Laura and I recently picked up a wonderful portrait lens to add to our collection: the Canon 50mm F1.2 L lens. It can do such a shallow depth of field, that the plane of focus is much less than an inch deep [0.84 inches, to be precise] even over a distance of several feet. To illustrate this, here is a sample picture of the inside of our Media Center PC, which I was repairing the evening the lens arrived:
If you look closely, you’ll notice that the one place I focused is the screw and tab right above it. Everything else in front or in back is out of focus.
Of course, this has some challenges, as well. The lens is great for low-light situations and shooting without artificial light – especially where we can get the shutter speed very high. However, using regular strobes it is a challenge – we can’t set the shutter very fast due to the fact that our strobe setup won’t allow us to fire any faster than 1/160. This means that in the studio, the largest aperture we can use even at ISO100 is f13. Oh, we can probably get away with f9 and push the exposure down in Lightroom, but adjusting exposure is tricky and we’d run the risk of the image not being properly exposed in some places due to some digital compression at the edges of the histogram [at the extreme ends of the dynamic light spectrum, that is either very light or very dark sections of the image] caused by the overexposure and resultant digital manipulation.
In other words, the picture wouldn’t quite be as good as it could be.
Mainly, this is due to the fact that our lights are “budget” lights – fairly inexpensive in the grand scheme of things. They’re not adjustable for output like the more expensive units, but we bought these for the “constant light” capabilities that allow us to plug in some [now] huge 50-watt daylight balanced fluorescent bulbs to replicate window light. The problem with this end, however, is that these are too dim. We have to use ISO400, f4.5 and 1/160 to properly expose. This has the positive effect of completely blurring the background, but the negative one of making the focal plane too narrow for more than one person’s portrait, or more especially a moving child [and they move a lot!]. This is much better than it used to be when we were using the 27-watt bulbs which forced us at ISO400, f4 to use 1/60.
In summary, our constant lights are too dim, but not as bad as they used to be and the strobes are too bright. After a shoot with a mother and child in the constant lights with the baby squinting into the soft box [which I had previously thought might be better for the baby since it wouldn’t “explode” with light when we took a picture], I’m much more inclined to use the strobes on people and the constant light on objects.
Although, the strobes work great on objects, too [ISO100, 50mm f13, 1/160]:
[I guess that dust on the helmet means I need to go for a ride…]