Wednesday, September 29, 2010

Fast Glass Pt. 2

http://articles.moneycentral.msn.com/Investing/Dispatch/market-dispatches.aspx?post=1810864&_blg=1,1810864So, I decided to add pictures to my description of Fast glass to help showcase what I am talking about.  I took all these pictures with a constant ISO (which was set to 200), I did this so I could show the affect changing the Aperture would have on the photos.  I was set to Av mode on my camera (aperture priority), so the camera would take the ISO and Aperture value that I choose and then chose a shutter speed to properly expose the photo (Review the exposure triangle here). 

Now I can hand hold my camera down to a shutter speed of about 1/60 with my 50mm lens on my camera.  Any lower and there is a high likelyhood of blur.  For this example however, I put my camera on a tripod and didn't use a flash or anything.  I just had the lights on in my living room.  A few things I want you to notice: 1 depth of field, notice how much is in focus in the first picture and how much is in focus on the last picture.  The first picture has very little in focus compared to the last one (see how each picture gets more and more in focus).  The lower the Aperture value (i.e. 1.8 vs 5.6) the less that will be in focus, the rest gets blurry.  2. notice how the shutter speeds change.  The first shutter speed is 1/60, the final one is 1/2 seconds.  There is no way on earth I could hold the camera still for half a second while the shutter is open.  If I wanted to use a higher aperture (like in the last photo) I would have to raise the ISO which creates more noise in the photo.  Anyway, here we go (these are all pictures of a quilt given to us for our wedding)...
F 1.8 shutter speed 1/60. Only picture I would have been able to hand hold the

 camera.

F2.8 Shutter Speed 1/30 Notice the Second diamond from bottom is starting to be in focus

F4.0 Shutter 1/15 More is in focus

F5.6 Shutter 1/8

F8.0 Shutter 1/4

F11 Shutter 1/2  Notice, pretty much everything is in focus (Depth of field) but only because nothing was moving.
Notice how every time I made the Aperture bigger the Shutter speed was cut in half.  That is because I was making it so there was one "stop" of light less. So the shutter had to be cut in half to make one "stop" more light so we would get the same exposure. 
If you want to see all the pictures larger in a one after another process click here.  You can also pull up the EXIF (shutter speed, iso, f settings) on the right side of the page if you click more information.  Hope this makes a little more sense.

2 comments:

  1. Very cool! I need (or should I say want) a new lens! I gotta get me one of those 50mm lens. I forget, does yours have auto and manual focus?
    -K

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  2. It does have both manual and auto focus.
    Some of the really fancy lenses allow you to focus in auto mode and then instantly be able to adjust it manually (so you would be overriding the auto focus). Neither of my lenses allow for that, but I'm not too sure I would use that.
    Here is a link to the lens I bought ($100).
    http://www.bhphotovideo.com/c/product/12142-USA/Canon_2514A002_Normal_EF_50mm_f_1_8.html
    It is my favorite lens and hardly/never leaves my camera. Although, parts of me wish I would have bought the model up ($350).
    http://www.bhphotovideo.com/c/product/12140-USA/Canon_2515A003_50mm_f_1_4_USM_Autofocus.html#reviews
    The focus is quieter and better in lower light. There is also a 85mm prime 1.8 lens ($380). http://www.bhphotovideo.com/c/product/12182-USA/Canon_2519A003_85mm_f_1_8_USM_Autofocus.html#reviews
    That also has the better focus motor.

    all in all, I love my 50mm lens, and I don't take it off my camera, my next lens will be a telephoto zoom, because that is the range I don't have covered.
    Hope that helps.

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