Originally posted by aaronjamesgray I hear a lot of people talk about the 40, either in XS or non-XS form. it gets good reviews, seems clean and shoots well. Not bad for an f/2.8.
But, if you already have a 35 f/1.4 (the Sigma art in my case) and a 50 f/1.4 (the FA in my case), is there ever a reason why you'd need a 40? A slower lens at that. Why would the 40 also not be released with a faster aperture? It's in the same length range. Shouldn't be that hard to produce.
Just idle curiosity on my part.
Apart from the excellent answers you have already been given, do not forget that Pentax always values it's past.
The DA 40mm 2.8 was harking back to the M series 40mm 2.8 released in 1976. This was the original pancake lens.
But the reason for the small size of the original was fashion. This was the 1970's, the era that saw Pentax release smaller cameras like the MX and ME. Olympus's small OM series cameras were huge sellers in this decade . Think also of the Sony Walkman. The trend was for small.
When in 2004 a requirement was for a small prime, they simply borrowed design cues from the past.
M 40/2.8 | The K-Mount Page