DA40 XS on the Q
The Pentax Q has a tiny little mouse dropping of a sensor, 1/2.3″ (a measurement as clear in information as liters/100km would be to a horse that just found out he had one horespower) What it means though is that it only has about 1/30 of the surface area of a 35mm film frame. If you want to equate the field of views between those two disparate sizes while using the same lens you need to multiply the focal length by 5.6 on the Q. In this case the DA 40 XS would wind up being the equivalent of a 224mm f2.8 lens on 35mm film. And that is what makes this a neat little combination, it functions like a close focus telephoto and because the lens is so thin it fits the little camera nicely. Another benefit of the small sensor is that it provides greater depth of field for a given aperture. I know that sounds counter intuitive in this ‘thin is in’ shallow depth of field mad world but when you’re measuring it in millimeters having a little extra in focus without the need to stop the lens down can be a real advantage. So not only is the DA40 XS a great lens on an APSc DSLR with an adapter it fits nicely on the Pentax Q and here is another hint ‘it fits on a 35mm SLR’ too Pentax-DA 40mm F2.8 XS on film.
