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PostPosted: Thu Aug 26, 2010 2:45 pm 
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The following link is a how-to blogpost about how
to get a good photo setup for taking pics of smallish
objects. The post focuses on electronics projects,
but I think the techniques can be applied to pictures
of instruments, which I've had trouble with.

http://www.adafruit.com/blog/2010/08/25 ... ohngineer/

Does anyone have any photo tips for instruments?
For example, how do you avoid the "banana effect"
on flutes? How do you light metal whistles to avoid
bad lighting effects and still get a good pic of a
non-metal mouthpiece?


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PostPosted: Thu Aug 26, 2010 2:55 pm 
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banana...back up

metal whistle...photoshop the mouthpiece later (guessing on this one)

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PostPosted: Thu Aug 26, 2010 3:20 pm 
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Denny wrote:
banana...back up

How does that help? Does zooming screw it up?


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PostPosted: Thu Aug 26, 2010 3:40 pm 
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You can avoid photo flashback on surfaces like brass, stainless and chrome by taking your pictures at a slight angle. This also works for oil paintings and objects under glass.


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PostPosted: Thu Aug 26, 2010 4:39 pm 
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fearfaoin wrote:
Denny wrote:
banana...back up

How does that help? Does zooming screw it up?

the parts of the flute are closer to being the same distance from the lens
nope, not at all

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PostPosted: Thu Aug 26, 2010 4:41 pm 
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on camera flash is great

when you have no other option

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PostPosted: Fri Aug 27, 2010 7:50 am 
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Pick a background that contrasts the majority of the instrument. For example, if you're shooting a blackwood flute, don't use a black background. If you're shooting a pvc whistle, don't choose a white background. I usually stick with solid backgrounds, not printed or textured ones just because it can have adverse effects on your photo. After all, you want the instrument to be the focus of the photo, not your shamrock print bedsheet or multicolored southwestern throw blanket (I've seen both of these in photos before!).

I always avoid using a flash because it washes everything out and doesn't show the beauty in colors and woods. That said, indoor fixed room lighting is terrible for taking photos so if you take the flash out of the equation you'll have to come up with some sort of lighting set up. I would always use at least two lights to see as much detail in the instrument as possible without creating too many harsh shadows that would obscure said details. The closer the lights are to the subject, the harsher shadows will be and the more intense your highlights will be. Moving the lights back a bit gives a nice even lighting.

If possible, fix your camera to a tripod and set the shutter speed slow. This will help ensure a crisp image and will give you better details of your instrument as the camera will have more time to gather light. If you try to do this while holding the camera then you'll have a very blurry image. On the contrary, if you hold the camera with a fast shutter speed you might get an in-focus image but you'll likely have some graininess in your photo that will obscure details, colors and textures.

As for the banana effect, remember that your lens is convex in proportion to your image. Think of it as looking at your face in the back of a spoon; whatever is closest to the spoon will appear the largest (i.e. your nose, glasses) and things will get smaller as they move towards the edges. If you back up your camera and zoom in then you will get the same closeness to your subject with less distortion. Still, when it comes to flutes, unless you have a particular need to show the flute put together, you're going to give the viewer more details if you shoot the flute disassembled because you can zoom in closer while still showing the whole thing. With an assembled flute you have to back up far enough to get the head and foot in the viewfinder and by then you can't really see any details.

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PostPosted: Fri Aug 27, 2010 7:57 am 
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Banana effect is due to crappy lenses. The technical term is barrel distortion. The worse the lens, the worse the effect. It can also be caused by a wide angle lens. So back up and use the zoom. But you can correct barrel distortion in software, if you choose.

For lighting, the easiest solution is to go outside on an overcast day.

Here's an unedited photo from an old digicam (coolpix 5000). It's laying on concrete and I'm standing up, using the zoom.

Image


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PostPosted: Fri Aug 27, 2010 9:33 am 
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highland-piper wrote:
Banana effect is due to crappy lenses.

What kind of crappiness are we talking
about here? Depth of field problem?

highland-piper wrote:
But you can correct barrel distortion in software, if you choose.

I'd like nothing more. Can you elaborate?
What technique might one use to fix this?


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PostPosted: Fri Aug 27, 2010 9:39 am 
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straycat82 wrote:
The closer the lights are to the subject, the harsher shadows will be and the more intense your highlights will be. Moving the lights back a bit gives a nice even lighting.

Hm. OK. What might your goals be in lighting
a whistle? Do you want to highlight the holes,
maybe, to make the edges stand out maybe?
There's a lot of info out there about how to
get light in the right place, but how do you
know what the right place is? Most of the
articles I find are about shadows on faces...
(I really am new to this visual thing.)

straycat82 wrote:
As for the banana effect, remember that your lens is convex in proportion to your image. Think of it as looking at your face in the back of a spoon; whatever is closest to the spoon will appear the largest (i.e. your nose, glasses) and things will get smaller as they move towards the edges. If you back up your camera and zoom in then you will get the same closeness to your subject with less distortion.

Yeah, that's the kind of detail I was looking for.
Thank you kindly.

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PostPosted: Mon Aug 30, 2010 10:48 am 
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fearfaoin wrote:
highland-piper wrote:
Banana effect is due to crappy lenses.

What kind of crappiness are we talking
about here? Depth of field problem?




No. You can think of lens distortion kind of like intonation in a whistle. It's built into the design. You can evaluate barrel distortion easily. Stand in a large room, straight out from a wall. Align the edge of the frame with the corner where the wall and the ceiling come together. In a good lens, this will be a straight line. Even in a wide angle lens this *can* be a straight line. I used to have a Nikon 35mm camera and my 24mm lens had essentially zero barrel distortion.

Anyway, in a not-so-good-lens you will see a curve. In some zoom lenses at the wide angle setting there will be pronounced barrel distortion, and at the telephoto setting there will be pincushion distortion (everything sucks in). If you have a lens like that, then you can usually find a sweet spot. In most zoom lenses there is the most distortion at the widest settings.

You can also shoot pictures of graph paper which will show you how much distortion you have.


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highland-piper wrote:
But you can correct barrel distortion in software, if you choose.

I'd like nothing more. Can you elaborate?
What technique might one use to fix this?


I use Photoshop at work. It's great software, but too expensive for most people. In photoshop you just go to "Filter", "remove lens distortion". I'm pretty sure Paint Shop Pro has a similar feature that probably works just as well.

There's also a program called panorama tools that can do an exceptional job (probably better than either of those mentioned above). It can be tedious to set up though, because there are many lens parameters that need to be configured. If you're lucky, you can google your camera and someone else has already figured them out.

If you scroll down this page to the bottom you can see an extreme amount of distortion, and an example of how well panorama tools can correct it:

http://www.photos-of-the-year.com/artic ... istortion/

Panorama tools:
http://www.all-in-one.ee/~dersch/


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PostPosted: Mon Aug 30, 2010 1:55 pm 
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highland-piper wrote:
You can also shoot pictures of graph paper which will show you how much distortion you have.

That is a great idea. I'm going to try that.

highland-piper wrote:
... If you're lucky, you can google your camera and someone else has already figured them out.

Great stuff! Thanks.


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PostPosted: Mon Aug 30, 2010 8:40 pm 
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I suggest that the more light the better, the best photos I've taken of my instruments have been outdoors under full sun. I agree with the moderate zoom suggestions to avoid distortion artifacts. Also having more light allows you to set your camera to lower ASA values to get the lowest noise possible in the image.


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PostPosted: Tue Aug 31, 2010 2:55 pm 
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Light is like sound -- quality beats quantity.

I generally have more problems with too much light producing harsh shadows and uncontrollable highlights -- but my camera is pretty old; I'm sure a newer camera would do better with harder light. With soft light you can always up the contrast in your image editing software.

My favorite place to take pictures of small things is my kitchen table. It's in a nook with windows facing north, east, and south. I usually take pictures when the sun is in the west, and I use the overhead lights to fine tune the shadows.

A tripod (even a cheap one) can do wonders when it's darker (or even if it's not). In the picture I posted above I was visiting my parents and didn't have my tripod or my kitchen, so adaptability was the word.


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PostPosted: Sun Sep 26, 2010 12:13 am 
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I suggest using a light tent for better light control in imaging anything with a shiny surface. There are commercial tents available starting at about $15 and ending at several hundreds of dollars. You can use a white lamp shade or make something yourself. There are many methods of building light tents outlined on the net. Once the tent has been made, use a seamless background in a contrasting color for the instrument to lay on. There are some rules to be remembered when using a light tent to photograph shiny objects, but the best one is to keep the reflection of the camera off the object.

Lighting can be accomplished by using lamps of identical type (color) on each side of the tent, and perhaps a lamp above and/or in front of the object. Soften all shadows by moving these lamps. The idea is to maximize the apparent size of the light sources and to make all of these sources from the same temperature lamps. If all else fails capture the image outside on a bright, but cloudy day - with or without a tent. The clouds actually create a big light tent.

The quality of the image will ultimately be dependent upon two factors: the quality of the lens, and the amount of control you are given by your camera. The barrel distortion factor has already been discussed. Many times the lens distortion can be minimized by minimizing your aperture. This increases depth of field and uses a very small portion of the lens right at the center. This is usually the clearest area of the lens.

As has been stated earlier, move further from the object to be captured and frame by zooming or use a long lens (at least 100mm on a 35mm camera). Then adjust the depth of field by using the smallest aperture (f-stop) that you can. As the lens increases in length and the aperture decreases, the differences in distance between the parts of the object and the focal plane of the camera become less, therefore minimizing distortion. Try to keep the camera at right angles to the centerline of the instrument if at all possible. (A tilt-shift lens will help solve this problem.)

Spot meter the image on either the brightest point , or darkest point of the object in either manual or aperture priority (small aperture). Remember that your eye sees a considerably wider range of light intensities than your camera does. Metering on the highs will cause the shadows to deepen (but we positioned the light to minimize the depth of the shadows). Metering only on the shadows may cause the highlights to over expose. If your object is a metal flute with a wooden mouthpiece, you may want to spot on both the metal, then on the mouthpiece. Those two values will be the ends of the range of shutter speeds that will be somewhat acceptable. Some of them may require the use of a tripod and remote shutter release (timed shutter release if a remote is not available.)

I hope this has helped.


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