09 May 2014

Something about photography: Part I maybe

Hi kids

So I guess this month's post is going to be about photography. Last weekend was AAA's spring photoshoot over Weeks' bridge and I realized a lot of people have misconceptions about how photos come out the way they do. So I thought I'd do a post about it.

Basically, there's something to be said about the difference between the effect of the camera body, lens and post-processing on a photo. A lot of people who don't know much about photography kind of lump the body and lens together as the 'camera' unit, and don't really think about post-processing. I used to be like this before I started taking photos. 

There were two cameras that we used primarily to shoot with. One was mine, a Sony NEX7 and Alex's, an Olympus EPL1. As you can tell from the images, the type of camera used doesn't matter as much as the lens or the post processing. Unless you're doing professional photos, a good kit lens will do you pretty well. A step up from that would be a fast lens for bokehgons in the background. (A fast lens is a lens with a big maximum aperture, or low f-stop number. This means it can let more light into the camera at once, and there is a shallower depth of field for subject focus (see physics textbook). For instance, the image below was shot with a lens at f2.0 which is relatively low. My lens ranges from f1.7 to f22.)

^bokehgons (bokeh = blurry background, bokehgonz = our slang for hexagon-shaped blurries)

There is also the difference between the types of photos your camera can produce. RAW and jpeg photos both can come out of your camera. Fancy cameras can even let you shoot both of these at the same time. RAW files are not really images at all, but they are a set of numbers that tell the information for each pixel. So, they are completely uncompressed and literally are the numbers that your sensor reads from the light entering the camera. If you have a 24 megapixel camera, each RAW file is 24 MB big. If you have a 10MP camera, your RAW files will be 10MB big and so on. Think of RAW as an intermediate step between taking the photo and making a JPG. More often then not, people will let the camera process the RAW into a JPG, but sometimes it's more helpful to immediately save the RAW and process it later on the computer. 

Here is a test shot I did with my camera, one that was RAW and which I converted into jpeg after loading onto my computer, and one that was converted by the camera into JPEG (neither have been post-processed except for the raw to jpeg conversion):

^RAW
^JPEG

(Both these taken with Sony Nex-7 with kit lens)

EDIT: The nex-7 seems to have a really subtle difference between RAW/JPEG that people can't quite spot so here's a starker example from another camera I found online (source):



The differences are pretty subtle, but basically the colors on the RAW without other tweaks are usually flatter/duller (In the bike photo, you can kind of see this in the sky, the contrast between the water and sky in the jpeg is greater with the sky being lighter, whereas in the RAW they are more similar). This is because the processor in the camera puts emphasis on certain things to make the picture look better, while an untweaked RAW is exactly what the camera sensor saw. Some of you might ask, "Why shoot RAW at all then?"

So the reason I'm even talking about this is that because RAW files leave behind all the extra numbers, they're much nicer to post-process or edit since there is a lot of information retained that may have been lost if it had been thrown out in a jpeg compression. For instance, if you had been shooting into the sun and your subject's face is dark, you could easily pull out their features if you have the RAW file even if in the photo it looks completely black. This would be nearly impossible to do with a jpeg.

For the AAA photoshoot, I post-processed pretty heavily, since it was cloudy that day I wanted to add more of a warm atmosphere and brighten things up since it was supposed to be a spring photoshoot derp (it was actually slightly drizzling while we were taking photos). Here you can see some before/after comparisons for reference (I use Photoshop CS6 to edit my photos, you can also use Appeture or Lightroom for this task):



Taken with Sony Nex-7, Pentax 50mm f1.7 lens

Since I use photoshop, I'm able to save the edits I make on one RAW file (in the end, it comes down to transformation functions on numbers in the RAW file) and apply them to other photos. I did about the same thing for every photo, for consistency's sake. Of course, what comes out of the transformation depends on the input of the RAW file. Since we were actually shooting RAWs with two cameras that day, you might be able to spot some differences between photos' coloring since I used the same filter transform for photos from both cameras since I was too lazy to make 2 separate filters to make them absolutely consistent derp. For each photo though, I had to fiddle with the sliders a bit for optimal brightness and contrast. 

So, to illustrate what I mean by post processing vs camera/lens:



this photo was taken with Olympus EPL1 &  Panasonic Lumix 20mm f1.7 lens.  

You can kind of tell that the Olympus RAW picture is a bit brighter than the one from the Sony. But with slapping on a filter and twiddling some sliders, we can make them more or less consistent with each other. 

Okay so now that we've got that out of the way, you might be wondering what post-processing can and cannot accomplish. Basically you can change pretty much anything with post-processing EXCEPT:

- Blurriness/motion blur:
unsalvageable. usually due to long shutter exposure


- Out of focus:
unsalvagable (the background is in focus, the subjects out of focus. click to zoom if you're unconvinced, this is a more subtle example). happens due to bad focusing, either autofocus focused on the wrong thing or manually


- Noise, to some extent:
^original test shot. usually due to high ISO
^50% noise reduce (You can do this in Adobe camera raw. This is already super high, I usually don't like to go above 20 or 25). you can still see the noise
^100% noise reduce

Note it is sometimes desireable to have some noise in your photos. Makes it look more film-like or nostalgic, and especially works well with black and white photos. That being said,  you can add it afterward.  Digital noise looks really bad compared to to real film grain though. 

This is a noisy ass photo and I kind of like it that way


Mostly, I just use post-processing for color correction/lighting adjustments or to remove skin blemishes for portraits. I have also been known to cut together two shots to get what I need out of them lolol: 


^ before and after of a headswap (I took another photo of Eric on the left and Jesika on the right was blinking, but it was easier to swap in Eric's head from that pic than Jesika's)

You will see the advertising industry use the liquify tool in post-processing to make models skinnier/shape things as they see fit (and garnering media criticism in its wake). I only use liquify for fun such as to give my male friends boobs or bigger biceps hehe.

This is getting long so I guess I'll wrap this up for now, hopefully that gives you a taste of what post-processing can achieve. If people like this maybe I'll do more about cameras/lenses/more about editing/let me know :3