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Thread: Reef Photography Workshop

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    Reef Photography Workshop

    I’ve been talking for a while about doing a photography workshop on RF, so after being hounded by Mike and Nikki, here’s the start!

    To begin with, let me run down my plan, or lack of one, for this workshop.

    I plan to start out with a few articles on the basics of exposure and light, which are really the core aspects of photography. (Aside from composition, which we’ll get to later.)

    These first few articles apply to all photography, not just reef tanks, but I do plan to get into some more reef-specific material a little later. Of particular interest here is white balance under reef lighting and how to deal with it.

    I suppose I’ll open by saying that photography is really nothing more than light, and how you allow it through the lens and onto your film or sensor. That’s really all there is to it.

    Sounds simple, right? =) I’ll try to present things in such a way that they’re understandable, but knowing me, that’ll probably come later when people start asking questions.

    Since I’ll be using a lot of terms that you may or may not know, but that are important to explaining photography and more important, expressing what you’re doing with it to other photographers, please ask questions if I don’t adequately explain a term. I’ll do my best to explain them as I use them.

    Just as a side note, I’ll be saying film throughout the article, but for most of us (myself included) it’s probably really a digital sensor of some sort.

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    Exposure and shutter speed:

    The single most important part of photography is exposure, or the amount of light being let through the lens. Ambient light is the variable that you typically have no control over, so you need to manipulate the things that you do. On most cameras, these things are shutter speed, aperture, and ISO or "film" speed.

    The first and easiest to explain is shutter speed. Its nothing more than how long the film is exposed to the light entering the lens; the longer the exposure, the brighter the image. The flip side of this is that the longer the exposure, the more objects in motion will blur, and the more pronounced effect an unsteady lens would show.

    Good exposure and fast enough shutter speed:

    70mm, 1/250s, F7.1, ISO1600

    Shutter speed too slow, making the whole image look out of focus:

    70mm, 1/30s, F22.0, ISO1600

    Good shutter speed, freezing the waving motion of the Xenia:

    70mm, 1/250s, F4.5, ISO1600
    I'm not sure why this ended up looking oversharpened either, but my Xenia decided to go into hiding after this shot and I couldn't get a better example

    Slightly too slow shutter speed, making the Xenia look slightly out of focus

    70mm, 1/30s, F/13.0, ISO1600

    Shutter speed is expressed in fractions of a second, typically. If you see a shutter speed of 125 on your camera, that indicates 1/125th of a second. Once you reach about 1/3 of a second, usually the display with switch to seconds, indicated by 0.3", for example. Speeds that slow probably aren.t of much use with reef photography, as even SPS polyps will blur at that point.

    Ok, so what do the numbers mean in terms of taking a picture? All other things being equal, doubling the length of time the shutter is open will double the amount of light. A shot at 1/30th of a second is approximately 8 times as bright as a shot at 1/250th of a second. This is especially important for lower light situations like a reef tank, where you don't have the kind of light availability as you would outside. To take a good in focus picture requires a lot of light and a fast shutter speed, which leads us to aperture.

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    F-stops, Irises and Pi

    Aperture is how wide the iris in the lens opens during the exposure. The wider it is, the more light is allowed in. Aperture also has the side effect which allowing more light in the form of depth of field, which I'll explain shortly.

    Aperture is quantified by what is referred to as an F-stop. You'll usually seem them expressed as something like F/1.0, F/2.8, F/5.6, etc. This is deliberate, since it tells the actual width of the aperture, although that's less important in these days of auto-metering. F/1.0 on a 50mm lens is a 50mm aperture. F/2.0 on a 50mm lens is a 25mm aperture. The "stop" part of F-stop refers to the fact that these numbers, which seem somewhat odd, are typically at 1/3 or ½ intervals between doubling the amount of light. F/3.2 is 1/3 of the way between F/2.8 (a common starting point) and F/4 (twice the amount of light as F/2.8). Now, 4 doesn't seem like it's twice 2.8, right? But, you have to remember that we're dealing with a more or less round aperture. F/2.8 at 50mm is ~18mm diameter or ~1000sqmm surface area. F/4 at 50mm is 12.5mm diameter, or ~500mm surface area.

    If you're confused by all the numbers, that's ok. Really, trust me. You don't have to compute the area of the circle in your head every time you want to change your aperture. That's what the "Stops" are there for, so you can familiarize yourself with a standard way of measuring it. Conveniently, we probably all have auto-exposure cameras these days that'll tell us if we.re way off on our exposure even if we.re setting both the shutter and aperture manually.

    So lets put these two things together. I want to take a picture of some zooanthids and I don't have a tripod handy, which is actually true, I lost my tripod mount before trying to write this, so I'm trying to handhold everything to get these examples out. =) I only have power compacts, so I'm not dealing with a lot of light. I can open the aperture of my lens as wide as it will go (F/2.8@70mm) and the camera meters at 1/250th of a second. No problem, I can handhold that.


    70mm, 1/250s, F2.8, ISO800

    Oops. Ok, so I focused on the back of the small cluster of zooanthids. It looks fine, but the three in the front are incredibly blurred. As a matter of fact, my depth of field is so thin it barely covers that single zooanthid, its only a few mm (A DoF calculator shows it as being ~8mm). Ok, so lets stop down to F/8.0 and see what happens there.


    70mm, 1/80s, F10.0, ISO3200

    Well, that's a little better. They're in focus, but don't have a lot of detail. What changed? Well, the ISO is up to 3200 now, which is the next section, but we could've gotten around the depth of field problem in a more obvious way.

    The obvious way is to use a tripod. Subjects that small are difficult to capture without one. The further away you can get from your subject, the wider your depth of field would be. Lets say I was able to get another foot away from the subject at the same distance (I was about 2. away from the zooanthids). At 3', my DoF at F/2.8 is about 18mm. That's almost as much as it was at F/8.0 at 2'.

    So what if, like me, you don't have a tripod available? Well, I have good news and bad news. The good news is that you can increase your ISO or film speed. to allow more light at the same shutter and aperture. The bad news, is that I was already at ISO800 for the first shot. Anything past that and even the highest quality cameras start to look bad. So the real answer there is to use a tripod, or lacking one, I've used a stack of books before. Anything you can do to steady the camera helps.
    Last edited by Llarian; 07-07-2005 at 12:56 AM. Reason: Stupid Word pasted my apostrophes as periods.

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    Ok, so what's ISO?

    ISO is also called film speed. "normal" film is ISO100, and it yields a sharp image with little noticeable grain. It also isn.t as sensitive to light so you can.t get as high a shutter or narrow an aperture with it as higher ISOs. Like the others, ISO is quantified in terms of doubling the amount of light. ISO200 allows twice as much light. ISO400 allows four times as much. ISO800, eight times. You get the picture. (Get it? Get the picture? Ha ha. never mind)

    So, why not just bump the ISO as far as it will go? The simple answer is that it looks like crap after a point. With film, the difference was the size of the individual grains, giving it that old picture look. You rarely see films above ISO800 because they just don't look very good. With digital, you have the concept of digital noise. The more sensitive you try to make the image sensor, the hotter it gets, and the more susceptible it is to interference. They.re getting better as times goes by, to the point where even ISO3200 is acceptable in some cases. (Photojournalism for example) Not so much for reef tanks though. Here's an example of the difference between ISO100 and ISO3200. I've cropped the image in extremely closely to the differences show up. For web stuff, this might not matter much. Its really a personal choice. Its worth pointing out that at ISO100, I couldn.t get a fast enough speed to capture the detail in the swaying Kenya Tree, whereas at ISO3200, I got the detail but all the noise as well. Somewhere around ISO400 or ISO800 would have probably looked fairly nice.


    200mm, F2.8, 1/80s, ISO100


    200mm, F2.8, 1/2500s, ISO3200

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    Confused you enough?

    So, there's my introduction to exposure. I should mention that I told Mike I'm a horrible teacher when he asked me to do this, so if confused you even further, blame him. =)

    As soon as I get a chance, I'm going to write up some information on white balance and macro and close-up photography (or at least that best I can do without owning a macro lens). Please question away and hopefully you guys can guide this workshop into something that'll make me learn as well.

    I hope some of this helped though, and if you guys help me become a better teacher, I'll see what I can do to help you all become better photographers. (Guess which of these tasks I think is more difficult?)

    -Dylan

    Addendum:

    Since it's always asked, I'm shooting with a Canon EOS 20D. All the pictures were taken with a Canon 24-70 F2.8L, except the ISO ones which were taken with a Canon 70-200 F2.8L IS, since I needed the image stabilization to get a shot at ISO100 without camera shake. I use Photoshop CS2 and RAW format files, but I did my best to not change the exposure or white balance beyond what the camera itself guessed it to be for the sake of example. If people want, I can do an article on RAW later in this workshop, but I think there might be less broad appeal there.

    Since somebody might ask, the ISO3200 image of the zooanthids doesn't exhibit the same grain as the kenya tree in my ISO comparison. Usually when I'm taking high ISO shots I use a program called Neat Image to remove a good deal of that grain from the picture. The tradeoff is that you lose some fine detail as well, so that's why that image seems "softer" than the others.

    For the other photographers out there, I realize these pictures suck, but I figured I'd rather take poor pictures of my tank to illustrate a point, rather than taking pictures of a ruler or something equally boring to illustrate depth of field. =)

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    Go ahead Dylan your doing Great!You've got me reading!Fire away!
    Is that a new tank or something?It looks very neat!

    Joey
    Last edited by Skipper J; 07-07-2005 at 01:28 AM.

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    Quote Originally Posted by Skipper J
    Is that a new tank or something?It looks very neat!

    Joey
    Yeah. Its only about a week old and mostly contains the contents of my old 5 gallon nano and some rock I got from johnehr.

    -Dylan

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    That explain the abundance of coralline algae and white clean sand!

    Question!
    How do I improve on my photograpy with an A95 Canon camera!
    When I used the macro I can only get close to a certain distance to have a clear focus.I figure it is a systems limitation but will there be any technique to have a sharper shot.

    For an aperture opening would you say that there is sweet spot that will make the color more crisp.This is of course with application of AQ Photography!

    What about the used of remote flash!Aren't there enough light with our halides assuming that it is the right color?

    Joey

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    Quote Originally Posted by Skipper J
    How do I improve on my photograpy with an A95 Canon camera!
    This is kinda like that old joke about how to get to Carnegie hall. The best way to get better with your particular camera is to use it. =)

    I'll answer the other questions more seriously though. =)

    When I used the macro I can only get close to a certain distance to have a clear focus.I figure it is a systems limitation but will there be any technique to have a sharper shot.
    Most consumer digicams have a "macro mode" you need to put it into to allow it to focus closer. In theory, your camera should be able to get within about 5cm of the subject with the lens fully zoomed out. If you're zoomed in, you raise the distance to about 25cm. All other things being equal, a wide-angle lens can focus much closer to an object than a telephoto, which appears to be true with your camera as well.

    For an aperture opening would you say that there is sweet spot that will make the color more crisp.This is of course with application of AQ Photography!
    Yes, but probably not so that you'd notice a difference until you get into fairly highend optics. Most modern SLR lenses have a sweet spot around F/8.0. I have no idea if this carries over into the consumer cameras or not. I would suspect that its probably closer to F/4 or F/4.5 on a more compact camera. What is universally true is that no lens is optically at its best when fully open or completely stopped down due to diffraction and some other optical issues with running them at the limits of their usable range.

    What about the used of remote flash!Aren't there enough light with our halides assuming that it is the right color?
    There is usually enough light with halides, especially if you have a tripod. You could probably use a remote flash, but I'm not sure how well it would penetrate the water. Anybody out there tried this? I'd imagine if you positioned a slave flash above the water you could use it to illuminate through the surface. As you correctly point out though, that's going to skew the camera's white balance guess. This can be corrected in one of a couple ways however, which I'll touch on when I have a chance to do the white balance part of the workshop.

    -Dylan

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    Hi Llarian, interesting post. This is the basic of photography. Photography is related to my job, as I am graphic designer and often photographer. Main problem with all explanation in topic is that most people use low end camera withouth manual settings. How to help them? For Aquarium photography it is very expensive to use analog (classic) camera which is equipped with more powerfull lenses and manual controls, so we use digital. I have all knowledge (as student of generation) and practice (lot of working years with big clients), but I use Fuji FinePix S602 Zoom camera with fixed lenses. If I use ISO above 400, my camera go on 1MPIX. (equipped with 100, 200, 400, 800 & 1600).
    Try to explane advantage of external flash, tripod, etc. Keep on topic, great idea!

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    Quote Originally Posted by Peca
    Hi Llarian, interesting post. This is the basic of photography. Photography is related to my job, as I am graphic designer and often photographer. Main problem with all explanation in topic is that most people use low end camera withouth manual settings. How to help them? For Aquarium photography it is very expensive to use analog (classic) camera which is equipped with more powerfull lenses and manual controls, so we use digital. I have all knowledge (as student of generation) and practice (lot of working years with big clients), but I use Fuji FinePix S602 Zoom camera with fixed lenses. If I use ISO above 400, my camera go on 1MPIX. (equipped with 100, 200, 400, 800 & 1600).
    Try to explane advantage of external flash, tripod, etc. Keep on topic, great idea!
    I agree that most are using digital at this point. My feeling with starting this (and from being asked about it at local meetings and elsewhere on the board) is that it'll be difficult to explain much about photography without the basics in place. That being said, I will admit I've not used a "consumer" digital camera for a while now, I'm used to digital SLRs. The last few consumer cameras I used still had the availability of aperature priority and sometimes even fully manual operation.

    Let me think a bit on how I can tailor this to apply to lower end cameras a little better, that's a valid point. I don't have one available to me right now, so its going to be a little harder for me to type up.

    -Dylan

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    Quote Originally Posted by Llarian
    This is kinda like that old joke about how to get to Carnegie hall. The best way to get better with your particular camera is to use it. =)
    -Dylan
    With the kind of hobby we have?The way you could share it with friends that often is to take photos!But then again I need the quality ones!You are right though used it and tinker with it!Experiment!

    Quote Originally Posted by Llarian
    Most consumer digicams have a "macro mode" you need to put it into to allow it to focus closer. In theory, your camera should be able to get within about 5cm of the subject with the lens fully zoomed out. If you're zoomed in, you raise the distance to about 25cm. All other things being equal, a wide-angle lens can focus much closer to an object than a telephoto, which appears to be true with your camera as well.-Dylan

    I think your right on the 5cm distance as I have just tried measuring the distance of the focus object.But it also looks like there is a corresponding right distance for it to focus properly.Otherwise if you insist on the composition that you like it would be out of focus like the attached picture.
    This is why I wonder if there is anything I can do to the camera set-up to improve this!

    1st Picture Details
    Focal length: 16.2mm
    Metering Mode: Center Weighted
    1/50-F/4

    2nd
    Focal Lengt: 16.2mm
    Metering Mode: Center Weigted
    1/60-F/6.3


    Continue on!We are learning!!!


    Good call Peca!!!I agree most of us will be using a low end camera but at least it should have a manual control otherwise what is there to control if it is all on auto mode.Composition is probably one.Cheers!

    Joey

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    For depth of field calculations, take a look at this link: http://www.dofmaster.com/dofjs.html

    It'll calculate the DoF for you particular camera.

    The other thing to try is zoom all the way out. Your focal length should be 8mm if I'm doing the math right. (Focal length is the field of view of the lens, it is not the same as where the focal plane is) At 8mm, you should be able to focus much much closer (probably about 1/5 the distance from the subject, and you should be able to get a deeper depth of field as well.

    From the first picture, it looks like you are just too close for the 16.2mm focal length, that's probably the tele-end of your zoom lens if I'm guessing right. I can't tell exactly what happened in the second, but I suspect its probably the same and its just hard to tell because of how narrow the DoF is.

    -Dylan

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    Butterflyfish
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    Great thread! I have to agree that you have to understand basic photography before we can talk intelligently about it. We need to understand the terminology, as a lot of the digital cameras have the same type of adjustments but use the classic jargon to define the settings. I know my camera has a white balance, a fillm speed, and I believe a shutter speed. People also need to read the manual and find out how to shut off the auto setting and allow yourself the priviledge of shooting in manual mode.

    Keep posting Dylan, I plan to learn a lot from you
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    This is going to be very interesting. Can't wait to understand about taking better pictures in bluer light.

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