tried that earlier and after re-reading your post and thinking it through, I realise what (I think) I did wrong, as they were not focused correctly.

I focused on the furthest part and took the image, then switched to manual to keep the settings BUT I actually switched the lens to manual too

I'll have another go
 
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#11
Assuming that things won't move between shots, if you want to get clarity throughout the image can you not just shrink the aperture, up the shutter to give greater depth of field? Or is something limiting you doing that?
Thanks James - I did do that but still wasn't quite happy with the result - maybe being too picky
 
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#12
You can also use hardware mounted on your tripod. I believe you leave the focus where it is (initially set manually) then rack the camera forward (or backwards) taking an exposure each time, precise movement can be created by using a high quality racking system.
I thought this only worked for subjects like a flower or maybe an insect, where the front to back focus points are not too far apart?
 
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#13
I thought this only worked for subjects like a flower or maybe an insect, where the front to back focus points are not too far apart?
Yes that's the general idea but it depends on what the "scene" is that Ian is talking about if it would work in his case. I think you can get some quite long racking systems that are self-contained these days.
 
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#14
Assuming that things won't move between shots, if you want to get clarity throughout the image can you not just shrink the aperture, up the shutter to give greater depth of field? Or is something limiting you doing that?
If, for example, you had a 28mm lens and focused at something 3 foot away, using f/16

Subject distance 3 ft

Depth of field
Near limit 1.94 ft
Far limit 6.56 ft
Total 4.62 ft

As you can see, you would not get far objects in focus.
If you focussed further away, the near object would not be as sharp as it could.
Also as you narrow aperture to f/16 and above, diffraction will worsen the image quality.

Focus stacking will be the right approach to get it all sharp.
 
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#16
You can also use hardware mounted on your tripod. I believe you leave the focus where it is (initially set manually) then rack the camera forward (or backwards) taking an exposure each time, precise movement can be created by using a high quality racking system.
I thought this only worked for subjects like a flower or maybe an insect, where the front to back focus points are not too far apart?
Yes that's the general idea but it depends on what the "scene" is that Ian is talking about if it would work in his case. I think you can get some quite long racking systems that are self-contained these days.
Not long enough to be useful beyond macro distances, though.

I mean, if the rack allows you to move the camera and lens forward by, say, 50cm - which would be quite a big thing to have mounted on your tripod - then you've only moved the focus point by 50cm. That's fine for macro and table-top photography where your depth of field might be only a few cm. But for most other applications 50cm isn't enough to make much of a difference.
 
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#18
Afternoon all,

I want to take 3 images of exactly the same scene, but all three with different focal points, and then merge all together so that I can get clarity throughout the image

Any ideas how I would do this please?

Was thinking that i'd have to take the first image, take a note of the settings, then switch to manual for the last two shots and program in the original settings?

Unless there is another way?

Thanks
Can you give more info what you’re trying to shoot? How close is the nearest object? Have you tried the hyperfocal method? For landscape with extreme depth of field beyond what can be achieved with hyperfocal I went to tilt shift lenses. I did try focus stacking but with little success.
 
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#19
Hi, it's actually the image I have on my thread for the 2019 52 week challenge
 
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#21
Sorry but not able to right now as I'm on my mobile.

It is easy to find though
 
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#23
For me that would be a quick and easy focus stacking shot, camera on a tripod and maybe 5 shots at different focus points, all manually focussed and with camera set to manual.
 
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#24
Thanks David.

Apologies as I've not watched the linked YouTube clips yet. Waiting for the missus to fall asleep first

In the mean time, do you mean get the settings, the switch the camera to manual and also the lens, then focus twisting the focus ring on the lens?
 
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#25
Yes, get the exposure you need first, then set them in manual mode so that there is no exposure variation. the camera will be on a tripod so alignment will not be an issue.

Then focus and take images at various points from front to back (or back to front!) of the planned final image without moving the camera or changing exposure settings.
 
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#28
You not allowed to watch YouTube?
:) Not whilst there is Emmerdale to watch (2 episodes) then catching up on Luther

Managed to watch it in the end and now starting to make sense. Will have a go later today

Again, thanks all for your help
 
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#31
I've tried this method for the first time over Christmas. Nikon D7200 and 80-200mm F2.8.
We had a large Poinsettia plant on the table so, from a distance, and the camera on tripod, I used autofocus to set the focus square in my live view to the nearest petal.
At F2.8, I zoomed in just to check sharpness. With everything settled, I used my remote shutter to fire the shot. Then, very carefully, WITHOUT MOVING THE CAMERA, I moved the focus point to another petal, used autofocus to get in pin sharp, zoomed in just to check it was sharp, then took another shot. I did this approx. 9 times, focusing on a different petal each time, front to back, left to right.
I then uploaded all files into PS and used the focus stack function which worked very well and was easy to do after watching a YouTube tutorial.
I was quite happy with the results for a first attempt, although I did miss out a couple of petals which clearly show as soft.
This is something you can try at home whilst the missus watches her soaps.
I will try and upload the result this evening if you want to see?
 
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#32
Thanks for the reply Jason, and always happy to see others results.

So each time you moved the focus point and refocused, did you also check the all the other settings were exactly the same as the previous one?
 
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#34
Thanks for the reply Jason, and always happy to see others results.

So each time you moved the focus point and refocused, did you also check the all the other settings were exactly the same as the previous one?
As it was a flat light room, nothing changed in the way of ambient light so no changes necessary. Just refocused and shot.
I imagine in a landscape, you would maybe have to adjust shutter speed to get exposure correct if the clouds were changing or brightness or the sky etc.
Im no expert so someone may correct me.
 
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#36
I quite fancy giving this focus stacking a bash. Is there a dedicated focus stacking thread on here?
 
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#37
Apologies if it's been mentioned but when reading the beginning of this thread it feels like the term 'manual' is maybe causing some confusion. Whether you use manual or auto focus shouldn't matter all that much as long as you increment the distance sensibly to make sure you get everything sharp that you want to be sharp. It's probably easier to do that in live view but whatever works for you is fine. The closer your subject is to the lens, the more shots you're likely to need to take but as others have said, playing around indoors is the way to go here.

The more important manual bit is to keep the exposure consistent. The simplest way to do this is to shoot manually, get the exposure settings sorted for your first shot, then just leave it as is for the others.

Without wishing to add complication, it's worth just mentioning focus breathing too. Some lenses effectively change focal length a little bit depending on subject distance. It means that even without adjusting zoom or camera position, composition can change slightly as you move through the focus range. I suspect photoshop and other software might well take this in its stride but if you're having problems, this could be an explanation.
 
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#38
Is it possible to focus stack a moving object? Physics tells me no, but I thought I'd ask anyway in case there's another technique which could allow it?
 
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#39
If the whole object is moving possibly a series of panning shots could work? Just a thought, not sure how to pull that off in practice.
 
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#40
PS in the Gavin Hoey example there is movement in the sea and the sky. As the beach scene is layered - beach, sea, sky, each was taken from a different focus point so the focus stack worked.

If the movement is taking place through the depth of field then I can’t think of a way to do it. I’ve tried and ended up with tilt shift.
 
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