Wednesday, September 4, 2013

Remarkable Low Noise



This is an unexpected surprise to me concerning the EOS 5D Classic - even though the ISO only goes to an unimpressive 3200, using the "extended" setting (all new DSLR's can now reach at least 12,800, with premium models going as high as 102,800, which is 5X better than the 8 year old 5D Classic), I was amazed to find how exceptionally absent the noise is with this older camera.

I took both of these pictures last night with the ISO set at 1600 in a very dimly lit room, and just to get any kind of realistic shutter speed (which ended up at an insane 1/4 sec) I had to apply an exposure compensation of -2 EV. The lens I was using was my 28-105 zoom, set at around 35mm, and so my Aperture was "wide open" at f4. So, in every respect, we're "way down there" - I've never had a full frame DSLR before, and I just surrendered an almost new Rebel T3i (APS-C 23mm size frame, 18 Megapixels) to buy this 8 year old 5D (Full Frame 35mm size, 12 Megapixels). Cost wise, it ended up being close to an even swap for me, although to get the 5D, I had to put out some extra cash to buy two lenses, pay for delivery,  and some unique accessories.

I thought these shots would be hopeless - with four things working against me:

  • Hand-holding a 1/4 sec shutter speed with no Image Stabilization
  • -2 EV - you "never do this with a digital camera", as you're shooting way down in the less-significant data
  • Wide open Aperture contributes softness to image
  • Using camera's next to very fastest ISO is bound to make a lot of noise / speckle
  • Dim ambient light with no AF Assist would normally result in extreme difficulty focussing
I shot these with RAW, which allows me to re-expose everything in Software - with RAW, you can reset the White Balance, lift a -2 EV exposure back up to normal (and usually end up lifting a lot of noise with it), and also apply noise reduction if needed. You can also vary the colour curve from the characteristic RAW linear curve to a more visually appealing S-curve that will enhance the look of your photo in many ways; usually this will increase noise also. To do RAW processing, I use Photivo, which is an Open Source (free) Adobe Lightroom clone for Linux, Windows and Mac.

I was totally blown away by the lack of noise in these shots, in spite of having these four significant factors all working against me. For the first one, Merlin, I didn't apply any noise reduction at all. For the second one, Larry, I applied one step. It is clear that a full frame DSLR is in another league entirely, in spite of what the usual specifications might tell you. In fact, it turns out this laughable ISO 1600 capability is behaving a lot more like 6400 - at least twice as good, and probably more. It turns out that even though you cannot select an ISO better than 3200 directly, you can safely do it indirectly by going into the basement with lots of negative Exposure Compensation, knowing that you can lift it back up with RAW software in post-processing. It's great to know that I can safely do that with this camera. The reason? Again, it is the laughable by today's standards specification of only 12 Megapixels on a full frame sized image sensor. This is what is called a very low "pixel density" and when you have that, you have a lot less pixel elements crammed onto the sensor surface, and this means each individual element is far more sensitive to light, which gives a much better signal to noise ratio. The 5D Classic was a professional camera, and a professional would know how to make this work for him, in spite of the extremely conservative specification placed on this camera in it's day - eight years ago.

Does this mean that owning the EOS 5D Classic is going to sway me back to being a digital fan? Well, I  can say this - what I've done here cannot be done with film easily. There is a Fuji Superia 1600 film on the market, but it's quite expensive. In theory, it would've given me the same shutter speed under the same conditions, but it's unknown to me how it would behave under dim tungsten lighting - a digital camera allows you to select any white balance, or even automate it. Also, it's guaranteed this film, as good as it might be, will show a significant amount of grain. Film and digital simply aren't the same thing, and comparisons made at this end - the dark end of things, will most certainly favour digital. I know this coming weekend, I'll be just fine shooting the cat show at ISO 1600 with my 5D Classic. I'm going to try a few shots with my Elan-7 loaded with Fuji X-tra 800 ISO, just to see how that works. From what I've seen, film works far better under bright light. When it comes to sunny daylight exposure, film says "bring it on", while digital seems almost afraid of it. I am eagerly awaiting a sunny day to try out the 5D in bright light, just to see if the full size sensor exhibits a more film-like behaviour at the bright end.

But do I like my EOS 5D Classic? Oh yeah! Very impressive.

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