Why lug a DSLR around?

Cameras of all sizes have been getting consistently better over the years.  The $600 (including lens) entry-level D3100 takes better pictures than the original $5,000 (body-only) D1 did years ago on its introduction. Compact cameras have benefited on a similar pace, from shooting VGA photos that were at best sufficient for the web, to being indistinguishable at smaller sizes and in the right lighting conditions from much more expensive cameras. The compact camera segment itself is under significant pressure, as an increasing number of people find themselves satisfied with the picture taking capabilities of their cell phones. With all these improvements, are the differences still worth all the extra weight that each size class brings with it?

The Rogers Cup was a great place to ask this question, as the first day that we made an impromptu trip there, I didn’t bring a DSLR and only had my S90 compact camera. I’m still really glad I brought it, but how did it do in general? Here’s Kim Clijsters during her practice, at 6:38pm last Saturday:

I was right up at the edges of the court, but my S90 was still at f/4.5 and ISO 320 to get even remotely enough speed to capture the shot. We were back the next day, same court, 6:34pm – this time, it was Svetlana Kuznetsova from Russia who was practicing:

This second shot was with the D7000 at f/5.6 and ISO 450, using the 70-300 VR lens.  At these small sizes, the pictures might not look too different quality wise – but click for larger versions, and you’ll see an enormous difference between the two. In addition, I was much further away with the second picture thanks to the added reach of the 70-300 (and I was only at 100mm!). Sitting for a brief period at an actual game at center court, I really needed the full reach of the 70-300:

At maximum zoom on the S90, the player pictured – Japan’s Kimiko Date-Krumm, in a match against China’s Zheng Jie – would have been six times smaller!

It goes without saying that sports, where both speed and reach are needed, are where you’d expect a DSLR to do well versus compact cameras. What’s worth emphasizing here is that it doesn’t take much equipment to get half-decent results; you could have gotten identical shots to the above with the D5100 ($800) and 70-300 VR lens ($550).  You could get near-identical results with the D3100 ($600) and the 55-300 DX VR lens ($350) that pro photographer Thom Hogan posted a positive review of today.  In fact, I dare say that even at my limited skill level, you’d even get basically the same results with a used D80/D200 and 70-300 non-VR, the combined used price of which is not far off what I paid for my S90 compact! Pro-level gear for sports gets very expensive, very quickly – to the tune of $5,500 if you want a 300/2.8 lens instead of the 70-300 I used – but you can still do pretty decently at your kids games for a tenth of the price (and only a little more than the price of a compact camera).

At the heart of these differences is just basic physics on the differing sensor sizes:

• The iPhone 4, which is very well-regarded and well-specified for a camera phone, has a 1/3.2″ sensor that’s roughly 4.5mm x 3.4mm = 15.3 mm^2 in total surface area.
• My PowerShot S90, generally considered to be a very competent compact, has a 1/1.7″ sensor that’s 7.6mm x 5.7mm = 43.3 mm^2 area (2.8 times larger than the iPhone 4 sensor)
• Nikon’s DX cameras, like the D5100 and D7000, have APS-C sensors that are 23.7mm x 15.7mm = 372 mm^2 area (8.6 times larger than my S90)
• Full-frame cameras like the D3 series are 36mm x 24mm = 864 mm^2 (2.3 times larger than DX cameras, and over 56 times larger than the iPhone 4 sensor!)

There’s a pretty notable difference between tiers, but the gap between a competent compact and an entry-level DSLR is by far the largest – and at the end of the day, more area means more photons can be captured. There are interchangeable lens formats like four-thirds that fall somewhat in the middle, but overall, it’s not surprising to see that results seem to be consistent with physics.

The other relevant difference not mentioned above is the lenses.  The iPhone 4 has a fixed 28mm-equivalent lens.  The S90 has a 28-105mm equivalent zoom range. My D7000 with the 18-200 has a 27-300mm equivalent zoom range, and the bag of three lenses I took on Sunday had a 15-450mm range (with some gaps in the middle). Of course, there are compact superzooms, and even cameraphone accessories, but you clearly give up a lot on the reach side with smaller cameras.

In the end, smaller cameras may suffice for many things, but since running kids is a big part of my agenda, I’ll still be lugging the heavier cameras around. I still just wish I had been last Saturday when we met Kim!