A question we were asked was how the DOF (depth of field) compared between the Sony PXW-Z150 and an older camera such as the Sony PMW-EX1. The sensor on the PXW-Z150 is one inch, twice the size of the older sony camera. The older camera however has a faster lens. The EX1 had the Fujinon 14x Optical Zoom, f/1.9, the Z150 has a Sony G 18x F/2.8-4.0 lens.

I was curious as to how the numbers would play out in terms of an actual look. Below is a very quick and dirty test to see the differences. It was just me (Jonathan), so a light stand is standing in for a simulated talking head shot.


The cameras were next to each other on tripods and exposed to roughly the same exposure. Now I must note that I didn’t have access to an EX1, so we used an EX3 which is an almost identical camera for this test.

If anything, it looks like the older camera has a very slight edge in shallow DOF. As noted in our review of the Sony PXW-Z150, it was never going to give you super shallow results.

Camera settings (to achieve similar exposure in the room)
Sony PXW-Z150: F4, 6db gain, Shutter 1/30

Sony PMW-EX3: F1.9, 0db gain, Shutter 1/60


Test 1
Simulates a MCU shot (head and shoulders). The cameras are placed roughly 2.5 meters from the subject (the light stand). The background is roughly 3 meters behind the subject. This is roughly mid-way through the zoom’s range.



Test 2
Simulates a CU shot (or somewhere between a CU and an ECU. Think mouth to eyes in shot). The same positioning was used as the test above. This is very close to the full tele end of the zoom (ignoring Clear Zoom on the Z150).



Another part of the orignal question was regarding low light performance. The new camera with twice the sensor size surely kills the old camera? I’m not so sure. I don’t have any shots to show unfortunately, but I did a few quick tests with the cameras side by side. Due to the much faster lens on the EX3, at the long end at least it might have the edge. It lets in a ton more light (more than double) and thus gives a pretty good result. The Z150 needs a lot of gain to keep up (but then its gain is a lot cleaner overall).

At the wide part of the lens (where the Z150 is at 2.8), even though it needs gain to keep up with te EX3, the overall image is nicer (to my eye at least).

Finally it was asked how the long end of the two cameras compare (with Clear Zoom enabled on the Z150). If you have enough light, you can get closer and still maintain a solid image.

Thanks to MichaelSlowe for the question.