Originally posted by plunkstar So...If the optics for the 1.4 were carried over from the M to the A, the only real drawback of the M is the lack of aperture data in the EXIF file and light metering, which is just a press of the green button or a DOF preview which is right next to the shutter button, so not much effort required, unless I am mistaken. On the plus side build quality is better and the M seems to be half the price.
You are a small bit mistaken. Yes, you can do stop-down metering with the M-series lenses, but the meter is limited to center-weighted averaging only and may not be fully reliable as compared to open-aperture reading with the A-series lens equivalent.
The advantages of A-series over M-series on a Pentax dSLR go like this:
- All exposure modes fully supported*
- Better meter accuracy**
- All three meter modes supported (matrix, center-weighted, and spot)
- P-TTL flash support***
- Exif includes set aperture
I shoot with both A-series and M-series lenses and would choose A-series over M-series for general shooting. That being said, I also would not pay a high premium just to get the "A" contacts. Some consider stop-down metering an inconvenience and I generally concur, though I learned on and currently own several stop-down meter film cameras. In practice, I swing both ways fairly easily.
Steve
* When "A" contacts are not present, all modes except M, B, and X default to Av mode at
maximum aperture only.
** The reasons for this are complex, but stop-down metering with even current model Pentax dSLRs is not fully linear with most lenses nor will there be consistent agreement with a wide-open reading for the same subject. This is a general problem across dSLR brands.
*** P-TTL support for A-series lenses is not as good as for AF lenses, but at least works for most subjects.