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Archive 2016 · Advice on focus stacking?
  
 
rdvisuals
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p.1 #1 · p.1 #1 · Advice on focus stacking?


I've been doing some product photography lately and for some shots I want maximum bokeh in the background but need a deeper depth of field for the section of the product I need to capture. So, I've taken a few shots with different focal lengths, and this works fairly well, but I have some issues with lens breathing and getting the images to stack perfectly in Photoshop.

I know I could buy a tilt-shift lens and get some better control of the focus fall-off, but I was wondering if anyone else has done focus-stacking with multiple shots and if you have any tips?



Nov 04, 2016 at 05:56 PM
Fred Amico
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p.1 #2 · p.1 #2 · Advice on focus stacking?


This may or may not have any relevancy for you, but the Olympus E-M1 with latest firmware allows for in-camera focus stacking, and it works quite well.


Nov 04, 2016 at 10:18 PM
rkgatteleport
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p.1 #3 · p.1 #3 · Advice on focus stacking?


Hi,

I've been doing some focus stacking on and off for a while when I can't get enough depth of field using a t/s lens.

On the focus breathing thing, the "right" way to do these is to have the camera on a rail and move the whole unit (or the object being shot) to change the focus point.

That said, most of the stacking tools seem to be able to deal with the breathing issue (well, at least good enough for my purposes).

When you're stacking the images in photoshop, are you using photoshop's auto-align and auto blend tools? I've found these usually work well enough (actually better than a lot of the dedicated tools I tried a while back), even for for fairly complex stacks (I shoot a lot of small stuff where I often end up with upwards of 30+ slices to start). While the photoshop toole seemed to work better than most of the other tools I tested at the time, they make a surprising number of wrong choices on layer/slice selection in my images that I have to fix manually.

There's actually a tutorial from adobe on using these tools for stacking images. To capture the images, I normally use the stacking tools in control my nikon.

Here's a couple of stacked images I did a while back:

https://www.facebook.com/266005023454853/photos/ms.c.eJyzNDAxMzA2MDGyNLIwNrfQswTxDS0MQHxTAyMo39wEwrcAAOSCCYc~-.bps.a.904601692928513.1073741854.266005023454853/904601802928502/?type=3&theater

https://www.facebook.com/266005023454853/photos/a.266009073454448.82484.266005023454853/874057335982949/?type=3&theater

Good Luck,
rkg
(Richard George)



Nov 05, 2016 at 03:20 PM
Peter Figen
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p.1 #4 · p.1 #4 · Advice on focus stacking?


Having done a LOT of focus stacked product photos, including two yesterday, I would strongly advise against moving the camera at all during the process. Software can deal with breathing much easier than it can deal with the the change in perspective from having the front of the lens moving in relation to the subject.

I use Helicon Focus for almost everything. The tools within Ps just aren't up to the task, both in resizing the multiple frames and, more importantly, in blending the exposures. In Helicon, don't use the defaults. I generally use the "C" option and in the preferences set the interpolation to the highest quality and slowest option. Takes longer, but what a difference it makes. You're still going to have issues is you have broad flat areas with no discernible detail trips up the software and gives weird artifacts that have to be fixed later.

It does sound like you're going to want to composite your focus stack into your bokeh'd out bg for desired effect. Most of the time, I'm just manufacturing my backgrounds out of thin air or whole cloth or whatever.

Here's an example that's been posted elsewhere on this forum, but it's 60 slices with a 24mm t/s-e on a 5DSR. The point of closest focus coincides with the closest focus on the lens, so I was at the limit of creating drama with that lens.





60 slice focus stack in Helicon Focus

  Canon EOS 5DS R    TS-E24mm f/3.5L II lens    24mm    f/11.0    1/2s    100 ISO    0.0 EV  




Nov 05, 2016 at 09:23 PM
Jeffrey
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p.1 #5 · p.1 #5 · Advice on focus stacking?


Peter, your work is great, Why would you need 60 frames to focus stack that image. Assuming (for discussion) that that tool is 10" long, then you were essentially re-focusing every 5/32 of an inch. At f11 that would seem excessive.


Nov 06, 2016 at 05:52 PM
 

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Peter Figen
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p.1 #6 · p.1 #6 · Advice on focus stacking?


Jeffrey - It might not have actually needed that many, but that's what I shot. Because the front tip is at minimum focus distance with the 24mm t/s-e lens, which is actually pretty close, the increments needed that close are much finer near the front, and even at f/11, there's not much overlap at the near end. I do try and make the increments bigger at the far end, but since it's a manual focus lens, it's all a guessing game anyway. I'd rather know that I'm not missing any slices than skip over something in the middle and have to figure out how to fix it.


Nov 06, 2016 at 07:36 PM
rdvisuals
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p.1 #7 · p.1 #7 · Advice on focus stacking?


Wow, thanks for the great answers and insights. A lot of product photos I've shot have been larger pieces from a bit further away, often with a 70-200. I was recently doing some smaller pieces closer up and using a 100mm macro and tried doing focus stacking for my first time. I didn't even realize Photoshop had a specific tool for this, nor did I know there were 3rd party apps as well.

I also didn't do more than about 4 images... not even close to 60! But I was shooting at f22 or even f32... Is there a reason to open up a bit to f11? I clearly need to do some more testing.



Nov 07, 2016 at 01:21 PM
Peter Figen
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p.1 #8 · p.1 #8 · Advice on focus stacking?


Yes, there's a big reason for not stopping down any more. Diffraction. Diffraction absolutely kills detail, especially in macro shots, where your actual f/stop is effectively smaller than the number marked on the lens. Technically, diffraction starts at about f/5.6 on a 4.1 micron pixeled camera like the 5DSR and the softening from diffraction gets gradually worse as you continue to stop down. By f/22 you've lost a ton of detail and by f/32, things are just mush. I mean, really crappy. This is something you can readily see if you're shooting tethered to a computer. Recently, when I was doing some macro stacking, using extension tubes at the closest focus with a 100mm macro, where the depth of field is just fractions of a millimeter at f/11, I thought I'd cheat just a little and move to f/16. The difference was so dramatic that it looked like I'd switched to a coke bottle. Back to f/11 and it was acceptable sharp. The reason I generally use f/11 is that it's a good compromise between getting enough overlap in the focus and not killing too much detail due to diffraction. And, of course, when you're farther away, you don't need so many slices, sometimes between five and twenty.


Nov 07, 2016 at 03:18 PM
rdvisuals
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p.1 #9 · p.1 #9 · Advice on focus stacking?


Peter Figen wrote:
Yes, there's a big reason for not stopping down any more. Diffraction. Diffraction absolutely kills detail, especially in macro shots, where your actual f/stop is effectively smaller than the number marked on the lens. Technically, diffraction starts at about f/5.6 on a 4.1 micron pixeled camera like the 5DSR and the softening from diffraction gets gradually worse as you continue to stop down. By f/22 you've lost a ton of detail and by f/32, things are just mush. I mean, really crappy. This is something you can readily see if you're shooting tethered to a computer. Recently, when I
...Show more

Very interesting. Thanks again for the info. Yeah, I don't think I'd like to have to re-focus for every millimeter of a product! If I end up shooting more smaller products, I'm definitely going to do some testing. For what I've recently done, I don't need all that high of a resolution (my final crops only need to be 2000x2000), so I could afford to back the camera away a tad to increase my DOF. I'm shooting with 5DmkIII, which doesn't have the resolution of your 5DSR, but I should still be OK. Even dealing with a dozen slices would be awfully cumbersome when photographing 20-30 different products! gulp.



Nov 07, 2016 at 04:37 PM
Peter Figen
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p.1 #10 · p.1 #10 · Advice on focus stacking?


I just did a shot this morning for a client - Riva Audio - where the camera is about five feet away - and in this case, it only took four images to cover focus, so it really does vary.


Nov 07, 2016 at 08:07 PM







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