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Working with lenses, and evaluating lens quality and performance can be, on the one hand, one of the easier things in photography to quantify. Optics is a well-understood science, there have been few breakthrough developments in lens construction since as far back as the 1950s. It’s been said that there have really been no discoveries in optical science since the ‘20s, in fact- although the introduction of metallic multi-coatings and glass formulae have certainly come a long way since the ‘60s. Getting performance numbers for lenses is almost as straightforward as hooking up a race-car to a dynamometer. The results are pretty much irrefutable. 

This has got to be the ultimate Head-2-Head.  We got together the Canon 5D Mk II, Canon 7D, Canon 50D, Hasselblad 31, Hasselblad 39, Nikon D3s, Nikon D300s, Nikon D700 and pulled together a willing (and patient) model and shot with every one of the cameras for three basic sets- a head-and-shoulders shot, a full-body shot (both with strobe) and a tungsten-lit portrait. 
 

It was a blast- but not without some hurdles.  You know, think of the last shoot you did with a model, and then asking her to just "do that thing you just did again", only 6 more times! 
 

It also was really interesting from a camera evaluation, hands-on shooting perspective.  Even with an assitant prepping the cameras, and some pretty good experience handling all of these products, there were some cameras I didn't like based on simple feel and controls alone.  We're working on a few comparison reviews including the big-chip Hasseys compared to the smaller DSLRs, a comparison between brands, and even a shootout within a brand's product line.  Stay tuned, but for the time being, take a look at some of the shots we did. 

What is noise?  Where does it come from?  How does it affect the image?  These are all good questions that are often answered by, "Well, it's like film grain...".  Although a good starting point, this really isn't correct, and even a little misleading. 

Film grain comes from increasing the size of the light sensitive silver-based crystals in the film's emulsion.  You see, when you try to boost the sensitivity of the emulsion by boosting the size of the crystals, a coarse, well, grainy effect. The grainy effect will correspond to the colors in the dye layers of the emulsion. 

Noise in a digital file comes from turning up the gain- the volume, if you will- on the base signal, and, as a result, turning up the "static" in the file, too.  The example I always use is trying to record a conversation in a restaurant- if you turn up the volume or sensitivity of the recording, you're turning up the background sounds too.  This all gets back to the basic electronic concept of signal to noise ratio- for every technology you have a signal- the stuff you want- and noise- the stuff you don't want.  The standard approach to getting rid of noise is to identify the noise and use that pattern to negate it. 

Here's a video tutorial illustrating how to setup and utilize the Lens Align focus calibration system. Be sure to check out this tool if you have a microfocus adjustment on your DSLR!