Gemstone Photography

[bonkycat]

Gemstone photography has been the biggest struggle for us, one that we are just now overcoming. It is also something that is frequently asked about on many forums.

I pulled a post from another thread that has been one of the best guidelines for us. Jamey and Ken, and many others have been a valuable source of information on this topic and I appreciate their input very much.

The reason I have selected this post is because it has worked for us and is the easiest for us to set up, take down and store with a 5 year old in the house.

I am posting the original thread and then following that with the items we use and the links I have found that offered the best prices.

Good luck to all!

[bonkycat]

The setup is basically similar to Jamey's, bar the camera and size of light box

I have a 12” and a 20” tabletop studio cube
2 x 10” reflectors & 2 x tabletop stands
1 x 5” reflector & 1 normal stand
Energy saving Daylight 30w x 2 for the 10” relflectors (6500k output)
Energy saving Daylight 15w x 1 for the 5” reflector (6500k output)
Nikon Coolpix P5000 & a 3" mini tripod for the camera
9.5" x 9.5" x 2.5" white reflective perspex riser/platform

I set the 2x 10" reflectors at each top corner of the cube left and right at the
front. With the rim of the reflector actually touching the cube material, (quite safe due to the low wattage of the bulbs.)

These are pointed down to the back opposite corners of the cube to give even spread of light. The third light (5" reflector can be used above and down or front and down, however I very rarely use it (only if I want sparkle added)

Once the lights are in position you need to take a Custom White Balance reading.

But before you do this, it is advisable to set the camera to 'Manual setting' or 'Aperture Priority setting'.

In manual, you will be able to set the aperture to f8 or above, with a good starting shutter speed of 60th sec.

The high aperture number will give you a good depth of focus. (however I used the aperture of f3.5 for my shots with a 60th of Sec shutter speed to take the gem pictures) each camera is different and you will need to play with the aperture and speed when taking the pictures to see which one give the best results.

Once aperture and shutter speed have been set, change the ISO equivalent setting to 64 or 80, (again camera's vary, mine was set to 64) and set the picture quality to 'fine' this will give good quality picture allowing you to enlarge without loss of quality.

Once that is done I point the camera directly into the cube and take a Custom White Balance reading with the camera, (any camera worth their salt will have this custom white balance facility) let the system calculate the light reading on the inside of the cube / box.

Riser is placed into the cube / light box and the specimen is placed on the riser.

Using my 3" tripod I set the camera to 'macro Scene' (the tulip) and auto focus to spot focus and focus once only, not continuously!

The two front legs of the tripod sit on the riser with the single back leg sitting on a solid book that fits snugly under the riser, this effectively lets you get approximately 3 -4 inches from the specimen allowing good frame fill without going beyond the macro focus limitations.

Do a pre-focus on the specimen the adjust the aperture compensation to + 1 to +1.7, you will see the background get gradually whiter, find best results.

Bear in mind the aperture compensation for white background is in the +1 to +1.7 area, for black background it will be in the -1 to -1.7 area.

Once you are happy set the camera to self timer (I use 3 sec) focus camera by depressing button half way once focus is locked and it is showing green (macro has found focus) depress shutter release fully and remove hands.

The self timer allows camera to settle so you will not get any camera shake even at slow speeds.

Please practice different aperture and shutter speeds along with the aperture compensation to achieve the best results.

Transfer pictures to your favorite publishing program I use Adobe Photoshop or Corel Paintshop Pro X

The only manipulation that I do in the program is cropping and adjusting brightness and contrast, but only very slightly. (no colour, saturation or Hue manipulation)

look at brightness first and adjust in increments of 5 points, then adjust contrast again in 5 point increments, (the contrast will lighten your background without doing too much to the colour) the idea is to maintain the colour of the stone as seen in the pure daylight 6400k lights.

Do not change the brightness or contrast by too many points as this has a detrimental effect. if you are using 15 points or more to get a good result, you need to be changing the settings used in the camera.

The picture could also be helped by doing a single sharpen or a sharpen more, (nothing else)

At this stage you will have beautiful looking stones to post.

I will photograph the setup showing these various steps to help out better.

Please be aware, this is how I take the photographs, everyone has their own way of doing this. Try different approaches if more than one set of directions have been posted and use the one you feel most happy with.

Regards

Ken
ISG Registered Gemologist Appraiser

[bonkycat]

We did exactly as listed above with the following alterations to the equipment or due to the limitations of our camera. The links are to the best prices I could find and where I purchased unless noted.

Equipment

We bought the 16" cube here:
http://stores.shop.ebay.com/Rackmoun...34Q2ec0Q2em322

We use 3 of these reflector clamp lights purchased at walmart for less:
http://www.harborfreight.com/cpi/cta...112&zmap=98486

We use 3 nvision 27watts 5500k bulbs from home depot. (we typically only have two of these on as the instructions above suggest)

We use a full size tripod.

We purchased the small set of 3 risers in white, black and clear acrylic. (the color of the riser varies with the color of the stone):
http://www.atenterprises.com/acrylic-risers.html

We purchased this grey card and are setting our white balance on the grey card in the lighted cube (this ships s l o w l y):
http://www.amazon.com/Opteka-Premium...ANFGGYXXN58HNF

Settings

We use the Aperture Priority setting (A) rather than manual and the (A) setting selects the shutter speed.

We use f8 (because we don't have f16 which Ken says is better)

We use ISO 50 because we only have a choice of 50 or 100 in the suggested range.

We usually set the aperture compensation to +1.3 with a clear riser and -1.0 with the black riser. This will vary with the background or riser used.

We set the self timer to 2 sec.

We don't have the best camera and we use no special lenses. You can see the latest round of images we have taken in the photo album in my profile.

Ken will need to answer any additional questions as we are using his instructions and have NO prior camera or photo skills. The only editing we have needed to do was crop and re-size and very occasionally adjusting the balance.

We also printed out Ken's instructions and followed them line by line so we wouldn't get confused

[Jamey S.]

I would highly recommend AGAINST using the brightness and contrast settings in any image editing program!! They are nasty tools and really damage the IQ of your images and don't even do their job correctly. Your best choice to use is either the Curves tool(best) or the Levels tool(2nd best) to adjust things, as they will do it correctly.

Also, for the white balance, you can simply stretch a coffee filter across the lens and set your custom white balance like that of the scene.

[bonkycat]

For cropping and resizing I use Jasc Paintshop Pro 8. If ever I feel I need to adjust the brightness or contrast, in this program I do the following:

With the image open in the editing software I first crop the image to a pre-set multiple of my final website image. (my site uses 160x120 and I upload an image double that - 320x240) This is where I decided how much gemstone will fill the final image. We are taking very large images, so even cropping doesn't get them to 320x240.

After cropping I click image, Resize. I set the Resize to 320x240, my resolution to 180, and check the box to resample using smart size.

At this point if it looks like I need to adjust the brightness/contrast I click adjust on my toolbar, brightness and contrast, levels.

It then shows me my input and output levels and I can adjust the low tones, mid tones or light tones independently. Here is a before and after of a kunzite that would not photograph on clear or white, but looks perfect on black.

I did need to adjust the brightness and contrast levels for the stone to look like it does in person.

Jamey, I am not familiar with curves. We are also finding that we get better images with white balance on grey than we did with white or the coffee filter. Any ideas?

[Stuart Wheeler]

Here is the link to the Opal Photograpghy guide i did a while ago. A lot of people have found it very helpful so far.

http://www.opulentopals.co.uk/articles.htm

Stuart

[Jamey S.]

Gray card will always give good WB, but the coffee filter over the lens should as well as long as you are not letting any stray light get in. I rubber band mine stretched over the lens to prevent this, otherwise your wb will be off. They also make slip on caps now that use the same principle as the coffee filter, like $8 shipped on Fleabay.

The only thing I can think of is you don't have it tight enough and/or stray light is getting in when set the WB.

One thing you should also do after downsizing your images is a local contrast enhancement. No matter which algorithm you use to perform the downsizing, the local contrast gets lost because of it, not all of it, just some of it. Many times this is perceived as a lack of sharpness or lack of "punch", or lack of duller colors. The human eye perceives many others things as sharpness aside from just normal sharpness. Even a clarifying USM can work as well to bring everything back as long as done one a separate layer so that one can lower the opacity of that layer(in turn lowering the effect) to bring it down to a level of correction of the image vs. adding to the image.

Also, here are some cheaper gray cards that ship faster typically as well.
http://cgi.ebay.com/Canon-18-Gray-Ca...3%3A2|294%3A50
http://cgi.ebay.com/DIGITAL-POCKET-P...3%3A1|294%3A50

[Crystal Star]

Thanks for all the tips, y'all. I need all the help I can get.

Jamey, the first link to the Canon dealer offers a really nice set, but my question is, would reading a book written for a Canon be of much help if you're shooting with another brand, like me using the Olympus C-750 UltraZoom? I'm sure there are correlations, but an Olympus dealer selling something like this would be better for me, or not?

[Jamey S.]

The Canon set I wasn't worried about the book, just the price for the card itself, hehe.

But, the book prolly would help, it all depends. Setting a custom WB is very similar between all makes/models of cameras.

[Jamey S.]

FYI, anyone looking for the ultimate gemstone photography set should check out this auction!!!
http://cgi.ebay.com/Raynox-Video-Mic...%3A1|294%3A200

This kit is the same one shown here:
http://www.rockhounds.com/rockshop/raynox.shtml

This is in essence the same set I use for my microscope shots when I don't feel like using the microscope! The only difference is I made mine from buying the pieces separately, lol, would have been cheaper this way!! The stand is basically a backlit copy stand, works very nicely as you can get light from under the piece as well as from on top with your normal diffused lighting. This is the exact setup I used to take these shots of a tiny little crystal on a silicon carbide crystal spray (the entire spray is only like 2-3mm in length).



If the filter thread size on your camera doesn't match what comes with the kit you can buy an adapter that fits from like 43 to 67mm filter thread sizes.