I thought that I do not have anything significant to add to Accretionary Wedge #41. My home country is very quiet geologically. Being far from the plate boundaries we rarely have anything dynamic happening here. I have experienced one earthquake but there is really not much to talk about. But then one event crossed my mind that happened several months ago while I was hiking in the Spanish Pyrenees. I have already shared a photo of a beautiful synclinal mountain I took the same day.

We were descending from a mountain pass while I heard a scared voice screaming my name maybe 20 meters up from where I was. I had no time to do anything. I just started to turn my head and the next moment got hit by a sizable cobble (maybe 15 cm in diameter). I was lucky to maintain my footing because otherwise everything could have ended very badly. It was not an edge of a cliff but more like a really steep slope down from where I was standing. Hence falling there doesn’t mean a certain death but the situation was still bad enough.

The cobble hit my ankle which was aching somewhat later but fortunately it caused no serious injury. Probably because my legs were protected by heavy hiking boots that softened the impact.

So with lots of exaggerations I could say that I am a survivor of a rock avalanche but let’s try to be reasonably modest. It was just one rock and the whole event is not worth much mentioning but if I really need to find some geological event that have most closely affected me, then I probably have to choose this one.

I never saw that rock again. It continued its jumping and rolling journey down the slope but I know it was conglomerate because the whole mountain is made of this rock type. Here are some pictures of this beauty.

I wish you all a happy new year with lots of interesting but preferably not too dangerous geology.

Jessica Ball wrote about her experience at AGU where she talked about the Geoblogosphere. She also pointed to an article written by Callan Bentley et al. which I found very interesting. My blog was not included in this study because I wasn’t an active blogger then but I thought that maybe some of my readers find it interesting what I have learned during the past few months of active geoblogging.

For some reason I like to express myself in a written format. I have written more than 1,000 articles to Estonian Wikipedia. These articles are mostly about geology. Now I really don’t know why didn’t I start a blog instead. Wikipedia has strict guidelines, you do not work for yourself, you get almost no feedback, and there are often conflicts with other contributors and trolls. Maybe I just couldn’t believe that someone would ever follow my blog. That probably is still true because then I wrote in Estonian and just didn’t realize that I could possibly do it in English. There are only one million people in the world understanding Estonian. You won’t find too many among them who would like to read a geoblog.

I was concerned that I can’t find followers with my poor English skills but it seems now that it is not a problem. Maybe because native English speakers are so used to read faulty or awkward English written by non-native speakers that they do not even notice anymore.

But on the other hand I feel that my writing skills have improved considerably during that short timeframe. It is somewhat astonishing because all I did for that was writing this blog. So it is the first benefit that I have received from it. I am used to read texts in English. Now I also have a way of practicing writing. There is no doubt that it could be very beneficial in the future.

Another benefit is that it is a great motivator. There are many things in my to-do list but I am sometimes lazy. I would not do some of it because there is no urgent need. But writing a blog and trying to keep updating regularly with more or less meaningful posts is a challenge. You always run the risk that you have nothing to write about anymore. So I need to keep working with new material and ideas. It is rewarding because I learn new things all the time.

I do keep a general record of how many people visit my blog but I do not feel comfortable posting a statistical overview here. Maybe because the numbers are still very modest. However, the trend in encouraging and greatly exceeds my expectations. That too is motivating to see the number of visitors grow almost every week. I will try to do my best to see the numbers going up in the future as well.

There are many more potential benefits. I hope that I am not even aware of some of them yet. Is there anything bad also? It simply can not be that blogging is entirely positive experience. Yes, there is one annoying aspect. It is time that always seems to be in short supply but I shouldn’t complain about that. Everyone seems to have the same problem. Time actually is not the problem – we all have 24 hours a day. The problem is that there is too much that we would like to do. Blogging is just one thing that takes large chunks out of our days. But I do not see it as a big problem until it helps me to improve in many ways and until it is a fun thing to do.

As a conclusion I would definitely encourage you to start blogging if you are not doing it yet. It has been rewarding for me and would most likely not hurt you as well.

There are several things you need to pay attention to if you wish to take good macro photos. Here are some tips I have acquired while learning this craft. Please note that I take macro photos of geological materials, mostly sand samples and rocks. Some of the advice given below may not be directly applicable or needed in other and more popular areas of macro photography.

Manual camera

Point-and-shoot cameras are not suitable for this job if you want really good results. You need to be able to manually set aperture, shutter speed, ISO, and white balance. I use Canon EOS 450D (Rebel XSi). The examples given below may not work directly with other models.

http://picasaweb.google.com/107509377372007544953/Coll#5852307320112952114
Good macro photo of a sand sample is in focus both horizontally (in every corner of the photo) and vertically (has adequate depth of focus). The colors are natural and the amount of light is just right – neither too bright nor too dark. I am not saying that this is a perfect photo but this is something I try to achieve and am satisfied with for now.

Macro lens

Really small objects like sand grains need macro lens. Only coarse sand can be successfully photographed with usual zoom lenses. I currently use Tamron 60 mm F/2 1:1 and Canon MP-E 65mm 1-5x macro lenses. If you will buy your macro lens, pay attention that it has at least 1:1 magnification. Anything less than that, 1:1.5 for example, is not real macro although salesmen sometimes call them that way.

What does this 1:1 mean? It means that at maximum magnification (1:1) you can take photos of objects measuring the size of your camera sensor. If the width of the sensor is 22 mm, then it is also the width of the object that will be photographed. Longer sides of my photos have 4272 pixels, so it means that there are 4272/22 = 194 pixels per one millimeter. This is good enough if you aim to photograph sand grains measuring 1 mm.

However, smallest sand grains by definition are only 63 micrometers in diameter. There will be only 12 pixels for every grain. That is definitely not enough if you want to use that sample as an identification guide of different minerals. To overcome that problem you need extreme macro lens like Canon MP-E 65mm 1-5× Macro. Yes, that allows to take photos of objects measuring only one fifth of the sensor.

Such magnification is comparable to most stereo microscopes. This macro lens is not cheap but it is still significantly more affordable than good microscope cameras. Here I use an opportunity to really warn you about the cheap microscope USB-cameras. This is garbage! You will only lose money while investing into this. I have tested several of these things.

If you want to take good images of really small objects then you have an option to choose between very expensive quality microscope cameras and significantly cheaper macro lenses for your camera. I recommend to go with the latter as it allows more flexibility and control which ultimately results in brighter and sharper images. The only downside, which I admit is annoying, is that you can not take images as soon as you see something interesting while examining your samples microscopically. But you never get good results without working hard, do you?

Sand sample photographed with stereo microscope and USB-camera. This camera is expensive and takes adequate images of thin sections. Yet, the picture of sand is too dark and lacks contrast. Doesn't seem to be appealing to me and would not make a good teaching material of mineral identification.

RAW

I strongly recommend to save your images in RAW format (possible with DSLR cameras). It allows you much more flexibility in photo processing. You can easily set white balance, correct wrong exposure, contrast, etc. This is the most important reason to use DSLR in my opinion. There are certainly other aspects too like ability to change lenses but many point-and-shoot cameras can take pictures of decent quality. Ability to save RAW sets SLR cameras apart from them. You really won’t use your camera’s potential if you are not shooting in RAW. However, RAW files are only good if you are willing to do post-processing. If not, then it will not benefit you. You need a software to view and edit RAW files. I use Camera Raw for that purpose. After you have converted your RAW files to images, I recommend to save them in TIFF format because JPG files lose quality every time you modify them and resave.

Tripod

You can not make good macro photos while holding a camera in your hands. You need a solid tripod. If you plan to use it indoors, then it would be a good idea to invest some more and get a really good one. I have to admit that mine is not as heavy as I’d like it to be and the legs of the tripod are frustratingly near to the object I am photographing.

I take mostly sand photos, so the object has to be placed horizontally while camera is directly above it. Why is it bad that the legs of the tripod are near? Because you want to set lamps all around the sample to get good lighting. These legs are just an obstacle that take the free room you’ll need for the lamps.

Remote release

You have to avoid shaking the camera while releasing the shutter. So you better do not touch the camera. Release the shutter remotely either from the computer your camera is connected to or with a remote control device.

Solid base

That should be obvious but I did that mistake earlier. Solid tripod will not help you if your sample is not standing still. Make sure that you place it on top of something heavy and firm.

Mirror lock

You may have a solid tripod, your sample is not vibrating and you do use remote release. Yet, your images are still not sharp. What is the problem? It may be the mirror inside your camera that is moving away from the light path just before the image is taken. When it moves, or more precisely when it stops moving, it shakes the camera a little and makes your picture less sharp than it ought to be. What to do about it? This mirror can be locked. It means that it will be removed from the light path when you press the remote release button which is several seconds before the photo is taken. Most of the slight wobble caused by the mirror will subside during that time. How to lock it? It depends on your camera. I have to choose Menu – Custom Functions – Enable Mirror lockup. You have to use your camera in manual mode (P, Tv, Av, M, or A-DEP) to access this part of your menu.

Connection with a computer

Your camera should be connected with your computer while you take images. You simply can not decide whether the photo is good enough or not when viewing it in the camera LCD screen. Let the software you got with your SLR directly download the images right after you take them and examine them carefully in full view to decide whether something needs to be changed. It may be lighting, aperture, sharpness, etc.

Manual mode

You should take the photos in full manual mode (M in Canon SLR). Do not let the camera decide the parameters. They are not very good at it. There are several things that you want to have full control of. I will cover them below.

Whether you want to have a manual focus depends. Some macro lenses do this job quite well with almost flat surfaces as sand grains, especially if you intend to use your photos in the web and will resize them later. However, if you want the best possible results, I recommend to focus manually. You need to magnify the image on the LCD screen (5-10 times) to be able to achieve the best possible results. If your object is more three-dimensional, you need to do it manually anyway because only you know which parts of the object need to be the sharpest. Some macro lenses have only manual focus. I do not recommend to watch your objects through the viewfinder. The view is often dim if you take macro photos which means that you have to seriously strain your eyes to make sure that your photos are in focus. Do not ruin your eyesight, it is not worth it. Use LCD screen and magnification to see fine details.

Object should be as flat as possible

Sure, you can make macrophotos of three dimensional real life objects but it comes at an expense of sharpness. There are many tradeoffs in photography just as everywhere else. More magnification means shallower depth of focus. If you need to use high magnification then you need to make sure that the object you are photographing is as planar as possible. I pour the sand I am photographing into the lid of a small and shallow micromount box and gently press the surface flat.

Of course, the object (sand surface) should be aligned as parallel as possible to the camera lens. Otherwise our photos will be sharp in one part of the photo only.

UPDATE: There is another and in many cases the only possible way if you want to take a sharp picture of a three-dimensional object. You should take multiple photos with different focal plane and later merge them into one sharp image with a special focus stacking software.

White balance

A gray card is used to correct the colors of photos.

Our cameras do not know what are the lighting conditions we use. The colors that will be recorded by the camera depend heavily whether we use direct sunlight, incandescent bulbs, fluorescent lights, etc. We have to make clear that our camera understands that correctly. There are several ways to accomplish that. I am covering here only the method that I use. This is very convenient method which I highly recommend.

I use a gray card. This card has specific neutral gray color with specific surface reflectability. Your camera already knows exactly how this card should look like because it is a strictly defined standard used in photography. If you take a photo of a gray card in the lighting conditions you are going to use subsequently and tell your camera that this is a gray card, then it automatically corrects the colors of the photos you will take from now on.

How to make it clear to your camera that you just made a photo of your gray card? There are „Custom WB“ in the menu of your camera. Choose it and then select the photo you just did of your gray card. Do not forget to set your camera to use Custom white balance after that. While you take the photo of a gray card, make sure that there is nothing else than the card in your picture.

If you purchase the card, make sure that it is entirely gray. There are color charts (with many colorful squares) as well but you will not need it to balance the colors.

These are mostly olivine grains. They are bright green when fresh and this color is adequately recorded in the first picture because I set the white balance by using a gray card. Something really awful seem to have taken place with the photo on the right. There are actually no more changes than white balance settings. I made it clear to the camera that I took this picture outside in the shade (color temperature 7000 K). In reality I used fluorescent bulbs (ca 4000 K). The result is that the camera falsely and greatly overcompensates by adding red color to the image. This example may be exaggerated but the concept of color temperature is of paramount importance. It must be addressed one way or another. Otherwise you are guaranteed to have ugly colors not reflecting the reality.

Lighting

You are going to need lots of light. I recommend to use several lamps (at least three) with powerful bulbs that cast light on the sample from different directions. These lamps should be near the sample but not too close. 10 cm works fine for me. Don’t worry that your sample may become too bright. It most likely won’t and you will regulate the amount of lighting later when setting shutter speed and aperture. You can use shorter shutter speed when you have lots of light which results in sharper images.

Bulbs should cast light on the sample from low angle. That is needed to amplify the 3D effect. It seems to me that if the lights are almost above the sample, the photo will be flat and boring and looks much more unprofessional.

Aperture

An aperture is an opening through which light enters your camera. It is set as an F-value. Macro lens I use allows me to choose an aperture between F2.0 and F22. Note that the smaller number means that the aperture is wider and larger number means it gets real narrow. Why do we need to set it? Because that’s the way to regulate the depth of focus and this is really important concept which should not be neglected. Smaller aperture (bigger number) means that we get better depth of focus which is needed to make sure that everything we want to show is in reasonably sharp focus. However, there is a tradeoff as well. Setting aperture smaller (increasing the value) means that our pictures start losing sharpness. That is another reason why we want the sand surface to be as flat as possible. My experience shows that F-values somewhere around 10 give me adequate depth of focus for sand photography while maintaining good sharpness. If you don’t want or can not make the surface reasonably flat (when photographing rocks for example) go for higher F-values. The slight loss of overall sharpness is not as noticeable as is the loss of sharpness in specific parts of your image.

Photo on the left has good depth of focus (F22) while photo on the right has only few grains in sharp focus (F2.0). This is why we need to use smaller aperture (larger F-values). However, it comes with a cost. The image on the left had an exposure time of 300 milliseconds while image on the right needed only 4 milliseconds. That should explain why good tripod is a must.

ISO

You want to take your photos with small ISO values (100 or 200). If you leave it to your camera to decide, it may choose ISO value 800 for example if it thinks that you do not have adequate lighting. Higher ISO values are used to make pictures in dimmer light. The tradeoff here is that your images become slightly more noisy. I recommend you make sure that you do have adequate lighting and then just force the camera to use ISO 100. However, this is probably one of the least important aspects discussed in this article. If you change ISO, you also have to adjust the shutter speed. Lowering ISO means you need longer exposure time. If you have to take the image while holding the camera in your hands, always try to find ways to make the shutter speed as short as possible. One good way to do it is to use higher ISO.

Shutter speed

Shutter speed is an exposure time. There is no fixed recommended value. It depends among other things on the values of ISO speed, aperture, and lighting. This is something that needs to be set separately for every photo you take. Take a photo and then decide whether you want it to be lighter or darker and accordingly adjust the shutter speed. Shutter speed 1/10 means that your cameras sensor will catch light only one tenth of a second. During that time your camera and the object you are photographing should be as still as possible. Chances for that are better if you use shorter shutter speed. However, you must use what you need. That’s why we have to make sure that our tripod and other methods that were discussed earlier guarantee that nothing moves even if it takes several seconds to take the image. Darker sand grains need longer time. Light-colored samples are therefore usually easier to work with.

I have written more about macro photography. Here is a tutorial for isolating photos on white and How to quickly enhance your pictures.