I have created my own LBA dilemma in having overlap lens with Pentax FA 77mm f/1.8 limited. I bought the 70mm after the Pentax K-x purchase. Having the trio of DA limited lens in 21/40/70 is great in traveling with compact lens design. The 70mm serves well for portraits and candid shots in event. Its size is more compact than the 77mm limited but not by much when the fixed lens hood is mounted on the 70mm.
Hood is mounted on the 70mm limited
When the hood is mounted, it look closer in size to the 77mm limited. The fixed size lens hood in 70mm seems to double the actual size of the lens. The 70mm is actually quite small in size like the 21mm limited.
Impressions & Notes
- The 70mm is closer to half the height of the 77mm when its hood is not mounted. Out of the DA limited lens in 21/35/40/70mm, I find the lens hood in the 70mm the biggest to be used that hide the compactness of the prime. I much prefer the thinner lens hood in the 21 and 40 limited.
- Sharpness is pretty in par with 77. At least, that is my impressions. Color is better in the 77mm if I have to find something to talk it down.
- The quick shift focus in 70mm wins it hand down for me as compared to the 77mm limited as I do find it great to have the overriding mechanics in quick shift which allow one to minor tune the focus after half-press.
- Auto-focus is faster in 70mm than the 77mm. It is noticeably faster in K-x.