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Focus stacking question

Numnuts

Member
Hi all i have a question for the more learned members here, have started doing bit of focus stacking in my OMD EM5 M11.

My main question is in regard to where to start the focus point. Some videos i have watched say that for bracketing, you should focus first on the very front of the subject
and let the bracketing start from that point, and then for stacking they say to focus a third of the way into the image.?

Why would you focus a third of the way into the image if your wanting to get focus right across the image from front to back.

The answer maybe obvious i just havent picked up on it yet. lol.

Any help would be appreciated.
 
A quick search found me this:


Read it thoroughly as it seems very pertinent for your needs. It looks like the 1/3 into scene recommendation is just a general starting point for enthusiasts, for general photography. It is likely based on the similar hyperfocal distance method.

I have been focus stacking for four years now, but I do it manually. For landscapes I find that four to eight images will handle subjects within a few inches to infinity. For macro I do well with eight to twelve images but realize that I should likely be doubling that. This may mean that you may need to do it manually, or take two or three auto stacking shots at different focus points then stack those 2 or 3 images manually.

Have fun, it is amazing what all this digital technology can allow us to do.
 
The "focus stacking" is the in-camera process, whereas the "bracketing" assumes external stacking. John is right the in-camera staking roughly follows the 1/3-2/3 hyperfocal scheme. I've used both and recently have gone almost exclusively to the in-camera stacking, mostly for convenience and because the latest in-camera stacking works really well..... just pick your initial focus point with care, which changes with your specified interval, the f stop of your lens and the distance from the subject. It takes some trial and error.
 
I've only really used focus stacking with macro and, until I try out the automatic feature on my Z7ii, I've always done it manually. That is to say, I position the focus point, take a shot, manually move the focus point, take another and so on. I generally cover the whole of the object I'm shooting. The larger the object in my viewfinder, the more shots I take. I also, generally, use the AF although sometimes, there will be a few focus points where AF struggles so I focus manually there. I generally process the images in Affinity.

As I said, I haven't used the automated feature in my camera yet. However, if its all automatic, why not use more focus points than fewer?
 
I've only really used focus stacking with macro and, until I try out the automatic feature on my Z7ii, I've always done it manually. That is to say, I position the focus point, take a shot, manually move the focus point, take another and so on. I generally cover the whole of the object I'm shooting. The larger the object in my viewfinder, the more shots I take. I also, generally, use the AF although sometimes, there will be a few focus points where AF struggles so I focus manually there. I generally process the images in Affinity.

As I said, I haven't used the automated feature in my camera yet. However, if its all automatic, why not use more focus points than fewe
The OP’s E-M5 II can accommodate up to 999 shots with automatic focus resetting between, all shot in a single burst. The resultant images then have to be “stacked” and merged in post processing. However, the feature that does the stacking and merging in-camera is limited to a set number of images. One can define the focus interval between shots to lengthen or tighten the overall in-focus area.
 
Aside from reading those articles, the best thing you can do to educate yourself is to grab yourself a ruler, and do some focus stacks and focus brackets of it. Pay attention to how the point of focus (easy to see when you are shooting a ruler!) moves based on image number and the mode you're using. Observe how you will get banded out of focus zones if you set your differential too high. Observe how your total depth of field is a function of focus differential and number of shots.

You need to get a feel for how it works, because Olympus made this feature difficult to use. Focus differential is ill defined, and there is no rule or calculator you can use to know in advance that if you take your shots a certain way it will turn out.

What Oly should do or should have done was allow you to select two points on the screen with the autofocus point, and then it would put everything in between them in focus. But instead we get to figure it out for ourselves. :)

Also note that when you do in camera stacking, the camera has a predilection to through out the near or far focus shots from the composite image. So when you look at the individual images, you will see focus traverse greater depth of field than you get in the composite image. Not much you can do about that if you're already at the shot limit.

On the plus side though, I have done hand held focus stacking where I could see my hands shake and was certain the stack would fail, and yet the camera still did a credible job of stitching them together. That's fun when it happens.

Good luck...
 
Aside from reading those articles, the best thing you can do to educate yourself is to grab yourself a ruler, and do some focus stacks and focus brackets of it. Pay attention to how the point of focus (easy to see when you are shooting a ruler!) moves based on image number and the mode you're using. Observe how you will get banded out of focus zones if you set your differential too high. Observe how your total depth of field is a function of focus differential and number of shots.

You need to get a feel for how it works, because Olympus made this feature difficult to use. Focus differential is ill defined, and there is no rule or calculator you can use to know in advance that if you take your shots a certain way it will turn out.

What Oly should do or should have done was allow you to select two points on the screen with the autofocus point, and then it would put everything in between them in focus. But instead we get to figure it out for ourselves. :)

Also note that when you do in camera stacking, the camera has a predilection to through out the near or far focus shots from the composite image. So when you look at the individual images, you will see focus traverse greater depth of field than you get in the composite image. Not much you can do about that if you're already at the shot limit.

On the plus side though, I have done hand held focus stacking where I could see my hands shake and was certain the stack would fail, and yet the camera still did a credible job of stitching them together. That's fun when it happens.

Good luck...
Good stuff Will. I would add that the in-camera stacking does a good job of aligning the individual shots should you move a little to the left , right, up , or down. However if you sway closer or further from the subject you will get poor (or no) results...... scaling of the individual images seems to be a shortcoming.
 
Thanks everyone for your thoughts, all great advice and i can see practicing with it is the key, the ruler idea is a good one so i can see exactly what the focus is doing and can adjust it accordingly.

I forgot to mention in my post im trying it out for macro water droplet type of shot to be specific., so getting the focus point and focus differential correct will be important.

Thanks for the link john, ill watch that as well.
 
The OP’s E-M5 II can accommodate up to 999 shots with automatic focus resetting between, all shot in a single burst. The resultant images then have to be “stacked” and merged in post processing. However, the feature that does the stacking and merging in-camera is limited to a set number of images. One can define the focus interval between shots to lengthen or tighten the overall in-focus area.

I never do the stacking and merging in-camera. Always in Affinity.
 
Thanks everyone for your thoughts, all great advice and i can see practicing with it is the key, the ruler idea is a good one so i can see exactly what the focus is doing and can adjust it accordingly.

I forgot to mention in my post im trying it out for macro water droplet type of shot to be specific., so getting the focus point and focus differential correct will be important.

Thanks for the link john, ill watch that as well.

I'm told that glycerine is often used instead of water because it drops more slowly.
 
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