Archive for the 'creations' Category

13
Nov
09

Photographic firsts

I recently posted two images on my photo blog, both of which represent firsts for me.  Since the photoblog is kind of minimalist, I didn’t write much about them there, but I thought I should maybe add some info about them here.

The first was taken using a zone plate, which I got ages ago but never used.  I got it last year at my birthday in a kit like this, which includes a device for holding photographic pinholes, the pinhole itself, and an adapter to make it fit my camera.  I had taken a few photos using the pinhole but never the zone plate.  I like the effect.  There are a couple of downsides to using either the pinhole or the zone plate, however.

First, these have incredibly narrow apertures, which means that, in order to get a correctly exposed image, you need a very long exposure or very high ISO setting.  I kept the ISO reasonably low but I used my tripod to give me the stability I needed for a long exposure.  I used a 1.3 second exposure, which, for a shot taken in the middle of the day, is really long.  This zone plate has f/56 (not 5.6, 56!), which is pretty wide for this type of device.  The pinhole I have is something like f/130, so it would require a much longer exposure.

Second, whereas taking photographs with traditional lenses is pretty forgiving when it comes to junk on your sensor, pinhole and zone plate photography is extremely unforgiving.  I had to do a bunch of spot removal in Lightroom to get rid of a bunch of ugly splotches on the image.  The image below is a 1:1 crop from an image I took of the same scene with the pinhole.  There are at least 4 spots that are clearly visible, though they vary in severity.  I had never noticed these spots before in shots taken using my normal lenses.  I guess if I want to do any more photography using my pinhole or zone plate, it’s probably time to have my sensor cleaned again.

Spots on my CCD

 

The most recent picture is my first foray into high dynamic range (HDR) photography.  I’ve been interested in this for a while but never really pursued it.  The point of HDR images is to make details visible in both the highlights and shadows of an image. Generally, both the camera sensor and any typical viewing medium (like a monitor or even printed photos) don’t have enough dynamic range to either properly capture or properly display details in both an image’s shadows and highlights.  There is just too much difference in brightness between the darkest parts and the lightest parts in a scene for the camera to capture everything or for it to all be faithfully reproduced on a monitor or print.  So some kind of workaround is necessary.

Due to the limitations of the camera’s sensor, capturing the details in both the highlights and shadows requires multiple images to be taken at different settings, a technique called exposure bracketing.  In the simplest case, exposure bracketing involves taking the following 3 photos: one that’s significantly underexposed (to capture details in the highlights), one that’s properly exposed, and one that’s significantly overexposed (to capture details in the shadows).  These images are then imported into a program on a computer that merges them to produce a composite image that has a much higher dynamic range than can be captured with a single exposure.  Unfortunately, this image also has a much higher dynamic range than can be displayed on a monitor or on a print, so another step is necessary.  This step is called tone mapping.

Tone mapping takes a HDR image that can’t be displayed and maps its brightness values back to a range of values that can be displayed.  When an image is captured, the darkest darks and the brightest brights are “clipped”, which means they’re simply cut off – detail in those areas is lost.  Taking multiple pictures of the same scene using different exposure settings gets back the data that was clipped.  Tone-mapping could simply clip the data again, however that would throw away the detail we want to preserve.  Instead, tone-mapping compresses the dynamic range, so that the details are preserved in both the highlights and shadows.  Modern tone mapping algorithms are actually quite a bit more complicated than simply compressing the dynamic range.  Rather, they operate on the data both globally and locally to try to maximize the extent to which details are visible in the image while simultaneously compressing the dynamic range to something that can be viewed on a monitor or print.  This often results in a very striking, though sometimes unnatural-looking image.

Yesterday I was looking through my to do list and I found a reminder to buy some software for making HDR before I graduate so I can take advantage of their (60%!!) educational discount.  Having just sold our exercise bike, I had some cash on-hand so I decided to go ahead and buy the software while I thought about it.  I bought Photomatix from HDRSoft for about $40 rather than the usual $100.  I remembered that I was out a month or two ago and for some reason decided to take some shots using exposure bracketing, so I looked through my Lightroom catalog and found a few sets of exposure bracketed images.  I picked the set that I liked best, exported it to Photomatix, created the HDR image, re-imported to Lightroom, fiddled a bit with saturation and noise reduction, and then exported from Lightroom to PixelPost.  Done.

Having a tripod makes HDR photography easier, so I’m looking forward to using my new tripod along with my new HDR software to produce some good looking images in the future.  Stay tuned.

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24
Oct
09

New Tripod

My birthday was a couple of weeks ago and in the weeks leading up to it, I spent some time trying to fill out my wish list on Amazon.  I would like to briefly plug their universal wish list button – you can add it to your browser’s bookmarks toolbar and then add anything you find on any website to your wish list.  That’s pretty handy.

Anyway, I have wanted a sturdy tripod for a while.  After a lot of looking, I decided that I wanted a ball head since I had grown tired of having to adjust two or three knobs in order to get my composition right.  I settled on the Manfrotto 322RC2. It seemed like it would allow incredibly fast composition changes and would be very comfortable to use.  So, that found its way onto my wish list.

By pooling together money I got for my birthday I was able to get the 322RC2 head with the Manfrotto 055XPROB tripod legs.  I haven’t had a lot of opportunities to use everything yet but so far I really like it.  The ball head is so nice.  It is super easy to change your composition, very quick, and it locks solidly into place.  The legs are big – if I extend the legs fully, the eyepiece of the camera is at eye level without raising the center column at all.  This is great because it maximizes stability and gives me some freedom to play around with shots that might require the camera to be above my eye level.

Continue reading ‘New Tripod’

11
Sep
09

New header image

The observant among you (who also follow my photoblog) may have noticed that my new header image is the bottom portion of this image.  If you did, congratulations.  If not, consider this post a plug for my photoblog.

09
May
09

Camera hook

Since I got my DSLR in 2007 I’ve been trying to work out a good scheme for storing it.  Basically, it resides either on my desk or in my camera bag.  Both of these locations are somewhat problematic.  If it’s on the desk, it gets in the way of things since it doesn’t really have a permanent place assigned to it.  If it’s in the camera bag, I have to dig it out whenever I want to use it, which is usually when one of the kids is doing something cute.  Unfortunately, I often miss shots because of the time it takes me to dig the camera out of the camera bag.

The whole situation was complicated this winter when I got a flash and a flash bracket.  I also got a Gary Fong LightSphere II on Alex‘s recommendation.  This setup produces great quality images but it’s pretty unwieldy.  In addition, the whole thing is very top-heavy and is prone to falling over if it’s set upright.  However, if I lay it down, it takes up a huge amount of desk real estate. Since I want to be ready to take pictures at a moment’s notice, I want to leave the whole thing put together but I couldn’t find a good way to store it all put together.

I’ve considered hanging it on some kind of hook before but I never got around to pursuing that idea until this week.  In designing it I made sure it would be able to handle the considerable weight of the camera, flash, and flash bracket.  I also spent a lot of time making sure that the camera would hang upright.  Finally, I designed in a little locking mechanism so the camera couldn’t be inadvertantly bumped off the hook.  In the photos below, you can see the results of my efforts.

img_3499_blog.jpg

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Overall, I’m really pleased with the way it turned out.  As they say, however, “the proof of the pudding is in the eating”, so it remains to be seen whether it actually accomplishes the goals I had for it.  For now, though, I’m content to sit and admire my handiwork.




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