Gemstone Photography - Technical Topic

Thought I should start a post for technical information or questions relating to gemstone photography.

First up....

I currently have the stock-standard 18 - 55mm lense ....for whatever that means. From my limited use, it obviously has a minimum focal length and enables a certain amount of functional zoom and when combined with the megapixel rating of my camera should be able to take a reasonable photo of a gemstone. I have maxed out the zoom amd minimised the distance betweeen the gemstone and the camera but am thinking ..... does a specific lense have a sweet spot or is it better to back it off a bit and crop/zoom my photo using a RAW capture mode ?

Could someone please educate me on lense size terminology, optimising the use of a specific lense and how to select a good macro lense for gemstone photography.

To answer that in the simplest fashion, it's function of the diagonal of the image plane inside the camera. This then illustrates how wide the image the lens can capture, 18mm is wide angle (depending on the imager), 55mm always used to be considered close to a standard lens in 35mm film days. In digital cameras the imager size is all important.



To put a specific size on these a full frame 35mm measures 36 x 24mm, lens focal lengths are based on the diagonal, so the diagonal of the 35mm full frame is 43mm which is why the 50mm lens is considered a 'standard lens', it's close to a 1:1 ratio.

My camera is a 4/3rds and is one in the M4/3 range of cameras, they have a universal mounting system for lenses which opens out a heap of options with different brands, prices and qualities.

For macro work see if you can get an extension tube, they are a cheap solution to creating a macro lens.

Moving on, so what's your 'standard lens'?

You have a Canon EOS 200d and this has an APSC sensor which is 22.3 x 14.9mm and 24.2mp, great resolution and can capture superb shots. What's your standard lens? Working on the diagonal your standard focal length is 27mm so the 18-55mm lens gives you a double width wide angle and a 2x telephoto which in the older times would be considered a 'Portrait Lens'

What happens when you have a play in the menu with the 'Aspect Ratio'?

Your full frame aspect ratio is 1:1.49, modern TVs have a 16:9 aspect ratio which is 1:1.77 so if you dial in 16:9, which a lot of people do, you are effectively cutting off the top and bottom of your imager and only using 22.3 x 12.6mm.

When photographing gems aspect ratio is irrelevant as you want to capture the best image with the biggest number of pixels for cropping later, so shooting in 16:9 is not the best idea.

It is always a great day when you learn something, thanks Dihuski.

Will look into extension tubes. The concept makes sense and savings advice is appreciated.

Great idea to start this topic Wally69. :Y:

My gem pictures have improved since using a reasonable camera. Still a leaps to learn.
Dihusky's comment about white balance inspired me to have a play last night instead of relying on auto. Gave me an opportunity to learn more about my camera.

Wally69 said:

I have maxed out the zoom amd minimised the distance betweeen the gemstone and the camera

Click to expand...

You may already know this but one has to be careful about minimizing the distance between the stone and the camera/lens as you may end up with too much reflection of the lens/camera showing in the stone which will show up as dark areas. Although it can be used to good affect also, by adding contrast in the stone between the black of the lens reflection and the colour of the stone.

Thus far on this topic no one has mentioned anything about post processing their images; a lot of the issues/problems mentioned here can be overcome with a few tweeks to say correct white balance,minor adjustments to exposure, improve detail in highlights, spot out dust and a few other adjustments as well to improve the final image. For those Canon users Canon's DPP (Digital Photo Professional) software is a good program to dip a toe into post processing and its free to canon camera owners, if you're inclined to spend a few dollars Adobe's Lightroom is a great program and one I've been using for years and it's quite easy to get up to speed with; Adobe also have a good range of video tutorials on how to get the best from Lightroom
Just though this subject might add another dimension to this interesting topic on photography.
Cheers, SinHof.

Wally you can also get Magnifying Filters ( not sure on the name) but basically you attach them to the front of your existing lens. It might be a cheaper alternative to extension tubes or a specific Macro Lens which can go into many $100s of dollars.
Mackka
Love this thread

I hear what you say SinHof and I agree that Post software can be a useful tool, but it should be a last resort and never be used as an excuse for bad photography.

Personally I feel people should understand a bit about cameras and develop the skills to take a good photograph which might only need minor tweaks in post, not massive corrections.

Good photography is becoming a dying art because of digital imaging, yet Canon for one recognise the art of photography and have an international competition for un-edited digital photography.

I come from the days pre-digital, shooting 35mm, 70mm, 4x5 & occasionally 10x8, we learn't about cameras, perspective, framing, light, response of film emulsions and the list goes on, film was expensive so we 'composed' our pictures. If I can pass on a few of those old school skills and help retain the 'art' of 'painting with light' I think that's worth while.

To give you an example, the shot below is an original piece of 4x5 film that I have hung onto for many years. It was a shot for Philips in around 1986 and everything was done 'in camera', no editing at all. I've just grabbed this sheet of film, stuck it to a white computer screen and re-photographed it then cropped around the outside, nothing else. This is what 'Photography' or 'to paint with light' used to be. Too many of today's photos are basically lies and misrepresentations and gem photography should be about truth.

Evening Dihusky,
It seems we have a similar background in photography going back to the good old days of film and certainly agree with the comments you made about post processing of digital images. I should have said "slight tweaks" in my post. There is no risk that countless hours working with large format cameras, 4x5 inch format in my case teaches you a lot. I have two LF cameras that still see some use, a Sinar monorail for studio work and a Linhof flatbed for field/landscape work; as an aside, there is a clue there to the origins of my user name. The digital world has certainly opened up photography to the masses, one only has to observe the photographic activity at weddings these days as an example.
This topic will no doubt be of interest to a good number of PA members, not just the macro aspect of photography but also making interesting images of other finds that folk here unearth.
Looking forward to further posts on this subject, SinHof.

Most cameras have a depth (DOF) preview button on them. Very handy.

Also, just go with a prime 50mm lense - F stop 1.4. use a tripod and available light, or a back lit situation on blotting paper. see what F stop 22 looks like.

There will be 50% less depth of field in front of the subject, so use a pencil and put a dot an inch in front of your subject

Then, have a play Wally69.

Hi SinHof, yep very similar backgrounds, had 'Blads, a P1 and a Toyoview, specialised in studio and architecture. The price of film and processing forced one to study ones image before hitting the button!

Nowadays almost unlimited storage on a camera is great but I thing it makes people a bit lazy and not work at getting a great shot, hit the button and hope for the best.

Where this group is concerned though it's different, they want to get a few good shots so are putting a lot of effort in to achieve this which I for one :clap: :clap: :clap: and hopefully we can help, tricky as one's not looking over their shoulder, but let's see how we go.

Looking forward to your input and help. :Y:

It's all about capturing small stuff.

There are basically three options for getting your camera to naturally capture small stuff, these are:

1. Dedicated Macro lenses; This is the most expensive option and with many of the modern lenses you can go very small indeed.
2. Extension tubes; This is a really good, economic option as they often come in sets of two or three and you can stack them together to capture smaller items. One big advantage is they are a simple tube internally, no lenses to get in the way, so you retain the original optical qualities of the lens you are using. If you have a macro lens these can be used to take you into the 'Micro' world.
3. Macro filters; These add to the front of your lens and unless you buy a very high quality one, can have a significant influence on the original optics of the lens they are attached to. They come in filter thread sizes and magnification factors so are not optically matched to your specific lens. Companies like Canon do have them but they tend to be optically matched for the longer focal length lenses, the 500D close-up Filter is for lenses 70-300mm for example.

Personally I would go for Extension tubes if I didn't have a dedicated macro lens.

Dihusky said:

2. Extension tubes; This is a really good, economic option as they often come in sets of two or three and you can stack them together to capture smaller items. One big advantage is they are a simple tube internally, no lenses to get in the way, so you retain the original optical qualities of the lens you are using. If you have a macro lens these can be used to take you into the 'Micro' world.

Click to expand...

This sounds like fun. This will probably help me try to get an image of inclusions inside some of the stones I've been playing with. Although ideally I probably should use a microscope. :/

Anyway ordered a set. I did see there was a huge difference in prices so did a bit of research. Ended up opting for a pair of JJC extension tubes which seemed to be the cheapest with quite good reviews.
Anything cheaper seemed to be very unreliable/useless.

Mr Magoo said:

Dihusky said:

2. Extension tubes; This is a really good, economic option as they often come in sets of two or three and you can stack them together to capture smaller items. One big advantage is they are a simple tube internally, no lenses to get in the way, so you retain the original optical qualities of the lens you are using. If you have a macro lens these can be used to take you into the 'Micro' world.

Click to expand...

This sounds like fun. This will probably help me try to get an image of inclusions inside some of the stones I've been playing with. Although ideally I probably should use a microscope. :/

Anyway ordered a set. I did see there was a huge difference in prices so did a bit of research. Ended up opting for a pair of JJC extension tubes which seemed to be the cheapest with quite good reviews.
Anything cheaper seemed to be very unreliable/useless.

Click to expand...

That's terrific, basically extension tubes only need the contacts to link the camera to the lens and a good mounting, so they don't have to be 'brand name', there's plenty of good, inexpensive ones around. Looking forward to hearing how they go. :Y:

Thanks for the education and suggestions

I am also waiting on delivery of a set of extension tubes. Added a lense cleaning kit to my purchase as well, bloody hound decided to stick her nose into it and see what all the fuss was about :bomb: :argh: 8.( :argh:

Wally69 said:

Thanks for the education and suggestions

I am also waiting on delivery of a set of extension tubes. Added a lense cleaning kit to my purchase as well, bloody hound decided to stick her nose into it and see what all the fuss was about :bomb: :argh: 8.( :argh:

Click to expand...

I fitted a Hoya UV filter to my lens just for the added protection. Clean it when required, bin it if it gets damaged...

Hi Folks,
Spent a bit of time today playing with some gear to have a crack at photographing a borrowed stone from my neighbour who is an avid faceter and he has asked on a few occasions if I could photograph some of his cut stones. I wanted to try controlling the camera via my laptop to better visualise the critical focus to optimise depth of field on the larger screen. First problem was I could not get the laptop software to recognise my aging Canon EOS20D with the EFS 60mm 2.8 macro lens, bugger.
The only other option was to use the Canon EOS 5D2 FF and an EF 24/70 2.8L 2 lens, not an ideal choice for macro work, however this combo worked well linked to the laptop and setting the focus was much easier than with the small screen on the camera which was the first aspect that I wanted to experiment with. Lighting was a flash unit mounted underneath the white styrene base and sheet of white paper the stone was sitting on, the stone was surrounded by an aluminium foil reflector and a white styrene reflector held over the top to bounce diffuse light onto the to of the stone. Today's effort was to see if this type of approach to macro work is worth pursuing and while it's work in progress and with a dedicated macro lens there is some merit in the concept.
Here's a couple of rough shots with the phone camera of the set-up and a heavily cropped shot of the stone in post and a few minor tweaks to the original RAW file.



Still plenty of room for improvement here at this point, just have to put in more time to try different approaches to lighting and backgrounds with different stones, bound to be a fun/frustrating learning curve going forward.
Cheers, SinHof.

Interesting setup :Y: , certainly worth working with, but I think it might be a bit beyond a few of the gang . Got some tabletop ideas I'm working on, just got to set them up on the weekend once I get the family Christmas lunch out of the way. Want to see how they go and add the setup development and image results as it progresses.

Good to see the experts dipping their toes :clap:

Watching with great interest.

HI Dihusky,
Have all this gear sitting around and have not used it for ages, this project was a chance to have a play with some of it with a view to coming up with layout that could be used for a range of stones including opals, work in progress. Working with the laptop should be OK for any of the folk here, given they have some reasonably current camera gear and software to get the two talking to each other, they should be up and running after a little practice. Look forward to see what you come up with.
Cheers, SinHof.