Here are some performance details on the 400mm Takumar. Like the 300, it does well handheld. It can be handheld down to 1/60 sec if you are experienced at doing this. I tried two shots at 1/30 sec and they were only slightly soft! Closeup work with outer bay tubes at f/5.6 was slightly soft but sharp at f/8. DOF when handheld closeups are attempted with tubes is quite limited. Infinity shots at f/4 were not soft but were not tack either. Out of focus, high contrast subjects had redish halos at f/4 and f/5.6 but these went away at f/8 and beyond. This fringing is not nearly as bad as the 600mm. The 400mm is sharp from f/8 to f/45 and similar in performance to the 300mm Takumar and Pentax. The DOF scale is more accurate than the 300 though. It seems to be about 1 1/2 stops off but more testing will be necessary to really be sure on this. When using a tripod, it is important to use a cable release with this lens. My shots with finger release were degraded. Even though this lens has a tripod mount, it is still susceptible to shutter vib. Shots taken at 1/4 sec were softer than at other speeds. Shots taken from 1/2 sec to one min were fine. Shots taken at 1/30 sec did not appear to be affected by shutter shake. I used a ten pound tripod for this test but feel that this is minimal for this lens. Two tripods are not needed when shooting the 400, as is the case for most 600mm work. This lens is sharp at f/45, 32 and 22. It is too early to say what the sharpest stop is. My guess so far is f/8. Is this lens sharp enough to be used for pro work? Yes. SR

-- Steve Rasmussen (srasmuss@flash.net), February 28, 2000

Answers

After much more shooting with this lens, my conclusion about the accuracy of the DOF scale is that it is better than I first suspected. It is only off by 1/2 stop.

-- Steve Rasmussen (srasmuss@flash.net), April 22, 2000.

John, I used the mirror lockup & cable on those slow tripod shots. SR

-- Steve Rasmussen (srasmuss@flash.net), April 28, 2001.

Putting a close up achromat in the rear filter space would cause aberrations. An achromat up front would be expensive due to the diameter. The outer bay tubes work well for me.

-- Steve Rasmussen (srasmuss@flash.net), April 25, 2002.

Thanks for the field test of an old but good lens. I have one question to ask. When you did the shutter test, did you use mirror lockup at the slow speeds or just a cable release?

-- John Miller (vwbus1967@earthlink.net), April 28, 2001.

Has someone ever tried to mount a close-up lens in the rear filter thread instead of using the tubes, or a combination of both? I have found the lens sharp too, but so difficult to use at intermediate speeds with an old body. But if it can be taken at 1 sec or more, or over 1/60 : perfect.

-- Paul Schilliger (pschilliger@smile.ch), April 24, 2002.