Photography - Focus Stacking, worth it?

[TheGoldSovereign]

So I've been playing around with imaging a lot before going mad and taking 1000s of photographs, I would like to try and get some consistency (though failing a little with colour)

My latest quest was to improve on the sharpness of my images, the issue being the coin needs to be tilted to the lens to get nice clean lighting effect, and with a macro lens this means the depth of field is very poor. To counteract this I've been shooting at f-stop of 8, but really to get the whole coin in focus it needs to be F13.

Introducing Focus Stacking, now this is even more time consuming and involves taking multiple images focusing at different points of the piece. This way I can take say 9 images at F4 (producing very small sections of sharp imaging), and then fuse them together 😲

My reason for posting, is to see views, is it all worth it? Also after staring at images for so long you get blind so general comments welcome also.

note: the F13 does look like a nice image because for some reason a little lustre is picked up, but usually this isn't the case. Please also middle mouse click the images to see them full size, attached size doesn't make the point clear

 

F4 - You can see how sharp the coin is in the middle, yet out of focus on the edges

 

F13 - Loss of detail throughout the whole coin, the legend more in focus but not properly

 

Focus Stacked - Essentially this is F4 across the whole coin, fused together

 

Comparison between F13 and Stacked images

 

 

[TheGoldSovereign]

A few other stacked images

 

[augur]

1 hour ago, sg86 said:

So I've been playing around with imaging a lot before going mad and taking 1000s of photographs, I would like to try and get some consistency (though failing a little with colour)

My latest quest was to improve on the sharpness of my images, the issue being the coin needs to be tilted to the lens to get nice clean lighting effect, and with a macro lens this means the depth of field is very poor. To counteract this I've been shooting at f-stop of 8, but really to get the whole coin in focus it needs to be F13.

My reason for posting, is to see views, is it all worth it?

F4 - You can see how sharp the coin is in the middle, yet out of focus on the edges

Are you using your USB microscope for these or a DSLR?

You can clearly see that top and bottom of the coin are out of focus due to its alignment. Resolution could be the "TelePrompTer" mirror or indeed focus stacking. The great advantage is that you can use the lens at its sharpest aperture (F-stop) but stacking can introduce some artefacts.

if you don't tilt the coin, can you get everything in focus at e.g. f5,6? In that case I would invest into a lighting and mirror setup. If not you should look into a DSLR that can shoot tethered (straight into editing software) or use a camera/lens setup that supports in camera focus stacking/bracketing to reduce your workflow.

i haven't worked out the colour reproduction on my side, yet; exposure bracketing alongside with focus bracketing in camera would be a treat. Olympus is very responsive to integrate such features via firmware updates if a point can be made. 

[TheGoldSovereign]

1 hour ago, augur said:

Are you using your USB microscope for these or a DSLR?

You can clearly see that top and bottom of the coin are out of focus due to its alignment. Resolution could be the "TelePrompTer" mirror or indeed focus stacking. The great advantage is that you can use the lens at its sharpest aperture (F-stop) but stacking can introduce some artefacts.

if you don't tilt the coin, can you get everything in focus at e.g. f5,6? In that case I would invest into a lighting and mirror setup. If not you should look into a DSLR that can shoot tethered (straight into editing software) or use a camera/lens setup that supports in camera focus stacking/bracketing to reduce your workflow.

i haven't worked out the colour reproduction on my side, yet; exposure bracketing alongside with focus bracketing in camera would be a treat. Olympus is very responsive to integrate such features via firmware updates if a point can be made. 

No this is DSLR on copy stand, this image you are referencing is to show how F4 on it's own doesn't work, so I'm not 100% sure on the point you're making about that bit

I have tried many times to lay the coin flat and get a nice effect, it's not possible. I'm not 100% sure this is related to my lighting either, it just seems to be the way coins photograph. I do have my DSLR tethered, images are taking from the computer. I would be interested to reduce workflow but even my Sony A6300 body doesn't support Focus stacking, I believe there aren't many bodies that do. I've written scripts to handle the alignment and then fusing so this part doesn't take much more time, taking the 9 shots and moving files around however does but can't be avoided.

I think colour wise my center weighted metering seems to work the best, I think the differences between coins are actually genuine, George V seem to be a lot more copper looking.

Is your opinion then that there are issues with my focus stacked image at the bottom? They look pretty decent but quite flat would be my only observation

 

[augur]

1 hour ago, sg86 said:

No this is DSLR on copy stand, this image you are referencing is to show how F4 on it's own doesn't work, so I'm not 100% sure on the point you're making about that bit 

I got that. But you obviously angle the coin because of lightning issues. If you get a sharp image at the sweet spot (in terms of sharpness usually f4.5-f5.6) you might not need to stack, just create the lighting environment by different means. 

Olympus offers even on simple bodies focus bracketing and on advanced bodies in camera focus stacking; the only problem: these in camera stacking files are already JPEG and dynamic range is an issue in coin photography, in particular proof and more so silver. Hence a focus bracketing HDR file would be useful here. 

1 hour ago, sg86 said:

I think colour wise my center weighted metering seems to work the best, I think the differences between coins are actually genuine, George V seem to be a lot more copper looking.

Without seeing the histogram of the RAW file it is hard to tell if the exposure maxes out the dynamic range of the sensor. But screens display an even more limited dynamic range, so you should apply a graduation curve raising the blacks and shadows and lowering the highlights and whites; again the histogram of the JPEG would be useful. 

 

1 hour ago, sg86 said:

I have tried many times to lay the coin flat and get a nice effect, it's not possible. I'm not 100% sure this is related to my lighting either, it just seems to be the way coins photograph.

You might be right here: direct light will produce a flat image, angeled light introduce a 3D reference. But shooting at an angle allows to see the relief even in a flat light situation, so the combined effect will make the coin pop out even more so.

Now you put me on a spot – will have to run my own tests with in camera stacking vs. HDR stacking and lighting angles...

[TheGoldSovereign]

4 minutes ago, augur said:

I got that. But you obviously angle the coin because of lightning issues. If you get a sharp image at the sweet spot (in terms of sharpness usually f4.5-f5.6) you might not need to stack, just create the lighting environment by different means. 

Olympus offers even on simple bodies focus bracketing and on advanced bodies in camera focus stacking; the only problem: these in camera stacking files are already JPEG and dynamic range is an issue in coin photography, in particular proof and more so silver. Hence a focus bracketing HDR file would be useful here. 

Yes, I can't get the depth using 4-5.6, only at an angle whereby the lighting isn't preferable. We are on the same page I think but I just can't get the coin looking at nice as in these photos, adjacent to the lens 

I'm pretty sure my camera body doesn't do focus bracketing, that would be awesome if it did! If you can prove me wrong I'm here to listen!

 

4 minutes ago, augur said:

You might be right here: direct light will produce a flat image, angeled light introduce a 3D reference. But shooting at an angle allows to see the relief even in a flat light situation, so the combined effect will make the coin pop out even more so.

Now you put me on a spot – will have to run my own tests with in camera stacking vs. HDR stacking and lighting angles...

Again I'm open to testing things, I played with HDR but it doesn't benefit here, exposure seems fine across the image with my current lighting setup. I only thought about this focus stacking yesterday when noticing the F13 images were so washed out, I did all of the above in a single day including the scripts so no doubt i've missed some stuff!

 

[augur]

11 minutes ago, sg86 said:

I'm pretty sure my camera body doesn't do focus bracketing, that would be awesome if it did!

Again I'm open to testing things, I played with HDR but it doesn't benefit here.

I only thought about this focus stacking yesterday when noticing the F13 images were so washed out, I did all of the above in a single day including the scripts.

Unless you use Helicon focus (would be interesting how the images differ from your software) or an A7 body Sony doesn't really support macro too well.

Maybe on circulation coins dynamic range is less of an issue but proof (hence the matte proof sovereigns) and silver are. 

Yes, from f8 you will start to see diffraction to blur up the image. Wouldn't be an issue if we weren't interested into the fine detail of the coins... it is really hard to reproduce what we see in hand but you are doing great work!

[TheGoldSovereign]

18 minutes ago, augur said:

Unless you use Helicon focus (would be interesting how the images differ from your software) or an A7 body Sony doesn't really support macro too well.

Maybe on circulation coins dynamic range is less of an issue but proof (hence the matte proof sovereigns) and silver are. 

Yes, from f8 you will start to see diffraction to blur up the image. Wouldn't be an issue if we weren't interested into the fine detail of the coins... it is really hard to reproduce what we see in hand but you are doing great work!

Ok and thanks, so in your opinion is it worth the effort focus stacking, better than the F13 image or not really? Maybe I'll just do it for shields and high grade coins or something

[augur]

I would do the extra legwork only for your own pleasure, as you said high grade shields and St. George. You are doing the community already a great service in providing high resolution pictures of all those sovereigns.

That way you can go the extra mile in a few select coins, including post processing etc. but until retirement I wouldn't embark in such a time consuming task.