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Author Topic: Better Coin Photos With a Cell Phone  (Read 1176 times)

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Offline VOTman

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Better Coin Photos With a Cell Phone
« on: February 15, 2021, 11:40:46 am »
I’m an ancient coin collector…, and I’m also a photographer.

Sometimes I see some poor quality photos posted.  As the coin itself is often well worn a poor photo makes it more difficult to appreciate the coin or even identify it.  There are multiple methods for taking good coin photos with professional cameras.  However, the simple one below works well with cell phone cameras…

 - First, clean your coin with a soft-hair brush, then blow off any residue.  If you don’t, dust will be very evident in your coin photos.

 - Don’t take photos at night or with artificial lighting.  Use even illumination like that from a daytime window (cloudy or sunny but no direct sun).

 - Under no circumstances should you hand-hold the camera or the coin, for a photo.  Coins require close-ups which greatly reduces the depth-of-field (the distance range where a coin remains in focus).  This depth-of-field is often less than 1mm!  A closeup also magnifies your hand-shaking.  Again, you can not handhold a coin for this.  Instead, lay the cell phone horizontally on some books (or other items) such that the camera lens hangs over the edge of the books towards the coin below.  See the cell phone setup photo.

 - Place the height of the phone so that it is as close to the coin as you can get it, such that it will still focus sharply at that close distance.

 - Center and enlarge the coin so that it fills the phone’s screen.

 - Gently tap the image of the coin on the phone’s screen.  This forces the camera to re-focus on the coin.

 - When ready, gently tap the shutter to take the photo.  If your phone has this feature use a time delay of a few seconds to avoid vibration.

 - Examine the finished photo by enlarging it.  If it doesn’t look right, learn what’s wrong and re-shoot until it looks good.

 - If needed, resize the photo to 2,000 pixels at its widest, then use a ~50% compression level.  Your 10-megapixel photo will now come in at a small ~260Kb, but still clean looking file size (as in my sample coin photo below).

As an experiment, I took two coin photos, one with a black background and the other with a white one, both using my six-year-old phone.  Check the results below.  The difference in the appearance of the photos is rather significant.  This is because of how the camera’s light meter reacts to the coin’s black or white background.  Though both are good photos more coin detail and better color balance are achieved when a coin is photographed with a black background (the darker the better).  A dark background also removes any coin shadows at its edges.

Cell phone cameras have less detail and more noise than professional cameras.  However, if done properly cell phones can still take very good coin photos for use here in the Forums.  You be the judge.


Click to Enlarge

Offline Virgil H

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Re: Better Coin Photos With a Cell Phone
« Reply #1 on: February 15, 2021, 07:25:15 pm »
Ken P,
Thank you so much for this. I struggle with photographing my coins and this is going to help Immensely. Very clear and easy to understand.

Virgil

Offline Stkp

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Re: Better Coin Photos With a Cell Phone
« Reply #2 on: February 15, 2021, 09:19:07 pm »
I will definitely use Ken's method next time. Stkp

Offline Jeffrey D1

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Re: Better Coin Photos With a Cell Phone
« Reply #3 on: March 01, 2021, 09:36:28 pm »
Very cool

What did use for the black background to make it so consistent and non distracting ?

I tried a test picture today on black and while the coin picture cans out really good- the black background was showing weave/grain of black material

I am very new to this. 

Are there any easy ways to stitch together both sides of the coin into one picture?

I guess I am trying to understand how to nail the background vs cropping and then stitch together

Thank you for the post.  I am happy with the photo my iPhone took

Best
Jeff

Offline Virgil H

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Re: Better Coin Photos With a Cell Phone
« Reply #4 on: March 05, 2021, 05:51:19 pm »
Hi Jeffrey,
I am not sure if my stitching method is the easiest or best, but it works for me. I use The Gimp, a free open source image editing program that is like PhotoShop. You can use most image editing programs. The terminology is hopefully familiar, but is written for Gimp.

1. Open first picture and crop it to the size of the coin.
2. Make adjustments to the image using levels, etc.
3. Increase the Canvas size, in Gimp, this is done via Image>Canvas Size. I double the width of the canvas. This does not do anything to the image of the coin and leaves a lot of room for pasting in the image of the other size.
4. Open other side of coin image and repeat 1-2.
5. Copy the other coin image. Can be done with Select All or drawing a box and copying.
6. Go to original image with larger canvas and paste in the other side of the coin "as a new layer."
7. Select the Move Tool and move the new layer to the correct place in the original image.
8. Flatten Image or Merge Visible Layers to make it one image with no separate layers.
9. Crop the entire image to get rid of any unneeded canvas.
10. Export or Save As a jpg file. This is the file you upload.

Note that an image I uploaded yesterday in Greek Coins Forum section used the above stitching method and was the first coin image I have done using Ken's Method and it is by far the best image I have ever taken or uploaded to this site.

Hope this helps.

Virgil

Offline Jeffrey D1

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Re: Better Coin Photos With a Cell Phone
« Reply #5 on: March 05, 2021, 08:29:28 pm »
very cool, Virgil and thanks for the tips

i downloaded GIMP and did a coin

obviously i have no idea what i'm doing beyond the instructions on this thread

but i think this turned out OK




Offline Virgil H

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Re: Better Coin Photos With a Cell Phone
« Reply #6 on: March 05, 2021, 10:36:05 pm »
Looks great to me. The biggest thing I have found is lighting and that depends on the coin and the adjustments you make to try and bring out detail. The biggest problem I was having was getting a good focus and Ken's instructions helped me big time on that. I think you nailed this one.

Virgil

Offline wolfgang336

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Re: Better Coin Photos With a Cell Phone
« Reply #7 on: April 03, 2021, 07:28:52 pm »
This post was a terrific help to me, Ken. I'm going a bit stir crazy with a new lockdown where I live, so photographing a bit of my collection with my cell has been a terrific relief! Cloudy natural light is key. Some samples below! (Different coins, obviously).


 

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