Thoughts on cameras with small sensors

This is an observation which could be easily put down with a lot of numbers and equations, but I try to keep this as brief and simple as possible.

Common wisdom:
Cameras with small sensors are always bad at low light situations.
Cameras with larger sensors are better in this case.

My observation (Doug could put this better in numbers and equations than me) is that in the case you are looking for a larger DoF at low light while preserving conveniently short exposure times, you are better off with a camera that has a small sensor and a wide-aperture lens. While keeping the advantage of the large aperture helping to keep the ISO setting low and the DoF is larger thanks to the smaller sensor compared to 36x24mm or other large sensors.

Of course - if you want to have small DoF, you need the larger sensor - this is a special case.

I think it is useful to be more use-case oriented and choose the tools accordingly.

Something to ponder...

Best regards,
Michael

Hi Michael,

In general, as you put it, I would tend to agree with your suggestion, however it would be better to specify if you need to keep the original frame constant or not.

Kind Regards,

Fotis

So what super wide open lenses are there for these small sensor cameras? I'd add that one needs to specify rapid accurate focus for serious consideration.

Of course, once could use a 50 1.2 on a Canon 7D but I think you want to have an even smaller sensor than APS-C size.

Asher

Just as ballpark figures:

Take a compact camera with a 2/3" sensor at 8mm focal length and f2 (like the Fuji X10).
At 3m focusing distance you end up with a DoF of 7-8m.

Take a D700 with a 35mm lens (do not forget that all this is approximate to give an idea) at f2.
You end up with less than 90cm of DoF.

Just think how far you have to stop down to achieve the same DoF with the larger sensor camera and what does it mean to ISO and/or exposure time. Solution: It is a little more than f8.

The D700 will probably still have the edge in this example, but by less than most would expect.
Focusing is less an issue for the compact camera here (and they are getting better) as the DoF is conveniently large reducing the risk of a miss.

If you need the edge, go for the larger camera, but you might be surprised that the smaller camera is not that bad in this case.

Samsung has announced the EX2F which starts at f1.4 at the short end of the zoom lens while having a 1/1.7" sensor.
There is the Olympus X-1 starting at f1.8
The Panasonic Lumix LX7 starts at f1.4 (and has f2.3 at the upper end of the zoom range).

Best regards,
Michael