Sunday, August 03, 2008

Adjusting Infinity Focus on the Pentax Super-Takumar 35mm f/3.5



I have a Pentax Super-Takumar 35mm f/3.5 lens in M42 mount which I got some months ago. It has been sitting in my drawer all this time because on the 1.5X DSLR it's equivalent to a 52.5mm, which would be interesting except it's slow at f/3.5.

I suddenly got interested in it because of this thread on the MFLenses forum. One of the posters opined that this lens (along with the Mir-1b 37mm f/2.8 which I also have and which also just sits in a drawer) are some of the top wide-angle lenses.

Update: the Mir-1b, which won the Grand Prize at the 1958 Expo in Brussels, is actually a Russian clone of the Zeiss Flektogon.

So I decided to take some photos (out the window) with the Pentax, and quickly discovered that it doesn't focus to infinity. Here's a photo I took with the Super-Tak, the Mir-1b, and the SMC-Pentax DA 16-45mm f/4 ED AL:



The Mir-1b at f/2.8 was sharper, and so was the SMC-DA at f/4. Also it was obvious (from the split-image focusing screen as well as from focus confirm on the K10D) that the Super-Takumar was not properly focused at infinity. Apparently this is a common woe of wide-angle old Pentax lenses.

I found this blog post which details how to adjust infinity focus on a similar lens. The fellow used a sink drain plug to get the front ring off, but I didn't have such a drain plug, so I used a pair of pliers with rubber grips:



Everything else was exactly the same as in the original blog post. Took only about 20 minutes of fiddling to get the right adjustment.

Before and after (100% crop):


Much better!!

That said, I got to try the neglected Mir-1b and it's unexpectedly good! It's extremely flare-prone so I screwed a Pentax hood to the front, making it look quite impressive (almost like a small Canon 17-40mm f/4 L):



It also has pretty good ergonomics, and seemingly better bokeh than the Super-Takumar.

Mir-1b 37/2.8Super-Takumar 35/3.5

1 comment:

Anonymous said...

:( Somehow I can never get the front ring out. Which direction to turn? The regular CCW direction?

Thanks!