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Reccomendations Sought For New Usb Coin Scope.

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Pillar of the Community
United States
3190 Posts
 Posted 12/06/2019  11:04 am  Show Profile   Bookmark this reply Add rmpsrpms to your friends list Get a Link to this Reply
Unfortunately again not the complete or consistent story. The photos you are showing are not apples-apples comparison. The study I did was not to compare 100% views, but to show at a fixed view and magnification how much better the FHD camera would perform due to oversampling. Indeed the image you're showing from the Canon is undersampled!!

Regarding the need to save to flash, do you honestly think you need to ask if I tried it?

My question about whether the camera or optics was limiting was in good faith. I don't remember any issues with 100% views, so I am assuming it is the optics you had problems with.

I still see only minimal justification to recommend any USB camera over the Rebel XS. You can take various inputs out of context and try to piece together a story to support the USB cameras, but bottom line is still the same...the available/inexpensive cameras that would compete with the XS simply don't have an acceptable functionality or workflow, in my opinion.
Contact me for photographic equipment or visit my home page at:
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Valued Member
Russian Federation
172 Posts
 Posted 12/06/2019  5:51 pm  Show Profile   Bookmark this reply Add Justwalking to your friends list Get a Link to this Reply
And yes FHD is better at magnification 1:1 compared to Canon in the same FOV. Just due to undersampling at Canon's sensor no matter how good it's lens.
Images at 100% always look blurred in macro due to diffraction.
The best way to capture more details is to "oversample" your linepairs but getting closer so each linepair is sampled with 4-8 pixels if it's monochrome. If it's a colorchip with bayer pattern which makes an unnatural resolution artifacts, it is good to oversample 8-16 times. So if we want to see more or less correct small detail they must be about 10-15 times more than pixel pitch or 0.04-0.06mm for Canon. With magnification on 27" monitor they will be 25.4 times larger. So then on monitor at 100% crop all detail less than 1-1.5mm are not completely correct or loose info about subject. It is pretty big spot 4-6 pixels on 1920H resolution monitor. It is with absolutely ideal math optics with infinity resolution.
You can't do anything with it. All you can do in this case at 1:1 magnification - is to shoot at higher magnification then resize.
But at higher magnification the cost of Canon increase to expensive level. You need another lens, need rails for stacking. The overall cost of system will be far higher than $300 probably.


Quote:
My question about whether the camera or optics was limiting was in good faith. I don't remember any issues with 100% views, so I am assuming it is the optics you had problems with.


I see that you unresized picture is also blurred but I don't call that is a problem. It is just what any system does.
I just did not upload them full size if it can't show more detail. Ray, you also did not show us 100% crop on easyzoom.
Correct me if I'm wrong.

I'm not very interesting to support USB. I'm not it's seller. But here is the topic called "Recommendations Sought For New Usb Coin Scope". I don't know why the Canon is here again.

If somebody wants to show only full-size coin then the Canon may be better. If he wants the universal tool for any reasonable magnification for coin — then the choise is wider: at least to obtain C-mount HDMI camera for cheap compared to Canon.
Edited by Justwalking
12/06/2019 5:52 pm
Pillar of the Community
United States
3190 Posts
 Posted 12/08/2019  7:50 pm  Show Profile   Bookmark this reply Add rmpsrpms to your friends list Get a Link to this Reply

Quote:
And yes FHD is better at magnification 1:1 compared to Canon in the same FOV. Just due to undersampling at Canon's sensor no matter how good it's lens.
Images at 100% always look blurred in macro due to diffraction.
The best way to capture more details is to "oversample" your linepairs but getting closer so each linepair is sampled with 4-8 pixels if it's monochrome. If it's a colorchip with bayer pattern which makes an unnatural resolution artifacts, it is good to oversample 8-16 times. So if we want to see more or less correct small detail they must be about 10-15 times more than pixel pitch or 0.04-0.06mm for Canon. With magnification on 27" monitor they will be 25.4 times larger. So then on monitor at 100% crop all detail less than 1-1.5mm are not completely correct or loose info about subject. It is pretty big spot 4-6 pixels on 1920H resolution monitor. It is with absolutely ideal math optics with infinity resolution.
You can't do anything with it. All you can do in this case at 1:1 magnification - is to shoot at higher magnification then resize.
But at higher magnification the cost of Canon increase to expensive level. You need another lens, need rails for stacking. The overall cost of system will be far higher than $300 probably.


Quote:
My question about whether the camera or optics was limiting was in good faith. I don't remember any issues with 100% views, so I am assuming it is the optics you had problems with.


I see that you unresized picture is also blurred but I don't call that is a problem. It is just what any system does.
I just did not upload them full size if it can't show more detail. Ray, you also did not show us 100% crop on easyzoom.
Correct me if I'm wrong.

I'm not very interesting to support USB. I'm not it's seller. But here is the topic called "Recommendations Sought For New Usb Coin Scope". I don't know why the Canon is here again.

If somebody wants to show only full-size coin then the Canon may be better. If he wants the universal tool for any reasonable magnification for coin — then the choise is wider: at least to obtain C-mount HDMI camera for cheap compared to Canon.


Lots to comment on in the above...

First, macro images at 100% are not always blurred. Diffraction blurring only comes into play when the effective aperture is significantly smaller than the DLA of the sensor. That said, it does take very high quality optics to achieve this, and beyond a certain magnification it is for sure not possible, but up to 2x it is possible to get sharp images at 100%.

Second, oversampling is for sure a good thing, but is very expensive. In general I prefer to downsize any published image by 2x to help with Bayer demosaicing errors, ie 4 pixels are downsampled into 1 published pixel. I've found that more downsampling gives only a little more improvement. But this means that a sharp final image needs 4x the sensor MP to fix those Bayer errors. That is either very expensive to buy the larger sensor, or expensive in time and effort to stitch images for best final result as you did in the image you posted.

Third, I'm still quite interested in the FHD type of camera for higher magnifications. I have not discounted them for this application, though it is certainly a niche. Most folks who put together the <$400 system use them for full coin imaging, not for varieties. A few do both. I still have more experiments to explore.

Indeed the images I post on EasyZoom are full-size, not downsampled. When viewed at maximum zoom they are at 100% pixel view. Finding an optimum way to get sharp and detailed images at 100% has been a quest of mine for many years. They are not as sharp as they could be if oversampled, but to get an oversampled image to downsize by 2x I'd need almost 400MP. This starts to seem feasible with cameras like the A7Rm4, with its 16-image composite at 240MP, but my testing of that camera did not yield good enough results to justify the cost or difficulty of the workflow. I am thinking that my next phase, rather than pixel-shifting, will be Super-Resolution. This at least doubles the workflow, but in general that's a lot less than what is needed for the A7Rm4, and the result is better (more natural and believable).

Finally, I don't see how you could still recommend the FHD/C-Mount camera vs the Canon for general use. The workflow issues are just too big a hurdle to overcome.
Contact me for photographic equipment or visit my home page at:
http://macrocoins.com
Valued Member
Russian Federation
172 Posts
 Posted 12/13/2019  4:31 pm  Show Profile   Bookmark this reply Add Justwalking to your friends list Get a Link to this Reply

Quote:
First, macro images at 100% are not always blurred. Diffraction blurring only comes into play when the effective aperture is significantly smaller than the DLA of the sensor. That said, it does take very high quality optics to achieve this, and beyond a certain magnification it is for sure not possible, but up to 2x it is possible to get sharp images at 100%.


Diffraction is always there. It's always the same, no matter what the pixel size. When the f-number is wider than the DLA, it means that the image is blurred so much by large pixels, that it's impossible to see the diffraction blur. Smaller pixels simply allow you to see the diffraction blur that was always there.
The size of the point of light in the final image is going to be the RMS of the components involved in making the image: imageSpot = SQRT(lensSpot^2 + sensorSpot^2).
Higher resolution sensors generally continue to deliver more detail than lower resolution sensors at apertures narrower than the DLA - until the Diffraction Cutoff Frequency (DCF) is reached.


Quote:
Second, oversampling is for sure a good thing, but is very expensive. In general I prefer to downsize any published image by 2x to help with Bayer demosaicing errors, ie 4 pixels are downsampled into 1 published pixel.
I've found that more downsampling gives only a little more improvement. But this means that a sharp final image needs 4x the sensor MP to fix those Bayer errors.
That is either very expensive to buy the larger sensor, or expensive in time and effort to stitch images for best final result as you did in the image you posted.


Yes, agreed that is very expensive (if it posiible at all to find such sensor on the market) and the optics for that are even more expensive. For 1" with same resolution lens is about 5X expensive than for 1/2", for 4/3 and higher it will be above $1000 for new and hard to find.
That is the reason to use small HR sensor with not so expensive HR lens made for small sensors.
Meanwhile to obtain such result with big sensor with larger pixels it is not enough to stitch just 6 frames. Then each frame must be stacket previosly due to higher magnification and very shallow DoF.
The overal time consumption will be much more to produce and compound not 6 frames but 6 times per 10 stacked for same MP sensor. And also needs very expensive hardware for stacking that cost more than whole $400 setup.
So this is the reason not to use just big sensor with big pixels on it.


Quote:
Third, I'm still quite interested in the FHD type of camera for higher magnifications. I have not discounted them for this application, though it is certainly a niche. Most folks who put together the <$400 system use them for full coin imaging, not for varieties. A few do both. I still have more experiments to explore.
Indeed the images I post on EasyZoom are full-size, not downsampled. When viewed at maximum zoom they are at 100% pixel view.


Finding an optimum way to get sharp and detailed images at 100% has been a quest of mine for many years.
They are not as sharp as they could be if oversampled, but to get an oversampled image to downsize by 2x I'd need almost 400MP.


Than the conclusion that this way is wrong till we have no 400MP sensors around.


Quote:

Finally, I don't see how you could still recommend the FHD/C-Mount camera vs the Canon for general use. The workflow issues are just too big a hurdle to overcome.


Yes, why not? General use is just push one knob on remote to save the frame on flash card or just to click mouse knob once if you lucky to find that mode in your soft. You can work in mode "what you see then what you get" via HDMI. Very simple compared vs Canon.
The result must not be too bad for whole size coin. And no need fanatically catch the focus in Dof.



That is not mean you need immediatly run to PC, insert flash to cardreader to show new photo to everybody.
Need to be a little more patient to make at least tenth shots. There a lot of space on the flash (at least up to 32Gb).
If you don't like this way for the only $120 per 16MP then it will cost $300 per usb-3 models with software.
Meanwhile my old 8MP USB-2 camera was able to control white balance, colors, sharpness etc. directly on PC screen via USB, there no HDMI output at all. The price was only $80 several years ago.
Edited by Justwalking
12/13/2019 4:33 pm
Pillar of the Community
United States
3190 Posts
 Posted 12/14/2019  5:48 pm  Show Profile   Bookmark this reply Add rmpsrpms to your friends list Get a Link to this Reply

Quote:
Diffraction is always there. It's always the same, no matter what the pixel size. When the f-number is wider than the DLA, it means that the image is blurred so much by large pixels, that it's impossible to see the diffraction blur. Smaller pixels simply allow you to see the diffraction blur that was always there.


Personally, I don't want to see diffraction blurring. I don't like blurry pictures.


Quote:
Meanwhile to obtain such result with big sensor with larger pixels it is not enough to stitch just 6 frames. Then each frame must be stacket previosly due to higher magnification and very shallow DoF.
The overal time consumption will be much more to produce and compound not 6 frames but 6 times per 10 stacked for same MP sensor. And also needs very expensive hardware for stacking that cost more than whole $400 setup.


Most folks using the <$400 setup don't even stack, let alone stitch, so I am not sure what you are saying that both stacking and stitching are required.

For sure if someone is doing only higher magnification work, then the FHD camera can make sense to reduce the need to stack due to increased DOF. In fact this is the basis for the inexpensive USB microscopes that are so ubiquitous. Those microscopes would be much less popular if you had to focus stack to get a good image from them! They rely on the lower magnification requirements due to the small sensor to provide acceptable DOF. But we all know how poor their quality is. With the <$400 setup, the idea is to get better quality than could be had with a cheap USB scope. With the FHD camera you have the option of using much higher quality optics than are used in the USB scopes, but ultimately the limitation must be diffraction physics with the small sensor.


Quote:
Yes, why not? General use is just push one knob on remote to save the frame on flash card or just to click mouse knob once if you lucky to find that mode in your soft. You can work in mode "what you see then what you get" via HDMI. Very simple compared vs Canon.
The result must not be too bad for whole size coin. And no need fanatically catch the focus in Dof.


OK, then what do you recommend? You are so adamant that your solution is much better than the DSLR solution, why don't you actually make a recommendation. What exact camera and optics do you recommend JW? Are you willing to stand up to your recommendation and help folks solve the inevitable problems they will face? It's not good enough to just throw out some ideas and then say "if you are lucky to find". Do the research. Buy some examples of the product. Make a proper report on how well the camera and optics work together over a range of coin sizes. Describe for us the way it is done, and make a list of equipment to make your recommendation happen. All you are doing is showing us what you can do with your particular and apparently unique set of equipment, and then saying it's the best way to do things, but that is not helpful to anyone on this forum.

Contact me for photographic equipment or visit my home page at:
http://macrocoins.com
Valued Member
Russian Federation
172 Posts
 Posted 12/19/2019  03:18 am  Show Profile   Bookmark this reply Add Justwalking to your friends list Get a Link to this Reply

Quote:
Personally, I don't want to see diffraction blurring. I don't like blurry pictures.

Sure. Nobody like it. Unfortunately trying to hide this blur by larger pixels you hide all details also. This blur and details will be spread by larger area of each pixel.


Quote:
Most folks using the <$400 setup don't even stack, let alone stitch, so I am not sure what you are saying that both stacking and stitching are required.

You was talking about my best HR pic on easyzoom. It was 4000x4000 being resized already. To obtain such resolution on large sensor it must be stitched from stacked frames.
Of course no need to stich with less magnification and resolution.


Quote:
Those microscopes would be much less popular if you had to focus stack to get a good image from them! They rely on the lower magnification requirements due to the small sensor to provide acceptable DOF. But we all know how poor their quality is.

Their quality is very poor, agreed. Low resolution sensor and cheap optics. But their prices about $40, not just less than $400. So this conparision as you say "apples vs oranges".)


Quote:
With the FHD camera you have the option of using much higher quality optics than are used in the USB scopes, but ultimately the limitation must be diffraction physics with the small sensor.

Sorry to repeat, but diffraction physics is exactly the same
on any sensor and even on the analog film frame. It is only optic's function.
All you can do is to show diffraction with all useful detail of the object at high resolutin or hide all details with diffraction at low resolution on large-pixels sensor on the same field of view.


Quote:
OK, then what do you recommend? You are so adamant that your solution is much better than the DSLR solution, why don't you actually make a recommendation. What exact camera and optics do you recommend JW?


No, no. I'm not ready to gave exact recommendation.
I just wanted to show overall concept and good alternative way for people familiar with optics and liked to try, not instruction where to buy optics, which camera, how to assemble and get good pics step by step for dummies.
But some useful info with examples of hardware and optics still available to see in my other threads.
For people who need universal tool for shoot whole coin and at higher magnification also(up to 4:1 in terms on FF camera) that match any tasks for coin pic. Sure, it will be less cost compared to Canon.


Quote:
All you are doing is showing us what you can do with your particular and apparently unique set of equipment, and then saying it's the best way to do things, but that is not helpful to anyone on this forum.

Very saddened by such a message. I hope that some users thanked me not in vain.
Edited by Justwalking
12/19/2019 04:08 am
Pillar of the Community
United States
3190 Posts
 Posted 12/19/2019  12:45 pm  Show Profile   Bookmark this reply Add rmpsrpms to your friends list Get a Link to this Reply

Quote:
All you can do is to show diffraction with all useful detail of the object at high resolutin or hide all details with diffraction at low resolution on large-pixels sensor on the same field of view.


I of course agree with the physics of what you're saying, but not the practicality. It's not useful to zoom in to see fuzzy details, even if they have a bit more information. I personally take the limit of zooming-in as the point at which the details start to become fuzzy, such that they start to become confusing and thus less useful. If you're already diffraction-limited with larger pixels, zooming in to smaller pixels will indeed give a little more information, at the expense of having to dig that information out of a fuzzy mess.


Quote:
For people who need universal tool for shoot whole coin and at higher magnification also(up to 4:1 in terms on FF camera) that match any tasks for coin pic. Sure, it will be less cost compared to Canon.


I don't agree. I have tried to make it work, and was not successful. You show some specific examples, but you're not supporting it. For folks to believe what you're saying, you should put together a set of equipment and show pics at different magnifications, from Dollar-size down to smaller than Dime-size for full coins, and details down to a mintmark. At that point you can support your claim of being lower cost than the <$400 (which is now actually <$300).



Contact me for photographic equipment or visit my home page at:
http://macrocoins.com
Pillar of the Community
United States
3190 Posts
 Posted 01/03/2020  11:38 pm  Show Profile   Bookmark this reply Add rmpsrpms to your friends list Get a Link to this Reply
@JustWalking...can you give any details on the type of camera you are using which over USB2.0 can transfer full resolution HD images?
Contact me for photographic equipment or visit my home page at:
http://macrocoins.com
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