Post by 150FromFundy on Feb 28, 2014 18:12:06 GMT -5
It’s hard to believe that I’m still posting pictures of minerals from the Princess Pat Mine. Unfortunately, every medium FRB must come to an end. rockncajun managed to stuff about 19.8 lbs. into a 20 lbs. box. Obviously, a clever and dedicated individual. Many thanks!
As promised in previous posts, I wanted to rant on about some “Tips and Tricks” for photographing fluorescent minerals under UV light. One of the many blogs that I researched said … “It’s simple. You just employ basic photography techniques.” Huh!
If you are a photographer, this post is not for you. If you are like me, and simply have a desire to take somewhat better UV pictures, please read on.
The first thing you must realize is that photographing a glowing UV mineral is a little like photographing a dimly lit coloured light bulb, or bulbs in an environment completely devoid of any other light. You are pushing the limits of the camera’s abilities. You need to understand, or be willing to learn about the features of your camera and how to adjust them if you want to get beyond the grainy and blurry images that your camera’s Auto mode will likely offer up.
CAMERA SETTINGS
This is assuming you have a digital SLR camera, or a “Point and Shoot” that offers SLR-like features.
[ISO] Set your camera for the lowest ISO possible. An ISO 100 is good, but many cameras will now let you go down to 64, or 50.
[Image Size] Set your camera for the maximum image size possible. 8, 10 and 12 Mega-pixels work well. If you have more, that is better. If you have less, maximize what you have.
[Image Quality] Set your camera for “Fine”, or the highest resolution possible.
If your camera offers a “Chrome”, or colour enhanced mode, use it to capture the vivid fluorescent colours.
[White Balance] Set the white balance to “Manual” and go through the adjustment procedure under white light on white paper to “calibrate” your camera’s colour balance.
[Sharpness] Set to “Hard”, or the “sharpest” setting your camera has to offer. This will minimize the blur effect from the long exposure times that we will get to.
[Photometry] Set your camera for “Spot Metering”. When your camera measures light, you want it to focus on the glowing rock, and not average the overall light.
[AF Mode] Turn auto-focus “Off”, if you can and focus manually.
If you can’t turn auto-focus off, set your camera for “Center”. When your camera measures distance, you want it to focus on the glowing rock, and not average things out. Auto-Focus is a problem to be discussed later on.
[Face Recognition] Set this to “Off” if it is a feature of your camera.
[EV Steps] Most defaults are +/- 1/3. You may want to increase this to +/- 2/3, or +/-1. You will need to vary this if it is an option for you to do so.
[Flash] Set the flash to “Off”.
[Custom Settings] If you camera allows you to save your custom settings, do so now.
BASIC SETUP
[Dark Room] You need one. I use a windowless bathroom, close the door and use a draft-stop to block any light from coming under the door. A closet may also be an option. Tape the door gap, if you have to. You need to find, or make the darkest area possible. Unfortunately, your camera will find any stray light that you miss.
[Lens Filter] You may need one! Based on what I have read, some camera lenses may actually fluoresce themselves. If you have one of these, you can buy a UV filter.
[Tripod] You need one. You will be working with long exposure times and must eliminate any movement, or jiggle in order to capture sharp images.
[Self-Timer] You need to use it (along with the tripod) to eliminate any camera jitter as you depress the shutter button. A remote shutter button will also work.
[UV Light Source] You need one. Long wave is more affordable and safer. Short wave is more expensive, hazardous to your health (when misused), but a little more varied and vivid.
Typical photography UV lights are in the 8W, 10W, or 12W range, but they are expensive. I have been struggling by with a small hand held 4W, so it can be done. With low wattage (low lumens), your light source has to be very close to the mineral, but not so close that your light is in the image.
For best results, your UV source needs to be located behind the camera lens. You may see a problem emerging here. Light needs to be as close as possible. Camera can’t be too close. Light can’t be in image. Light needs to be behind camera. You will have to experiment here, which loosely translates to … I haven’t figured everything out yet.
[Light Box] You need one. Actually, you need a dark box. The box is not to control the light, but rather to control the backdrop of your photos. I made a simple open box (bottom, two sides and one end) from black foam-core board and duct tape from any craft shop.
[Dust Off] You need some! Actually any canned compressed air will do. Dust is your enemy as most dust/lint will fluoresce a brilliant blue-white under UV light. You need to blow your rock and your light box every time you change the rock. Don not “gobber blow”! Did I mention saliva can also be fluorescent. Things you learn the hard way!
[Clean Minerals] You need them! Remember, dust is your enemy as most dust/lint will fluoresce a brilliant blue-white under UV light. Wash your mineral specimens under running water and scrub them thoroughly with a soapy nylon brush. Allow your minerals to air dry in a clean environment. Don’t make the mistake of drying them with your favorite dish towel, or a paper towel. I mistakenly did this. I actually thought I had discovered a new UV asbestos fiber on my specimens until I clued in that it was fibres from the dish towel glowing brilliantly.
BASIC CAMERA MODE AND TECHNIQUE
[Mode] Set your camera mode to “Aperture Priority”, or to fully “Manual” mode. Most references that I have researched recommend Aperture Priority. In this mode, you set the aperture and let the camera pick the correct exposure time based on the available light. This is why [Photometry]=Center and [Auto Focus]=Center settings described above are important. Typical exposure times may be in the 8, 10, 12 second range, or longer depending what your camera picks. Experienced photographers that go with fully “Manual” mode may use exposure times of 45 seconds, or more.
[Macro] or [Super Macro] Set your camera to “Macro” or to “Super Macro” depending on your setup and focal length.
[Zoom] Zoom in on your glowing mineral in order to fill the frame. Use your lens zoom. Do not use your digital zoom. It’s all about preserving as much resolution as possible.
[Aperture] or [F-stop] Open up your aperture as wide as possible to gather as much light as possible. You need to experiment in the range of f4, f8, or f10.
[Ev] The default setting is probably Ev=0. You need to decrease Ev by a step, or two for photographing a bright object on a dark background. This is why [EV Steps]=+/- 1/3, 2/3 and 1 settings described above is important. You may need to increase the [Ev Steps] to gain a broader range of increment when you decrease Ev by a step, or two.
When you decrease Ev by a step, or two, you will notice that the focal length changes for without varying the aperture. This is where everything still gets blurry for me, so I won’t attempt to explain it.
PICK AN APERTURE, STEP DOWN THE Ev
What you need to do is pick an aperture setting and take a photo with Ev=0. Set Ev=-1/3 and take another photo. Set Ev=-2/3 and take another photo. Repeat until you are at the bottom end of your Ev step range.
Now pick another aperture and repeat the above, once again stepping down the Ev through its full range.
THE PROBLEM WITH AUTO FOCUS
When you are trying to focus with a given aperture and Ev setting, you may find that you do not get a focus lock, or you get a blur warning, or your camera simply flashes lights at you. Take the picture anyways, if the camera will allow you.
This is where you want to manually focus if your camera allows you to. There are many problems with Auto Focus when doing macro photography under low light conditions. Once again, this is where everything still gets blurry for me, so I won’t attempt to explain it.
The key is to experiment to determine what aperture setting and what Ev setting work for you, your camera, and your setup.
SEPARATING THE GOOD FROM THE BAD
Now that you have a number of photos of the same mineral with various Aperture and Ev settings, you need to figure out which is the best one.
In many photos, you may have no image at all. Sometimes what looks good on the LED display is not captured by the camera. Focus on the images that have captured the most light and delete the rest.
Your remaining images may look good from far, but be far from good. Use your photo viewer to magnify the image and pan around. Try a 1:1 magnification, and then really zoom in.
Check the boundary between fluorescent mineral and black background. If this edge is sharp and clean, you may have a keeper. If this edge is not sharp, it may be another delete. Check for edges between contrasting colours on the mineral. Once again, if the edges are sharp and clean, you may have a keeper. If these edges are not sharp, it may be another delete. Check for individual speckles on dark areas. You know what comes next. Keep, or delete!
When you narrow down to your best two or three photos, use your photo editor to crop and adjust the brightness only! Do not be tempted to adjust the pretty colours. Keep it real and authentic as possible. If possible, compare your image to the mineral under UV light and see if you have faithfully reproduced the colours. What I have learned about UV minerals … in general, many locations and many minerals have distinct and expected colours. If you alter these and misrepresent them, some knowledgeable UV collector will call you out.
Pick your best photo. Right click on the photo icon and select Properties. When the dialogue box pops up, click on Detailed Properties. Scroll down and note the aperture F-stop, the Ev and the exposure time settings. Compare with your next to best photos.
After you repeat the above procedure a few times on a few minerals, you should notice a pattern of aperture F-stop and Ev settings that work best for you. With practice over time, you should be able to eliminate the above procedure and go directly to your now known settings. That is, until you change something. Once you move to a new location, add a new light, or alter the conditions of your set-up in any way, you should go through the detailed procedure to once again determine your best settings.
Darryl.