I’m a big fan of shallow Depth of field, where the background smears out to a gooey mush and the subject is kept sharp. If you’ve ever tried to take shallow DOF photos with a digital compact camera, you know that it’s really hard. The smaller the sensor/film size, the deeper the depth of field becomes. To understand how this affects real life picture taking, I took a quick and dirty test with four different cameras. Here are the results.
Warning, this is not a scientific test. Everything was improvised, using camera placement to keep subject roughly the same size and place. All photos were taken at f2.8. The 35mm photo was scanned from a 10×15cm print, the 120mm was a quick&dirty scan on a Canonscan 8800F without dust removal. Don’t mind the terrible look on the scan, the exposure in real life is much nicer.
This is taken with the Canon G9 digital compact, a 12megapixel camera with a 35-210mm lens. Shot at f2.8 at around 35mm.
This is taken with the Canon 40D and the 17-55 f2.8 IS at f2.8 at around 35mm.
This photo is taken with one of the smallest 35mm film rangefinders, the Olympus XA. It has a prime lens at 35mm/f2.8.
This 120mm medium film format photo is shot with a Mamiya c330. The lens is a f2.8 80mm.
Summary
If you’re looking for creamy bokeh and good subject/distance separation, you won’t find that in a digital compact camera. You need to move back a lot and zoom in to get similar background blur, but of course that changes perspective and makes things flatter (which you might want if shooting portraits). Even the 1.6crop camera 40D has noticeable more DOF than the 35mm one. Just look at the tripod legs the bear sits on. The medium format is totally different looking, it really melts the background completely. For me, it has made me want a full-frame digital SLR, but in the meantime I have these great film cameras that I paid next to nothing for! The medium format camera cost one third of the price of the Canon G9. If you’re into shallow DOF you should just get yourself a couple of rangefinders or a medium format camera right away.
Update: A different DOF comparison with Canon lenses and full frame vs crop: http://www.seriouscompacts.com/2007/12/canon-lenses-on-full-frame-vs-crop.html
If you compare a 50mm f/1.8 lens on a full frame camera with a 28mm f/1.8 lens on a crop camera, the end result will be similar when it comes to framing. But the larger sensor will still yield about 1 & 1/3 stop less DOF.
If you’re shooting with a crop DSLR, you should get wide lenses with low aperture values to get shallow DOF. This was taken with a Canon EF 28mm f/1.8 at f/1.8. Notice the shallow DOF – my nose is out of focus. Yes, I have a big nose, but still.
Links
Test of the Minolta Autocord medium format camera
Get yourself a rangefinder!
4 classic rangefinders: Shootout!