Gemstone Trials

Gemstone Trial

Whilst visiting Stump Cross Caverns I was passing through the gift shop and the small gemstone bags that are often on sale at such places caught my eye. Taking a bag and two small lumps of amethyst I set off home to try out shooting some gemstones with my macro!

All shots taken with:
Cannon ESO 400D
Sigma 150mm f2.8 Macro lens
Speedlite 580M2 + diffuser (its still the toilet paper idea!)
Tripod 055XPROB + 322RC2

For exif data save and review properties of the thumbnail version only – exif not attached to larger versions of shots.

To take these shots I did the following:

1) I set my stones on top of a white sheet which was placed on a window ledge with the sun coming through the windows. I used this to provide a light source from behind my stones

2) I set the tripod and camera up facing the stones – I went for a mostly straight on to slightly above angle for these shots.

3) For these shots I decided to shoot at full, and proper, macro – 1:1 ratio. This meant also using a focusing rail as well between camera and tripod head. This allowed me to move the camera back and forth to bring the stone into focus each time as for full macro the focus must remain fixed.

4) For settings I was fairly free setting as this is the first time I have done such shots. I tended to stick to wide apertures as a rule (f13 and f16) so as to get a good depth of field in the shots. I also used mirror lock up and the camera timer (no camera remote) to reduce and shake on part of actually taking the shot.

5) I also used the preflash to get the flash to auto set itself – as I had done in the cave.

The Results

f13, ISO 100, 1/20sec no flash
A test shot in manual mode – I rather like the effect, though a little dark it does show up the details sharp and clear.

f13, ISO 100, 1/30sec, flash fired – shot in aperture priority mode
A second shot, this time in aperture priority mode, the flash this time adding to the effect of the shot.

f13, ISO 100, 1/10sec, no flash, aperture priority mode
A third shot – this time testing out the auto shutter speed settings without the flash. The shot came out well – without the slight darkness of my first and without the rather harsher light of the second.

f13, ISO 100, 1/50sec, no flash, aperture priority mode
A shot where I was fairly sure of what I wanted the effect to be – that of a bright stone with a darker background – hence the faster shutter speed. This worked well and there is only a little boost to the blacks in processing the RAW shot, but not quite as dark as I was after.

f13, ISO 100, 1/40sec, no flash, aperture priority mode
A shot highlighting (very well) why I really should keep a diary of what conditions were at the time of shooting (its all so easy to forget little details that go into making a shot and hoping that EXIF will record all that you need). This shot was a darker background than before despite the slower shutter speed – this is as a result of a cloud that blocked the sun at around this time. This meant less light was needed (I had set exposure compensation to a lower value to boost the darker areas to get the effect I was after) to get the lower exposure value.
All in all a shot I am very pleased with in result – a boost to the blacks to get them really black, as opposed to darker brown, and the shot was done.

f13, ISO 100, 1/6sec, flash fired, aperture priority mode
Back to shooting brighter shots this was with flash (and no cloud) though the sun was getting lower in the sky, but still bright. This and the next few shots were taken under the same settings as I was now shooting to a different style – highkey rather than the lowkey of before. All in all I am pleased with the set, though I can see times when either flash or the window have lead to overexposed sections – something that softer light and a thicker bit of toilet paper would have been handy to help solve.

f13, ISO 100, 1/4sec, flash fired, aperture priority mode

f13, ISO 100, 1/4sec, flash fired, aperture priority mode

f13, ISO 100, 1.3sec, flash fired, aperture priority mode
Possibly my favourite shot of the gemstones – a very interesting and detailed stone to photograph.

f13, ISO 100, 30sec, flash fired, aperture priority mode
A shot taken later in the evening when it was darker – lights in the room off and the light from the window now reduced – hence the longer shutter speed selected by the camera.

And there ends the gemstones – overall I was very pleased with the results for a first time shooting such subjects and defiantly something that I will repeat.

Lessons Learnt:

1) A wider aperture – I suspect f16 – would be of use for the larger stones, such as the amethysts to get more of the stone in focus

2) Ambient light from the window worked well for this series of shots – though it might work better if the sun is not directly shining through the window – something to experiment with for the more highkey shots to prevent overexposed sections

3) Write a diary when shooting – possibly the most important lesson taken away from this shoot!


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