35mm F2 is not 35mm f2. You’ll see.

I shot a photo with my X100 of the great CliveCoffee pourover stand. Here it is

I was happy with the image overall, but not so much my main focus point, or the focus, front to back of the pourover stand. So later on, I grabbed my 5D MkII Canon, slapped the 35mm f1.4 L lens on it, and took this photo.

Similar depth of field, but I’m happier with my focus point, and I like this angle better. But there is a problem in comparison. This shot has slightly more blur in the background, but is shot at f3.2 (not f2.0 like the Fuji X100 shot above was done at).

I’ve long known that the image capture size, be it film or a CCD or CMOS sensor, has a lot to do with depth of field representation in a photograph. For instance, most magazine shots of food, beverages and such are usually done with medium-format cameras using 120 film, which is many times larger than 35mm. The bokeh, the background blur, is luscious with these cameras.

You can see the difference yourself between a typical point and shoot camera with a fingernail sized sensor, and a APS-C sensor camera, like most cheaper dSLRs or the Fuji X100, which has a sensor the size of a large postage stamp. Background blur is very hard impossible to achieve on a P&S camera compared to a dSLR.

Same is true then, when going from APS-C sensors to a full frame (35mm film) sensor. Here’s a shot of this same Clive Coffee brewer at f2.2 with a 35mm lens on my 5D MkII full frame camera.

I’m posting the f2.2 shot because I blew out the highlights too much on my f2 sample. But you get the picture here. The background is much more blurred than the Fuji 35mm (equiv) f2 shot above.

Several things are at play here. The Fuji shot is actually a 23mm lens photograph, when you take into account background blur. The “35mm equivalent” is only relative to the scene capture because of the lens crop. It is not applicable to the background blur. To do this test right, I’d have to shoot a 24mm lens at f2 on the Canon 5D MkII. But I don’t have a lens capable of going to 24mm and f2 (my 24-105L lens is a f4 minimum aperture lens). Still, I’m betting the 24mm f2 will have more blur in the background on a full frame camera than it will on a smaller sensor, cropped frame camera.

Anyway, when people talk about f2 on a point and shoot, or on a APS-C camera, the amount of bokeh, background blur always increases the larger the sensor (or film medium) is. F1.8 on the little Olympus P&S doesn’t even come close to looking like the f2 results on the Fuji; and Fuji’s f2 performance, while really good, can’t touch what a full frame lens shooting at the same aperture can do.