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DE razor geometry. A system for measuring aggressive razors.

Behold, the poor man's comparator. 🤣

Features:

- Zero Optical Distortion
- 1200 dpi resolution
- Razor is perfectly flat and perpendicular to camera
- Free

This is what a 1200 DPI scan looks like on my home office all-in-one printer/photocopier. To deal with the blade being on a different plane than the edge of the razor, I just cut it in half as straight as possible, and loaded it back in the razor so that it was flush. It's nowhere near as good as the photos @Rosseforp has been taking recently, and orders of magnitude worse than the genuine comparator photos he took of the English Tech, but it has it's virtues.

Not an good solution by any stretch, the DPI really needs to be 12,000, and ideally it would 120,000. It's a fun thought experiment though. I like the fact that it's perfectly perpendicular to the camera and that it has zero distortion from a curved lens. It's nowhere near high enough resolution though.

 
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Even failed experiments are useful. Two things stood out at me when looking at photocopy/picture:

1. The blade was loaded skewed. It's super obvious in this case, but this happens to some degree even on a $500 CNC razor. The blade is always skewed at least 0.05mm from one side to the other. When we're trying to take measurements accurate to 0.01mm, having the blade skewed by 0.05 makes a one-sided measurement of exposure by a $12,000 comparator useless. To be truly accurate, it's necessary to take a photo of both sides of the razor individually, take the exposure measurements of each side and average the two exposure measurements.

2. Pretty much every edge on a razor is rounded. That's true of cast razors like this one, and it's true of CNC razors because they've been tumbled to round over every edge. This can make it hard to see what the actual profile of the razor is. Backlighting largely eliminates this problem, and offers the best possible view of the true profile of the razor. There may be other solutions to this problem, but backlighting makes a lot of sense.

Both of these things might be obvious to everyone else, but this photocopier scan turned the lightbulb on for me, so I thought I'd post it in case it was helpful to anyone else. Also, I'm bound to forget about it, so this will help me remember why my measurements are wrong in the future. 😃
 
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An alternative method to using photos
and image analysis software like
ImageJ is the use of a newer model iPhone 12 Pro device ,which is
equipped with a LiDar sensor,
combined with any of the 3D scanning apps available.

High precision measurments can
be extracted from a 3D model ( or
mesh ) of any given razor .
I've had android phones for a decade at this point, but if the iPhone 12 can take lidar scans with 0.01mm resolution, I'll switch to iPhone tomorrow. Is it really that accurate? 😳
 

Esox

I didnt know
Moderator
You also need to buy a light source and a tripod if you are starting from zero because he wanted to figure out a setup any member could easily purchase and produce similar photos for comparison.
Lighting is tricky, especially with ultra close focusing distances. I use natural light as much as I can but I've even used an LED flashlight in a pinch. I also use a tripod and even though my little Canon has built in image stabilization I still use the 2 second timer so that even minute shake from the tripod at pressing the button is gone.

My tripod cost me $5CAD from aliexpress. Its sure isnt a Slick or a Velbon like I use to own but for $5 its a lot more than I imagined. Its much the same as this one.


This is and interesting option. I know absolutely nothing about cameras or photography, so I have no idea if this is any good, but we've probably all got smartphone cameras. Adding a 15x zoom for $45 fits the budget. I don't know what the implications would be for measurement accuracy though.


I didnt even know these things existed but they seem to work pretty well. If you click on the reviews and see all pictures, you'll find this one and a whole bunch more.

Untitled.png

Thats a screenshot of the picture in the review. Below are my base adjustments in CS5.

NIKCollection.png

The finished image.

Adjusted.png

I could likely get more detail and contrast out of it with different filters but that took me all of about 7 seconds to do. The only thing I'm curious about is the depth of field and if that can be adjusted. Theres a review where someone said that manipulating the lens housing can increase the depth of field but, for the price of it, I think its pretty good.


If you're still thinking about it, there are a couple of those on the big auction site with under $100 Buy It Now pricetags at the moment. One sold this morning for $99.
It's a low priority at the moment but something I still think about. I would want something with focus stacking ability, that narrows the choices quickly.


I knew I remembered the below post, it only took 20 minutes to find it haha.

So I think I'm going to keep PS CC for a while. Other than the fact I'm bumbling around trying to figure out the interface and where once familiar (from PSE 15) tools are located, the first effort at focus stacking went extremely well. PS CC did a brilliant job of aligning 4 differently focused images.

These four shots were all taken with a Canon 100mm f2.8 macro as full res .jpg (26 mp):



This is the stacked image:



Being that I'm fairly well addicted to macro, this sort of capability will be extremely handy for certain images. I have 6 days remaining in the trial but I haven't seen anything that would make not want to try it for at least a year!
Also see my post following the above where I mentioned the Helicon Focus software.
 
My tripod cost me $5CAD from aliexpress. Its sure isnt a Slick or a Velbon like I use to own but for $5 its a lot more than I imagined. Its much the same as this one.
I don't understand how they can even sell the bubble level that's mounted on it for that price, let alone the rest of it. That's just bonkers.

Also see my post following the above where I mentioned the Helicon Focus software.
Picolay is another good option. It's is open-source & free. It's a 60 second operation to import photos and focus stack the images. Like this:

 
It's a low priority at the moment but something I still think about. I would want something with focus stacking ability, that narrows the choices quickly.
The trickiest part of getting high resolution picture of a blades edge is that it sits 2mm below the edge of the razor on most modern razors that cover the blade tabs. The blade tabs are what create this problem. One solution is focus stacking, the other solution is to cut the blade in half, so it sits flush with the edge of the razor. Voila! No depth of field issue.



Incidentally, this makes a huge difference when taking pictures of a backlit razor. The blade was basically invisible when I used a regular full size blade, but when I used the one I cut in half, and brought it flush with the edge of the razor, I got a crystal clear shot of the blade (compared to what I usually get that is).



As a side note, I finally have photographic evidence that the blade in an R41 doesn't touch the combs, you can actually see the sliver of light between the blade and the baseplate going back 4-5mm. It's not rigid because it's not clamped, it's cantilevered.
 
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Esox

I didnt know
Moderator
I don't understand how they can even sell the bubble level that's mounted on it for that price, let alone the rest of it. That's just bonkers.
Mine I think is a little taller than the one I linked. Its 43"s high from base of the feet to base of the camera platform. Thats a 1' ruler beside it.

IMG_3474.JPG

I've had it 8 years or so and its still fine. Its actually better now that its broken in. The finishing was a bit rough haha but its certainly functional.


Picolay is another good option. It's is open-source & free. It's a 60 second operation to import photos and focus stack the images.
My problem is, my Camera doesnt let me adjust the focus. Its completely auto in that regard.


The trickiest part of getting high resolution picture of a blades edge is that it sits 2mm below the edge of the razor on most modern razors that cover the blade tabs. The blade tabs are what create this problem. One solution is focus stacking, the other solution is to cut the blade in half, so it sits flush with the edge of the razor. Voila! No depth of field issue.
You've discovered the very same problem I've had lol. Because my camera is auto focus only, it's taken me as long as 30 minutes, if not longer, manipulating the focus field by moving the tripod slightly while holding the shutter button half way down to maintain focus but moving the focus point to where I wanted it!

Its difficult to put a price on that tiresome, frustrating, aggravating job but, $140CAD wasnt it lol.
 
The advantage to a USB microscope, other than it's what you have, is it's all in one. I just personally see the advantage of even a cheap compact camera outweighing the advantage in spite of the additional items needed. In fact, a cell phone clamp with a tripod mount would give the USB microscope a run for it's money as I intend to prove!
I don't own anything at this point, but I've got $50. The best profile picture I've seen to date has been from a USB microscope so that's the front runner. I can't wait to see a photo from the clip-on macro lens though. I'm going to plunk my $50 down on whatever gives the highest resolution photo of the apex of the blade. 😃

@APBinNCA, you got an teaser photos for us with the Xenvo? My "buy button" trigger finger is getting itchy...
 

APBinNCA

Contributor
@APBinNCA, you got an teaser photos for us with the Xenvo? My "buy button" trigger finger is getting itchy...
Sorry, better put the finger in a finger trap! I wouldn't buy that particular one. If you watch that video I posted, he demonstrates the 100mm macro. Remember, you also need to budget for some kind of phone support if you want this to work out well. I don't have all the pieces I need yet to even post a teaser. I am willing to help with ideas and research, but getting everything together will take time. I hope @Rosseforp gets you some juicy new photos with his D610 to hold you over! :a12:
 

APBinNCA

Contributor
Alright, I guess the real add on macro lens is more than I remember. The kit you want to order is as good as any for the price. At least it gives you a chance to try things, but I am not vouching for it. Here is a link to the lenses on B&H, if nothing else for the reviews. There is one kit on there in your budget that seems reasonably well rated
Wherever you buy from, pick up a little desktop tripod and phone clamp and maybe one of the little tripods with a clamp on the other end to hold your razor. I can find them for you if you want.
 
I hope @Rosseforp gets you some juicy new photos with his D610 to hold you over!
Not sure when I will try that out, but I found out why I have been using the Camera USB app. The Digital Microscope app doesn't have the crosshairs and grid functions. I just need to line up the razor with the camera, then switch to the digital microscope to take the pictures.
:popc::popc::popc:
I have been getting sidetracked a bit when buyers come looking at our condo, plus I have been downstairs in the garage working on LHF handles on my new Sherline miniature lathe.
 
Alright, I guess the real add on macro lens is more than I remember. The kit you want to order is as good as any for the price. At least it gives you a chance to try things, but I am not vouching for it. Here is a link to the lenses on B&H, if nothing else for the reviews. There is one kit on there in your budget that seems reasonably well rated

Wherever you buy from, pick up a little desktop tripod and phone clamp and maybe one of the little tripods with a clamp on the other end to hold your razor. I can find them for you if you want.
Sadly, the cell phone option is out for me. I've got an ancient Samsung Galaxy S7 with a 12MP camera. Somewhere along the last 5 years of involuntary software updates they bricked the "pro" mode so that manual focus is no longer an option. There doesn't appear to be any way to fix this. The autofocus is pretty much useless for anything closer than 1 foot away. My options are down to a camera or the USB microscope. :(
 

APBinNCA

Contributor
Alright, here is a photo of what I am working on. I really didn't want to post this prematurely, it's mostly disappointment.

This is the limit of my phone camera resolution without a lens attached. This is shot inside a makeshift tent. I have backlit photos, but they are even worse.

The issues are as suspected, lighting, focus and stability. As to lighting, the sensor requires a minimum illumination or the quality goes down. Backlighting does not provide it and creates artifacts around the edges. This is try number 638 with different lighting levels and distances. Focus may not be solvable and I hadn't anticipated this being the deal breaker. There is simply no way to get it to focus where I want and I resorted to shooting multiple in a row to confuse it. Stability is solvable with a very affordable cell phone tripod.

I wanted to test some things before ordering anything. It can probably work with a macro lens and the above mentioned tripod for under $50. I personally don't think it is worth it at this point and feel pretty defeated.
The best photo I have is in the bathroom shot with light from a skylight, but I can't share it because it's not as clean as I thought!😱

IMG_1438.jpeg

As an aside, the last time I did product photography was with a large format and studio lighting. I took this as a challenge to see if I could outdo the microscope, I was wrong.:surrender:
 
Alright, here is a photo of what I am working on. I really didn't want to post this prematurely, it's mostly disappointment.

This is the limit of my phone camera resolution without a lens attached. This is shot inside a makeshift tent. I have backlit photos, but they are even worse.
It was a 100% successful experiment in my book. Figuring out what doesn't work is pretty damn important, and it often highlights stuff that proves instrumental down the line. I feel your pain on the makeshift tent and 638 tries though. Here is a picture of my own failed backlighting experiment complete with 2MP external webcam. 🤣



That puts the microscope back in the front runner seat for me, I think I'm going to buy one. If the Iphone 12 can't beat it, I don't think any stand alone camera in my $50 budget will either. The macro lens for cell phone cameras still looks like it might be a viable option for folks that can use manual focus (unlike mine) though.
 
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Not sure when I will try that out, but I found out why I have been using the Camera USB app. The Digital Microscope app doesn't have the crosshairs and grid functions. I just need to line up the razor with the camera, then switch to the digital microscope to take the pictures.
That's awesome! I thought your pictures were already amazing and it already puts us at +/- 0.05mm accuracy. If you can line up the picture and then use the software, that bumps us up from 1 megapixel to 2 megapixels, and I think that puts us in +/- 0.025mm territory.

If you take 2 pictures (one focused on the blade apex and one on the razor profile) and post them here, I can focus stack them in 60 seconds with Picolay. I think that get's us to +/- 0.01mm, which is way better than anyone else has ever accomplished to date. That's probably better than most manufacturers have ever seen their own product. That would easily count as mission accomplished and then some in my book! 😃
 
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Here is the first picture I took with the digital microscope at 1600 x 1200 of my Karve SBD
Karve SBD digtal.jpg
Interestingly, I didn't use any additional lighting, these shots were taken using the LED light from the microscope at full power. The picture below was taken at slightly higher magnification, but the focus is very clear without any stacking.
Karve SBD1 digital.jpg
Oh, the handle I was working on.
20210613_174513[1].jpg
The top handle is 37 grams, the bottom is 18 grams.
20210613_174539[1].jpg
The top handle is mostly solid, the bottom handle is mostly hollow.
20210613_174602[1].jpg
And the glamour shot, the top handle in this picture is 17.5 grams and is also hollow.
 
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