Coin Community Family of Web Sites
Like us on Facebook! Subscribe to our Youtube Channel! Check out our Twitter! Check out our Pinterest!
Username:
Password:
Save Password
Forgot your Password?

Welcome Guest! Need help? Got a question? Inherit some coins?
Our coin forum is completely free! Register Now!

Diabolical Little Denaro: Sycaphate

 
To participate in the forum you must log in or register.
Author Previous TopicReplies: 15 / Views: 1,029Next Topic  
Pillar of the Community
2087 Posts
 Posted 11/26/2018  11:39 am Show Profile   Bookmark this topic Add austrokiwi to your friends list Get a Link to this Message
I am doing a presentation next year and am starting to put the pictures together. This Denaro of Enrico Dandolo ( Venice around 1200) is probably the worst coin I will have to image. It is dome-shaped so the only way to get a hi-res image ( for projection is stacking). This post is just me whining about the challenges of the coin. I am showing the worst side of the coin( the outside curve). The edge is porous from corrosion and the lighting really needs attention to get rid of the hot spots. This stack ( from 133 140mb individual shots) is my first go but really needs to be redone. I will try again tomorrow. I expect most of my time will be spent getting the lighting right.

This image took zerene stacker 15 minutes of hot work( the LEDs burned red on the motherboard( they are set to show the CPU temperature) INitial editing of the raw files was done on Capture One 10. To "compensate" for diffraction I used the deconvolution option. I plan to do an LCC. Camera Sony A7RII, lens SK 45 2.8 set wide open there are sharper lenses but they lose out(IMO) to the wider aperture of the 45mm.

Here a link to a large size JPG https://drive.google.com/file/d/1x4...?usp=sharing that picture will show all the warts with this practice attempt.



Pillar of the Community
2087 Posts
 Posted 11/26/2018  2:28 pm  Show Profile   Bookmark this reply Add austrokiwi to your friends list Get a Link to this Reply
Take 2. Used a white background for taking the photo and improved the lighting.. not quite there yet
Pillar of the Community
2087 Posts
 Posted 11/26/2018  3:28 pm  Show Profile   Bookmark this reply Add austrokiwi to your friends list Get a Link to this Reply
As I thought the other side (concave) was heaps easier. In all shots, the magnification is 1.25X
Pillar of the Community
United States
4212 Posts
 Posted 11/26/2018  4:37 pm  Show Profile   Bookmark this reply Add fioti to your friends list Get a Link to this Reply
I like the richness of the 3rd shot. Great pics!
Pillar of the Community
Learn More...
United States
8694 Posts
 Posted 11/26/2018  11:39 pm  Show Profile   Bookmark this reply Add pepactonius to your friends list Get a Link to this Reply
All the stacking effort seems to have paid off in nice results.

I always hate having to stack for small coins, high-relief, or curved coins (like the 2014 baseball coins from the US). I see that the US mint is planning four more curved coins in 2019, including a large 5-ounce one.

How much difference does the deconvolution make, if you are shooting at f/2.8, which is around effective f/6 or f/7 at 1.25x?

Is the SK 45mm f/2.8 better than the Printing-Nikkor at 1.25X?
Pillar of the Community
2087 Posts
 Posted 11/27/2018  12:53 am  Show Profile   Bookmark this reply Add austrokiwi to your friends list Get a Link to this Reply

Quote:
How much difference does the deconvolution make, if you are shooting at f/2.8, which is around effective f/6 or f/7 at 1.25x?


I didn't work out the magnification until after I had taken the shots and posted the first two images. A couple of years ago I tested what the Deconvolution di to images. It effectively gave me an extra stop.


Quote:
Is the SK 45mm f/2.8 better than the Printing-Nikkor at 1.25X?


No, and yes.

No; the printing Nikkor beats the SK hands down on resolution and overall image quality( at that magnification).

Yes; the SK geometry makes it considerably easier to set the lights(it wasn't that easy with the SK). The working distance at that magnification really limited my lighting options. Later today I will be playing around with different options to try and get better images of that ( swear words) coin. I know from past experience that once I am around 2X-4X the little SK at 2.8 gives me the best images simply because of its wider aperture.


When I do the final images I will be ( guessing here) closer to 1.75X. At 1.25X there was still sensor space available.

Its the second time I have tried to image a concave coin and by far the worst experience. the previous coin was a Hungarian bronze coin of larger size and much better condition. I really was surprised how the porosity of parts of that Venetian Denaro-piccolo complicated the imaging process.
You can see one of the other issues I still need to sort out in the first 2 images. With the coin sitting dome-up, the edge was sitting on the background and shadows from that edge blended into the coin( best way I can describe it) into the background. For the other side of the coin, the edges were a few mm off the background. I will be looking at a way to lift the coin up off the background for that problematic side.
Edited by austrokiwi
11/27/2018 01:13 am
Pillar of the Community
2087 Posts
 Posted 11/27/2018  04:39 am  Show Profile   Bookmark this reply Add austrokiwi to your friends list Get a Link to this Reply
2 hours of work and I am getting close on the horrible side. I am still having an issue...the edge just seems way too soft. I set the start of the stack ( I run the stack shop from the lowest shot first) at a point I was sure was past the point of focus(on the edge) with the aim that as the stack moved up the stack would sweep through the focus. The step increment was 30um I haven't checked but I thought sure that is smaller than necessary.

For lighting, I used a half ping pong ball as a diffuser, but there is some light leakage from above resulting in at least one hot spot. I could with more work get rid of it but am starting to think the time an effort may not be warranted. As mentioned in an earlier post this time I mounted the coin so the edges we above the background.

Editing was in raw using Capture one 10 for Sony. Deconvolution was applied and I created and applied an LCC. See this link to understand how I did that:

https://www.phaseone.com/Search/Art...ticleid=2047

I shot in raw the stack was from 85 shots, stacked using Dmap in Zerene Stacker.

The picture is best viewed from a metre and a half away. I am viewing using a Hi-resolution calibrated ( 2 days ago) monitor. So if you're using a low res monitor you may not see the faults that scream at me


I have attached a significantly reduced Jpeg attached to this post for those who want to look at the final tif file here is a link. be warned you will have to download.. if on a metered connection it is probably not a good idea

https://drive.google.com/open?id=1z...m1mmy5Ew16lD


Edited by austrokiwi
11/27/2018 04:53 am
Pillar of the Community
Learn More...
United States
8694 Posts
 Posted 11/27/2018  07:43 am  Show Profile   Bookmark this reply Add pepactonius to your friends list Get a Link to this Reply

Quote:
I am still having an issue...the edge just seems way too soft.


I'm wondering if you're having the same problem that I noticed -- steeply-sloping surfaces with Zerene Stacker DMAP mode come out fuzzy and without detail. Maybe if the slope is greater than the cone angle for the incoming light (NA-dependent) it causes trouble? Here are some examples:


(shot through an NGC slab):


(shot with NA=0.28 microscope objective):


100% crop of the above:
Pillar of the Community
2087 Posts
 Posted 11/27/2018  11:07 am  Show Profile   Bookmark this reply Add austrokiwi to your friends list Get a Link to this Reply
Pepactonius, thanks for pointing that out. I went through the individual shots and the edges were sharper than the stacked image. I redid the stacks using Pmax and there is an improvement. magnification is 1.65 times

Here is a Gdrive link( very large file) to the Tif file:

https://drive.google.com/open?id=15...DyJ4_MV_58za

Attached is a much reduced Jpeg


Edited by austrokiwi
11/27/2018 11:12 am
Pillar of the Community
2087 Posts
 Posted 11/28/2018  05:04 am  Show Profile   Bookmark this reply Add austrokiwi to your friends list Get a Link to this Reply
Pepactonius=====> I keep on looking at the results from Pman and Dmax and keep thinking I can do better. I am unfamiliar with editing in Zerene. Do you think I will get any substantive change in the image if I stack using both methods and then edit? I have found the video tutorials and will go through them I do find it had relating the instructions for a fruit fly or Flower to a coin( my inexperience). Are there significant differences between the subjects?
Pillar of the Community
2087 Posts
 Posted 11/28/2018  07:00 am  Show Profile   Bookmark this reply Add austrokiwi to your friends list Get a Link to this Reply
Started again completely changed the rig setup. USed the printing Nikkor 105mm @ F 3.5. Set the magnification to 1.4 to keep in the best zone for the lens. Dmax was used and the result is as good as I could want. No deconvolution and no LCC( didn't see any advantage in it for the PN, even for dust mapping.

Colours are different but I find that is normal for the PN

The full image is here ( Large file)
https://drive.google.com/open?id=1v...Cl_AoYWo9ve9

I did have some hardware issues. Several times during the stacking the computer crashed. I think I have sorted it. I gave it a good internal dust, and changed the fan setting to high performance and recalibrated all the fans. The computer has a mild overclock (4400 GHz) and I think I was seeing thermal shut down as the fan profile was wrong( somehow it wasn't set at the fan profile I thought it was. at least I hope that was the issue.



Edited by austrokiwi
11/28/2018 07:05 am
Pillar of the Community
United States
3266 Posts
 Posted 11/28/2018  11:02 am  Show Profile   Bookmark this reply Add rmpsrpms to your friends list Get a Link to this Reply
And the 105mm Printing Nikkor comes to the rescue!

For a coin with a domed relief, 3D rendering would be very cool. Have you tried this with such a coin before?

I was unable to view the image properly on Drive for some reason. I could see the small image but could not zoom in.
Contact me for photographic equipment or visit my home page at:
http://macrocoins.com
Pillar of the Community
2087 Posts
 Posted 11/28/2018  11:27 am  Show Profile   Bookmark this reply Add austrokiwi to your friends list Get a Link to this Reply
Its a high mp Tif file so I think you have to download it to view properly.

I finished imaging the coin to my satisfaction. The final image is here (140mb)

https://drive.google.com/open?id=1t...YZfYRFoAqIOd


It was a huge amount of work for such a tiny and inexpensive coin. However, it was good practice.

I had created 3D video in 2016 of a Hungarian bronze Scyphate(spelt correctly this time) of Bella II ( or was it III. It was an interesting little clip.
Pillar of the Community
Learn More...
United States
8694 Posts
 Posted 11/28/2018  12:16 pm  Show Profile   Bookmark this reply Add pepactonius to your friends list Get a Link to this Reply

Quote:
Pepactonius=====> I keep on looking at the results from Pman and Dmax and keep thinking I can do better. I am unfamiliar with editing in Zerene. Do you think I will get any substantive change in the image if I stack using both methods and then edit? I have found the video tutorials and will go through them I do find it had relating the instructions for a fruit fly or Flower to a coin( my inexperience). Are there significant differences between the subjects?


I never did any manual editing of Zerene Stacker images. Also, I stay away from PMAX most of the time, since it sometimes fails spectacularly (with bizarre results) for some targets.


Quote:
The computer has a mild overclock (4400 GHz) and I think I was seeing thermal shut down as the fan profile was wrong( somehow it wasn't set at the fan profile I thought it was. at least I hope that was the issue.


I don't know what type of CPU you have, but I thought the modern Intel CPUs are supposed to throttle back as they approach their maximum temperature. I am investigating putting together a new computer early next spring, and I hear that overheating is a big issue with CPUs like the Intel 9900K, especially when overclocked (even though properly-behaving motherboards should reduce the clock to keep the long-term power dissipation below the official TDP of 95 watts). Even the VRMs can overheat with these new CPUs when overclocked. I'm definitely going to stick with stock frequencies and not overclock.




Pillar of the Community
United States
3266 Posts
 Posted 11/28/2018  12:24 pm  Show Profile   Bookmark this reply Add rmpsrpms to your friends list Get a Link to this Reply
Looks good. I was able to download this time. Does the reverse look similar to obverse but with different inscriptions?
Contact me for photographic equipment or visit my home page at:
http://macrocoins.com
Pillar of the Community
2087 Posts
 Posted 11/28/2018  12:41 pm  Show Profile   Bookmark this reply Add austrokiwi to your friends list Get a Link to this Reply

Quote:
I don't know what type of CPU you have, but I thought the modern Intel CPUs are supposed to throttle back as they approach their maximum temperature.


I expected it to throttle back. My machines heart is an I7-6900. Its fan cooled and I have been remiss cleaning the inside. I have subsequently removed the 2 fans from the CPU cooler and cleaned out heaps of dust. I am hoping that is all the issue was.


Quote:
Does the reverse look similar to obverse but with different inscriptions?


that's correct
  Previous TopicReplies: 15 / Views: 1,029Next Topic  
 
To participate in the forum you must log in or register.

Coin Community Member eBay Sales

Certified Coins   Certified VAMs   Certified Errors  




Disclaimer: While a tremendous amount of effort goes into ensuring the accuracy of the information contained in this site, Coin Community assumes no liability for errors. Copyright 2005 - 2020 Coin Community Family- all rights reserved worldwide. Use of any images or content on this website without prior written permission of Coin Community or the original lender is strictly prohibited.
Contact Us  |  Advertise Here  |  Privacy Policy / Terms of Use

Coin Community Forum © 2005 - 2020 Coin Community Forums
It took 0.83 seconds to rattle this change. Powered By: Snitz Forums 2000 Version 3.4.05