Extended Depth of Field Image Stacking

Legacy Forum Archive welcome-mat
1

I have been browsing what some are now calling “Edge Porn” and identified that many of the images I see are lacking “Depth of Field”. Now, I am not saying you are doing anything wrong. This is just a product of looking at something under a microscopic and the limitations of our present camera technology. Or, you can just look at like this, we have amazing eyes that do this for us automatically and we humans can’t figure out how to duplicate it in a digital camera yet. Many of you may have access to Adobe Photoshop. The video below will show you how to import your photos and effectively “stack them”. It’s easy to do in post photography editing.

Basically, you will start by ensuring the camera is perfectly still and then you snap a photo. Adjust the focus a little and snap another photo. Do these steps as many times as you need too. Concentrate on your edge but also on the areas around your focal point.

And then the magic part… After you have stacked and imported your images in photoshop, you can blend the different photos together to reveal a blur free clean image which is a composite of the all of them.

All the grooves and scratches will be revealed almost like 3D. Adobe creates layer masks for you which block the blurry parts of your images taken at different depths of field and then reveals the parts that are in focus.

Let me know what you think.

[attachment file=“Focus Stacked Example.jpg”]

https://www.youtube.com/watch?v=iYA7wb2Vkz8

2

Would HDR help in this case?

3

Now you are on to something; High Dynamic Range (HDR) should probably be its own topic

HDR, as its name implies, is a method that aims to add more “dynamic range” to photographs, where dynamic range is the ratio of light to dark in a photograph. Instead of just taking one photo, HDR uses three photos, taken at different exposures. You can then use image editing software to put those three images together and highlight the best parts of each photo. In the case of HDR on smartphones, your phone does all the work for you—just snap your picture and it’ll spit out one regular photo and one HDR photo. The result is something that should look more like what your eyes see, rather than what your camera sees.

Because we are imaging “Shiny Bevels” or polished scratches combining both HDR and Depth of Field Image Stacking would be a perfect combo. This is a little trickier because you don’t want to lose any details. Some microscopes and cameras do both of these things but rarely do they do them both together.

When I made the post, I was thinking about those with the inexpensive VEHO cameras. With Photoshop you can accomplish the same thing as a more expensive camera (Dino Lite). That does both EDOF and HDR.

I have seen some great photos and wanted to contribute to make them even better. Looking back, I would not have purchased a Dino-lite with these features (sacrificing magnification) when you can just take more photos and import them into Adobe Photoshop stacking them and probably get a better result. In fact, I am going to trade mine in for a higher magnification USB microscope.

Composite.jpg
Composite.jpg1341×515 145 KB

https://helpx.adobe.com/photoshop/how-to/photoshop-merge-to-hdr.html

4

Thanks a lot! That’s a very interesting video, even more because I am not only interested in knife sharpening, but also in photography. I watched it in one go . (The video also shows the option for creating panorama photographs, something I knew that existed in Photoshop, but not where and how to use it.)

Image stacking can be useful because microscopes (as the guy in the video already says for macro-photography) have a very shallow depth of field. There is only one but, but it’s a pretty big one I think: you need a pretty good USB-microscope to make the photographs this video is about. The major challenge with my own $80 or so (3 years ago) Veho microscope or the cheap Dino-Lites microscopes is not getting a good magnification, but getting a good focus.

I think Clay is the only one who has shown photographs here of the same edge with the focus at different locations. And now I cannot recall whether he combined them into one image…

5

Wow, now we’re talking HDR too . This is turning into a very interesting topic . Which Dino-Lite did you get, MirrorEdge, and which microscope are you considering?

The video you linked to may have at once made my desire for an HDR option on my only-three-years-old Canon DSLR superfluous. I’ve immediately bookmarked it .

6

I am presently using a Dino Lite AM4815ZTL ($899.00 US) but am probably going to pick up a AM4515T8 (in exchange $849.00) http://www.dino-lite.com/products_detail.php?index_m1_id=0&index_m2_id=0&index_id=38.

My observations with the AM4815ZTL; I like the Long Working Distance (LWD) but I bought it for the EDOF and the HDR features. I honestly thought it would substitute for higher magnification ( I was wrong). The problem is… that we need a 200X or better magnification to see the edge of a blade which is where all the good “edge porn” is at.

The AM4815ZTL can only go to 140X (when you combine the features), it takes great photos, however, the handicap is the magnification. The Dino Capture 2.0 software is available for all the models and that is what I really need with the improved magnifications. I have 20X, 30X, 60X loupes and handheld 120X microscope from Carson, so, I don’t need the lower magnifications that I will lose by getting the AM4515T8. I will lose the long working distance advantage but with Adobe Photoshop, I will regain the edge I was looking for (EDOF and HDR).

The below photo is from a AM4815ZTL thee inches from the stage. I took four HDR photos at different focus’s and then merged them (Stacked Them) with Adobe Photoshop for the improved Extended Depth of Field advantage. The same feature within the camera is hard to control and not worth the money. All in all, the magnification is more important 700X-900x according to Dr Matt 357 will let me see the edge and with the Focus Stacking (EDOF), I should be where my budget will allow at the moment.

[attachment file=“HDR EDOF Example of AM4815ZTL.jpg”]

https://www.youtube.com/watch?v=49ERZiDbDj4

7

I’m not sure about either. My concerns -

In order for focus stacking to work properly, you need to keep camera still and move focusing points. With modern DSLRs it’s fairly simple. Even simplest ones have multiple focus points. So you put camera on tripod and shoot away while changing focusing point for each shot. Now, I don’t have digital microscope, but I thought that it only has one single focus point. Am I mistaken here?

 

As for HDR, it really depends on the end goal. If you want to see what’s in the shadows, then sure. But why would you care about that?

8

First off love the topic and where this discussion is going. Ive actually been stalled out in my sharpening due to a lack of better imaging within budget constraints.

I just have one question at this point. How are you changing the focus without moving the scope? On mine and most others Ive seen its adjusted by rotating a collar built into the scope body. Will photoshop compenate when stacking for images being slightly off?

The idea of getting the highest quality images with the highest magnification, for the lowest price possible is a Grail item so thank you once again for bringing this to the forefront!

Aloha, Cliff

9

The key to success is a good USB microscope stand. Any of the cheap microscopes will work, however, as indicated above the more magnification you have, the better. All you have to do is adjust the height of the microscope on the stand to get your different focal depths. Most of the USB Microscopes you would not want to adjust the focus dial directly because this will disturb the camera at microscopic levels and you may lose the subject of the photo.

Watch DrMatt357 video above at the time stamp 11:59. He shows a quality stand and what I am typing about.

“Now, I don’t have digital microscope, but I thought that it only has one single focus point. Am I mistaken here?” No you’re not, this is exactly the point. Because a macro lens or a microscope only have the single focus point at any one moment the focus stacking of images allows you to focus the camera many different times and then later stack those focused images to reveal a clear crisp photo. Even with DSLR cameras you will not be able to have the whole “plain of view” in focus at the same time. EDOF or focus stacking will greatly improve those photos as well.

For a “live” example of what you would see in a microscope watch the same video closely at minute 9:00. By taking photos at each focus depth you can later assemble the photos and produce an amazingly clear image.

I was hoping to save the High Dynamic Range (HDR) discussion for later, however, this is an important point. Photos are basically capturing the reflection of light. Digital camera’s capture that light and assemble the individual points of light into a digital image we call a photo. Capturing different Exposure’s (HDR) for the same scene (a whole different topic) is using the available light both the bright spots and the dark shadows to produce amazing photos. Because the photos of blades edges are shiny. Taking photos with multiple exposures of variable light and then merging them together will produce a photo more representative of what a person eyes would normally see in the real world. All we are doing (ultimately) is trying to reproduce what we see as accurately as possible.

By keeping these two things in mind when we are taking photos, we can greatly improve our images for comparison of grits sizes and scratch patterns of different grits. The more detail we can achieve in each photo the better representation of the actual result will be recorded.

It can be difficult to describe or communicate results of scratch patterns in multiple different images, however, if you stack them in this way, you can have one photo with all the desirable details. As least, I know that I get lost in the details when I see multiple images of the same blade edge.

Note: I am not a professional photographer. I just want to share what I have learned about photographing blade edges. Which is why I initiated this discussion on this forum. Everyone can take pictures, with a little support we can all take great “compositions of light”!

10

O.K. Guys I got permission to use Dr. Matts video officially. So here it is… I was able to explain better how to accomplish this by incorporating his video with my input. If you like this please let me know.

https://youtu.be/kTeBSPEaAwQ

11

The problem with moving point of view instead of shifting focusing point while keeping POV constant is that it might introduce unwanted image artifacts that aren’t there in reality. And you won’t know about it unless you carefully analyze all the images involved in focus stacking. But if it works for you - great!

As for HDR, you can easily do it if you can change aperture and shutter speed of your microscope.

12

You are on point Dima, thanks for you feedback and observation! The methods I am suggesting here are just to help everyone improve the photos they are taking with the tools that are presently available to us. Sometimes buying a new tool (microscope) isn’t the answer. Post editing photos is not a “novice” thing to do, however, it doesn’t take a professional either. Just having a little extra knowledge is all it takes to make remarkable improvements to your images.

Most of the inexpensive microscopes we use and even the high end cameras for microscopes do not allow the adjustment of shutter speed or aperture. I wish they did. FYI, there hasn’t been a modern digital photo taken these days, that hasn’t be edited in some way after it is taken (Cropping, White Balance, Exposure, Color Balance, rotation or complete Photoshop “manipulating” or removing perceived flaws). This is simply because our cameras do not accurately represent what we physically see with our naked eyes (Yet). With the advent of High Definition (HD) we are getting much closer.

Wow, I have seen some awesome HD T.V.’s lately that look like I can just reach out and touch the subject of the image. This isn’t by accident. In fact, HD is so good now that any flaw in the subject is obvious. Have you notice that T.V. anchors are now wearing much more make up and almost look like plastic, (LOL), I have.

With the added benefit of High Dynamic Range HDR and specifically the subject of this post Extended Depth of Field (EDOF), everyone can make improvement really easily. This post is tailored to those who wish to take photos of blade edges and are not happy with what they see not those that are. Everyone can find much more information on the internet about these processes but first we must know of the possibilities.

13

I seriously considered EDOF s few years ago, but all of my work with the 'scope is handheld and I didn’t want to take the blade out of the vise every time I wanted to take a still image.

I do use my sharpie to mark the locations (just below the bevel shoulder) of serious defects, so I can go directly to them to measure my progress. Don’t need to check the entire edge every time once you’ve reached the apex.

14

I am actually taking the images while its attached to the wickededge vise. I have a lot of new things I want to share. I have even managed to record a time laps of a entire wicked edge sharpening session (bevel view only). The whole process is Hands free from the camera/microscope.

This was my second topic post and based on the responses and warm welcome I have received, I now feel a part of the team!! I am preparing a semi formal bio so everyone can know who is behind “MirrorEdge” . This is the welcome mat after all. I work with and for the largest knife wielding community in the world. In my opinion it’s a knife sharpeners dream. More to come…

15

Very Cool! Well done Mirror! Can you show a stacked pic of the one in my video VS the narrow depth of field?

 

16

I can’t find the video, can you post it or send it to me via e-mail?

17

Thanks a lot for your contributions, MirrorEdge. A whole new world is opening up for me… someone who has for years been struggling with making proper microscope images.

I am very curious about the results you have been able to get until now.

18

I have been lacking access to the resources I once had available to me so I have been searching for new methods and incorporating what I know of DSLR photography into the world of micro small. It has turned out to be harder than I thought. But I am getting better. As I have posted earlier, I purchased a Dino Lite scope with built in EDOF and HDR, however, the magnification just isn’t enough to see what I wanted to see, so, I have requested a upgrade from the dino lite distributor sunrise dino. I am getting the 900X scope but this has different limitations that may have led to a dead end. I feel based on seeing Clays images that this may fall just a little short as well. I wish I had found this forum sooner.

I am looking at a similar metallurgy scope like Clay uses, however, I have been monitoring the prices of the newest HD models too. I think the trick is going to be blending everything together I just haven’t found the perfect “chemistry” yet. I have found some really cool 3D scopes out now too. These look really cool but are outrageously expensive and I must add completely ridiculous for a hobby even professional knife sharpening.

Once I get the perfect kit together I will share my results, I promise. I have had some great success with the tools I have already mentioned but I want more (LOL). It is possible to get great result with just about every camera product on the market with the right combination of patience and tenacity. This started out as a sharpening diagnostic tool for me but has turned out to be much more. I have also looked into 3D imaging of blade edges as well. I have a structure sensor (http://structure.io/) that is giving me some results but not what I am looking for. That is what led to the modeling of the blade edge with clay in my other post.

19

I’ve had very limited success with image stacking so far. I’ve been trying it off and on for a couple of years. I’m not sure what’s failing for me but I’ll keep at it.

20

Here is an attempt I made in 2014. Let me know if you guys think it was a significant improvement. Here are the four originals, taken at slightly different focus points:

1.jpg
1.jpg750×1000 72.6 KB

2.jpg
2.jpg1000×563 91.3 KB

3.jpg
3.jpg1000×563 87.5 KB

4.jpg
4.jpg1000×563 92 KB