Stones I have cut

[Mackka]

If the camera has it use Mirror Lock.
Mackka

 

[Mr Magoo]

Looking at the first shot Lefty, the colour has been altered by the lighting and in this case it has worked, the give away is the colour of the foam behind the stone, outdoor white balance and indoor shot with incandescent light, the second shot has the right white balance as the foam is white, as for the true colour of the stone, that's a tough one as stones absorb different wavelengths of light and by refracting can alter the perceived colours.

Add to this our eyes automatically adjust to millions of different points of light to balance what we see, a camera can't do this, it sees light over a defined range.

The second shot is damn good as everything is crisp and sharp and the colours, though incorrect to you are true to the camera.

I sketched up a quick diagram which might help a few folks, its about interpreting Depth of Field, which is the distance over which a lens can focus.

https://www.prospectingaustralia.com/forum/img/member-images/10304/1543386328_dof_chart.jpg

This might be of more benefit to Pat as his shots are all 'soft'.

What the chart shows is the relation ship between the lens iris opening, shutter speed and the depth of field, I used to use this to explain this to students many years ago and often saw that 'caa ching' moment as the 'penny dropped'

In this chart the overall exposure doesn't change, only the depth of field and this is how you can control it, particularly important when using macro lenses which have a notoriously shallow depth of field.

One thing it says loud and clear is how handy a tripod is for a good depth of field because the iris in the lens is going to be small and the shutter speed slow so camera shake becomes a big factor or you have to add a heap more light.

One trick is using multiple exposures, hold steady and rattle off a bunch of shots using the multiple exposure setting, one might be nice and sharp.

If you want to get the maximum amount of light available, sunlight can be turned into soft light by adding a sheet of greaseproof (baking) paper between the sun and the stone.

Another trick is changing the ISO, if the ISO is on 200 and you shutter is say 1/8th by going to 1600 ISO your shutter will change to 1/60th without changing the aperture so you've lessened the camera shake problem with a faster shutter speed.

Each time you change the aperture or shutter by one setting you are either 1/2ing or doubling the amount of light entering the camera.

Hope I haven't confused too many

Some great info there Dihusky. :Y:
I'm using a Olympus PEN E-P2 which is a mirror-less camera using the micro four thirds lens system. The lens I am using is a 60mm macro which I think is the same as 120 mm (35 mm equiv).
I'll be studying your posts carefully as I'm have quite a few issues. Focus is one. I think it may partly be because I'm using a crappy tripod (Slik 650) which shakes as I try to manual focus (trying to capture a weird inclusion in a half cut Topaz). I use the timer to minimize shake when taking the shot but I think the focus is already out as once I connect to the lappy it's not that sharp in the blown up image. I'm also wondering if long exposure from poor lighting is not helping. :/
Looking at getting another camera so I can see a larger image on a pc screen and can remotely change the focus and shoot remotely. The Olympus OM-D E-M1 would do this and also give an in camera focus stacking option. :money:

But I thinking reading your tips and pointers may set me in the right direction and save me some coin.

 

[MegsyB007]

I think you guys should start a new thread about how to get the best pics out of your camera! Very informative - but a bit off topic here...

 

[Lefty]

The funny thing about faceting is, it appears to be gaining a following and so many people want stones cut buy local facetors. I now have 2 jewellers who want stuff done now. How are you other blokes poised for cutting for a fee?

Absolutely! My mate is a manufacturing jeweller and we have a bit of a thing going. Us local Aussie cutters may not be able to compete on price with countries where stones are cut for not much more than a bowl of rice a day, and one Australian dollar buys about ten thousand of the local dollar equivalents - but I say that our work is superior. That's not to say that a cutter in one of those places could not deliver a high standard with some decent equipment, it's just that they are under pressure to simply churn stones out as fast as possible and quality is very much a secondary consideration. Cutting stones overseas may be cheap but the quality is often not there (Lamberts can be ok) and tends to lack imagination - you tend to get back an endless stream of round and oval brilliants and a few other designs, things that are fast and easy to pump out, factory production line style.

When earth treasures become nothing more than widgets to rip through and spit out as fast as absolutely possible, there's no love in the work. I treat every stone as an individual and strive to get the best out of it (whether I can photgraph that successfully or not). We are craftsmen, not factory line packagers.

 

[Lefty]

*Craftspersons

 

[Dihusky]

Wally69 has just started a photography topic, and I've answered his first question which may help a few folks understand some basic info about lenses.

https://www.prospectingaustralia.com/forum/viewtopic.php?id=28731

Pat I have a GH4 which is also an M4/3 camera, love them, my photos are taken with the 60mm macro, it's a superb piece of Olympus Optics and Olympus make some of the best, particularly in the scientific area.

 

[Lefty]

Here's a pretty one! A 5.6 carat garnet with a strong colour-shift property. Bright purple in natural daylight, bright red with pinkish-purple tinges under incandescent bulb and maroon toned under fluorescent.

Natural daylight (overcast)

Incandescent bulb

 

[Pat Hogen]

Really nice colour alteration, would have been easier to swallow if the tone under fluorescent was BLUE

I want to send you a special diagram for garnet, only if you have a 72 index wheel.

 

[Lefty]

I would like a blue garnet!! Bloody rare as hens teeth!

Cheers Pat, but I only have a 96 and an 80.

 

[Mr Magoo]

Fantastic colour Lefty. The last garnet I cut was also a colour shift but not as beautiful as that. Reddy Orange to tan malaia garnet.
Funny though, this time the camera doesn't want to see it.

What type of garnet is it, do you know?

 

[Lefty]

Cheers MM, acquired the rough from Glen Huntly about 6 months ago, they were labled but Glen didn't write it on tbe bag, just the carat weight and price per carat. I recall that it originates from Africa but not sure about other specifics.

Amazing colour, had me looking closely for natural features. But yes, it contains irregularly distributed groupings of the tiny "three-directional" crystals Ive seen at tbe loupe level in nearly all other garnets I've ever cut.

 

[MegsyB007]

Well I've just learnt something today - I didn't know garnets could be blue! Huh!

That's yet another very lovely gem Lefty! :Y:

 

[Lefty]

Thanks Megsy

Yes, like sapphires they come in a wide range of colours and hues. Some shade of red is the most common colour but they can be most colours. Blue ones are incredibly rare, I think a few were found about 5 years ago in the Ural mountains in Russia.

 

[LONEWOLF]

A beautiful Stone there Lefty..... Well cut too. erfect: .. You know I love Garnets... :heart: I never knew Garnets came in Blue... I will have to have a Google on them...
Hope the Fires weren't too close to you... I saw Lowmead was threatened....

LW...

 

[Wally69]

Nice clarity for a chunky garnet there Lefty

Incidentally, I had a half cut one fly off the dop last week, still havent found the darn thing......it has turned me blue.

 

[Pat Hogen]

Seriously, fellas, I wouldn't get too wound up in the blue garnet interpretation.

When Lefty said "maroon - toned under fluorescent" I tendered that it would be preferable to be blue - toned under fluorescent, because qld is maroons and nsw is blue - yeh?

Oh well, lead balloon territory!

But with regards to quality garnets, Lawrie and Yolanda Berthelsen in Townsville sell very good quality raspberry garnet on ebay and is highly respectable and genuine. He will accept returns if not satisfied and will answer all questions honestly.

 

[Lefty]

Seriously, fellas, I wouldn't get too wound up in the blue garnet interpretation.

When Lefty said "maroon - toned under fluorescent" I tendered that it would be preferable to be blue - toned under fluorescent, because qld is maroons and nsw is blue - yeh?

You know us fossickers is slow to catch on Pat :lol:

But with regards to quality garnets, Lawrie and Yolanda Berthelsen in Townsville sell very good quality raspberry garnet on ebay and is highly respectable and genuine. He will accept returns if not satisfied and will answer all questions honestly.

Good to know, thanks - are they Fullarton river stones?

 

[Lefty]

A beautiful Stone there Lefty..... Well cut too. erfect: .. You know I love Garnets... :heart: I never knew Garnets came in Blue... I will have to have a Google on them...
Hope the Fires weren't too close to you... I saw Lowmead was threatened....

LW...

Cheers LW - yes, the fires went through the Lowmead area but I don't know how much countryside was actually burned. I know a bloke who lives there and last I heard he was ok. I think they stopped it reaching the little township.

 

[Lefty]

Nice clarity for a chunky garnet there Lefty

Incidentally, I had a half cut one fly off the dop last week, still havent found the darn thing......it has turned me blue.

Cheers Wally

Nothing makes you bluer than a stone coming off the dop.

Except maybe when you offer this stone for sale on a facebook sales group and somebody makes a comment suggesting they think it is fake/synthetic But he deleted it again after about a minute - which is about how long it takes to use the internet to educate yourself about the existence of real, naturally - occurring colour-shift gemstones :lol:

 

[Lefty]

After a bit of a hiatus, it's time to get back to faceting! Here's a nice little honey-coloured Rubyvale zircon, finished at a little under 2 carats. It has a slight silky have but not enough to detract from it.