I have just purchased a recently produced DA70 (manufacturing date: 10/2010, in Vietnam), I am really not impressed with the cleanliness of the lens but actually the current Pentax lens factory indeed!
Just view the comparison photos below. Left is the Macro shot of the DA70, right is the Sony E18-55, which was made in Thailand:-
(Click to Enlarge; Both photos taken at the same time at the same place with the same camera body and lens - Dust outside the glass was briefly blown away for both lenses before taking the shots.)
It can be seen that the Sony NEX kit lens of mine is obviously cleaner and there is little dust particles inside.
There are various huge amount of small dust and particles *inside* the lens for my new DA70. In fact, I have also inspected, inside my almost ten-year old FA43, there is yet little of similar dust particles! :-o So, I just wonder, if the current QC, and/or simply tidiness, of the Pentax Vietnam factory is/are just so poor? I then inspected my older DFA 100 Macro lens, which was yet made in Vietnam (bought in early 2005). I was shocked to learn that my that DFA has far less similar dust particles, neither! >:-[
In this connection, I have made an inquiry to the shop which I purchased my DA Limited lens and asked them to open another box of DA70 to verify the problem, they've told me that they found the same! They further told me that I am not the first customer to enquire this problem. Indeed, they have received similar complaints before about the DA*16-50 lens before so that they did check with Pentax China about that, but the *official* answer was that, "It is Normal", Just!
N.B. The outside of my DA70 Limited lens is very clean when I first opened the box.
Anyhow, my new DA70 is superb in optical quality and very fortunately, it has no other quality issues as widely reported for other DA*/Limited lenses before. Just say it has no de-centred defect and AF issues which were found for several DA*55 test samples sent to the DPR for testing! My copy of the DA70 lens is astonishingly sharp at f/2.8 and is quite acceptable at 2.4. There is no mis-focusing of any for most of the time, even for the lens to be wide opened, at least for outdoor shootings. The grey description and 3d feel of this lens are both superb. All in all, I have no complaint about this lens practically so far. The only complain is about how dirty this lens is *inside*! :-(
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