^The E-P1 on a Sigma 300-800mm f5.6. On a 4/3 camera, this Sigma lens covers an equivalent field of view to 600 to 1600mm. I have not done the arithmetic to figure out what it will be on a M4/3 E-P1 or GF-1.
If you have some legendary regular lenses from your film cameras, and provided that the right converter is available, should you invest in a full-frame DSLR or shift allegiance to an interchangeable-lens serious compact?
The question lingers over my mind after I checked out the full-framed A850 last week.
Deterioration of Optical Quality
For some technical reason of the imaging sensor, full-frame DSLRs demand harder from regular lenses than the SLRs do. The top-rate regular lenses perform less good optically on full-frame DSLRs than on SLRs. No wonder that since the advent of the fuller-sized digital cameras, digital-specific lenses have been launched.
Simply put, these full-frame DSLRs exaggerate the optical weaknesses of lenses in relation to sharpness, chromatic aberration, distortion and falloff especially along the edges.
In the case of serious compact cameras, the smaller sensors make use of the central area of a regular lens. That is to say, on these serious compacts, the regular lenses will see much milder optical defects along the edges. It follows that, unlike on full-frame digital cameras, the widest aperture in the case of these compact cameras is still desirable.
Insignificant Image Quality Difference
In addition, unless you make large prints regularly, the extra image quality afforded by a full-frame DSLR is not actually visible. Fact is, some professional photographers have noted that even for 20 by 20 inches prints, the full-frame sensor doesn't have an obvious advantage over the APS-C sensor.
In other words, you will be better off with a smaller-sensor camera on a regular lens. This applies to all APS-C sized sensors. But now we have the better option of M4/3 cameras.
Theoretically, M4/3 cameras boast an additional benefit. In taking photos, a larger quantity of blurry images are caused by the operating reflex mirror and shutter. Since the M4/3 cameras do away with the reflex mirror (another one if Samsung's NX camera), the camera probably suffers a lower failure rate due to the vibration.
Back to the question: Investing in a M4/3, or any interchangeable-lens serious compact for that matter, is more preferable than in a full-frame or even a APS-C sensor DSLR. On second thought, this conclusion still makes sense even if the old regular lenses cannot operate on the serious compacts. Well, portability counts. I could sell my old Minolta lenses if I have to make the choice.
The serious compact cameras are gradually taking the throne of the popular camera market. The juggernaut this trend is.