What causes the "crushed ice" look?

[Rockdiamond]

Hi everyone,
there have been a few recent discussions about photographing diamonds- and focus .
I was thinking about this and realized that the photos actually show something that can help explain why some diamonds show their facets well- while others exhibit the dazzling pinfire flashes called "crushed ice"



the photos are both the same stone, taken under very similar lighting and photographic conditions.
In the photo on the right, the camera is actually focused on the "skin" of the diamond- which allows us to clearly see the facet pattern.
Yet in person, this stone has a "crushed ice" appearance.
In the photo ohn the left, the camera is focused deeper into the diamond- more closely replicating what our eyes do. Once we focus further into the diaomond, the "virtual facets" take over- obscuring the possiblity of seeing the facet pattern.

Cameras can define focus more than the human eye- especially since the reuslt is a static photograph.
The human eye does not have such ability ( well some folks might) but in general when we look at such stones we can not define the facet pattern.

 

[antelope1]

That's really cool! Explains why some photos of "modified" cushions (which should look like crushed ice) don't look like crushed ice when you look at them online.

But -- I'm either dyslexic (quite possible) or I don't really understand what you mean by the "skin" of the diamond? Is the "skin" the table? Or the pavilion? Because as an amateur photographer, I would have thought that photographing a diamond is like taking a photo in a mirror. If the focal plane is on the surface of the mirror, the stuff in the mirror is fuzzy but the stuff on the mirror (e.g., dust or fingerprints) should be clear. So the focal plane for the diamond on the right should be in the pavilion or bisecting the girdle, and the focal plane of the photo on the left is parallel to the table. Maybe?

Any photographers out there have opinions on this?

 

[Rockdiamond]

Hi Antelope- great question!
What is the "skin" of a diamond?

When grading diamonds for clarity we look at the stone in many different perspectives.
One way is to look "into" the diamond, since inclusions are generally inside the stone.
Looking at the diamond, with a loupe we can move the focal point allowing us to focus on things inside the diamond. That would equate to the photo on the left.
but even if a diamond is clean inside, we still need to examine the surface. This is done by tilting the diamond so we can look at light reflected off the outside ( the skin) of the stone- thereby allowing us to find any surface inclusions, chips or abrasions present. This is how the camera is focused in the photo on the right.

 

[kenny]

IMHO the crushed ice look is the result of a cutting style with lots of facets in a pattern so dense with facets that they look almost random.

Photography, (both where you choose to focus the lens, and how deep the depth of focus is set with the f-stop) can make it look like crushed ice that is melting a bit so it's blury or hard frozen so the edges of every facet and virtual face from table to culet are razor sharp.

But overall to me the crushed ice look is more the result of the cut than the photography.

 

[Rockdiamond]

Great point Kenny- the look of the stone is based on the cutting- but I realized that this aspect allows photos to be used to demonstrate the look, to a degree.

 

[JulieN]

Both pictures are of crushed ice. The one on the left is melting crushed ice, and the one on the right is hard crushed ice.

 

[Rockdiamond]

Good point Julie- I chose those two photos mainly because both had a consistent position of stone in relation to the light and camera.
Here's a shot that has best focused on the skin of the stone- which is a problem for me, as even tiny bits of dust can easily be seen. That's a good way to show what I*'m talking about- the focus of this shot is precisely at the diamond's surface ( skin)

Here's an interesting thought- the skin is in perfect focus- how is the bottom of the stone in focus? What are we looking at when we see a diamond- how much skin, and how much from the inside?

I believe these elements are the characteristics that produce either an organized defined facet pattern- or a virtual cacophony of virtual facets- all reflecting off each other- and back to your eye

 

[yennyfire]

Hmmm, so if I understand you correctly Rock, what you're saying is that a stone that DOES have a crushed ice appearance in real life may not look that way in a photo depending on how it was taken? I guess that's the exact reason that the experts amongst you out there are always suggesting that there's no substitute for seeing a stone in person. Very helpful, thank you for taking the time to post the photos and explanation.

 

[clgwli]

Kenny are you speaking of depth of field and not depth of focus? F/stop relates to how much light is let in (aperture) and I guess I am not seeing what that has to do with just a focus. Sorry nitpicking here, just trying to understand what you were trying to say.

As for the stones, I do see the pinfire in both pictures as I have said in other threads. Then again I am looking at the shape and size of the fire in both photos. In the one where the camera is focused deeper into the stone it does look more like what I see when I am just kind of looking into my stone. I can actually see the facet structure of the bottom of the stone far more clear, but the rest of the stone is kind of out of focus.

The photo where I see the camera focused on the skin, I can more easily see the entire facet structure better. I do see the pinfire, but it is smaller and more in the "background" The very center of the stone doesn't look quite as in focus as the other does though which I find interesting.

I've been playing a lot since I received my beautiful bucket of crushed ice with my camera and I've noticed exactly as David has posted here. One thing I have noticed as I look through my photos, the f/stop and ISO remain the same but the shutter speed changes. The faster the shutter speed for me, the more mine look like the photo on the left. The slower shutter speeds the more like the ones on the right mine look. I think that part could also account for why the one on the left looks "brighter" than the one on the right. Because with a slower shutter speed more light is coming in as well.

I am not using tripods or fancy set ups with mine. Just real world lighting (no spot lighting ever in my photos) and my point and shoot (sadly my macro lens bit the dust years ago and I never replaced).

 

[kenny]

Kenny are you speaking of depth of field and not depth of focus? F/stop relates to how much light is let in (aperture) and I guess I am not seeing what that has to do with just a focus. .

There are two ways to control how much light gets in.
1. How long the shutter is open, aka shutter speed.
2. The size of the variable hole (aperture) in the lens.

# 2 also happens the have the effect of changing the depth of field (aka depth of focus).
The smaller the hole the deeper the area that is in focus, both in front of and behind the point that you focused on.

 

[clgwli]

Kenny are you speaking of depth of field and not depth of focus? F/stop relates to how much light is let in (aperture) and I guess I am not seeing what that has to do with just a focus. .

There are two ways to control how much light gets in.
1. How long the shutter is open, aka shutter speed.
2. The size of the variable hole (aperture) in the lens.

# 2 also happens the have the effect of changing the depth of field (aka depth of focus).
The smaller the hole the deeper the area that is in focus, both in front of and behind the point that you focused on.

Kenny I think I know a thing or two (or more) about photography as well I am well aware what both shutter speed and the f/stop levels do (and particularly how it affects appearance on close up shots). Hopefully I made that somewhat clear in my post explaining what I see when I take photos.

I seriously have never heard the term depth of focus. Not in any classes, from books or from pros I've talked with. Always depth of field or field of depth. That's why I was confused. ETA: I was thinking you were trying to talk about focal length and not entirely sure what that had to do with f/stop. I hope that makes sense.

 

[kenny]

Kenny are you speaking of depth of field and not depth of focus? F/stop relates to how much light is let in (aperture) and I guess I am not seeing what that has to do with just a focus. .

There are two ways to control how much light gets in.
1. How long the shutter is open, aka shutter speed.
2. The size of the variable hole (aperture) in the lens.

# 2 also happens the have the effect of changing the depth of field (aka depth of focus).
The smaller the hole the deeper the area that is in focus, both in front of and behind the point that you focused on.

Kenny I think I know a thing or two (or more) about photography as well I am well aware what both shutter speed and the f/stop levels do. Hopefully I made that somewhat clear in my post explaining what I see when I take photos.

I seriously have never heard the term depth of focus. Not in any classes, from books or from pros I've talked with. Always depth of field or field of depth. That's why I was confused.

I've heard depth of field and depth of focus both used to describe the same thing, the former being more common and the latter being more intuitive for people not versed in photography terms.

 

[clgwli]

Kenny are you speaking of depth of field and not depth of focus? F/stop relates to how much light is let in (aperture) and I guess I am not seeing what that has to do with just a focus. .

There are two ways to control how much light gets in.
1. How long the shutter is open, aka shutter speed.
2. The size of the variable hole (aperture) in the lens.

# 2 also happens the have the effect of changing the depth of field (aka depth of focus).
The smaller the hole the deeper the area that is in focus, both in front of and behind the point that you focused on.

Kenny I think I know a thing or two (or more) about photography as well I am well aware what both shutter speed and the f/stop levels do. Hopefully I made that somewhat clear in my post explaining what I see when I take photos.

I seriously have never heard the term depth of focus. Not in any classes, from books or from pros I've talked with. Always depth of field or field of depth. That's why I was confused.

I've heard depth of field and depth of focus both used to describe the same thing, the former being more common and the latter being more intuitive for people not versed in photography terms.

Crap I misread you there a minute ago so I totally edited in case you saw it. And I understand... just not a term that I had not heard before. Guess I talk to the right (or wrong) people

 

[kenny]

I just took two pics with the camera manually focused on the same point, the pear on the piano keyboard.

Notice the pear is in focus in both but on the left most of the keys are blurry.
In the right one more keys in front of and behind the pear are also in focus.

The right pic has greater depth of field.
This is the result of making the adjustable hole in the lens (the aperture) smaller.
Sure when the hole is smaller it lets less light in but the same amount of light got in on both pics because the camera is smart enough to leave the shutter open longer when a smaller aperture is used.

The only thing I changed was the aperture.
I did not touch the focus knob on the lens and this system does not have autofocus.
The right one required a shutter speed of several seconds so I had the camera on a tripod.

 

[yssie]

I just took two pics with the camera manually focused on the same point, the pear on the piano keyboard.

Notice in the left pic most keys are blurry?
In the right one more keys in front of and behind the pear are also in focus.

The right one has greater depth of field.
This is the result of making the hole in the lens (the aperture) smaller.
Sure when the hole is smaller it lets less light in but the same amount of light got in on both pics because the camera is smart enough to leave the shutter open longer when a smaller aperture is used.

The only thing I changed was the aperture.
I did not touch the focus knob on the lens and this system does not have autofocus.

Thats... a fantastic example, Kenny!

 

[Rockdiamond]

Wow, that's a beautiful photo Kenny.
Are you a piano player? I really got the feel of the keys in the photo of the right- like I could reach out and touch them

Were you using special lighting?

 

[clgwli]

I agree great example. Most of the photography I did had very small depth of field. I did a lot of floral photography so you can imagine why I would do it that way.

I do know that with a point and shoot though, things change differently than I would change them manually. I am sure that makes sense. I really cannot do anything with stones with what I currently own, so I am stuck using macro on my camera (ETA: I mean on my point and shoot... I cannot do anything with my DLSR). It seems with the point and shoots everything remains the same except shutter speed. And if not using a tripod it would absolutely make sense why my more focused ones have a faster shutter speed. In that respect a point and shoot is unique. I am getting shutter speeds of like 1/413 seconds instead of 1/400. I think you would understand what I am saying. Instead of steps of shutter speeds, I am getting more infinite ranges of speed. Kind of cool in that respect.

Some day I will get a macro lens again and play more with stones. But for now following around my son, the point and shoot is FAR better since it fits into my pocked and can record video

Oh and your piano looks gorgeous!!! I have one that my mom bought 2nd hand for us as kids. I love playing and so very glad now that my son wants me to play so he can dance. Before he would try to play with me (which is difficult to do to say the least LOL)

 

[kenny]

Wow, that's a beautiful photo Kenny.
Are you a piano player? I really got the feel of the keys in the photo of the right- like I could reach out and touch them

Were you using special lighting?

Thanks, yes I play classical.

No special lighting, in fact no artifical lighting at all. (Flash was used for the following pic obviously)
The only light source for the pear pics was this huge window, which shadowlessly illuminates the keyboard.

 

[clgwli]

Now I am jealous. To have that lighting on your keys from the window (which way does it face btw? I prefer South or East facing myself). And to have such a pretty grand (I assume) from that last photo.

ETA: did you just change photos while I posted? I loved the color shot even better.

 

[kenny]

Sorry I'm a notorious editor.
I never edit for deception, just what I think is more clarity.

Edit: The window faces East so I have heavy drapes protecting the piano from morning sun.

 

[kelpie]

Interesting...

Can you explain why fancy diamonds are so often cut in this style? I figured the busyness of the facets must add the illusion of intensity to the color. I wish there were more fancy colored diamonds in the more traditional (non modified?) facet patterns. My only fancy is a copper pink radiant, which is a pretty unusual cut to see on the street and yet the majority of fancies for sale seem to be radiants or modified cushions, or even if they're in a different shape they still give me the impression of a lot more facets than I'd see in the typical white diamond in that shape.

 

[kenny]

Interesting...

Can you explain why fancy diamonds are so often cut in this style? I figured the busyness of the facets must add the illusion of intensity to the color. I wish there were more fancy colored diamonds in the more traditional (non modified?) facet patterns. My only fancy is a copper pink radiant, which is a pretty unusual cut to see on the street and yet the majority of fancies for sale seem to be radiants or modified cushions.

Naturally-colored diamonds are frequently cut in radiants and other cuts that keep the light bouncing around in the stone several times before finally coming out the top.
The more times it travels through the colored material the more body color the light picks up and the higher color grade it may get - raising the price.

Cuts like round, emerald and asscher let the light out after fewer trips through the diamond so you see fewer of those with colored diamonds.

 

[clgwli]

Sorry I'm a notorious editor.
I never edit for deception, just what I think is more clarity.

Edit: The window faces East so I have heavy drapes protecting the piano from morning sun.

Eh so am I. I totally understand. I re-read what I write and think that it isn't clear. Only once in a while do I edit when I realize I read something wrong (which isn't totally uncommon for this dyslexic chick who loves built in spell checks on browsers now)

I would imagine you'd want to protect that beautiful finish on the piano with the drapes. I love playing and reading in the sun (we have a wonderful picture window facing south that I enjoy in the afternoon while my son naps) but I know it wouldn't do well for that piano. Mine is significantly more beat up, but it has great memories since it is the one I learned to play on. I still appreciate a beautiful looking piano though. Maybe when I am ready to pass this one on to my son, I'll buy myself a nice one! In the mean time a beautiful finish on a piano is probably a bad idea in this house.

 

[kenny]

Maybe when I am ready to pass this one on to my son, I'll buy myself a nice one! In the mean time a beautiful finish on a piano is probably a bad idea in this house.

clgwi you should buy a book.
The Piano Book, Buying and Owning a New or Used Piano, by Larry Fine.

Best $20 a piano shopper can spend.
If you think buying a diamond is a minefield buying a piano used OR new is even worse.
This book will REALLY help.

Many diamond sellers hate PS because it educates customers.
Likewise many piano sellers hate The Piano Book.

RD, sorry for the threadjack.

 

[Rockdiamond]

Interesting...

Can you explain why fancy diamonds are so often cut in this style? I figured the busyness of the facets must add the illusion of intensity to the color. I wish there were more fancy colored diamonds in the more traditional (non modified?) facet patterns. My only fancy is a copper pink radiant, which is a pretty unusual cut to see on the street and yet the majority of fancies for sale seem to be radiants or modified cushions, or even if they're in a different shape they still give me the impression of a lot more facets than I'd see in the typical white diamond in that shape.

That is a great question- and there's no simple answer.
Kind of like photography, diamond cutting is an art. Since the medium is so very costly, results are judged not only for beauty- but for return on investment.
Like photograhy, different methods are used based on the natural material
I've seen some cutters really improve over time in fancy colors.
It's a different mentality as compared to cutting colorless.

One reason Radiant and Cushion are preferred is that the nature of the cut allows a far wider variety of facet shape, and placement. Both are already "modified " brilliant, so cutters have a lot more freedom
There can be a lot of advantages to this, as compared to a round, for example- where the cutter's hands are basically tied, in terms of design.
Not simply weight and color retention, but also cutting to eliminate existing imperfection in the rough.
For this reason larger sized step cut, and round brilliant diamonds of fancy colors are far more rare.

No problem on the tj Kenny - we need to start a musicians thread over in Hangout.....

 

[Karl_K]

If I may...
This is the way I was taught:
The depth of field is how much is in focus.
The focus depth is how far into the scene(diamond in this case) the focus point is.
So you can get those 2 pictures that David posted above with the same DOF but a different focus depth.
Shallow Focus depth with a shallow DOF is used to create beauty shots of diamonds that can hide many flaws.

 

[ChunkyCushionLover]

Focus = Where in the image is the sharpest (Ie Front, Middle or Back).
Depth of Field = How much of the image is sharp (Only The Back, Back and Middle, or Front Middle and Back)

Kenny posted one of the most classical examples from Photography 101. Here is another one, the flower has the same focus, same lense, lighting, ISO and camera in both shots.



This is all fine for a basic photography lesson but none of this is telling the story about the source of crushed ice or small virtual facets.
The camera doesn't light the diamond, doesn't control which areas are lit or by what relative intensity. This is controlled by the lighting and the proportions of the diamond.

 

[Rockdiamond]

What the camera does is freeze an instant in time.
I don't use a tripod, so I can't have the shutter open very long- not that I manually control shutter speed or aperture with my camera.
The point is that the camera can focus in ways we can't. Producing photos showing the facet patterns on diamonds that have the type of cut where you can't see the facet patterns.

This is also true with a loupe- which allows infinite depth of field adjustment. Loupe the diamond, see the facets.
Hold it 12-18 inches form your face- crushed ice.

 

[clgwli]

I admit I love this discussion here as to different ways to get certain looks in pictures. I don't think much about it with my point & shoot but I sure as heck do when I use my DSLR.

Most of the photography I did was along the lines of the f/5.6 example that CCL posted. obviously when I did family shots the depth of field would be totally different since I would want it larger. I might look through my lenses again to see if I can play and have some fun taking photos. I am not sure I will be able to focus enough on the stones though. Cameras definitely do get images that our eyes can't always see!

And Kenny thanks for the recommendation. I'll add that to my list to read!

 

[Rockdiamond]

Here's a question for Kenny- or anyone else who has a thought on this....
Which of the two Pear/Piano photos more closely approximates what our eyes actually see?