These two lenses are similar in focal and speed, size and weight (both about 150g). The focals are "standard" on film SLRs but now on Pentax DSLRs, they have become short tele something. The A lens is actually much looking like the black Limiteds in appearance, which actually copy the look and aesthetic design from the A lenses. The Pentax A 50/2 was sold at HK$350 in 1995 when it was discontinued. Now, the FA 43/1.9 Limited is lately being sold at approximately HK$6,200 at the streets of Hong Kong, which is 17.7 times(!) for the cost difference without taking inflation into account. And, the current exchange rate of 1 US$ equals to 7.8 HK$, for reference.
My this shootout will show you how these lenses are different and mine are about ten-year and twenty-year old respectively.
Infinity Scene:-
| Aperture | FA 43/1.9 Limited | A 50/2 |
| f/2 |  |  |
| f/2.8 |  |  |
| f/4 |  |  |
| f/5.6 |  |  |
| f/8 |  |  |
| f/11 |  |  |
Some observations of mine:-
1. The A lens produces warmer tone (which is more faithful to the real scene) whilst the Limited is yet a bit cooler;
2. The Limited lens is a bit more contrasty;
3. IQ wise, the Limited is acceptable at f/2.8 and good at f/4 (for both centre and corners). f/11 is still good but f/8 is just slightly better;
4. IQ wise, the A lens is marginally acceptable at f/2.8 (with more corner blur and the centre is not sharp enough) and good to very good at f/4 to f/5.6 (for both centre and corners). Both f/8 and f/11 are excellent and actually are even a bit sharper than the 43 Limited.
Long Distance (Not Infinity):-
| Aperture | FA 43/1.9 Limited | A 50/2 |
| f/2 |  |  |
| f/2.8 |  |  |
| f/4 |  |  |
| f/5.6 |  |  |
| f/8 |  |  |
| f/11 |  |  |
Some observations of mine:-
1. Contrasts are more or less the same this time for both lenses;
2. Flare control of the limited lens is better from f/2.8 and onwards and in contrast, that of the A lens is poor until f/4;
3. IQ wise, the Limited is acceptable at f/2.8 and good at f/4 (for both centre and corners). f/11 is nice but is not as good as f/8, possibly owing to diffraction limit reached;
4. IQ wise, the A lens is only somehow acceptable at f/4 (still with slight corner blur and ghost image starts to disappear, but not totally). IQ becomes good at f/5.6 (for both centre and corners). I regard f/2 and f/2.8 are practically not much usable under that situation as ghosting and soft image rendition are real and obvious problems. Both f/8 and f/11 are still excellent, though, fortunately.
Near Distance and Bokeh:-
| Aperture | FA 43/1.9 Limited | A 50/2 |
| f/2 |  |  |
| f/2.8 |  |  |
| f/4 |  |  |
| f/5.6 |  |  |
| f/8 |  |  |
My observations for this? Well, I think it would be better for you to observe and judge this time, as a homework and exercise for learning how to be a qualified measurbator! ;-)
Test Notes:-
1. Single AF mode is used for FA 43, MF according to AF Indication for the A 50;
2. Av Mode, ISO 100, Matrix Metering, No Exposure Compensation, on Tripod, 2 sec Timer, SR Off;
3. Auto White Balance, Portrait Custom Image with Factory Default Parameters, EXIF data preserved;
4. All pictures are resized to 3,999 pixels in width. To download the original un-retouched full size images, you need to go to my following Photobucket album to select the option and download:-
http://smg.photobucket.com/albums/v313/RiceHigh/K-x_Review/Standard_Prime_Shootout/?start=all
Read Also:-
RiceHigh's Subjective Ratings on Pentax AF Lenses on Pentax DSLRs 2010
Standard Zoom Mega Shootout! (DA Vs FAJ Vs DAL Vs SA Vs FA!)